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Although not RECOMMENDED, an endpoint MAY automatically associate a metrics audit request with a prior relevant event notification, if any, regardless of the time-lag between the two. -- The document seems to lack a disclaimer for pre-RFC5378 work, but may have content which was first submitted before 10 November 2008. If you have contacted all the original authors and they are all willing to grant the BCP78 rights to the IETF Trust, then this is fine, and you can ignore this comment. If not, you may need to add the pre-RFC5378 disclaimer. (See the Legal Provisions document at https://trustee.ietf.org/license-info for more information.) -- Couldn't find a document date in the document -- date freshness check skipped. Checking references for intended status: Informational ---------------------------------------------------------------------------- -- Missing reference section? 'RFC 3550' on line 2502 looks like a reference -- Missing reference section? 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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Internet Engineering Task Force R.Kumar 3 Internet Draft D.Auerbach 4 Document: draft-auerbach-mgcp-rtcpxr-07 C. Sivachelvan 5 Category: Informational Cisco Systems 6 Expires: May 1, 2008 D. Hancock 7 CableLabs 8 B. Hare 9 Arris 10 Nov. 1, 2007 12 RTCP XR VoIP Metrics Package for the Media Gateway Control Protocol 13 draft-auerbach-mgcp-rtcpxr-07 15 Status of this Memo 17 By submitting this Internet-Draft, each author represents that any 18 applicable patent or other IPR claims of which he or she is aware have 19 been or will be disclosed, and any of which he or she becomes aware 20 will be disclosed, in accordance with Section 6 of BCP 79. 22 Internet-Drafts are working documents of the Internet Engineering Task 23 Force (IETF), its areas, and its working groups. Note that other 24 groups MAY also distribute working documents as Internet-Drafts. 26 Internet-Drafts are draft documents valid for a maximum of six months 27 and MAY be updated, replaced, or obsoleted by other documents at any 28 time. It is inappropriate to use Internet-Drafts as reference material 29 or to cite them other than as "work in progress." 31 The list of current Internet-Drafts can be accessed at 32 http://www.ietf.org/ietf/1id-abstracts.txt. 34 The list of Internet-Draft Shadow Directories can be accessed at 35 http://www.ietf.org/shadow.html. 37 This Internet-Draft will expire on May 1, 2008. 39 Abstract 41 The main intent of this document is to define a Media Gateway Control 42 Protocol (MGCP) package to control the reporting of metrics supported 43 by the VoIP metrics block in RTCP Extended Reports as specified in [RFC 44 3611]. It also allows the call agent to control whether or not the 45 gateway will request a peer device via SDP to send the VoIP metrics 46 block in RTCP Extended Reports and whether it will respond positively 47 MGCP RTCP-XR Package 4/12/2007 48 package also allows the reporting of metrics defined for RTCP Sender 49 Reports and Receiver Reports [RFC 3550] and the reporting of session 50 description parameters (based on the ones defined in RFC 2327, RFC 2198 51 etc.). 53 Conventions used in this document 55 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 56 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 57 document are to be interpreted as described in BCP 14, RFC 2119. 59 Table of Contents 61 1. Introduction 62 2. VoIP Metrics Package Definition 63 2.1 Local Connection Options 64 2.1.1 Responses to the xrm/mcr local connection option 65 2.1.1.1 Response to a value of "off" 66 2.1.1.2 Response to a value of "on" 67 2.1.1.3 Response to a value of "negotiate" 68 2.1.2 Impact of the xrm/mcr LCO on VoIP metrics block exchange 69 2.2 MGCP Protocol Procedures 70 2.2.1 DeleteConnection Procedures 71 2.2.2 AuditConnection Procedures 72 2.2.3 ModifyConnection Procedures 73 2.3 The LVM and RVM Lines for reporting Local And Remote Metrics 74 2.3.1 Inclusion/Omission of XRM/LVM and XRM/RVM parameters 75 2.3.2 XRM/LVM and XRM/RVM parameter values 76 2.3.3 Procedures for the resetting of metrics 77 2.3.4 Impact redundancy and FEC on packet loss computations 78 2.3.5 Parameter Extension Mechanism 79 2.3.6 Formal Syntax of VoIP Metrics Package 80 2.3.7 Impact of media state changes on VoIP metrics 81 2.3.8 Applicability of VoIP metrics to Voice Band Data 82 2.3.9 Applicability of VoIP metrics to Fax Relay and Text Relay 83 3. Call Flow Examples 84 3.1 Metrics Reporting during Call agent-initiated Delete Connection 85 3.2 Metrics Reporting during Gateway-initiated Delete Connection 86 3.3 Metrics Reporting during Audit Connection 87 3.4 Metrics Reporting during Modify Connection 88 4. Security Considerations 89 5. IANA Considerations 90 5.1 Package Registration 91 5.2 Extension Registration 92 6. Changes from earlier drafts 93 MGCP RTCP-XR Package 4/12/2007 94 6.1 Changes from the -00 version to the -01 version 95 6.2 Changes from the -01 version to the -02 version 96 6.3 Changes from the -02 version to the -03 version 97 6.4 Changes from the -03 version to the -04 version 98 6.5 Changes from the -04 version to the -05 version 99 6.6 Changes from the -05 version to the -06 version 100 6.7 Potential future updates 101 7. Normative References 102 8. Acknowledgments 103 9. Copyright Statement 105 1. Introduction 107 This document defines a Media Gateway Control Protocol (MGCP) [RFC 108 3435] package that enables the collection and reporting of metrics that 109 measure the quality of traffic on two-way VoIP connections. This 110 capability is based on and utilizes the VoIP Metrics Block of the RTCP 111 Extended Report as specified in [RFC 3611]. 113 In accordance with [RFC 3435], the term "gateway" is used to denote the 114 device controlled via MGCP. This is not intended to preclude the use of 115 MGCP or of this package to control devices that are not, in the 116 strictest terms, media gateways. For the purposes of this package, the 117 terms "media gateway", "gateway" and "endpoint" are used 118 interchangeably. Also, the terms "media gateway controller" and "call 119 agent" are used interchangeably. 121 In addition to the parameters in the RTCP XR VoIP metrics block, this 122 package allows the collection of statistics defined for RTCP Sender 123 Reports and Receiver Reports [RFC 3550]. The ConnectionParameters 124 structure [RFC 3435] allows the reporting of the local, but not the 125 remote, version of statistics defined for RTCP Sender Reports and 126 Receiver Reports [RFC 3550]. To report both the local and remote 127 versions of these RTP statistics, this package MAY be used. Note that 128 this package does not affect the collection or reporting of connection 129 parameters defined in the base MGCP specification (RFC 3435). Nor does 130 it affect the sending of RTCP Sender Reports (SR) and Receiver Reports 131 (RR). 133 This package also includes session description parameters (based on the 134 ones defined in RFC 2327, RFC 2198 etc.). These MAY be reported via 135 this package to obviate the need for call agents to snoop SDP session 136 descriptors. 138 This package makes a distinction between collecting, responding and 139 reporting. The term "collecting" refers to the process of calculating 140 and accumulating local metric data and accumulating remote metric data 141 received in RTCP Sender, Receiver and Extended Reports from the remote 142 device. The term "responding" in the context of this package is 143 limited to the sending of accumulated local metric data via RTCP 144 MGCP RTCP-XR Package 4/12/2007 145 Extended Reports to the remote device as specified in [RFC 3611]. Note 146 that this package does not control the communication of session 147 statistics via RTCP Sender Reports (SR) and Receiver Reports (RR). 148 These reports MUST be sent in the manner REQUIRED of all RTP endpoints 149 [RFC 3550]. The term "reporting" refers to the process of reporting the 150 accumulated local and remote metric data for the connection to the Call 151 Agent in either a DeleteConnection, ModifyConnection or AuditConnection 152 command sequence. 154 An endpoint will "collect" local session metrics for several reasons: 156 - To report metrics in the "northbound" direction via the XRM/LVM 157 and XRM/RVM parameters specified in this package. 158 - To communicate metrics in the "east-west" direction via RTCP 159 extended reports, 160 - To report metrics in the "northbound" direction via other 161 mechanisms such as connection parameters [RFC 3435] and log 162 transfers not addressed in this document, 163 - To communicate metrics in the "east-west" direction via RTCP 164 Sender Reports and Receiver Reports. 166 The sets of metrics collected for these purposes are not the same. This 167 package is limited to defining the metrics that MAY be reported via the 168 XRM/LVM and XRM/RVM lines. This MAY or MAY not be a superset of the 169 metrics that MAY be communicated via the VoIP metrics block in RTCP 170 extended reports. 172 The Call Agent can ask an endpoint to enable or disable the reporting 173 of metrics via this package. Enabling this reporting also enables the 174 "east-west" communication of metrics via the RTCP XR VoIP metrics block 175 from the local endpoint's perspective. Whether this "east-west" 176 communication actually takes place also depends on the peer endpoint's 177 capabilities. When it disables "northbound" reporting via this package, 178 the call agent MAY either disable the "east-west" communication of 179 metrics via the RTCP XR VoIP metrics block, or it MAY require the 180 endpoint to communicate the VoIP metrics block in the "east-west" 181 direction if the remote end requests it. Disabling "northbound" 182 reporting via this package has no impact on the use of RTCP Sender 183 Reports or Receiver Reports. 185 Like RTCP-XR [RFC 3611], this package focuses on voice metrics. 186 However, it does examine the relevance of these metrics to other media 187 modes such as voice band data [ITU V.152], fax relay [ITU T.38] and 188 text relay [ITU V.151]. The MGGCP-based reporting of metrics that are 189 unique to the voice band data, fax relay and text relay will need to be 190 defined in other MGCP packages. 192 MGCP RTCP-XR Package 4/12/2007 193 The metric data reported to the Call Agent via this package when a 194 connection is deleted, modified or audited represents the data that was 195 accumulated/averaged over a computation interval. This package allows 196 this interval to be selected in a flexible manner. This interval MAY 197 encompass the time since the last metrics reset, if any, or since the 198 start of the session (in the absence of resets). Alternately, this 199 interval MAY consist of a relatively short period (e.g. 5 seconds) 200 prior to metrics capture and reporting. The metrics reset is commanded 201 by the call agent in the case of feature invocations such as call 202 transfer or call pick-up. 204 In the case of media mode shifts (such as voice to voice band data), 205 this package allows the resetting of metrics or their seamless 206 continuation in to the new mode. In the case of call agent-controlled 207 media mode shifts, this resetting is controlled by the call agent. In 208 the case of autonomous, endpoint-controlled media mode shifts, this 209 resetting is also under endpoint control. The preferred behavior, 210 which might not be followed by all endpoints, is for the metrics to be 211 reset. 213 Note that, in some implementations, metrics are not reset during media 214 mode shifts. Instead, metrics that are applicable in the new mode 215 continue to be accumulated/averaged as before. Also, for metrics that 216 are not applicable in the new mode, further computation is suspended 217 until when another media mode shift renders these metrics relevant 218 again. 220 The VoIP Metrics package definition is provided in Section 2. This 221 includes a detailed description of relevant MGCP protocol procedures, a 222 list of parameters that can be reported via this package, and an 223 analysis of the applicability of these parameters to voice band data, 224 fax relay and text relay. In Section 3, we provide four call flow 225 examples showing how to use the package. Security considerations are 226 found in Section 4, followed by the IANA considerations and references. 227 Table 1 lists the metrics based on the VoIP metrics block in RTCP 228 Extended Reports [RFC 3611]. It also includes parameters that address 229 the metrics computation interval and the occurrence of metrics resets 230 since session start. Table 2 lists the metrics based on RTCP Sender 231 Reports and Receiver Reports [RFC 3550]. Note that Table 2 uses the 232 metrics definitions in [RFC 3550] and [RFC 3435] as is, without 233 attempting to improve them by specifying, for instance, a better 234 method for handling duplicates. Table 3 lists session parameters, most 235 of which are from RFCs which define SDP constructs (e.g. RFC 2327, RFC 236 2198, RFC 2733). Tables 4, 5 and 6 list the applicability of the 237 metrics and session parameters in Tables 1, 2 and 3 respectively to fax 238 relay. Tables 7, 8 and 9 do the same for text relay. 240 MGCP RTCP-XR Package 4/12/2007 241 2. VoIP Session Metrics Package Definition 243 A package is defined for VoIP session metrics. 245 Package Name: XRM 246 Package Version: 0 248 This package defines the following parameters: 250 - A new local connections option, "mcr" (Metrics Reporting) for 251 enabling and disabling metrics reporting via this package. Note 252 that metrics collection via MGCP might use other mechanisms (e.g. 253 the connection parameters in the base MGCP specification, RFC 254 3435) that are not impacted by this local connection option. 255 - A new parameter line, "MMO" (Media Metrics Option) that allows 256 the call agent to request local and remote metrics in a modify 257 connection response, and/or to reset the local and remote 258 metrics. 259 - A new parameter line, "LVM" (Local VoIP Metrics), for reporting 260 locally collected metrics. 261 - A new parameter line, "RVM" (Remote VoIP Metrics), for reporting 262 remotely collected metrics communicated to the reporting endpoint 263 via RTCP Extended Reports, Sender Reports and Receiver Reports. 265 2.1 Local Connection Options 267 The local connection option (LCO) parameter, "xrm/mcr", is an OPTIONAL 268 parameter with one of the following three values: 270 - "off": Disables the reporting of metrics via this package AND the 271 "east-west" communication of metrics via the RTCP XR VoIP metrics 272 block 273 - "on": Enables the reporting of metrics via this package AND the 274 "east-west" communication of metrics via the RTCP XR VoIP metrics 275 block. Whether this "east-west" communication actually takes 276 place also depends on the peer endpoint's capabilities. 