idnits 2.17.1 draft-ietf-manet-dlep-credit-flow-control-00.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (May 1, 2018) is 2186 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-16) exists of draft-ietf-manet-dlep-da-credit-extension-04 == Outdated reference: A later version (-08) exists of draft-ietf-manet-dlep-pause-extension-03 Summary: 0 errors (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group B. Cheng 3 Internet-Draft D. Wiggins 4 Intended status: Standards Track Lincoln Laboratory 5 Expires: November 2, 2018 L. Berger 6 LabN Consulting, L.L.C. 7 May 1, 2018 9 DLEP Credit-Based Flow Control Messages and Data Items 10 draft-ietf-manet-dlep-credit-flow-control-00 12 Abstract 14 This document defines new DLEP protocol Data Items that are used to 15 support credit-based flow control. The Data Items enable separate 16 but related functions: traffic classification and credit window 17 control. Traffic classification information is used to identify 18 traffic flows based on frame/packet content such as destination 19 address. Credit window control is used to regulate when data may be 20 sent to an associated virtual or physical queue. The Data Items are 21 defined in an extensible and reusable fashion. Their use will be 22 mandated in other documents defining specific DLEP extensions. This 23 document also introduces DLEP sub-data items. 25 Status of This Memo 27 This Internet-Draft is submitted in full conformance with the 28 provisions of BCP 78 and BCP 79. 30 Internet-Drafts are working documents of the Internet Engineering 31 Task Force (IETF). Note that other groups may also distribute 32 working documents as Internet-Drafts. The list of current Internet- 33 Drafts is at https://datatracker.ietf.org/drafts/current/. 35 Internet-Drafts are draft documents valid for a maximum of six months 36 and may be updated, replaced, or obsoleted by other documents at any 37 time. It is inappropriate to use Internet-Drafts as reference 38 material or to cite them other than as "work in progress." 40 This Internet-Draft will expire on November 2, 2018. 42 Copyright Notice 44 Copyright (c) 2018 IETF Trust and the persons identified as the 45 document authors. All rights reserved. 47 This document is subject to BCP 78 and the IETF Trust's Legal 48 Provisions Relating to IETF Documents 49 (https://trustee.ietf.org/license-info) in effect on the date of 50 publication of this document. Please review these documents 51 carefully, as they describe your rights and restrictions with respect 52 to this document. Code Components extracted from this document must 53 include Simplified BSD License text as described in Section 4.e of 54 the Trust Legal Provisions and are provided without warranty as 55 described in the Simplified BSD License. 57 Table of Contents 59 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 60 1.1. Key Words . . . . . . . . . . . . . . . . . . . . . . . . 4 61 2. Traffic Classification . . . . . . . . . . . . . . . . . . . 4 62 2.1. Traffic Classification Data Item . . . . . . . . . . . . 5 63 2.1.1. Traffic Classification Sub Data Item . . . . . . . . 6 64 2.2. DiffServ Traffic Classification Sub Data Item . . . . . . 7 65 2.2.1. Router Receive Processing . . . . . . . . . . . . . . 8 66 2.3. Ethernet Traffic Classification Sub Data Item . . . . . . 8 67 2.3.1. Router Receive Processing . . . . . . . . . . . . . . 10 68 3. Credit Window Control . . . . . . . . . . . . . . . . . . . . 10 69 3.1. Data Plane Considerations . . . . . . . . . . . . . . . . 12 70 3.2. Credit Window Messages . . . . . . . . . . . . . . . . . 12 71 3.2.1. Credit Control Message . . . . . . . . . . . . . . . 12 72 3.2.2. Credit Control Response Message . . . . . . . . . . . 13 73 3.3. Credit Window Control Data Items . . . . . . . . . . . . 13 74 3.3.1. Credit Window Initialization . . . . . . . . . . . . 14 75 3.3.2. Credit Window Associate . . . . . . . . . . . . . . . 16 76 3.3.3. Credit Window Grant . . . . . . . . . . . . . . . . . 17 77 3.3.4. Credit Window Status . . . . . . . . . . . . . . . . 18 78 3.3.5. Credit Window Request . . . . . . . . . . . . . . . . 20 79 3.4. Management Considerations . . . . . . . . . . . . . . . . 21 80 4. Compatibility . . . . . . . . . . . . . . . . . . . . . . . . 21 81 5. Security Considerations . . . . . . . . . . . . . . . . . . . 21 82 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 83 6.1. Message Values . . . . . . . . . . . . . . . . . . . . . 21 84 6.2. Data Item Values . . . . . . . . . . . . . . . . . . . . 22 85 6.3. DLEP Sub Data Item Registry . . . . . . . . . . . . . . . 22 86 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 23 87 7.1. Normative References . . . . . . . . . . . . . . . . . . 23 88 7.2. Informative References . . . . . . . . . . . . . . . . . 23 89 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . 24 90 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 24 92 1. Introduction 94 The Dynamic Link Exchange Protocol (DLEP) is defined in [RFC8175]. 