277 - "negotiate": Disables the reporting of metrics via this package. 278 However, the endpoint is REQUIRED to communicate the VoIP metrics 279 block in the "east-west" direction if the remote end requests it. 281 For example, 283 L: a:PCMU, xrm/mcr: on 285 assigns a value of "on" to the "mcr" LCO. 287 In CreateConnection commands, the xrm/mcr LCO value defaults to 288 "negotiate". In ModifyConnection commands, the xrm/mcr LCO value 289 MGCP RTCP-XR Package 4/12/2007 290 defaults to its current value for the connection. Thus, if 291 LocalConnectionOptions are either omitted or the xrm/mcr LCO is not 292 included in a ModifyConnection command, the previous xrm/mcr LCO value 293 for the connection is retained. 295 An MGCP endpoint supporting this package SHALL always use SDP to 296 request the VoIP metrics block from the remote device if the value of 297 the "xrm/mcr" LCO is set to "on". However, even if the value of value 298 of the "xrm/mcr" LCO is "on" or "negotiate", the endpoint SHALL NOT 299 send the VoIP metrics block in RTCP Extended Reports (XR) unless the 300 remote device has requested this block via SDP signaling. Thus, for 301 MGCP endpoints supporting this package, the permission in [RFC 3611] to 302 send RTCP XR blocks in the absence of the "rtcp-xr" SDP attribute is 303 revoked. 305 Note that the value of the "xrm/mcr" LCO does not affect the collection 306 or reporting of connection parameters in the connection parameters line 307 (P: line) as defined in the base MGCP specification [RFC 3435]. Nor 308 does it affect the sending of RTCP Sender Reports (SR) and Receiver 309 Reports (RR). An endpoint supporting this package MUST continue to 310 include the connection parameters (P:) line in an audit connection 311 response where this data is requested, in a delete connection response 312 and in a gateway-initiated delete connection. There can be overlap if 313 equivalent parameters are also reported via this package in procedures 314 for the deletion and audit of connections. There is no overlap in the 315 case of modify connection responses since these do not include the 316 connection parameters line. 318 2.1.1 Responses to the xrm/mcr local connection option 320 This section details the endpoint's response to each of the xrm/mcr LCO 321 values. 323 2.1.1.1 Response to a value of "off" 325 On receiving this value, the endpoint MUST erase any local or remote 326 VoIP metric data previously collected for the connection, and MUST 327 instruct the far-end device to stop sending RTCP XR VoIP Metrics Report 328 Blocks. The endpoint MUST ignore an SDP request for metrics and MUST 329 NOT transmit local metrics to the peer device. The local endpoint 330 MUST NOT report XR metrics upon receiving or initiating a 331 DeleteConnection sequence and MUST NOT report XR metrics when 332 responding to a ModifyConnection command or an AuditConnection 333 command. 335 MGCP RTCP-XR Package 4/12/2007 336 2.1.1.2 Response to a value of "on" 338 On receiving this value in a CreateConnection or ModifyConnection 339 command, if not already doing so, the endpoint MUST: 341 - Start collecting/calculating the metrics which it will expose to 342 the Call Agent via this package. 343 - Instruct the far-end device to start sending the VoIP Metrics 344 block in RTCP Extended Reports by including an "rtcp-xr" 345 attribute with a value of "voip-metrics" in the SDP. 346 - Report local and remote metrics via the XRM/LVM and XRM/RVM lines 347 defined below in the response to DeleteConnection that targets a 348 single connection, in the response to a ModifyConnection when 349 these metrics are requested, in the response to an 350 AuditConnection when these metrics are audited, and when sending 351 a DeleteConnection command for a single connection. 353 2.1.1.3 Response to a value of "negotiate" 355 On receiving this value, the endpoint disables the "northbound" 356 reporting of metrics, via this package, to the call agent. Also, it 357 sets an internal flag to indicate that it will respond positively to 358 SDP requests by the remote peer device to send the VoIP metrics block 359 in RTCP Extended Reports. 361 2.1.2 Impact of the xrm/mcr LCO on VoIP metrics block exchange 363 This section details the concepts introduced in the previous section 364 regarding the use of the xrm/mcr local connection option to govern the 365 endpoint's behavior regarding the negotiation, via SDP, of the VoIP 366 metrics block in RTCP extended reports [RFC 3611]. 368 RFC 3611 adds a new SDP attribute called "rtcp-xr" that can be used by 369 an endpoint to ask the remote device to send RTCP Extended Reports. 370 This attribute is encoded as follows: 372 rtcp-xr: 374 This rtcp-xr attribute can be used as either a session-level or media- 375 level attribute. See [RFC 3611] for more information. Only one of the 376 xr-format values, voip-metrics, is within the scope of this package. 378 For an endpoint supporting this package, the inclusion of the voip- 379 metrics value in an rtcp-xr attribute line in its SDP local session 380 descriptions SHALL be per the following rules: 382 MGCP RTCP-XR Package 4/12/2007 383 - The voip-metrics value SHALL be included if the xrm/mcr LCO is 384 set to "on". 385 - The voip-metrics value SHALL NOT be included if the xrm/mcr LCO 386 is set to "off" or "negotiate". 388 The inclusion or exclusion of any other xr-format values (denoting 389 other RTCP XR blocks) in the rtcp-xr SDP attribute line is independent 390 of the xrm/mcr LCO. This is not addressed by this package. 392 The response of an endpoint supporting this package to the receipt from 393 a remote peer of an SDP remote session description with an rtcp-xr 394 attribute line that has voip-metrics as one of its values (or its only 395 value) SHALL be as follows: 397 - The endpoint MUST send RTCP Extended Reports with the VoIP 398 metrics block to the remote peer if the xrm/mcr LCO is "on" or 399 "negotiate". 400 - The endpoint SHALL NOT send RTCP Extended Reports with the VoIP 401 metrics block to the remote peer if the xrm/mcr LCO is "off". 403 Regardless of the value of the xrm/mcr LCO, an endpoint supporting this 404 package SHALL NOT send RTCP Extended Reports with the VoIP metrics 405 block to the remote peer if any of the following is true: 407 - The rtcp-xr attribute is not included in the SDP remote session 408 description. 409 - The rtcp-xr attribute is included in the SDP remote session 410 description but "voip-metrics" is not one of its values. This 411 includes the case in which the attribute has an empty parameter 412 list. 414 [RFC 3611] allows endpoints that uses SDP (e.g. MGCP endpoints) to 415 exchange RTCP Extended Reports without prior SDP signaling, which is 416 OPTIONAL. This allowance is rescinded for endpoints supporting this 417 package which MUST implement the SDP signalling specified in this 418 section. 420 2.2 MGCP Protocol Procedures 422 2.2.1 DeleteConnection Procedures 424 These procedures refer to call agent-initiated delete connection 425 commands that are targeted at a specific connection ID and to gateway- 426 initiated delete connection commands. They do not apply to call agent- 427 initiated delete connection commands that are targeted at all 428 connections associated with a call, an endpoint, an endpoint group or a 429 gateway. In the latter case, the XRM/LVM and XRM/RVM lines (described 430 in detail below) SHALL NOT be returned. 432 MGCP RTCP-XR Package 4/12/2007 434 Endpoints supporting this package MUST report local metrics in the 435 XRM/LVM parameter line in delete connection responses and in gateway- 436 initiated delete connection commands if and only if the local 437 connection option xrm/mcr is set to "on". 439 Endpoints supporting this package MUST report remote metrics, if 440 available, in the XRM/RVM parameter line in delete connection responses 441 and in gateway-initiated delete connection commands if and only if the 442 local connection option xrm/mcr is set to "on". 444 We do not define a mechanism for suppressing metrics reporting in 445 response to a delete connection command that is targeted at a specific 446 connection ID. In situations (such as a switchover)where the call agent 447 needs to delete connections without retaining any records of the 448 connections, it can use the version of the delete connection procedure 449 that targets all connections associated with a call, an endpoint, an 450 endpoint group or a gateway [RFC 3435]. No metrics are returned in 451 response to this version of the delete connection command. 453 2.2.2 AuditConnection Procedures 455 This package defines two new RequestedInfo values to be used with an 456 AuditConnection (AUCX). These allow a call agent to explicitly request 457 that the endpoint return the current values of either the local or 458 remote metrics. The request does not reset the values. When one or 459 both of these RequestedInfo values are included in an AUCX command, the 460 endpoint MUST return the appropriate metric values if available. The 461 two new RequestedInfo values are: 463 XRM/LVM Return the local voice metric values. 464 XRM/RVM Return the remote voice metric values. 466 The call agent MAY audit the local and remote voice metrics at any 467 time. Some example uses of this capability are: 469 - Audits in response to a "quality alert" event notification 470 [RFC 3660], 471 - Audits in response to an event notification that MAY lead to 472 a media transition e.g. a fax tone event ('ft') or a modem tone 473 event ('mt') [RFC 3660]. 474 - Audits in response to an event notification of a media transition 475 e.g. the start of a gateway-controlled fax procedure 476 {fxr/gwfax(start)} [FAX PKG]. 478 A quality alert event notification MAY be sent in response to a metrics 479 threshold crossing by an endpoint supporting the RTP package defined in 480 MGCP RTCP-XR Package 4/12/2007 481 RFC 3660. When audited within a time window T1 after sending a quality 482 alert, the endpoint SHOULD respond with metrics captured at the time of 483 the threshold crossing rather than metrics captured in response to the 484 associated metrics audit request. 486 In the case of events that MAY lead to a media state transition (e.g. 487 voice to voice band data or fax relay), the endpoint SHOULD respond to 488 a metrics audit received within a time window of T1 with metrics 489 captured just prior to the event notification rather than at the time 490 of the audit. In the case of events that report a media state 491 transition, the endpoint SHOULD respond to a metrics audit received 492 within a time window of T1 with metrics captured just prior to the 493 state transition rather than at the time of the audit. Naturally, the 494 reported values are captured prior to any parameter reset ensuing from 495 the media state change. 497 A value of five seconds is RECOMMENDED for the time window, T1, used to 498 associate an event notification with a metrics audit. However, the 499 value of this window depends on the application. Although not 500 RECOMMENDED, an endpoint MAY automatically associate a metrics audit 501 request with a prior relevant event notification, if any, regardless of 502 the time-lag between the two. 504 The rules in the MGCP base specification [RFC 3435] for handling audits 505 of unsupported parameters and parameters for which an endpoint has no 506 values MUST be followed. As a result: 508 - If an endpoint that does not understand the XRM/LVM or XRM/RVM 509 parameter is audited for that parameter, it MUST NOT generate an 510 error. Instead, the parameter MUST be omitted from the audit 511 response. Since this rule is based on the MGCP base 512 specification, it also applies to endpoints that do not support 513 this package. 514 - If an endpoint that does not have values for the XRM/LVM or 515 XRM/RVM parameter is audited for that parameter, it MUST NOT 516 generate an error. Instead, the parameter MUST be included in the 517 audit response with an empty value. 519 2.2.3 ModifyConnection Procedures 521 This package defines a new MGCP parameter, the MediaMetricsOption 522 ("MMO") that MAY be OPTIONALly included in a ModifyConnection command 523 on an "XRM/MMO" line. This parameter is forbidden in all other MGCP 524 commands and responses. It can have one of the following four values: 526 - "REP" (report). This option commands the endpoint to report local 527 and remote metrics via this package. Local and remote session 528 parameters MAY also be reported. 530 MGCP RTCP-XR Package 4/12/2007 531 - "RES" (reset). This option commands the endpoint to reset the 532 local and remote metrics. 533 - "RR" (report and reset). Local and remote metrics are first 534 reported and then reset. Local and remote session parameters MAY also 535 be reported. 536 - "NULL". No metrics (local or remote) are reset or reported. This 537 value is equivalent to omitting the "XRM/MMO" line in the 538 ModifyConnection command. Of course, it is more efficient and, 539 therefore, preferable to omit the XRM/MMO line than to use it with an 540 explicit value of "NULL". 542 Note that the XRM/MMO parameter is specific to a ModifyConnection 543 command and its value does not persist following the end of a 544 ModifyConnection procedure. Therefore, this package does not define a 545 RequestedInfo value for auditing the XRM/MMO parameter. 547 Also note that metrics are not reported in response to a "REP" or "RR" 548 value of the XRM/MMO parameter if the value of the XRM/MCR local 549 connection option is "off" or "negotiate". 551 When the value of the XRM/MMO parameter is REP or RR, then the 552 available metrics are reported, as applicable, in the XRM/LVM and 553 XRM/RVM lines defined below. In order to comply with the ABNF rules in 554 [RFC 3435], the connection parameters line (the P: line) SHALL NOT be 555 included in a ModifyConnection response. However, metrics equivalent to 556 the connection parameters (Table 2) can be included in the XRM/LVM and 557 XRM/RVM lines. 559 The metrics that are reset and/or reported in response to the XRM/MMO 560 parameter include metrics associated with RTCP extended reports (Table 561 1) and metrics associated with RTCP sender reports and receiver reports 562 (Table 2). 564 See the section titled "Procedures for the resetting of metrics" for 565 the values assigned to metrics on reset. 