95 It provides the exchange of link related control information between 96 DLEP peers. DLEP peers are comprised of a modem and a router. DLEP 97 defines a base set of mechanisms as well as support for possible 98 extensions. DLEP defines Data Items which are sets of information 99 that can be reused in DLEP messaging. The base DLEP specification 100 does not include any flow identification beyond DLEP endpoints or 101 flow control capability. There are various flow control techniques 102 theoretically possible with DLEP. For example, a credit-window 103 scheme for destination-specific flow control which provides aggregate 104 flow control for both modem and routers has been proposed in 105 [I-D.ietf-manet-credit-window], and a control plane pause based 106 mechanism is defined in [I-D.ietf-manet-dlep-pause-extension]. 108 This document defines DLEP Data Items and Messages which provide flow 109 identification, and a flow control mechanism for traffic sent from a 110 router to a modem. Flow control is provided using one or more 111 logical "Credit Windows", each of which will typically be supported 112 by an associated virtual or physical queue. Traffic sent by a router 113 will use traffic flow classification information provided by the 114 modem to identify which traffic is associated with each credit 115 window. In this case, a flow is identified based on information 116 found in a data plane header and one or more matches are associated 117 with a single flow. (For general background on traffic 118 classification see [RFC2475] Section 2.3.) Credit windows may be 119 shared or dedicated on a per flow basis. The Data Items are 120 structured to allow for reuse of the defined traffic classification 121 information with non-credit window applications as well as reuse of 122 the credit window based flow control with different traffic 123 classification techniques. 125 This document defines traffic classification based on a DLEP 126 destination and flows identified by either DiffServ [RFC2475] DSCPs 127 (differentiated services codepoints) or IEEE 802.1Q 128 [IEEE.802.1Q_2014] Ethernet Priority Code Points (PCP). The defined 129 mechanism allows for credit windows to be shared across traffic sent 130 to multiple DLEP destinations and flows, or used exclusively for 131 traffic sent to a particular destination and/or flow. The extension 132 also supports the "wildcard" matching of any flow (DSCP or PCP). 133 Traffic classification information is provided such that it can be 134 readily extended to support other traffic classification techniques, 135 or be used by non-credit window related extensions, such as 136 [I-D.ietf-manet-dlep-pause-extension] or even 5-tuple IP flows. 138 Note that this document defines common Messages, Data Items and 139 mechanisms that are reusable. They are expected to be required by 140 DLEP extensions defined in other documents such as found in 141 [I-D.ietf-manet-dlep-da-credit-extension]. 143 This document defines support for traffic classification using a 144 single new Data Item in Section 2.1 for general support and two new 145 sub Data Items are defined to support identification of flows based 146 on DSCPs and PCPs. The document supports credit window control by 147 introducing two new DLEP messages in Section 3.2, and five new DLEP 148 Data Items in Section 3.3. 150 1.1. Key Words 152 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 153 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 154 "OPTIONAL" in this document are to be interpreted as described in BCP 155 14 [RFC2119] [RFC8174] when, and only when, they appear in all 156 capitals, as shown here. 158 2. Traffic Classification 160 The Traffic Classification Data Item is used to represent a list of 161 flows that may be used at the same time for traffic sent from a 162 router to a modem. The data plane information used to identify each 163 flow is represented in a separate sub Data Item. The Data Item and 164 Sub Data Item structure is intended to be independent of any specific 165 usage of the flow identification, e.g., flow control. The Sub Data 166 Item structure is also intended to allow for future traffic 167 classification types, e.g., 5-tuple flows. While the structure of 168 the Data Items is extensible, actual flow information is expected to 169 be used in an extension dependent manner. Support for DSCP and PCP- 170 based flows are defined via individual sub Data Items below. Other 171 types of flow identification, e.g., based on IP protocol and ports, 172 may be defined in the future via new sub Data Items. 