567 The MMO parameter is needed to handle situations in which the call 568 agent invokes a feature that alters the media stream in a manner that 569 renders previous metrics values inapplicable to the new situation. 570 Examples are call transfer and call pick-up. It is also useful in 571 situations in which the call agent choreographs a media state 572 transition such as from voice to voice band data [ITU V.152] or fax 573 relay [ITU T.38]. 575 2.3 The LVM and RVM Lines for reporting Local And Remote Metrics 577 The "XRM/LVM" and "XRM/RVM" lines are for the reporting of local and 578 remote metrics respectively. For example, an endpoint that is recording 579 MGCP RTCP-XR Package 4/12/2007 580 local metrics and has received remote metrics returns the following 581 lines in a DLCX response: 583 XRM/LVM: PLC=1, JBA=2, JBR=7 ... 584 XRM/RVM: PLC=0, JBA=0, JBR=3 ... 586 The parameters that MAY be reported in an XRM/LVM or XRM/RVM line fall 587 into the following categories: 589 - Parameters that define the metrics computation interval and 590 indicate whether any metrics resets have occurred since session 591 start. These are listed in Table 1. 592 - Parameters based on the VoIP metrics block [RFC 3611]. These are 593 listed in Table 1. 594 - Parameters based on Sender Reports and Receiver Reports [RFC 595 3550]. These are listed in Table 2. 596 - Parameters that describe the session. These are listed in Table 597 3. Many of these are based on SDP parameters such as those 598 specified in RFC 2327, RFC 2198, RFC 2733 etc. 600 Although Tables 1-3 include top-level definitions of these parameters, 601 some of their technical details MAY need to gleaned from the 602 references. For instance, the meaning of "standard" vs. "enhanced" 603 packet loss concealment must be obtained from [RFC 3611]. 605 Note that the rationale for allowing the reporting of parameters based 606 on RTCP Sender Reports and Receiver Reports (Table 2) in the XRM/LVM 607 and XRM/RVM lines is two-fold: 609 - The connection parameters line (the P: line) in the MGCP base 610 protocol [RFC 3435] does not address remote metrics, 611 - The ABNF for packet loss in RFC 3435 is inconsistent with its RFC 612 3550-based textual definition of packet loss. 614 Note that the latency metric in the connection parameters line (the P: 615 line) is not included in Table 2 since it is already included in the 616 RTCP XR VoIP metrics block as the round trip delay. RTCP XR [RFC 3611] 617 allows any method for its computation, including methods based on [RFC 618 3550] or on the DLRR report block in [RFC 3611]. 620 2.3.1 Inclusion/Omission of XRM/LVM and XRM/RVM parameters 622 In general, the inclusion of a parameter from Tables 1-3 in the 623 XRM/LVM or XRM/RVM lines is subject to: 625 - The availability of the parameter. 626 - Local policy regarding its inclusion. 628 MGCP RTCP-XR Package 4/12/2007 629 The following rules apply only to endpoints supporting this package: 631 DLCX/MDCX/AUCX rule for XRM/LVM: This rule applies to: (i) Endpoint 632 responses to call agent-initiated delete connection commands that are 633 targeted at a specific connection ID, (ii) Endpoint-initiated delete 634 connection commands, (iii) Endpoint responses to modify connection 635 commands that request session metrics via the XRM/MMO line, (iv) 636 Endpoint responses to audit connection commands that include "XRM/LVM" 637 in the RequestedInfo list. In each of these contexts, the XRM/LVM line 638 MUST be included by an endpoint supporting this package. Further, this 639 endpoint MUST compute at least one metric from the VoIP metrics block 640 (Table 1) and report it in the XRM/LVM line. All other parameters 641 (Tables 2 and 3) are completely OPTIONAL. Their inclusion depends on 642 local policy. The endpoint MUST omit all parameters that are not 643 computed locally rather than include them with dummy values (e.g. 127 644 for the various MOS parameters). 646 DLCX/MDCX rule for XRM/RVM: This rule applies to: (i) Endpoint 647 responses to call agent-initiated delete connection commands that are 648 targeted at a specific connection ID, (ii) Endpoint-initiated delete 649 connection commands, (iii) Endpoint responses to modify connection 650 commands that request session metrics via the XRM/MMO line. In each of 651 these contexts, the XRM/RVM line MUST be included if the remote peer 652 sends VoIP metrics blocks [RFC 3611] in RTCP Extended Reports. If the 653 remote device indicates that a particular VoIP metrics block parameter 654 is unavailable by sending a dummy value, then the dummy value MUST be 655 reported or the parameter MUST be omitted from the XRM/RVM: line. For 656 example, the dummy value of 127, if used, indicates that the signal 657 level, noise level, residual echo return loss, the various R-factors 658 and MOS estimates are unavailable. If the VoIP metrics block is not 659 received from the remote device, the endpoint MAY omit the XRM/RVM line 660 even if it has non-VoIP metrics block parameters to report in the 661 XRM/RVM line, such as metrics communicated via RTCP Sender Reports (SR) 662 and Receiver Reports (RR). The endpoint MAY, of course, include the 663 XRM/RVM line with known non-VoIP metrics block parameters (Tables 2 and 664 3) when the VoIP metrics block is not communicated by the remote end. 665 If the remote device indicates that a particular Sender/Receiver Report 666 parameter is unavailable by assigning it a dummy value (such as an 667 inter-arrival jitter of 0), the endpoint MAY either omit it in the 668 XRM/RVM line or assign it a dummy value. 670 AUCX rule for XRM/RVM: This rule applies to endpoint responses to audit 671 connection commands that include "XRM/RVM" in the RequestedInfo list. 672 In this context, the XRM/RVM line MUST be included even if no VoIP 673 metrics blocks are received in RTCP extended reports from the remote 674 device. This line MAY, however, be empty if no data pertaining to RTCP 675 XR VoIP metrics block (Table 1) is provided by the remote device. 676 Alternately, the local endpoint MAY include other known remote 677 MGCP RTCP-XR Package 4/12/2007 678 parameters (Tables 2 and 3) in the XRM/RVM line. If the remote device 679 sends the VoIP metrics block in RTCP Extended Reports and indicates 680 that a particular parameter is unavailable by sending a dummy value, 681 then the dummy value MUST be reported or the parameter MUST be omitted 682 from the XRM/RVM: line. If the remote device indicates that a 683 particular Sender/Receiver Report parameter is unavailable by assigning 684 it a dummy value (such as an inter-arrival jitter of 0), the endpoint 685 MAY either omit it in the XRM/RVM line or assign it a dummy value. 687 Rule for disallowed values: An endpoint receiving a disallowed value in 688 the VoIP metrics block MAY omit it in the XRM/RVM line. For example, 689 RFC 3611 does not allow a value of 60 in the 8-bit MOS-LQ field in the 690 VoIP metrics block. 692 2.3.2 XRM/LVM and XRM/RVM parameter values 694 The metrics used in the XRM/LVM and XRM/RVM lines (Tables 1-3) are, 695 except when otherwise noted, cumulative/average values over a 696 computation interval. This interval MAY be indicated via the OPTIONAL 697 computation interval (CMPI) parameter in Table 1. The CMPI parameter 698 indicates the period of time over which the XRM/LVM and XRM/RVM 699 parameters are computed. When the CMPI parameter is omitted, the 700 computation interval SHALL be defined as the period from the last 701 metrics reset (if any) up to the time of metrics reporting. If the CMPI 702 parameter is omitted and there has been no metrics reset, then the 703 computation interval SHALL be defined as the period from the start of 704 the session up to the time of metrics reporting. 706 The procedures for communicating voice quality metrics in the XRM/LVM 707 and XRM/RVM lines are invoked at one of the following instances: 709 - the DeleteConnection procedures are invoked end of a session, 711 - the ModifyConnection procedures are invoked end of a call phase, 712 such as when a call transfer is invoked or when the call agent 713 effects a media state transition (e.g. voice to voice band data) 715 - the AuditConnection procedures MAY be invoked whenever the call 716 agent needs a snapshot of the metrics. For instance, these 717 procedures MAY be invoked in response to event notifications from 718 the endpoint. Examples from RFC 3660 of such event notifications 719 are tone events ('ft' and 'mt') and quality alerts ('qa'). 721 The general use is to not use the CMPI parameter for these procedures 722 and to reports metrics accumulated/averaged from the start of the 723 session or from the time of the last metrics reset, as applicable. One 724 exception where an explicit computation interval, conveyed via CMPI, is 725 RECOMMENDED is when the XRM/RVM lines are communicated in response to 726 MGCP RTCP-XR Package 4/12/2007 727 an audit connection that is associated per Section 2.2.2 with a quality 728 alert ('qa') event. In this case, the metrics values of interest are 729 those that pertain to some short interval (e.g. 1-5 seconds) 730 immediately before the threshold crossing occurrence. 732 The OPTIONAL Reset Occurrences ("ROC") parameter is useful in 733 indicating whether a prior reset of metrics has occurred. Although some 734 resets are commanded by the call agent via ModifyConnection procedures, 735 the endpoint is not precluded from autonomously resetting its VoIP 736 metrics. For example, the endpoint MAY reset its metrics when it 737 changes the mode of a media stream (e.g. from voice to voice band 738 data). Since such autonomous resets are not universally implemented, it 739 is beneficial to explicitly indicate their occurrence. For example, 740 ROC=1 in conjunction with an omitted CMPI parameter indicates that the 741 reported metrics have been accumulated/averaged for just the current 742 call phase and not for the entire call duration. 744 It is RECOMMENDED that the unstable or indeterminate periods at the 745 start and end of a call or call phase be factored out of metrics 746 computation. The duration of these guard bands is left to the 747 implementation. 749 Note that the metrics formats used by the call agent to store and 750 report metrics might be different from the formats used in this 751 package. For instance, the media gateway controller can convert the 752 binary representation [RFC 3611] of network packet loss into a fixed- 753 point percentage. Thus, an NLR value of 20 (Table 1) might be stored or 754 displayed as 7.81%. 756 MGCP RTCP-XR Package 4/12/2007 757 TABLE 1: PARAMETERS BASED ON THE RTCP XR VOIP METRICS BLOCK 758 --------------------------------------------------------- 759 | Parameter | Code | Value | 760 | | | | 761 --------------------------------------------------------- 762 |Computation | CMPI |The period, in milliseconds, from | 763 |Interval | |the start of metrics computation to| 764 | | |the time of metrics capture for | 765 | | |reporting purposes. This parameter | 766 | | |MAY be omitted. A value of 0 is | 767 | | |equivalent to its omission. | 768 | | |Expressed as an integer number. | 769 --------------------------------------------------------- 770 |Reset | ROC |Whether the metrics have been | 771 |Occurrences | |one or more times since session | 772 | | |start. Expressed as a boolean with | 773 | | |"1" indicating one or more resets | 774 | | |and "0" indicating the absence of | 775 | | |of resets. These resets MAY be | 776 | | |commanded by the call agent, or | 777 | | |autonomously triggered by the | 778 | | |endpoint. This parameter is | 779 | | |OPTIONAL and MAY be omitted. Its | 780 | | |omission does not imply anything | 781 | | |regarding the occurrence of | 782 | | |metrics resets. | 783 --------------------------------------------------------- 784 |Network | NLR |The proportion of packets lost | 785 |packet loss | |since the start of metrics | 786 |rate | |computation expressed as an 8-bit | 787 | | |binary fraction obtained by | 788 | | |dividing the number of packets lost| 789 | | |in the transmission path by the | 790 | | |total number of packets expected by| 791 | | |the receiver, multiplying this | 792 | | |value by 256 and taking the integer| 793 | | |portion of the result. Computed | 794 | | |after taking any loss mitigation | 795 | | |due to FEC and/or redundancy into | 796 | | |account. The numbers of duplicated | 797 | | |packets and discarded packets do | 798 | | |not enter into this calculation. | 799 --------------------------------------------------------- 800 MGCP RTCP-XR Package 4/12/2007 801 --------------------------------------------------------- 802 | Parameter | Code | Value | 803 | | | | 804 --------------------------------------------------------- 805 |Jitter |JDR |The proportion of the packets | 806 |buffer | |discarded by the receiving | 807 |discard | |jitter buffer since the start of | 808 |rate | |metrics computation expressed as an| 809 | | |8-bit binary fraction obtained by | 810 | | |dividing the number of packets | 811 | | |discarded by the jitter buffer | 812 | | |by the total number of packets | 813 | | |expected by the receiver, | 814 | | |multiplying this value by 256 | 815 | | |and taking the integer portion | 816 | | |of the result. Computed | 817 | | |after taking any loss mitigation | 818 | | |due to FEC and/or redundancy into | 819 | | |account. The number of duplicate | 820 | | |packet discards does not enter | 821 | | |into this calculation. | 822 --------------------------------------------------------- 823 |Burst loss | BLD |The average proportion (since the | 824 |density | |start of metrics computation) of | 825 | | |lost and discarded packets | 826 | | |occurring during burst periods | 827 | | |expressed as an 8 bit | 828 | | |binary fraction obtained by | 829 | | |dividing the sum of the number of | 830 | | |packets detected as lost during | 831 | | |burst periods and the number of | 832 | | |packets discarded by the jitter | 833 | | |buffer during burst periods by | 834 | | |the total number of packets | 835 | | |expected by the receiver, | 836 | | |multiplying this value by 256 | 837 | | |and taking the integer portion | 838 | | |of the result. Computed | 839 | | |after taking any loss mitigation | 840 | | |due to FEC and/or redundancy into | 841 | | |account. Duplicate packet discards | 842 | | |are excluded from this computation.| 843 --------------------------------------------------------- 844 MGCP RTCP-XR Package 4/12/2007 845 --------------------------------------------------------- 846 | Parameter | Code | Value | 847 | | | | 848 --------------------------------------------------------- 849 |Gap loss | GLD |The average proportion (since the | 850 |density | |start of metrics computation) of | 851 | | |lost and discarded packets | 852 | | |occurring during gap periods | 853 | | |expressed as an 8 bit binary | 854 | | |fraction obtained by | 855 | | |dividing the sum of the number of | 856 | | |packets detected as lost during | 857 | | |gap periods and the number of | 858 | | |packets discarded by the jitter | 859 | | |buffer during gap periods by | 860 | | |the total number of packets | 861 | | |expected by the receiver, | 862 | | |multiplying this value by 256 | 863 | | |and taking the integer portion | 864 | | |of the result. Computed | 865 | | |after taking any loss mitigation | 866 | | |due to FEC and/or redundancy into | 867 | | |account. Duplicate packet discards | 868 | | |are excluded from this computation.| 869 --------------------------------------------------------- 870 |Burst |BD |The average duration of the burst | 871 |duration | |periods, in milliseconds. Computed | 872 | | |from the start of metrics | 873 | | |computation. Bursts are determined | 874 | | |after taking any loss mitigation | 875 | | |due to FEC and/or redundancy into | 876 | | |account. | 877 --------------------------------------------------------- 878 |Gap |GD |The average duration of the gap | 879 |duration | |periods, in milliseconds. Computed | 880 | | |from the start of metrics | 881 | | |computation. Bursts are determined | 882 | | |after taking any loss mitigation | 883 | | |due to FEC and/or redundancy into | 884 | | |account. | 885 --------------------------------------------------------- 886 MGCP RTCP-XR Package 4/12/2007 887 --------------------------------------------------------- 888 | Parameter | Code | Value | 889 | | | | 890 --------------------------------------------------------- 891 |Round trip |RTD |The round trip delay, in | 892 |network | |milliseconds, between the RTP | 893 |delay | |interfaces of the local and | 894 | | |remote call endpoints. Valid | 895 | | |values MUST be greater than or | 896 | | |equal to 0 milliseconds. This | 897 | | |could be computed on the basis of | 898 | | |RFC 3550, or the DLRR report | 899 | | |block in [RFC 3611] or any other | 900 | | |valid method. The average of all | 901 | | |measurements since the start of | 902 | | |metrics computation SHOULD be used.| 903 --------------------------------------------------------- 904 |End system |ESD |The end system (endpoint) delay, in| 905 |delay | |milliseconds, comprising the | 906 | | |encode, decode and jitter buffer | 907 | | |delay. Valid values MUST be | 908 | | |greater than or equal to 0 | 909 | | |milliseconds. The average of all | 910 | | |measurements since the start | 911 | | |metrics computation SHOULD be used.| 912 --------------------------------------------------------- 913 |Signal |SL |The ratio of the average signal | 914 |level | |level to a 0 dBm0 reference, | 915 | | |expressed in dB. This is | 916 | | |expressed as an integer with an | 917 | | |OPTIONAL negative ("-") sign. | 918 | | |When the sign is omitted, a | 919 | | |positive value is assumed. | 920 | | |Typical values SHOULD generally | 921 | | |be between -15 and -20. | 922 | | |This metric SHALL be averaged | 923 | | |from the start of metrics | 924 | | |computation. A value of 127 | 925 | | |indicates that the parameter is | 926 | | |unavailable. | 927 --------------------------------------------------------- 928 MGCP RTCP-XR Package 4/12/2007 929 --------------------------------------------------------- 930 | Parameter | Code | Value | 931 | | | | 932 --------------------------------------------------------- 933 |Noise |NL |The ratio of the silent period | 934 |level | |average background noise level to | 935 | | |a 0 dBm0 reference, in dB. This | 936 | | |is expressed as an integer without | 937 | | |a +ve or -ve sign. No sign is | 938 | | |necessary since this value MUST be | 939 | | |equal to or less than 0 dB. A value| 940 | | |of 127 indicates that the parameter| 941 | | |is unavailable. A +ve or -ve sign, | 942 | | |if used, SHALL be ignored. | 943 | | |The metric SHALL be averaged from | 944 | | |the start of metrics computation. | 945 --------------------------------------------------------- 946 |Residual |RERL |The echo return loss after the | 947 |echo return | |effects of echo cancellation, in | 948 |loss | |dB. This value is expressed as | 949 | | |a positive integer without a | 950 | | |negative sign. A value of 127 | 951 | | |indicates that the parameter is | 952 | | |unavailable. Thus, RERL=23 | 953 | | |indicates an echo loss of 23 dB | 954 | | |after factoring in any echo | 955 | | |cancellation. This metric SHALL be | 956 | | |averaged from the start of metrics | 957 | | |computation. | 958 --------------------------------------------------------- 959 |Minimum gap |GMN | The gap/burst transition | 960 |threshold | | threshold; the RECOMMENDED value | 961 | | | is 16. Values in the range 1 - - | 962 | | | 255 are permitted. | 963 --------------------------------------------------------- 964 MGCP RTCP-XR Package 4/12/2007 965 --------------------------------------------------------- 966 | Parameter | Code | Value | 967 | | | | 968 --------------------------------------------------------- 969 |R-factor |NSR | Conversational quality | 970 |(Conversat- | | R-factor for the "inner segment", | 971 |-ional | | of the call, which is the VoIP | 972 |quality) | | session on which | 973 | | | the endpoint resides. This value | 974 | | | represents the conversational | 975 | | | quality of the RTP session | 976 | | | calculated per ITU G.107. Valid | 977 | | | values are greater than 0 and | 978 | | | less than or equal to 120. A | 979 | | | value of 127 indicates that the | 980 | | | parameter is unavailable. This | 981 | | | parameter is computed from the | 982 | | | start of metrics computation. | 983 | | | When the term 'R-factor' is used | 984 | | | without further qualification, | 985 | | | this parameter is implied. | 986 --------------------------------------------------------- 987 |R-factor |RLQ | A value representing the | 988 |(Listening | | listening quality of | 989 |quality) | | the RTP session; | 990 | | | calculated as per ITU-T | 991 | | | Recommendation G.107. Valid | 992 | | | values are greater than 0 and | 993 | | | less than or equal to 120. A | 994 | | | value of 127 indicates that the | 995 | | | parameter is unavailable. This | 996 | | | parameter is computed from the | 997 | | | start of metrics computation. | 998 --------------------------------------------------------- 999 |External |XSR | Listening quality R-factor for an | 1000 |R-factor | | "external segment" which is any | 1001 | | | call segment external to the VoIP | 1002 | | | session on which the endpoint | 1003 | | | resides. This value is | 1004 | | | calculated per ITU-T | 1005 | | | Recommendation G.107. Valid | 1006 | | | values are greater than 0 and | 1007 | | | less than or equal to 120. A | 1008 | | | value of 127 indicates that the | 1009 | | | parameter is unavailable. This | 1010 | | | parameter is computed from the | 1011 | | | start of metrics computation. | 1012 --------------------------------------------------------- 1013 MGCP RTCP-XR Package 4/12/2007 1015 --------------------------------------------------------- 1016 | Parameter | Code | Value | 1017 | | | | 1018 --------------------------------------------------------- 1019 |Estimated |MLQ | An estimated receiving end | 1020 |MOS-LQ | | listening quality MOS. The | 1021 | | | nominal range of MOS scores is | 1022 | | | 1-5. Before being expressed in | 1023 | | | MGCP, the MOS score is | 1024 | | | multiplied by 10 and any | 1025 | | | fractional part is truncated. | 1026 | | | This results in an integer with | 1027 | | | valid values in the range 10 - 50.| 1028 | | | A value of 127 indicates that | 1029 | | | the parameter is unavailable. | 1030 | | | This parameter is computed from | 1031 | | | the start of metrics computation. | 1032 --------------------------------------------------------- 1033 |Estimated |MCQ | An estimated receiving end | 1034 |MOS-CQ | | conversational quality MOS. The | 1035 | | | nominal range of MOS scores is | 1036 | | | 1-5. Before being expressed in | 1037 | | | MGCP, the MOS score is | 1038 | | | multiplied by 10 and any | 1039 | | | fractional part is truncated. | 1040 | | | This results in an integer with | 1041 | | | valid values in the range 10 - 50.| 1042 | | | A value of 127 indicates that | 1043 | | | the parameter is unavailable. | 1044 | | | This parameter is averaged from | 1045 | | | the start of metrics computation. | 1046 --------------------------------------------------------- 1047 |Packet loss |PLC | The type of packet loss | 1048 |concealment | | concealment algorithm in use; | 1049 |type | | SHOULD be one of the following | 1050 | | | enumeration values: | 1051 | | | 0 - Unspecified | 1052 | | | 1 - Disabled | 1053 | | | 2 - Enhanced | 1054 | | | 3 - Standard | 1055 --------------------------------------------------------- 1056 MGCP RTCP-XR Package 4/12/2007 1057 --------------------------------------------------------- 1058 | Parameter | Code | Value | 1059 | | | | 1060 --------------------------------------------------------- 1061 |Jitter |JBA | The adaptability of the jitter | 1062 |Buffer | | buffer. Should be one of the | 1063 |Adaptability| | following enumeration values: | 1064 | | | 0 - Unknown | 1065 | | | 1 - Reserved | 1066 | | | 2 - Non-adaptive | 1067 | | | 3 - Adaptive | 1068 --------------------------------------------------------- 1069 |Jitter |JBR | The jitter buffer adjustment | 1070 |Buffer | | rate. Value is between 0 and | 1071 |Rate | | 15. | 1072 --------------------------------------------------------- 1073 |Nominal |JBN | Current nominal delay in | 1074 |jitter | | milliseconds that corresponds to | 1075 |buffer | | the nominal jitter buffer delay | 1076 |delay | | for packets that arrive exactly | 1077 | | | on time. The last computed value | 1078 | | | is used. | 1079 --------------------------------------------------------- 1080 |Maximum |JBM | Current maximum delay in | 1081 |jitter | | milliseconds that corresponds to | 1082 |buffer | | the earliest arriving packet | 1083 |delay | | that would not be discarded. In | 1084 | | | simple queue implementations, | 1085 | | | this MAY correspond to the | 1086 | | | nominal jitter buffer delay. In | 1087 | | | adaptive jitter buffer | 1088 | | | implementations, this value MAY | 1089 | | | dynamically vary up to the | 1090 | | | absolute maximum jitter buffer | 1091 | | | delay (see below). The last | 1092 | | | computed value is used. | 1093 --------------------------------------------------------- 1094 |Absolute |JBS | Absolute maximum delay in | 1095 |maximum | | milliseconds that an adaptive | 1096 |jitter | | jitter buffer can reach under | 1097 |buffer | | worst case conditions. This is | 1098 |delay | | a configured parameter. For fixed | 1099 | | | jitter buffers, this must be set | 1100 | | | to the maximum jitter buffer | 1101 | | | delay. | 1102 --------------------------------------------------------- 1103 MGCP RTCP-XR Package 4/12/2007 1104 --------------------------------------------------------- 1105 | Parameter | Code | Value | 1106 | | | | 1107 --------------------------------------------------------- 1108 |MOS-LQ |MLES | Algorithm used to estimate the | 1109 |Estimation | | the MOS-LQ metric, MLQ. This | 1110 |Algorithm | | is expressed as a human-readable | 1111 | | | character string with an | 1112 | | | unrestricted set of values. | 1113 --------------------------------------------------------- 1114 |MOS-CQ |MCES | Algorithm used to estimate the | 1115 |Estimation | | the MOS-CQ metric, MCQ. This | 1116 |Algorithm | | is expressed as a human-readable | 1117 | | | character string with an | 1118 | | | unrestricted set of values. | 1119 --------------------------------------------------------- 1120 |R-factor |RFES | Algorithm(s) used to estimate | 1121 |Estimation | | the one or more R-factors | 1122 |Algorithm(s)| | reported. This is expressed as a | 1123 | | | human-readable character string | 1124 | | | with an unrestricted set of | 1125 | | | values. This string MAY contain | 1126 | | | separate descriptions for the | 1127 | | | algorithms pertaining to the | 1128 | | | R-factors NSR, MLQ and XSR | 1129 | | | described above. | 1130 --------------------------------------------------------- 1131 MGCP RTCP-XR Package 4/12/2007 1132 TABLE 2: PARAMETERS BASED ON RTCP SENDER AND RECEIVER REPORTS 1133 --------------------------------------------------------- 1134 | Parameter | Code | Value | 1135 | | | | 1136 --------------------------------------------------------- 1137 |Packets sent |PS | The number of packets that were | 1138 | | | were sent on the connection since| 1139 | | | the start of metrics computation.| 1140 | | | Does not include any FEC packets | 1141 | | | sent on a different SSRC or port.| 1142 --------------------------------------------------------- 1143 |Octets sent |OS | The number of payload octets that| 1144 | | | were sent out on the connection | 1145 | | | since the start of metrics | 1146 | | | computation. Header and padding | 1147 | | | octets are not included. Nor are | 1148 | | | octets in redundant or FEC | 1149 | | | payloads/packets. | 1150 --------------------------------------------------------- 1151 |Packets |PR | The number of packets that were | 1152 |received | | were received on the connection | 1153 | | | since the start of metrics | 1154 | | | computation. Does not include any| 1155 | | | FEC packets received on a | 1156 | | | different SSRC or port. | 1157 --------------------------------------------------------- 1158 |Octets |OR | The number of payload octets that| 1159 |received | | were received on the | 1160 | | | connection since the start of | 1161 | | | metrics computation. Header and | 1162 | | | padding octets are not included. | 1163 | | | Nor are octets in redundant or | 1164 | | | FEC payloads/packets. | 1165 --------------------------------------------------------- 1166 MGCP RTCP-XR Package 4/12/2007 1168 --------------------------------------------------------- 1169 | Parameter | Code | Value | 1170 | | | | 1171 --------------------------------------------------------- 1172 |Packets |PL | The total number of media packets| 1173 |lost | | that have been lost since the | 1174 | | | beginning of metrics computation.