174 The list of flows contained in the Data Item can be used per sender 175 or shared across multiple senders. Each list of flows is identified 176 using a "Traffic Classification Identifier" or "TID" and is expected 177 to represent a valid combination of data plane identifiers that may 178 be used at the same time. Each flow is identified via a "Flow 179 Identifier" or "FID". Each FID is defined in a sub Data Item which 180 carries the data plane identifier or identifiers used to associate 181 traffic with the flow. A DLEP destination address is also needed to 182 complete traffic classification information used in extensions such 183 as flow control. This information is expected to be provided in an 184 extension specific manner. For example, this address can be provided 185 by a modem when it identifies the traffic classification set in a 186 Destination Up Message using the Credit Window Associate Data Item 187 defined in Section 3.3.2 . 189 2.1. Traffic Classification Data Item 191 This sections defines the Traffic Classification Data Item. This 192 Data Item is used by a modem to provide a router with traffic 193 classification information. When an extension requires use of this 194 Data Item the Traffic Classification Data Item SHOULD be included by 195 a modem in any Session Initialization Response Message that also 196 indicates support for an extension that requires support for the 197 credit window control mechanisms defined in this document, e.g., see 198 [I-D.ietf-manet-dlep-da-credit-extension]. Updates to previously 199 provided traffic classifications or new traffic classifications MAY 200 be sent by a modem by including the Data Item in Session Update 201 Messages. More than one Data Item MAY be included in a message to 202 provide information on multiple traffic classifiers. 204 The set of traffic classification information provided in the data 205 item is identified using a Traffic Classification Identifier, or TID. 206 The actual data plane related information used in traffic 207 classification is provided in a variable list of Traffic 208 Classification Sub Data Items. 210 The format of the Traffic Classification Data Item is: 212 0 1 2 3 213 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 214 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 215 | Data Item Type | Length | 216 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 217 |Traffic Class. Identifier (TID)| Num SDIs | Reserved | 218 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 219 | Traffic Classification Sub Data Item 1 | 220 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 221 : ... : 222 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 223 | Traffic Classification Sub Data Item n | 224 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 226 Data Item Type: TBA1 228 Length: Variable 230 Per [RFC8175] Length is the number of octets in the Data Item, 231 excluding the Type and Length fields. 233 Traffic Classification Identifier (TID): 235 A 16-bit unsigned integer identifying a traffic classification 236 set. There is no restriction on values used by a modem, and there 237 is no requirement for sequential or ordered values. 239 Num SDIs: 241 An 8-bit unsigned integer indicating the number of Traffic 242 Classification Sub Data Items included in the Data Item. A value 243 of zero (0) is allowed and indicates that no traffic should be 244 matched against this TID. 246 Reserved: 248 MUST be set to zero by the sender (a modem) and ignored by the 249 receiver (a router). 251 Traffic Classification Sub Data Item: 253 Zero or more Traffic Classification Sub Data Items of the format 254 defined below MAY be included. The number MUST match the value 255 carried in the Num SDIs field. 257 A router receiving the Traffic Classification Data Item MUST locate 258 the traffic classification information that is associated with the 259 TID indicated in each received Data Item. If no associated traffic 260 classification information is found, the router MUST initialize a new 261 information set using the values carried in the Data Item. When 262 associated traffic classification information is found, the router 263 MUST update the information using the values carried in the Data 264 Item. In both cases, a router MUST also ensure that any data plane 265 state, e.g., see Section 3.1, that is associated with the TID is 266 updated as needed. 268 2.1.1. Traffic Classification Sub Data Item 270 All Traffic Classification Sub Data Items share a common format that 271 is patterned after the standard DLEP Data Item format, see [RFC8175] 272 Section 11.3. There is no requirement on, or meaning to sub Data 273 Item ordering. Any errors or inconsistencies encountered in parsing 274 sub Data Items are handled in the same fashion as any other Data Item 275 parsing error encountered in DLEP. 277 The format of the Traffic Classification Sub Data Item is: 279 0 1 2 3 280 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 281 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 282 | Sub Data Item Type | Length | 283 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 284 | Value... : 285 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 287 Sub Data Item Type: 289 A 16-bit unsigned integer that indicates the type and 290 corresponding format of the Data Item's Value field. Sub Data 291 Item Types are managed according to the IANA registry described in 292 Section 6.3. 