| 1175 | | | This is defined to be the number | 1176 | | | of packets expected less the | 1177 | | | number of packets actually | 1178 | | | received, where the number of | 1179 | | | packets received includes any | 1180 | | | which are late or duplicates. | 1181 | | | Thus packets that arrive late are| 1182 | | | not counted as lost, and the loss| 1183 | | | MAY be negative if there are | 1184 | | | duplicates. This metric does not | 1185 | | | take any loss mitigation due to | 1186 | | | redundancy or FEC into account. | 1187 --------------------------------------------------------- 1188 |Inter- |IAJ | Per [RFC 3550], the inter-arrival| 1189 |arrival | | jitter is defined to be | 1190 |jitter | | the mean deviation (smoothed | 1191 | | | absolute value) of the difference| 1192 | | | in packet spacing at the | 1193 | | | the receiver compared to the | 1194 | | | sender for a pair of packets. | 1195 | | | This metric is averaged from the | 1196 | | | start of computation and is | 1197 | | | expressed in milliseconds. | 1198 | | | The corresponding connection | 1199 | | | parameter in [RFC 3435] is JI. | 1200 --------------------------------------------------------- 1201 MGCP RTCP-XR Package 4/12/2007 1202 TABLE 3: SESSION DESCRIPTION PARAMETERS 1203 --------------------------------------------------------- 1204 | Parameter | Code | Value | 1205 | | | | 1206 --------------------------------------------------------- 1207 |SSRC |SSRC | SSRC of the measured stream. | 1208 | | | If it changes due to a collision,| 1209 | | | the last value is used. | 1210 | | | Represented as the decimal | 1211 | | | equivalent of a 32-bit word. | 1212 --------------------------------------------------------- 1213 |Source IP |IPAS | The source IP address for | 1214 |address | | the stream under measurement | 1215 --------------------------------------------------------- 1216 |Source IP |IPTS | This indicates whether the source| 1217 |address type | | IP address is IP version 4 or 6. | 1218 --------------------------------------------------------- 1219 |Destination |IPAD | The destination IP address for | 1220 |IP address | | the stream under measurement. | 1221 --------------------------------------------------------- 1222 |Destination |IPTD | This indicates whether the | 1223 |IP address | | destination IP address is | 1224 |type | | IP version 4 or 6. | 1225 --------------------------------------------------------- 1226 |Source |RTUS | The source RTP/UDPTL port for | 1227 |RTP/UDPTL | | the stream under measurement. | 1228 |port | | | 1229 --------------------------------------------------------- 1230 |Destination |RTUD | The destination RTP/UDPTL port | 1231 |RTP/UDPTL | | for the stream under measurement| 1232 |port | | | 1233 --------------------------------------------------------- 1234 |Source |RTCS | The source RTCP port for | 1235 |RTCP port | | the stream under measurement. | 1236 --------------------------------------------------------- 1237 |Destination |RTCD | The destination RTCP port for | 1238 |RTCP port | | the stream under measurement. | 1239 --------------------------------------------------------- 1240 |Codec |VCD | The last voice or voice band data| 1241 |(voice or | | codec used. This is expressed | 1242 |voice band | | as a character string | 1243 |data) | | corresponding to a MIME subtype | 1244 | | | from [IANA RTP] (e.g. " G726-40")| 1245 | | | or as an experimental codec name | 1246 | | | starting with "X-". | 1247 --------------------------------------------------------- 1248 MGCP RTCP-XR Package 4/12/2007 1249 --------------------------------------------------------- 1250 | Parameter | Code | Value | 1251 | | | | 1252 --------------------------------------------------------- 1253 |Secondary |VCDS | In the case of RFC 2198 | 1254 |codec | | redundancy, the secondary codec | 1255 |(voice or | | used. Semantics identical to | 1256 |voice band | | primary codec. (See VCD parameter| 1257 |data) | | above.) | 1258 --------------------------------------------------------- 1259 |Media |MMOD | This indicates whether the | 1260 |Mode | | the media carried by the session | 1261 | | | is audio ("a"), voice band data | 1262 | | | ("v"), fax relay ("f"), modem | 1263 | | | relay ("m") or text relay ("t"). | 1264 | | | The last mode is indicated by | 1265 | | | this parameter. Audio and text | 1266 | | | relay packets MAY be interleaved | 1267 | | | in the text relay mode. | 1268 | | | Voice band data, fax relay, modem| 1269 | | | relay and text relay are defined | 1270 | | | in [ITU V.152], [ITU T.38], | 1271 | | | [ITU V.150.1] and [ITU V.151] | 1272 | | | respectively. All of these media,| 1273 | | | with the exception of modem | 1274 | | | relay, can be transported via | 1275 | | | RTP. | 1276 --------------------------------------------------------- 1277 |Sample rate |SMPL | The rate at which media is | 1278 |(voice or | | is sampled (samples per second) | 1279 |voice band | | for the last voice or voice band | 1280 |data) | | data codec used. | 1281 --------------------------------------------------------- 1282 |Codec frame |FRSZ | The number of octets in a codec | 1283 |size | | frame for the last voice or | 1284 |(voice or | | voice band data codec. | 1285 |voice band | | | 1286 |data) | | | 1287 --------------------------------------------------------- 1288 |RTP payload |PLSZ | The number of octets in a the RTP| 1289 |size | | packet payload for the | 1290 |(voice or | | last voice or voice band data | 1291 |voice band | | codec used. | 1292 |data) | | | 1293 --------------------------------------------------------- 1294 MGCP RTCP-XR Package 4/12/2007 1295 --------------------------------------------------------- 1296 | Parameter | Code | Value | 1297 | | | | 1298 --------------------------------------------------------- 1299 |Packetization|PKRT | The number of RTP packets per | 1300 |rate | | second for the last voice or | 1301 |(voice or | | voice band data codec used. | 1302 |voice band | | | 1303 |data) | | | 1304 --------------------------------------------------------- 1305 |Silence |SSUP | This indicates whether silence | 1306 |Suppression | | suppression, also known as Voice | 1307 |State | | Activity Detection (VAD)is | 1308 | | | enabled. The last value is used. | 1309 | | | It is assumed that silence | 1310 | | | suppression is accompanied by | 1311 | | | comfort noise generation. | 1312 --------------------------------------------------------- 1313 |Echo |ECAN | This indicates whether echo | 1314 |Cancellation | | cancellation is enabled. The last| 1315 |State | | value is used. | 1316 --------------------------------------------------------- 1317 |Redundancy |VRED | This indicates whether | 1318 |State | | redundancy [RFC 2198] was used | 1319 |(voice or | | for the last voice or voice band | 1320 |voice band | | data codec. | 1321 |data). | | | 1322 --------------------------------------------------------- 1323 |FEC State |VFEC | This indicates whether | 1324 |(voice or | | Forward Error Correction | 1325 |voice band | | [RFC 2733] was used for the last | 1326 |data). | | voice or voice band data codec. | 1327 | | | RFC 2733 FEC MAY be used in | 1328 | | | conjunction with RFC 2198 | 1329 | | | redundancy. | 1330 --------------------------------------------------------- 1331 |SSRC of the |FSRC | SSRC of the received FEC stream, | 1332 |received FEC | | if any. If it changes due to a | 1333 |stream | | collision, the last value is | 1334 | | | used. Represented as the decimal | 1335 | | | equivalent of a 32-bit word. | 1336 --------------------------------------------------------- 1337 MGCP RTCP-XR Package 4/12/2007 1338 --------------------------------------------------------- 1339 | Parameter | Code | Value | 1340 | | | | 1341 --------------------------------------------------------- 1342 |Destination |IPAF | The destination IP address for | 1343 |IP address | | the FEC stream received with the | 1344 |for FEC | | RTP media stream. Identical to | 1345 | | | IPAD (above) if the FEC stream | 1346 | | | is sent to the same | 1347 | | | IP address as the media | 1348 | | | stream under measurement. In | 1349 | | | either case, the IP address type | 1350 | | | is per the IPTD parameter above. | 1351 --------------------------------------------------------- 1352 |Destination |RTFD | The destination RTP port for any | 1353 |RTP port | | FEC stream received with the RTP | 1354 |for FEC | | media stream. Identical to | 1355 | | | RTUD (above) if the FEC stream | 1356 | | | is sent to the same | 1357 | | | RTP port as the media | 1358 | | | stream under measurement. | 1359 --------------------------------------------------------- 1361 2.3.3 Procedures for the resetting of metrics 1363 The metrics associated with the XRM/LVM and XRM/RVM lines MAY be 1364 reset/reinitialized in response to the XRM/MMO parameter in a 1365 ModifyConnection command from the call agent, or autonomously by the 1366 endpoint when a media state transition (e.g. from voice to voice band 1367 data) occurs. Also, as a rule an SSRC change SHOULD NOT reset VQ 1368 metrics. This is consistent with the base MGCP protocol [RFC 3435]. 1369 SSRC can occur due to rare collision events [RFC 3550]. 1371 The impact of reset depends on the semantics of each individual 1372 parameter. In general, the following actions are taken during metrics 1373 reset: 1375 - All counters are set to 0. 1376 - Measurements that are not counts are set to an unknown value. 1377 For example, 127 indicates an unknown value for the signal level, 1378 noise level, RERL, the various R-factors and MOS estimates. 1379 Further, any computations of the average, minimum and maximum 1380 values associated with these measurements are restarted. 1381 - The Reset Occurrences (ROC) parameter is not changed. 1382 - Configuration parameters such as the absolute maximum jitter 1383 buffer delay and session-related parameters (Table 3) reflect current 1384 values. 1386 MGCP RTCP-XR Package 4/12/2007 1387 2.3.4 Impact redundancy and FEC on packet loss computations 1389 The packet loss and discard parameters based on the RTCP XR VoIP 1390 metrics block [RFC 3611] are computed after taking redundancy and FEC 1391 into account. Thus, the following parameters from Table 1 SHALL be 1392 computed after taking the effect of redundancy (e.g. RFC 2198) and/or 1393 FEC (e.g. RFC 2733) into account: 1395 - Network packet loss rate, NLR 1396 - Jitter buffer discard rate, JDR 1397 - Burst loss density, BLD, and burst duration, BD 1398 - Gap loss density, GLD, and gap duration, GD 1400 By contrast, the packet receipt and packet loss parameters based on 1401 RTCP Sender Reports (SR) and Receiver Reports (RR) do not take 1402 redundancy or FEC into account. They are meant to be indicative of 1403 impairments "on the wire" than in end-to-end service. Thus, the packets 1404 lost (PL) parameter in Table 2 does not take into account any loss 1405 mitigation due to redundancy (e.g. RFC 2198) or FEC (e.g. RFC 2733) 1406 into account. 1408 2.3.5 Parameter Extension Mechanism 1410 The XRM/LVM and XRM/RVM lines MAY include vendor extension parameters 1411 that begin with an "X-". An MGCP entity that receives an extension 1412 parameter in these lines MUST ignore it if it cannot understand it. 1414 Since these parameters introduce an unmanaged name space, there is a 1415 potential for name clashing. Vendors are consequently encouraged to 1416 include some vendor specific string, e.g. vendor name or stock ticker 1417 symbol, in their vendor extensions. For example, if Acme Widgets, a 1418 fictional company, wishes to use metric "ABC", it is preferable to use 1419 the name "X-acmewidgets-ABC" rather than "X-ABC". 1421 Vendors MAY register new metrics in an IANA registry of MGCP names of 1422 VoIP metrics. The "X-" prefix is not germane to a metric following 1423 registration. 1425 2.3.6 Formal Syntax of VoIP Metrics Package 1427 The following describes the ABNF encoding [RFC 2234] for the parameters 1428 defined in this package. Per MGCP conventions, all parameters defined 1429 in this package are case-insensitive. 1431 The standard tokens SP, WSP, ALPHA, DIGIT, HEXDIG etc. are per RFC 1432 2234. 1434 MediaMetricsOption = "XRM/MMO:" *WSP ("REP"/"RES"/"RR") 1435 MGCP RTCP-XR Package 4/12/2007 1437 RemoteVoIPMetrics = "XRM/LVM:" *WSP [VoIPMetric *("," *WSP 1438 VoIPMetric)] 1439 ; zero or more local metrics 1440 ; zero metrics are permitted in AUCX responses 1442 RemoteVoIPMetrics = "XRM/RVM:" *WSP [VoIPMetric *("," *WSP 1443 VoIPMetric)] 1444 ; zero or more remote metrics 1446 VoIPMetric = ComputationInterval 1447 / ResetOccurrences 1448 / NetworkPacketLossRate 1449 / JitterBufferDiscardRate 1450 / BurstLossDensity 1451 / GapLossDensity 1452 / BurstDuration 1453 / GapDuration 1454 / RoundTripNetworkDelay 1455 / EndSystemDelay 1456 / SignalLevel 1457 / NoiseLevel 1458 / ResidualEchoReturnLoss 1459 / MinimumGapThreshold 1460 / RFactor-CQ 1461 / RFactor-LQ 1462 / ExternalRFactor 1463 / EstimatedMOS-LQ 1464 / EstimatedMOS-CQ 1465 / PacketLossConcealmentType 1466 / JitterBufferAdaptability 1467 / JitterBufferRate 1468 / JitterBufferNominal 1469 / JitterBufferMax 1470 / JitterBufferAbsMax 1471 / MOSLQEstimationAlgorithm 1472 / MOSLQEstimationAlgorithm 1473 / RfacorEstimationAlgorithms 1474 / InterArrivalJitter 1475 / PacketsSent 1476 / OctetsSent 1477 / PacketsReceived 1478 / OctetsReceived 1479 / PacketsLost 1480 / SSRC 1481 / SourceIPAddress 1482 / SourceIPAddressType 1483 / DestinationIPAddress 1484 MGCP RTCP-XR Package 4/12/2007 1485 / DestinationIPAddressType 1486 / SourceRTPPort 1487 / DestinationRTPPort 1488 / SourceRTCPPort 1489 / DestinationRTCPPort 1490 / VoiceOrVBDprimaryCodec 1491 / VoiceOrVBDsecondaryCodec 1492 / MaxCharacterRate 1493 / MediaMode 1494 / SampleRate 1495 / CodecFrameSize 1496 / RTPpayloadSize 1497 / PacketizationRate 1498 / SilenceSuppression 1499 / EchoCancellation 1500 / RFC2198RedundancyForVoiceOrVBD 1501 / RFC2733FECforVoiceOrVBD 1502 / FECstreamSSRC 1503 / FECDestinationIPAddress 1504 / FECDestinationRTPPort 1505 / UnregisteredExtension 1506 / RegisteredExtension 1508 ComputationInterval = "CMPI" = 1*20(DIGIT); 1510 ResetOccurrences = "ROC" = "0"/"1"; 1512 NetworkPacketLossRate = "NLR=" 1*3(DIGIT) ;0-255 1514 JitterBufferDiscardRate = "JDR=" 1*3(DIGIT) ;0-255 1516 BurstLossDensity = "BLD=" 1*3(DIGIT) ; 0-255 1518 GapLossDensity = "GLD=" 1*3(DIGIT) ; 0-255 1520 BurstDuration = "BD=" 1*5(DIGIT) ; 0-65535 1522 GapDuration = "GD=" 1*5(DIGIT) ; 0-65535 1524 MinimumGapThreshold = "GMN=" 1*3(DIGIT) ; 1-255 1526 RoundTripNetworkDelay = "RTD=" 1*4(DIGIT) ; 1528 EndSystemDelay = "ESD=" 1*4(DIGIT) ; 1530 SignalLevel = "SL=" ["-"] 1*3(DIGIT) ;-128 to 127 1532 NoiseLevel = "NL=" 1*3(DIGIT) 1533 MGCP RTCP-XR Package 4/12/2007 1534 ; 0 to 127, indicates dB below 0 dBm0 1536 ResidualEchoReturnLoss = "RERL=" 1*3(DIGIT) ;0-127 1538 RFactor-CQ = "NSR=" 1*3(DIGIT) 1539 ;0-120, or 127 1541 RFactor-LQ = "RLQ=" 