294 Length: Variable 296 Copying [RFC8175], Length is a 16-bit unsigned integer that is the 297 number of octets in the sub Data Item, excluding the Type and 298 Length fields. 300 2.2. DiffServ Traffic Classification Sub Data Item 302 The DiffServ Traffic Classification Sub Data Item is used to identify 303 the set of DSCPs that should be treated as a single flow, i.e., 304 receive the same traffic treatment. DSCPs are identified in a list 305 of DiffServ fields. An implementation that does not support DSCPs 306 and wants the same traffic treatment for all traffic to a destination 307 or destinations would indicate 0 DSCPs. 309 The format of the DiffServ Traffic Classification Sub Data Item is: 311 0 1 2 3 312 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 313 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 314 | Must be two (2) | Length | 315 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 316 | Flow Identifier (FID) | Num DSCPs | DS Field 1 | 317 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 318 | DS Field 2 | ... | DS Field n | 319 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 321 Length: Variable 323 Length is defined above. For this Sub Data Item, it is equal to 324 three (3) plus the value of the Num DSCPs field. 326 Flow Identifier (FID): 328 A 16-bit unsigned integer representing the data plane information 329 carried in the sub Data Item that is to be used in identifying a 330 flow. The value of 0xFFFF is reserved and MUST NOT be used in 331 this field. 333 Num DSCPs: 335 An 8-bit unsigned integer indicating the number of DSCPs carried 336 in the sub Data Item. A zero (0) indicates a (wildcard) match 337 against any DSCP value. 339 DS Field: 341 Each DS Field is an 8-bit whose definition is the same as 342 [RFC2474]. 344 0 1 2 3 4 5 6 7 345 +---+---+---+---+---+---+---+---+ 346 | DSCP | CU | 347 +---+---+---+---+---+---+---+---+ 349 DSCP: differentiated services codepoint 350 CU: currently unused, MUST be zero 352 2.2.1. Router Receive Processing 354 A router receiving the Traffic Classification Sub Data Item MUST 355 validate the information on receipt, prior to using the carried 356 information, including potentially updating the data behavior as 357 determined by the extension requiring the use of the Sub Data Item. 358 Validation failures MUST be treated as an error as described above. 360 Once validated, the receiver MUST ensure that each DS Field value is 361 listed only once across the whole Traffic Classification Data Item. 362 Note, this check is across the Data Item and not the individual sub 363 Data Item. If the same DS Field value is listed more than once 364 within the same Traffic Classification Data Item, the Data Item MUST 365 be treated as an error as described above. 367 2.3. Ethernet Traffic Classification Sub Data Item 369 The Ethernet Traffic Classification Sub Data Item is used to identify 370 the VLAN and PCPs that should be treated as a single flow, i.e., 371 receive the same traffic treatment. Ethernet Priority Code Point 372 support is defined as part of the IEEE 802.1Q [IEEE.802.1Q_2014] tag 373 format and includes a 3 bit "PCP" field. The tag format also 374 includes a 12 bit VLAN identifier (VID) field. PCPs are identified 375 in a list of priority fields. An implementation that does not 376 support PCPs and wants the same traffic treatment for all traffic to 377 a destination or destinations would indicate 0 PCPs. Such an 378 implementation could identify a VLAN to use per destination. 380 The format of the Ethernet Traffic Classification Sub Data Item is: 382 0 1 2 3 383 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 384 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 385 | Must be two (3) | Length (8) | 386 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 387 | Flow Identifier (FID) |NumPCPs| VLAN Identifier (VID) | 388 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 389 | Pri. 1| Pri. 2| Pri. 3| Pri. 4| Pri. 5| Pri. 6| Pri. 7| Pri. 8| 390 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 392 Length: Variable 394 Length is defined above. For this Sub Data Item, it is equal to 395 eight (8). 397 Flow Identifier (FID): 399 A 16-bit unsigned integer representing the data plane information 400 carried in the sub Data Item that is to be used in identifying a 401 flow. The value of 0xFFFF is reserved and MUST NOT be used in 402 this field. 404 Num PCPs: 406 A 16-bit unsigned integer representing the data plane information 407 carried in the sub Data Item that is to be used in identifying a 408 flow. 410 VLAN identifier (VID): 412 A 12-bit unsigned integer field indicating the VLAN to be used in 413 traffic classification. A value of zero (0) indicates that the 414 VID is to be ignored and any VID is to be accepted during traffic 415 classification. 417 Priority: 419 Each Priority Field is an 4-bit whose definition includes the PCP 420 field defined in [IEEE.802.1Q_2014] 421 0 1 2 3 422 +---+---+---+---+ 423 | PCP |DEI| 424 +---+---+---+---+ 426 PCP: Priority code point 427 DEI: currently unused, MUST be zero 429 2.3.1. Router Receive Processing 431 A router receiving the Traffic Classification Sub Data Item MUST 432 validate the information on receipt, prior to the using the carried 433 information, including potentially updating the data behavior as 434 determined by the extension requiring the use of the Sub Data Item. 435 Validation failures MUST be treated as an error as described above. 437 Once validated, the receiver MUST ensure that each Priority Field 438 value is listed only once across the whole Traffic Classification 439 Data Item. Note, this check is across the Data Item and not the 440 individual sub Data Item. If the same Priority Field value is listed 441 more than once within the same Traffic Classification Data Item, the 442 Data Item MUST be treated as an error as described above. 444 3. Credit Window Control 446 This section defines additions to DLEP used in credit based flow 447 control. In addition to the Traffic Classification Data Item, two 448 new messages and five Data Items are defined to support credit window 449 control. The use of credit window control impacts the data plane. 451 The credit window control mechanisms defined in this document support 452 credit based flow control of traffic sent from a router to a modem. 453 The mapping of specific flows of traffic to a particular credit 454 window is based on the Traffic Classification Data Item defined in 455 Section 2.1. Both types of DLEP endpoints, i.e., a router and a 456 modem, negotiate the use of extension during session initialization, 457 e.g., see [I-D.ietf-manet-dlep-da-credit-extension]. When using 458 credit windows, data traffic is only allowed to be sent by the router 459 to the modem when there are credits available. 461 Credits are managed on a per logical "Credit Windows" basis. Each 462 credit window can be thought of as corresponding to a queue within a 463 modem. Credit windows may be shared across, or dedicated to, 464 destinations and data plane identifiers, e.g., DSCPs, at a 465 granularity that is appropriate for a modem's implementation and its 466 attached transmission technology. As defined below, there is a 467 direct one-for-one mapping of credit windows to flows as identified 468 by FIDs carried within the Traffic Classification Data Item. Modems 469 pass to the router information on their credit windows and FIDs prior 470 to a router being able to send data when an extension requiring the 471 use of credit window control is used. In addition to the traffic 472 classification information associated with an FID, routers provide an 473 initial credit window size, as well as the maximum size of the 474 logical queue associated with each credit window. The maximum size 475 is included for informative and potential future uses. 477 Modems provide an initial credit window size at the time of "Credit 478 Window Initialization". Such initialization can take place during 479 session initiation or any point thereafter. It can also take place 480 when rate information changes. Additional "Credit Grants", i.e., 481 increments to Credit Window size, are provided using a Destination Up 482 or the new "Credit Control" Message. A router provides its view of 483 the Credit Window, which is known as "Status", in Destination Up 484 Response and the new "Credit Control Response" Messages. Routers can 485 also request credits using the new "Credit Control" Message. 487 When modems provide credits to a router, they will need to take into 488 account any overhead of their attached transmission technology and 489 map it into the credit semantics defined in this document. In 490 particular, the credit window is defined below to include per frame 491 (packet) MAC headers, and this may not match the actual overhead of 492 the modem attached transmission technology. In that case a direct 493 mapping, or an approximation will need to be made by the modem to 494 provide appropriate credit values. 496 Actual flows of traffic are mapped to credit windows based on flow 497 identification information provided by modems in the Traffic 498 Classification Data item defined in Section 2. This data item 499 supports traffic classification on a per destination or more fine 500 grain level. Routers use the combination of the DLEP identified 501 destination and flow information associated with a credit window in 502 order to match traffic they send to specific credit windows. 504 When a destination becomes reachable, a modem "Associates" 505 (identifies) the appropriate traffic classification information via 506 the TID to be used for traffic sent by the router to that 507 destination. As defined, each credit window has a corresponding FID. 508 This means that the use of FIDs, TIDs and the association of a TID to 509 a DLEP destination enables a modem to share or dedicate resources as 510 needed to match the specifics of its implementation and its attached 511 transmission technology. 