1*3(DIGIT) 1542 ;0-120, or 127 1543 ExternalRFactor = "XRF=" 1*3(DIGIT) ;0-120, or 127 1545 EstimatedMOS-LQ = "MLQ=" 1*3(DIGIT) ; 10-50, or 127 1547 EstimatedMOS-CQ = "MCQ=" 1*3(DIGIT) ; 10-50, or 127 1549 PacketLossConcealmentType= "PLC=" ("0" / "1" / "2" / "3") 1551 JitterBufferAdaptability = "JBA=" ("0" / "1" / "2" / "3") 1553 JitterBufferRate = "JBR=" 1*2(DIGIT) ;0-15 1555 JitterBufferNominal = "JBN=" 1*5(DIGIT) ;0-65535 1557 JitterBufferMax = "JBM=" 1*5(DIGIT) ;0-65535 1559 JitterBufferAbsMax = "JBS=" 1*5(DIGIT) ;0-65535 1561 MOSLQEstimationAlgorithm = "MLES=" ALPHA 1*127 (permittedchar) 1562 ;first character must be alphabetic 1563 MOSCQEstimationAlgorithm = "MCES=" ALPHA 1*127 (permittedchar) 1564 ;first character must be alphabetic 1565 RfactorAlgorithms = "RFES=" ALPHA 1*127 (permittedchar) 1566 ;first character must be alphabetic 1567 InterArrivalJitter = "IAJ=" 1*3(DIGIT) ; 1568 PacketsSent = "PS=" 1*9(DIGIT); 1569 OctetsSent = "OS=" 1*9(DIGIT); 1570 PacketsReceived = "PR=" 1*9(DIGIT); 1571 OctetsReceived = "OR=" 1*9(DIGIT); 1572 PacketsLost = "PL=" ["-"] 1*9(DIGIT); 1573 SSRC = "SSRC=" 1*10 (DIGIT); 0-4,294,967,296 1574 SourceIPAddressType = "IPTS=" ("IPv4" / "IPv6") 1575 DestinationIPAddressType = "IPTD=" ("IPv4" / "IPv6") 1576 SourceIPAddress = "IPAS=" (IPv4address / IPv6address) 1577 ; IPv4address and IPv6address defined in RFC 3261 1578 DestinationIPAddress = "IPAD=" (IPv4address / IPv6address) 1579 ; IPv4address and IPv6address defined in RFC 3261 1580 SourceRTPPort = "RTUS=" 1*5(DIGIT) ;1024-65535 inclusive 1581 DestinationRTPPort = "RTUD=" 1*5(DIGIT) 1582 MGCP RTCP-XR Package 4/12/2007 1583 ;1024-65535 inclusive 1584 SourceRTCPPort = "RTCS=" 1*5(DIGIT) ;1024-65535 inclusive 1585 DestinationRTCPPort = "RTCD=" 1*5(DIGIT) 1586 ;1024-65535 inclusive 1587 VoiceOrVBDprimaryCodec = "VCD=" ALPHA 1*31 (permittedchar) 1588 ;first character must be alphabetic 1589 VoiceOrVBDsecondaryCodec = "VCDS=" ALPHA 1*31 (permittedchar) 1590 ;first character must be alphabetic 1591 MaxCharacterRate = "CPS=" 1*2 (DIGIT) 1592 MediaMode = "MMOD=" "a" / "v" / "f" / "m" / "t" / ALPHA 1593 ; audio, voice band data, fax relay, modem relay, text relay 1594 ; the token ALPHA is to permit additional future definitions 1595 SampleRate = "SMPL=" 1*7 (DIGIT) 1596 CodecFrameSize = "FRSZ=" 1*3 (DIGIT) 1597 RTPpayloadSize = "PLSZ=" 1*3 (DIGIT) 1598 PacketizationRate = "PKRT=" 1*5 (DIGIT) 1599 SilenceSuppression = "SSUP=" ("on" / "off") 1600 EchoCancellation = "ECAN=" ("on" / "off") 1601 RFC2198RedundancyForVoiceOrVBD = "VRED=" ("on" / "off") 1602 RFC2733FECforVoiceOrVBD = "VFEC=" ("on" / "off") 1603 FECstreamSSRC = "FSRC=" 1*10 (DIGIT); 0-4,294,967,296 1604 FECDestinationIPAddress = "IPAF=" (IPv4address / IPv6address) 1605 ; IPv4address and IPv6address defined in RFC 3261 1606 FECDestinationRTPPort = "RTFD=" 1*5(DIGIT) 1607 ;1024-65535 inclusive 1608 UnregisteredExtension = "X-" ExtensionName "=" ExtensionVal 1609 RegisteredExtension = ExtensionName "=" ExtensionVal 1610 ExtensionName = 1*32 (ALPHA) 1611 ExtensionVal = 1*32 (alphanum) 1612 ;More precise definition in extension specifications 1614 alphanum = ALPHA / DIGIT 1615 permittedchar = alphanum / permittedspecialchar 1616 permittedspecialchar = "-" / "_" / "." / "!" / "~" / "*" / 1617 "'" / "(" / ")" / SP 1619 2.3.7 Impact of media state changes on VoIP metrics 1621 The RECOMMENDED endpoint behavior when the media state changes (e.g. 1622 from voice to voice band data or vice versa) is to reset/reinitialize 1623 the parameters in Tables 1, 2 and 3. Section 2.3.3 describes the 1624 procedures for this resetting/reinitialization. 1626 However, it is recognized that some endpoints MAY continue to 1627 accumulate or average parameters across media state changes. For 1628 example, an endpoint MAY continue to accumulate parameters such as 1629 packet loss rate (NLR) and to average parameters such as round trip 1630 delay (RTD)across transitions between voice and voice band data. If 1631 metrics computation is carried over from one media state to another, 1632 MGCP RTCP-XR Package 4/12/2007 1633 then metrics and parameters that do not apply to the new state (such as 1634 MOS-LQ in the case of fax relay)SHOULD be placed in a suspended state 1635 until another state transition (such as fax relay to voice in the case 1636 of MOS-LQ) renders them applicable again. If any reporting activity 1637 occurs during their suspension, the last applicable value SHOULD be 1638 conveyed. 1640 If the session is initially established in a mode for which some of the 1641 metrics and parameters in Tables 1-3 do not apply, then these 1642 parameters MUST be omitted or dummied out (per the rules in Section 1643 2.3.1) for any reporting while they are inapplicable. For example, if 1644 an endpoint uses this package to convey the metrics for a session that 1645 is currently in the T.38 fax relay mode in which it was initially 1646 established, then the MOS-LQ parameter MUST be omitted or dummied out 1647 (by setting it to 127). 1649 2.3.8 Applicability of VoIP metrics to Voice Band Data 1651 For the definition of voice band data, see [ITU V.152]. Voice band data 1652 sessions are RTP sessions. RTCP is REQUIRED in conjunction with any RTP 1653 session [RFC 3550]. However, the various blocks in RTCP-XR, such as the 1654 VoIP metrics block, are not. They must be negotiated at session 1655 establishment. 1657 Also note that, since this document is focused on voice, it lacks key 1658 voice band data metrics. 1660 The parameters from the RTCP XR VoIP metrics block (Table 1) and the 1661 RTCP Sender/Receiver Reports (Table 2) MAY be applied to voice band 1662 data. The session description parameters (Table 3) are also applicable 1663 to voice band data. 1665 Note that the utility of the various MOS scores and R-factors might be 1666 limited for voice band data since there is no correlation of the 1667 various MOS scores and R-factors with the end-users' perspective of the 1668 quality of the modem or fax transmission. Notwithstanding, some 1669 implementations MAY elect to use the MLQ metric as an indicator of the 1670 transmission quality of voice band data channel. 1672 For some voice band data sessions, echo cancellation is turned off. For 1673 others, it is turned on. If echo cancellation is off, then RERL reverts 1674 to the Echo Return Loss of the hybrid transformer or acoustic coupling 1675 path. However, some implementations might not measure this parameter in 1676 the absence of an active echo canceller. In such cases, this parameter 1677 will be omitted in the XRM/LVM and XRM/RVM lines, or set to a dummy 1678 value (127) in the XRM/RVM line. 1680 MGCP RTCP-XR Package 4/12/2007 1681 Many voice band data sessions [ITU V.152] use fixed-length jitter 1682 buffers. If this is the case, then this will be reflected in the JBA 1683 parameter (set to "non-adaptive"), the JBR parameter (set to 0) and the 1684 JBS parameter (set to JBM). 1686 2.3.9 Applicability of VoIP metrics to Fax Relay and Text Relay 1688 Since this document is focused on voice, it lacks key metrics related 1689 to fax [ITU T.38], text [ITU V.151] and modem [ITU V.150.1] relay. 1690 Other specifications such as [FAX PKG] will address in a 1691 comprehensive manner the reporting via MGCP of the metrics 1692 that pertain to the various relay modes. 1694 However, it is instructive to examine how the parameters defined in 1695 this document apply to various relay mechanisms. Tables 4, 5 and 6 1696 examine the relevance of the metrics and session parameters listed in 1697 Tables 1, 2 and 3 to fax relay [ITU T.38]. Tables 7, 8 and 9 examine 1698 the relevance of the metrics and session parameters listed in Tables 1, 1699 2 and 3 to text relay [ITU V.151]. 1701 Note that the basic definitions of parameters from Tables 1, 2, and 3 1702 are not repeated in Tables 4 through 9. All that these tables address 1703 is the applicability of these parameters to fax relay and text relay. 1704 Parameters from Tables 1, 2 and 3 that are not relevant to fax relay 1705 are not listed in Tables 4, 5 and 6. Similarly, parameters from Tables 1706 1, 2 and 3 that are not relevant to text relay are not listed in Tables 1707 7, 8 and 9. 1709 Relay sessions (fax or text) get established in two ways. In the first 1710 case, the session is established as a fax or text relay session during 1711 call set-up. In the second case, it is established as an audio session 1712 which is transitioned, at media gateways, to fax relay or text relay 1713 on the receipt of certain tones or stimuli. A variant of this second 1714 case involves a transition from audio to voice band data and 1715 subsequently to fax relay or text relay. 1717 RTCP is REQUIRED in conjunction with any RTP session [RFC 3550]. This 1718 includes RTP-based fax relay and RTP-based text relay. However, the 1719 various blocks in RTCP-XR, such as the VoIP metrics block, are not. 1720 They must be negotiated at session establishment. Note that, in 1721 contrast to RTP-based relay sessions, RTCP is not applicable to non-RTP 1722 relay such as UDTPL-based fax relay [ITU T.38]. 1724 Note that burst parameters (burst loss density, gap loss density, burst 1725 duration, gap duration and the minimum gap threshold) are not germane 1726 to relay mechanisms (such as fax relay or text relay) since such relay 1727 streams are not continuous for significant periods of time. Any burst 1728 characterization is, therefore, likely to be deceptive. 1730 MGCP RTCP-XR Package 4/12/2007 1732 Also note that the various R-factors and MOS scores in Table 1 are not 1733 applicable to baseband data transmission such as fax relay or data 1734 relay. 1736 TABLE 4: PARAMETERS FROM TABLE 1 THAT ARE APPLICABLE TO FAX RELAY 1737 +-----------------+-----------------------------------------------+ 1738 | PARAMETER | APPLICABILITY TO FAX RELAY | 1739 | from Table 1 | | 1740 +-----------------+-----------------------------------------------+ 1741 |Network packet |Loss refers to fax relay packets which MAY be | 1742 |loss rate(NLR) |UDPTL or RTP [ITU T.38]. Computed after FEC | 1743 | |and/or redundancy processing. As described | 1744 | |in [ITU T.38], the FEC and redundancy | 1745 | |schemes applicable to UDPTL fax relay and RTP | 1746 | |fax relay are different. | 1747 +-----------------+-----------------------------------------------+ 1748 |Jitter buffer |Discards refer to fax relay packets which MAY | 1749 |discard rate |be UDPTL or RTP [ITU T.38]. Computed after FEC | 1750 |(JDR) |and/or redundancy processing. As described | 1751 | |in [ITU T.38], the FEC and redundancy | 1752 | |schemes applicable to UDPTL fax relay and RTP | 1753 | |fax relay are different. | 1754 +-----------------+-----------------------------------------------+ 1755 |Round trip |Not very useful for fax relay sessions. Can be | 1756 |network delay |computed using RTCP for RTP-based fax relay. | 1757 |(RTD) |There is no standard mechanism for round-trip | 1758 | |delay computation in the case of UDPTL-based | 1759 | |fax relay. | 1760 ------------------------------------------------------------------- 1761 |End system delay | Not very useful for fax relay sessions. | 1762 |(ESD) | | 1763 +-----------------+-----------------------------------------------+ 1764 MGCP RTCP-XR Package 4/12/2007 1766 TABLE 5: PARAMETERS FROM TABLE 2 THAT ARE APPLICABLE TO FAX RELAY 1767 +-----------------+-----------------------------------------------+ 1768 | PARAMETER | APPLICABILITY TO FAX RELAY | 1769 | from Table 2 | | 1770 +-----------------+-----------------------------------------------+ 1771 |Packets sent |Refers to fax relay packets, which MAY be UDPTL| 1772 |(PS) |or RTP. Does not include any RTP FEC packets | 1773 | |sent on a different SSRC or port. | 1774 +-----------------+-----------------------------------------------+ 1775 |Octets sent |Refers only to T.4 image octets in | 1776 |(OS) |primary UDPTL/RTP payloads/packets. Octets in | 1777 | |redundant/FEC payloads/packets are not counted.| 1778 +-----------------+-----------------------------------------------+ 1779 |Packets |Refers to fax relay packets, which MAY be UDPTL| 1780 |Received |or RTP. Does not include any RTP FEC packets | 1781 |(PR) |received on a different SSRC or port. | 1782 +-----------------+-----------------------------------------------+ 1783 |Octets received |Refers only to T.4 image octets in | 1784 |(OR) |primary UDPTL/RTP payloads/packets. Octets in | 1785 | |redundant/FEC payloads/packets are not | 1786 | |counted. | 1787 +-----------------+-----------------------------------------------+ 1788 |Packets lost |Refers to lost UDPTL/RTP fax relay packets | 1789 |(PL) |without taking into account any loss mitigation| 1790 | |due to redundancy or FEC. As described | 1791 | |in [ITU T.38], the FEC and redundancy | 1792 | |schemes applicable to UDPTL fax relay and RTP | 1793 | |fax relay are different. | 1794 +-----------------+-----------------------------------------------+ 1795 MGCP RTCP-XR Package 4/12/2007 1796 TABLE 6: PARAMETERS FROM TABLE 3 THAT ARE APPLICABLE TO FAX RELAY 1797 +-----------------+-----------------------------------------------+ 1798 | PARAMETER | APPLICABILITY TO FAX RELAY | 1799 | from Table 3 | | 1800 +-----------------+-----------------------------------------------+ 1801 |SSRC |Not applicable to UDPTL-based fax relay. For | 1802 |(SSRC) |RTP-based fax relay, this is the SSRC of the | 1803 | |RTP fax relay stream. | 1804 +-----------------+-----------------------------------------------+ 1805 |Source IP address| Applicable to fax relay sessions. | 1806 |(IPAS) | | 1807 +-----------------+-----------------------------------------------+ 1808 |Source IP address| Applicable to fax relay sessions. | 1809 |type (IPTS) | | 1810 +-----------------+-----------------------------------------------+ 1811 |Destination IP | Applicable to fax relay sessions. | 1812 |address (IPAD) | | 1813 +-----------------+-----------------------------------------------+ 1814 |Destination IP | Applicable to fax relay sessions. | 1815 |address type | | 1816 |(IPTD) | | 1817 +-----------------+-----------------------------------------------+ 1818 |Source RTP/UDPTL | Applicable to fax relay sessions. | 1819 |port (RTUS) | | 1820 +-----------------+-----------------------------------------------+ 1821 |Destination | Applicable to fax relay sessions. | 1822 |RTP/UDPTL port | | 1823 |(RTUD) | | 1824 +-----------------+-----------------------------------------------+ 1825 |Source RTCP | Applicable to RTP-based fax relay sessions. | 1826 |port (RTCS) | | 1827 +-----------------+-----------------------------------------------+ 1828 |Destination RTCP | Applicable to RTP-based fax relay sessions. | 1829 |port (RTCD) | | 1830 +-----------------+-----------------------------------------------+ 1831 |Media Mode (MMOD)| Applicable to fax relay sessions. | 1832 +-----------------+-----------------------------------------------+ 1833 |SSRC of received |Applicable to RTP-based fax relay if FEC is | 1834 |FEC stream |used in conjunction with it. | 1835 |(FSRC) | | 1836 +-----------------+-----------------------------------------------+ 1837 |Destination IP |Applicable to RTP-based fax relay if FEC is | 1838 |address for FEC |used in conjunction with it. | 1839 |(IPAF) | | 1840 +-----------------+-----------------------------------------------+ 1841 MGCP RTCP-XR Package 4/12/2007 1842 +-----------------+-----------------------------------------------+ 1843 | PARAMETER | APPLICABILITY TO FAX RELAY | 1844 | from Table 3 | | 1845 +-----------------+-----------------------------------------------+ 1846 |Destination RTP |Applicable to RTP-based fax relay if FEC is | 1847 |port for FEC |used in conjunction with it. | 1848 |(RTFD) | | 1849 +-----------------+-----------------------------------------------+ 1851 TABLE 7: PARAMETERS FROM TABLE 1 THAT ARE APPLICABLE TO TEXT RELAY 1852 +-----------------+-----------------------------------------------+ 1853 | PARAMETER | APPLICABILITY TO TEXT RELAY | 1854 | from Table 1 | | 1855 +-----------------+-----------------------------------------------+ 1856 |Network packet |Packet loss is computed for a stream of packets| 1857 |loss rate(NLR) |sharing an SSRC and, therefore, the same | 1858 | |sequence number space. This is either a | 1859 | |stream of RTP-based text relay packets or an | 1860 | |interleaved stream of audio and text relay | 1861 | |packets. This loss rate is computed after FEC | 1862 | |and/or redundancy processing. | 1863 +-----------------+-----------------------------------------------+ 1864 |Jitter buffer |The discard rate is computed for a stream of | 1865 |discard rate |packets sharing an SSRC and, therefore, the | 1866 |(JDR) |same sequence number space. This is either a | 1867 | |stream of RTP-based text relay packets or an | 1868 | |interleaved stream of audio and text relay | 1869 | |packets. This loss rate is computed after FEC | 1870 | |and/or redundancy processing. | 1871 +-----------------+-----------------------------------------------+ 1872 |Round trip |Applicable to text relay sessions. | 1873 |network delay | | 1874 |(RTD) | | 1875 +-----------------+-----------------------------------------------+ 1876 |End system delay |Applicable to text relay sessions. | 1877 |(ESD) | | 1878 +-----------------+-----------------------------------------------+ 1879 MGCP RTCP-XR Package 4/12/2007 1880 TABLE 8: PARAMETERS FROM TABLE 2 THAT ARE APPLICABLE TO TEXT RELAY 1881 +-----------------+-----------------------------------------------+ 1882 | PARAMETER | APPLICABILITY TO TEXT RELAY | 1883 | from Table 2 | | 1884 +-----------------+-----------------------------------------------+ 1885 |Packets sent |Refers to text relay packets. If these packets | 1886 |(PS) |share an SSRC with an interleaved audio stream,| 1887 | |it refers to the composite stream. Does not | 1888 | |include any FEC packets sent on a different | 1889 | |SSRC or port. | 1890 +-----------------+-----------------------------------------------+ 1891 |Octets sent |Refers only to payload octets in primary RTP | 1892 |(OS) |payloads/packets. Payload octets include text | 1893 | |octets and audio octets sent with the same | 1894 | |SSRC. Octets in redundant or FEC | 1895 | |payloads/packets are not counted. | 1896 +-----------------+-----------------------------------------------+ 1897 |Packets received |Refers to text relay packets. If these packets | 1898 |(PR) |share an SSRC with an interleaved audio stream,| 1899 | |it refers to the composite stream. Does not | 1900 | |include any FEC packets received on a different| 1901 | |SSRC or port. | 1902 +-----------------+-----------------------------------------------+ 1903 |Octets received |Refers only to payload octets in primary RTP | 1904 |(OR) |payloads/packets. Payload octets include text | 1905 | |octets and audio octets received with the same | 1906 | |SSRC. Octets in redundant or FEC | 1907 | |payloads/packets are not counted. | 1908 +-----------------+-----------------------------------------------+ 1909 |Packets lost |Refers to text relay packets. If these packets | 1910 |(PL) |share an SSRC with an interleaved audio stream,| 1911 | |it refers to the composite stream. Does not | 1912 | |take into account any loss mitigation due to | 1913 | |due to redundancy or FEC. | 1914 +-----------------+-----------------------------------------------+ 1915 MGCP RTCP-XR Package 4/12/2007 1916 TABLE 9: PARAMETERS FROM TABLE 3 THAT ARE APPLICABLE TO TEXT RELAY 1917 +-----------------+-----------------------------------------------+ 1918 | PARAMETER | APPLICABILITY TO TEXT RELAY | 1919 | from Table 3 | | 1920 +-----------------+-----------------------------------------------+ 1921 |SSRC |Applicable to text relay sessions and sessions | 1922 |(SSRC) |with interleaved text relay and audio packets. | 1923 +-----------------+-----------------------------------------------+ 1924 |Source IP |Applicable to text relay sessions and sessions | 1925 |address (IPAS) |with interleaved text relay and audio packets. | 1926 +-----------------+-----------------------------------------------+ 1927 |Source IP address|Applicable to text relay sessions and sessions | 1928 |type (IPTS) |with interleaved text relay and audio packets. | 1929 +-----------------+-----------------------------------------------+ 1930 |Destination IP |Applicable to text relay sessions and sessions | 1931 |address (IPAD) |with interleaved text relay and audio packets. | 1932 +-----------------+-----------------------------------------------+ 1933 |Destination IP |Applicable to text relay sessions and sessions | 1934 |address type |with interleaved text relay and audio packets. | 1935 |(IPTD) | | 1936 +-----------------+-----------------------------------------------+ 1937 |Source RTP/UDPTL |Applicable to text relay sessions and sessions | 1938 |port(RTUS) |with interleaved text relay and audio packets. | 1939 +-----------------+-----------------------------------------------+ 1940 |Destination |Applicable to text relay sessions and sessions | 1941 |RTP/UDPTL port |with interleaved text relay and audio packets. | 1942 |(RTUD) | | 1943 +-----------------+-----------------------------------------------+ 1944 |Source RTCP |Applicable to text relay sessions and sessions | 1945 |port (RTCS) |with interleaved text relay and audio packets. | 1946 +-----------------+-----------------------------------------------+ 1947 |Destination RTCP |Applicable to text relay sessions and sessions | 1948 |port (RTCD) |with interleaved text relay and audio packets. | 1949 +-----------------+-----------------------------------------------+ 1950 |Media Mode |Applicable to text relay sessions and sessions | 1951 |(MMOD) |with interleaved text relay and audio packets. | 1952 +-----------------+-----------------------------------------------+ 1953 |SSRC of received |Applicable if FEC is used. | 1954 |FEC stream (FSRC)| | 1955 +-----------------+-----------------------------------------------+ 1956 |Destination IP |Applicable if FEC is used. | 1957 |address for FEC | | 1958 |(IPAF) | | 1959 +-----------------+-----------------------------------------------+ 1960 |Destination RTP |Applicable if FEC is used. | 1961 |port for FEC | | 1962 |(RTFD) | | 1963 +-----------------+-----------------------------------------------+ 1964 MGCP RTCP-XR Package 4/12/2007 1965 3. Call Flow Examples 1967 The following examples are partial call flows for the case where the 1968 XRM/mcr local connection option is set to "on". Only one endpoint's 1969 perspective is shown. In this example, the remote endpoint sends voice 1970 metrics to this endpoint via RTCP Extended Reports, Sender Reports and 1971 Receiver Reports. 1973 Note that these are call flow examples and not examples of typical 1974 metrics values. These values have not been derived from real-world 1975 situations and, therefore, do not necessarily have the right numeric 1976 relationship between themselves. 1978 3.1 Metrics Reporting during Call agent-initiated Delete Connection 1980 Step 1: 1981 The Call Agent issues a CreateConnection command to the endpoint 1982 instructing it to use PCMU media encoding and to invoke RTCP XR metric 1983 collection, responding and reporting: 1985 CRCX 1000 ds/ds1-1/1@gw-o.example.net MGCP 1.0 1986 C: 1 1987 L: a:PCMU, xrm/mcr: on 1988 M: recvonly 1990 Step 2: 1992 The endpoint acknowledges the command and includes the rtxp-xr 1993 attribute set to "voip-metrics": 1995 200 1000 OK 1996 I:1 1998 v=0 1999 o=- 25678 753849 IN IP4 128.96.41.1 2000 s=- 2001 c=IN IP4 128.96.41.1 2002 t=0 0 2003 m=audio 3456 RTP/AVP 0 2004 a=rtcp-xr:voip-metrics 2006 Step 3: 2008 The endpoint receives a ModifyConnection command containing an LCO with 2009 no xrm/mcr parameter, which indicates that the endpoint SHOULD continue 2010 to use the previously received value of "on". Since the received SDP 2011 also contains the rtcp-xr attribute with a value of "voip-metrics", it 2012 MGCP RTCP-XR Package 4/12/2007 2013 is safe to assume that both ends will exchange the VoIP metrics block 2014 in RTCP Extended Reports (XR). 2016 MDCX 1001 ds/ds1-1/1@gw-o.example.net MGCP 1.0 2017 C: 1 2018 I: 1 2019 L: a:PCMU;G728 2020 M: sendrecv 2021 I:1 2023 v=0 2024 o=- 4723891 7428910 IN IP4 128.96.63.25 2025 s=- 2026 c=IN IP4 128.96.63.25 2027 t=0 0 2028 m=audio 4082 RTP/AVP 0 2029 a=rtcp-xr:voip-metrics 2031 Step 4: 2033 The endpoint acknowledges the command and, since VoIP metrics 2034 collection/reporting is still "on", includes the rtxp-xr attribute set 2035 to "voip-metrics": 2037 200 1001 OK 2039 v=0 2040 o=- 25678 753849 IN IP4 128.96.41.1 2041 s=- 2042 c=IN IP4 128.96.41.1 2043 t=0 0 2044 m=audio 3456 RTP/AVP 0 2045 a=rtcp-xr:voip-metrics 2047 Step 5: 2049 The Call Agent eventually issues a DeleteConnection: 2051 DLCX 1100 ds/ds1-1/1@gw-o.example.net MGCP 1.0 2052 C: 1 2053 I: 1 2055 Step 6: 2057 The endpoint acknowledges the command and returns the standard MGCP 2058 connection parameters along with the XRM/LVM line and the XRM/RVM line. 2060 MGCP RTCP-XR Package 4/12/2007 2061 This endpoint elects to include the remote equivalents of the 2062 connection parameters on XRM/RVM line. Note that the remote end has 2063 indicated that the ITU G.107 specification has been used to compute the 2064 R-factors and that a proprietary algorithm, "Acme Widgets 233", has 2065 been used to compute MOS-LQ. The remote end has not indicated the 2066 algorithm used to compute MOS-CQ, which is on of the metrics that it 2067 has communicated via an RTCP extended report. Also note that new lines 2068 shown here are for document formatting reasons only. 2070 250 1100 OK 2071 P: PS=5000, OS=200000, PR=6000, OR=340000, PL=800, 2072 JI=27, LA=180 2073 XRM/LVM: NLR=28, JDR=14, BLD=128, GLD=10, 2074 BD=55, GD=1000, RTD=180,ESD=30, SL=-15, NL=20, 2075 RERL=23, GMN=16, NSR=63, RLQ=61, XSR=65, MLQ=33, MCQ=31, PLC=3, 2076 JBA=3, JBR=8, JBN=40, JBM=80, JBS=120, SSRC=27513888, 2077 IPAD=128.96.41.1, RTPD=3456, VCD=PCMU, VPT=0, MMOD=a, SMPL=8000, 2078 PKRT=200, SSUP=on, ECAN=on, VRED=off, VFEC=off 2079 XRM/RVM: NLR=6, JDR=2, BLD=50, GLD=3, BD=20, GD=6000, RTD=180, 2080 ESD=23, SL=-16, NL=25, RERL=23, GMN=16, NSR=80, RLQ=82, XSR=77, 2081 MLQ=37, MCQ=35, PLC=3, JBA=3, JBR=8, JBN=30, JBM=60, JBS=100, 2082 MLES=Acme widgets 233, RFES=ITU G.107,PS=6800, OS=272000, 2083 PR=4900, OR=196000, IAJ=15, SSRC=832829, IPAD=128.96.63.25, 2084 RTPD=4082, VCD=PCMU, VPT=0, MMOD=a, SMPL=8000, PKRT=200, SSUP=on, 2085 ECAN=on, VRED=off, VFEC=off 2087 3.2 Metrics Reporting during Gateway-initiated Delete Connection 2089 Step 1: 2091 The Call Agent issues a CreateConnection command to the endpoint 2092 instructing it to use PCMU media encoding and to invoke RTCP XR metric 2093 collection and reporting: 2095 CRCX 1000 ds/ds1-1/1@gw-o.example.net MGCP 1.0 2096 C: 1 2097 L: a:PCMU, xrm/mcr: on 2098 M: recvonly 2100 Step 2: 2102 The endpoint acknowledges the command and includes the rtxp-xr 2103 attribute set to "voip-metrics": 2105 200 1000 OK 2106 I:1 2107 MGCP RTCP-XR Package 4/12/2007 2108 v=0 2109 o=- 25678 753849 IN IP4 128.96.41.1 2110 s=- 2111 c=IN IP4 128.96.41.1 2112 t=0 0 2113 m=audio 3456 RTP/AVP 0 2114 a=rtcp-xr:voip-metrics 2116 Step 3: 2118 The Endpoint issues a DeleteConnection command including the connection 2119 parameters along with the XRM/LVM line and the XRM/RVM line: 2121 DLCX 1100 ds/ds1-1/1@gw-o.example.net MGCP 1.0 2122 C: 1 2123 I: 1 2124 E: 900 - - Hardware error 2125 P: PS=5000, OS=200000, PR=6000, OR=340000, PL=800, 2126 JI=27, LA=180 2127 XRM/LVM: NLR=28, JDR=14, BLD=128, GLD=10, 2128 BD=55, GD=1000, RTD=180,ESD=30, SL=-15, NL=20, 2129 RERL=23, GMN=16, NSR=63, XSR=65, MLQ=33, MCQ=31, PLC=3, JBA=3, 2130 JBR=8, JBN=40, JBM=80, JBS=120, SSRC=27513888, IPAD=128.96.41.1, 2131 RTPD=3456, VCD=PCMU, VPT=0, SMPL=8000, 2132 PKRT=200, SSUP=on, ECAN=on, VRED=off, VFEC=off 2133 XRM/RVM: NLR=6, JDR=2, BLD=50, GLD=3, BD=20, GD=6000, RTD=180, 2134 ESD=23, SL=-16, NL=25, RERL=23, GMN=16, NSR=80, XSR=77, MLQ=37, 2135 MCQ=35, PLC=3, JBA=3, JBR=8, JBN=30, JBM=60, JBS=100, PS=6800, 2136 OS=272000, PR=4900, OR=196000, IAJ=15, SSRC=832829, 2137 IPAD=128.96.63.25, RTPD=4082, VCD=PCMU, VPT=0, SMPL=8000, 2138 PKRT=200, SSUP=on, ECAN=on, VRED=off, VFEC=off 2140 Note that the RLQ parameter is not included in the XRM/LVM or the 2141 XRM/RVM lines. This is just an example of allowed parameter omission. 2142 This example could have very well been constructed with the RLQ 2143 parameter. 2145 Step 4: 2147 The Call Agent acknowledges the command: 2149 200 1100 OK 2151 3.3 Metrics Reporting during Audit Connection 2152 MGCP RTCP-XR Package 4/12/2007 2153 Step 1: 2155 The Call Agent issues a CreateConnection command to the endpoint 2156 instructing it to use PCMU media encoding and to invoke RTCP XR metric 2157 collection, responding and reporting: 2159 CRCX 1000 ds/ds1-1/1@gw-o.example.net MGCP 1.0 2160 C: 1 2161 L: a:PCMU, xrm/mcr: on 2162 M: recvonly 2164 Step 2: 2166 The endpoint acknowledges the command and includes the rtxp-xr 2167 attribute set to "voip-metrics": 2169 200 1000 OK 2170 I:1 2172 v=0 2173 o=- 25678 753849 IN IP4 128.96.41.1 2174 s=- 2175 c=IN IP4 128.96.41.1 2176 t=0 0 2177 m=audio 3456 RTP/AVP 0 2178 a=rtcp-xr:voip-metrics 2180 Step 3: 2182 The endpoint receives a ModifyConnection command containing an LCO with 2183 no xrm/mcr parameter, which indicates that the endpoint SHOULD continue 2184 to use the previously received value of "on". Since the received SDP 2185 also contains the rtcp-xr attribute with a value of "voip-metrics", it 2186 is safe to assume that both ends will exchange the VoIP metrics block 2187 in RTCP Extended Reports (XR). 