513 The defined credit window control has similar objectives as the 514 control found in [I-D.ietf-manet-credit-window]. One notable 515 difference from that credit control is that in this document, credits 516 are never provided by the router to the modem. 518 3.1. Data Plane Considerations 520 When credit windowing is used, a router MUST NOT send data traffic to 521 a modem for forwarding when there are no credits available in the 522 associated Credit Window. This document defines credit windows in 523 octets. A credit window value MUST be larger than the number of 524 octets contained in a packet, including any MAC headers used between 525 the router and the modem, in order for the router to send the packet 526 to a modem for forwarding. The credit window is decremented by the 527 number of sent octets. 529 A router MUST identify the credit window associated with traffic sent 530 to a modem based on the traffic classification information provided 531 in the Data Items defined in this document. Note that routers will 532 typically view a DLEP destination as the next hop MAC address. 534 3.2. Credit Window Messages 536 Two new messages are defined in support for credit window control: 537 the Credit Control and the Credit Control Response Message. Sending 538 and receiving both message types is REQUIRED to support the credit 539 window control defined in this document. 541 3.2.1. Credit Control Message 543 Credit Control Messages are sent by modems and routers. Each sender 544 is only permitted to have one message outstanding at one time. That 545 is, a sender (i.e., modem or router) MUST NOT send a second or any 546 subsequent Credit Control Message until a Credit Control Response 547 Message is received from its peer (i.e., router or modem). 549 Credit Control Messages are sent by modems to provide credit window 550 increases. Modems send credit increases when there is transmission 551 or local queue availability that exceeds the credit window value 552 previous provided to the router. Modems will need to balance the 553 load generated by sending and processing frequent credit window 554 increases against a router having data traffic available to send, but 555 no credits available. 557 Credit Control Messages MAY be sent by routers to request credits and 558 provide window status. Routers will need to balance the load 559 generated by sending and processing frequent credit window requests 560 against a having data traffic available to send, but no credits 561 available. 563 The Message Type value in the DLEP Message Header is set to TBA2. 565 A message sent by a modem, MUST contain one or more Credit Window 566 Grant Data Items as defined below in Section 3.3.3. A router 567 receiving this message MUST respond with a Credit Control Response 568 Message. 570 A message sent by a router, MUST contain one or more Credit Window 571 Request Data Items defined below in Section 3.3.5 and SHOULD contain 572 a Credit Window Status Data Item, defined in Section 3.3.4, 573 corresponding to each credit window request. A modem receiving this 574 message MUST respond with a Credit Control Response Message based on 575 the received message and Data Item and the processing defined below, 576 which will typically result in credit window increments being 577 provided. 579 Specific processing associated with each Credit Data Item is provided 580 below. 582 3.2.2. Credit Control Response Message 584 Credit Control Response Messages are sent by routers to report the 585 current Credit Window for a destination. A message sent by a router, 586 MUST contain one or more Credit Window Status Data Items as defined 587 below in Section 3.3.4. Specific receive processing associated with 588 the Credit Window Status Data Item is provided below. 590 Credit Control Response Messages sent by modems MUST contain one or 591 more Credit Window Grant Data Items. A Data Item for every Credit 592 Window Request Data Item contained in the corresponding Credit 593 Control Response Message received by the modem MUST be included. 594 Each Credit Grant Data Item MAY provide zero or more additional 595 credits based on the modem's transmission or local queue 596 availability. Specific receive processing associated with each Grant 597 Data Item is provided below. 599 The Message Type value in the DLEP Message Header is set to TBA3. 601 3.3. Credit Window Control Data Items 603 Five new Data Items are defined to support credit window control. 