2189 MDCX 1001 ds/ds1-1/1@gw-o.example.net MGCP 1.0 2190 C: 1 2191 I: 1 2192 L: a:PCMU;G728 2193 M: sendrecv 2195 v=0 2196 o=- 4723891 7428910 IN IP4 128.96.63.25 2197 s=- 2198 c=IN IP4 128.96.63.25 2199 MGCP RTCP-XR Package 4/12/2007 2200 t=0 0 2201 m=audio 4082 RTP/AVP 0 2202 a=rtcp-xr:voip-metrics 2204 Step 4: 2206 The endpoint acknowledges the command and, since VoIP metrics 2207 collection/reporting is still "on", includes the rtxp-xr attribute set 2208 to "voip-metrics": 2210 200 1001 OK 2211 I:1 2213 v=0 2214 o=- 25678 753849 IN IP4 128.96.41.1 2215 s=- 2216 c=IN IP4 128.96.41.1 2217 t=0 0 2218 m=audio 3456 RTP/AVP 0 2219 a=rtcp-xr:voip-metrics 2221 Step 5: 2223 The Call Agent eventually issues a AuditConnection that requests the 2224 XRM/LVM and XRM/RVM lines but not the P (connection parameters) line: 2226 AUCX 1100 ds/ds1-1/1@gw-o.example.net MGCP 1.0 2227 C: 1 2228 I: 1 2229 F: XRM/LVM, XRM/RVM 2231 Step 6: 2233 The endpoint acknowledges the command and returns the XRM/LVM line and 2234 the XRM/RVM line. This endpoint elects to include the local and remote 2235 equivalents of the connection parameters in the XRM/LVM and XRM/RVM 2236 line. Also note that new lines shown here are for document formatting 2237 reasons only. 2239 200 1100 OK 2240 XRM/LVM: NLR=28, JDR=14, BLD=128, GLD=10, 2241 BD=55, GD=1000, RTD=180,ESD=30, SL=-15, NL=20, 2242 RERL=23, GMN=16, NSR=63, RLQ=61, XSR=65, MLQ=33, MCQ=31, PLC=3, 2243 JBA=3, JBR=8, JBN=40, JBM=80, JBS=120, PS=5000, OS=200000, 2244 PR=6000, OR=340000, PL=800, IAJ=27, SSRC=27513888, 2245 IPAD=128.96.41.1, RTPD=3456, VCD=PCMU, VPT=0, MMOD=a, SMPL=8000, 2246 MGCP RTCP-XR Package 4/12/2007 2247 PKRT=200, SSUP=on, ECAN=on, VRED=off, VFEC=off 2248 XRM/RVM: NLR=6, JDR=2, BLD=50, GLD=3, BD=20, GD=6000, RTD=180, 2249 ESD=23, SL=-16, NL=25, RERL=23, GMN=16, NSR=80, RLQ=82, XSR=77, 2250 MLQ=37, MCQ=35, PLC=3, JBA=3, JBR=8, JBN=30, JBM=60, JBS=100, 2251 PS=6800, OS=272000, PR=4900, OR=196000, IAJ=15, SSRC=832829, 2252 IPAD=128.96.63.25, RTPD=4082, VCD=PCMU, VPT=0, MMOD=a, SMPL=8000, 2253 PKRT=200, SSUP=on, ECAN=on, VRED=off, VFEC=off 2255 3.4 Metrics Reporting during Modify Connection 2257 Step 1: 2259 The Call Agent issues a CreateConnection command to the endpoint 2260 instructing it to use PCMU media encoding and to invoke RTCP XR metric 2261 collection, responding and reporting: 2263 CRCX 1000 ds/ds1-1/1@gw-o.example.net MGCP 1.0 2264 C: 1 2265 L: a:PCMU, xrm/mcr: on 2266 M: recvonly 2268 Step 2: 2270 The endpoint acknowledges the command and includes the rtxp-xr 2271 attribute set to "voip-metrics": 2273 200 1000 OK 2274 I:1 2276 v=0 2277 o=- 25678 753849 IN IP4 128.96.41.1 2278 s=- 2279 c=IN IP4 128.96.41.1 2280 t=0 0 2281 m=audio 3456 RTP/AVP 0 2282 a=rtcp-xr:voip-metrics 2284 Step 3: 2286 The endpoint receives a ModifyConnection command containing an LCO with 2287 no xrm/mcr parameter, which indicates that the endpoint SHOULD continue 2288 to use the previously received value of "on". Since the received SDP 2289 also contains the rtcp-xr attribute with a value of "voip-metrics", it 2290 is safe to assume that both ends will exchange the VoIP metrics block 2291 in RTCP Extended Reports (XR). 2293 MGCP RTCP-XR Package 4/12/2007 2295 MDCX 1001 ds/ds1-1/1@gw-o.example.net MGCP 1.0 2296 C: 1 2297 I: 1 2298 L: a:PCMU;G728 2299 M: sendrecv 2301 v=0 2302 o=- 4723891 7428910 IN IP4 128.96.63.25 2303 s=- 2304 c=IN IP4 128.96.63.25 2305 t=0 0 2306 m=audio 4082 RTP/AVP 0 2307 a=rtcp-xr:voip-metrics 2309 Step 4: 2311 The endpoint acknowledges the command and, since VoIP metrics 2312 collection/reporting is still "on", includes the rtxp-xr attribute set 2313 to "voip-metrics": 2315 200 1001 OK 2316 I:1 2318 v=0 2319 o=- 25678 753849 IN IP4 128.96.41.1 2320 s=- 2321 c=IN IP4 128.96.41.1 2322 t=0 0 2323 m=audio 3456 RTP/AVP 0 2324 a=rtcp-xr:voip-metrics 2326 Step 5: 2328 The Call Agent eventually issues a ModifyConnection with the XRM/MMO 2329 line requesting that local and remote metrics be reset and reported. 2331 MDCX 1001 ds/ds1-1/1@gw-o.example.net MGCP 1.0 2332 C: 1 2333 I: 1 2334 L: a:PCMU;G728 2335 M: sendrecv 2336 XRM/MMO: RR 2337 MGCP RTCP-XR Package 4/12/2007 2338 Step 6: 2340 The endpoint acknowledges the command and returns the XRM/LVM line and 2341 the XRM/RVM line. The endpoint does not include the connection 2342 parameters line since this would violate [RFC 3435]. Instead, it 2343 includes the local and remote equivalents of the connection parameters 2344 in the XRM/LVM and XRM/RVM line. Also note that new lines shown here 2345 are for document formatting reasons only. 2347 200 1001 OK 2348 XRM/LVM: NLR=28, JDR=14, BLD=128, GLD=10, 2349 BD=55, GD=1000, RTD=180,ESD=30, SL=-15, NL=20, 2350 RERL=23, GMN=16, NSR=63, RLQ=61, XSR=65, MLQ=33, MCQ=31, PLC=3, 2351 JBA=3, JBR=8, JBN=40, JBM=80, JBS=120, PS=5000, OS=200000, 2352 PR=6000, OR=340000, PL=800, IAJ=27, SSRC=27513888, 2353 IPAD=128.96.41.1, RTPD=3456, VCD=PCMU, VPT=0, MMOD=a, SMPL=8000, 2354 PKRT=200, SSUP=on, ECAN=on, VRED=off, VFEC=off 2355 XRM/RVM: NLR=6, JDR=2, BLD=50, GLD=3, BD=20, GD=6000, RTD=180, 2356 ESD=23, SL=-16, NL=25, RERL=23, GMN=16, NSR=80, RLQ=82, XSR=77, 2357 MLQ=37, MCQ=35, PLC=3, JBA=3, JBR=8, JBN=30, JBM=60, JBS=100, 2358 PS=6800, OS=272000, PR=4900, OR=196000, IAJ=15, SSRC=832829, 2359 IPAD=128.96.63.25, RTPD=4082, VCD=PCMU, VPT=0, MMOD=a, SMPL=8000, 2360 PKRT=200, SSUP=on, ECAN=on, VRED=off, VFEC=off 2362 4. Security Considerations 2364 This package inherits the security considerations of the base MGCP 2365 protocol. A possible new security issue involves a remote device 2366 placing extra burden on a local endpoint by requesting metric 2367 collection on that local endpoint. This threat can be mitigated by the 2368 call agent specifically prohibiting the generation of local metrics 2369 using the local connection option: xrm/mcr: off. 2371 5. IANA Considerations 2373 5.1 Package Registration 2375 The IANA is hereby requested to register the following MGCP package: 2377 Package Title Name Version 2378 ------------- ---- ------- 2379 RTCP XR metrics XRM 0 2381 5.2. Extension Registration 2383 The IANA is requested to create a registry of MGCP names of vendor- 2384 specified VoIP metrics. These metrics MAY be used in the XRM/LVM and 2385 MGCP RTCP-XR Package 4/12/2007 2386 XRM/RVM lines defined in this package. Such a metric SHALL be described 2387 in a specification ("source document") approved by an accredited 2388 standards organization such as the IETF or ITU. This document MAY be 2389 informative and MAY address more than one metric. It MUST include: 2391 - Contact name, email address and telephone number. 2392 - Metric name, as an alphabetic character string 2393 - Description of and ABNF notation for the permitted 2394 range of values, 2395 - A functional description of the metric i.e. what it 2396 measures and how it is to be used, 2397 - Optionally, the measurement algorithm and any IPR statements 2398 associated with it. 2400 6. Changes from earlier drafts 2402 6.1 Changes from the -00 version to the -01 version 2404 All changes from the -00 version to the -01 version of this draft are 2405 backwards compatible. All new features in the 01 version are OPTIONAL. 2407 Note that the -00 version was incorporated into the PacketCable 1.5 2408 specifications. 2410 Changes from the -00 version to the -01 version are: 2412 - Inclusion of statistics from the RTCP sender and receiver reports, 2413 with the exception of latency which is already present in the RTCP XR 2414 VoIP metrics block. The reporting of these statistics via this package 2415 is OPTIONAL. 2417 - Inclusion of session description parameters based on the ones defined 2418 in RFC 2327, RFC 2198 etc. This included media description parameters 2419 such as codec type. 2421 - Inclusion of a modify connection procedure for the reporting and 2422 resetting of voice quality metrics. 2424 - Clarification of cumulative vs. interval metrics. For the SR/RR 2425 metrics, these rules are inherited from connection parameters in [RFC 2426 3435]. 2428 - Inclusion of a new G.107-based parameter, RLQ, for indicating the 2429 listening quality of a VoIP session. 2431 - Inclusion of a new parameter, MLES, for indicating the algorithm used 2432 to estimate the MOS-LQ metric. 2434 MGCP RTCP-XR Package 4/12/2007 2435 - ABNF correction for requiring at least one metric in the XRM/LVM 2436 line. 2438 - Inclusion of a mechanism for defining vendor extension metrics that 2439 can be used in this package, and a mechanism for OPTIONALly registering 2440 these metrics with the IANA. 2442 6.2 Changes from the -01 version to the -02 version 2444 All changes from the -01 version of this draft to the -02 version are 2445 backwards compatible. These are: 2447 - Included the impact of redundancy (e.g. RFC 2198) and FEC (e.g. 2448 RFC 2733) on packet loss computation. 2449 - Corrections of errors and typos in the ABNF. 2451 6.3 Changes from the -02 version to the -03 version 2453 All changes from the -02 version of this draft to the -03 version are 2454 backwards compatible. These are: 2456 - Added the parameters FSRC, IPAF and RTFD to Table 3 to fully 2457 cover the case in which an RFC 2733 FEC is used. 2458 - Added section 2.3.9 on the applicability to fax relay and text 2459 relay of the VoIP metrics and session parameters reported via 2460 this package. 2462 6.4 Changes from the -03 version to the -04 version 2464 All changes from the -03 version of this draft to the -04 version are 2465 backwards compatible. These are: 2467 - Clarification that metrics MAY be reset during media mode shifts, 2468 and that this is the preferred behavior. 2469 - Clarified how an audit connection MAY be associated with a 2470 preceding event notification. This is based on temporal 2471 proximity. Included recommendation to report the metrics captured 2472 just prior to the event. 2473 - Included two new parameters that MAY be OPTIONALly reported: the 2474 computation interval (CMPI) and the number of reset occurrences 2475 (ROC). 2476 - Included section 2.3.7 describing the impact of media state 2477 changes on VoIP metrics. 2479 6.5 Changes from the -04 version to the -05 version 2480 Spelling errors. 2482 6.6 Changes from the -05 version to the -06 version 2483 Formatting. 2485 6.7 Changes from the -06 version to the -07 version 2486 Formatting. 2488 6.8 Potential future updates 2489 - Add list of acronyms 2490 MGCP RTCP-XR Package 4/12/2007 2491 7. Normative References 2493 [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate 2494 Requirement Levels", BCP 14, March 1997. 2496 [RFC 3435] F. Andreasen, B. Foster, "Media Gateway Control Protocol 2497 (MGCP) Version 1.0", January 2003. 2499 [RFC 3611] T. Friedman, R. Caceres, A. Clark, "RTP Control Protocol 2500 Extended Reports (RTCP XR)", November 2003. 2502 [RFC 3550] H. Schulzrinne, S. Casner, R. Frederick and V. Jacobson, 2503 "RTP: A Transport Protocol for Real-Time Applications", July 2003. 2505 [RFC 2327] M.Handley and V. Jacobson, "SDP: Session Description 2506 Protocol", April 1998. 2508 [RFC 3660] B.Foster and F.Andreasen, "Basic Media Gateway Control 2509 Protocol (MGCP) Packages", December 2003. 2511 [RFC 2234] D.Crocker and P.Overell, "Augmented BNF for Syntax 2512 Specifications: ABNF", November 1997. 2514 [RFC 3261] J.Rosenberg, H.Schulzrinne, G.Camarillo, A.Johnston, 2515 J.Peterson, R.Sparks, M.Handley, E.Schooler, "SIP: Session Initiation 2516 Protocol", June 2002. 2518 [RFC 2198] C.Perkins, I.Kouvelas, O.Hodson, V.Hardman, M.Handley, 2519 J.C.Balot, A.Vega-Garcia and S. Fosse-Parisis, "RTP Payload for 2520 Redundant Audio Data", September 1997. 2522 [RFC 2733] J.Rosenberg, H.Schulzrinne, "An RTP Payload format for 2523 Generic Forward Error Correction", December 1999. 2525 [IANA RTP] http://www.iana.org/assignments/media-types/audio/. 2527 [US-ASCII] Coded Character Set--7-Bit American Standard Code for 2528 Information Interchange, ANSI X3.4-1986. 2530 [ITU V.152] Procedures for supporting Voice-Band Data over IP Networks, 2531 ITU V.152, January 2005. 2533 [FAX PKG] draft-andreasen-mgcp-fax-04.txt, Media Gateway Control 2534 Protocol Fax Package, F. Andreasen. 2536 [RFC 4103] RTP Payload for Text Conversation, Gunnar Hellstrom and Paul 2537 Jones. 2539 MGCP RTCP-XR Package 4/12/2007 2540 [ITU V.150.1] Modem-over-IP networks: Procedures for the end-to-end 2541 connection of V-series DCEs, ITU V.150.1, January 2003. 2543 [ITU V.151] Procedures for the end-to-end connection of analogue PSTN 2544 text telephones over an IP network utilizing Text Relay, 2545 Telecommunications Industries Association (TIA) Technical Draft TR- 2546 30.1/05-03-006, Tampa, FL, Feb 28 - March4, 2005. 2548 [ITU T.140] Protocol for multimedia application text conversation, 2549 February 1998. Also, addendum 1, February 2000. 2551 [RFC 2793] G. Hellstrom, RTP Payload for Text Conversation. Also, its 2552 upcoming successor documents: G. Hellstrom and P. Jones, draft-ietf- 2553 avt-rfc2793bis-09, and G. Hellstrom and P. Jones, draft-ietf-avt-audio- 2554 t140c-00. 2556 [ITU T.35] Procedure for the allocation of ITU-T defined codes for non- 2557 standard facilities, February 2000. 2559 [ITU T.38] Procedures for real-time Group 3 facsimile communication 2560 over IP networks, September 2005. 2562 [ITU P.VTQ] Add a reference when ITU P.VTQ becomes a standard for MOS- 2563 LQ. 2565 8. Acknowledgments 2567 Contributors to this document include Alan Clark, Joe Stone, Flemming 2568 Andreasen, Robert Biskner, Michael Ramalho, Paul Jones, Steve White, 2569 Kevin Connor, Jim Frauenthal, Tom Hock, Prakash Bhat, David Ensign and 2570 the PacketCable NCS Specification Team. 2572 9. Copyright Statement 2574 Copyright (C) The IETF Trust (2007). 2576 This document is subject to the rights, licenses and restrictions 2577 contained in BCP 78, and except as set forth therein, the authors retain 2578 all their rights. 2580 This document and the information contained herein are provided on an 2581 "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS 2582 OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND 2583 THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS 2584 OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE 2585 INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED 2586 WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.