604 The Credit Window Initialization Data Item is used by a modem to 605 identify a credit window and set its size. The Credit Window 606 Association Data Item is used by a modem to identify which traffic 607 classification identifiers (flows) should be used when sending 608 traffic to a particular DLEP identified destination. The Credit 609 Window Grant is used by a modem to provide additional credits to a 610 router. The Credit Request is used by a router to request additional 611 credits. The Credit Window Status is used to advertise the sender's 612 view of number of available credits for state synchronization 613 purposes. 615 Any errors or inconsistencies encountered in parsing Data Items are 616 handled in the same fashion as any other data item parsing error 617 encountered in DLEP, see [RFC8175]. In particular, the node parsing 618 the Data Item MUST terminate the session with a Status Data Item 619 indicating Invalid Data. 621 3.3.1. Credit Window Initialization 623 The Credit Window Initialization Data Item is used by a modem to 624 identify a credit window and set its size. This Data Item SHOULD be 625 included in any Session Initialization Response Message that also 626 indicates support for an extension that requires support for the 627 credit window control mechanisms defined in this document, e.g., see 628 [I-D.ietf-manet-dlep-da-credit-extension]. Updates to previously 629 identified credit windows or new credit windows MAY be sent by a 630 modem by including the Data Item in Session Update Messages. More 631 than one data item MAY be included in a message to provide 632 information on multiple credit windows. 634 The Credit Window Initialization Data Item identifies a credit window 635 using a Flow Identifier, or FID. It also provides the size of the 636 identified credit window. Finally, a queue size (in bytes) is 637 provided for informational purposes. Note that to be used, a FID 638 must be defined within a Traffic Classification Data Item and the 639 associated TID must be provided via a Credit Window Association Data 640 Item. 642 The format of the Credit Window Initialization Data Item is: 644 0 1 2 3 645 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 646 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 647 | Data Item Type | Length (16) | 648 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 649 | Flow Identifier (FID) | Reserved | 650 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 651 | Credit Value : 652 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 653 : Credit Value | 654 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 655 | Scale | Credit Window Size | 656 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 658 Data Item Type: TBA4 659 Length: 16 661 Per [RFC8175] Length is the number of octets in the Data Item. It 662 MUST be equal to sixteen (16). 664 Flow Identifier (FID): 666 A flow identifier as defined by the Traffic Classification Data 667 Item. The FID also uniquely identifies a credit window. 669 Reserved: 671 MUST be set to zero by the sender (a modem) and ignored by the 672 receiver (a router). 674 Credit Value: 676 A 64-bit unsigned integer representing the credits, in octets, to 677 be applied to the Credit Window. This value includes MAC headers 678 as seen on the link between the modem and router. 680 Scale: 682 An 8-bit unsigned integer indicating the scale used in the Credit 683 Window Size fields. The valid values are: 685 Value Scale 686 ------------ 687 0 B - Bytes (Octets) 688 1 KB - Kilobytes (B/1024) 689 2 MB - Megabytes (KB/1024) 690 3 GB - Gigabytes (MB/1024) 692 Credit Window Size: 694 A 24-bit unsigned integer representing the maximum size, in the 695 octet scale indicated by the Scale field, of the associated credit 696 window. 698 A router that receives a Credit Window Initialization Data Item MUST 699 ensure that the FID field value has been provided by the modem in a 700 Traffic Classification Data Item carried in either the current or 701 previous message. If the FID cannot be found the router SHOULD 702 report or log this information. Note that no traffic will be 703 associated with the credit window in this case. After FID 704 validation, the router MUST locate the credit window that is 705 associated with the FID indicated in each received Data Item. If no 706 associated credit window is found, the router MUST initialize a new 707 credit window using the values carried in the Data Item. When an 708 associated credit window is found, the router MUST update the credit 709 window and associated data plane state using the values carried in 710 the Data Item. It is worth noting, that such updates can result in a 711 credit window size being reduced, for example, due to a transmission 712 rate change on the modem. 714 3.3.2. Credit Window Associate 716 The Credit Window Associate Data Item is used by a modem to associate 717 traffic classification information with a destination. The traffic 718 classification information is identified using a TID value that has 719 previously been sent by the modem or is listed in a Traffic 720 Classification Data Item carried in the same message as the Data 721 Item. 723 A single Credit Window Associate Data Item MUST be included in all 724 Destination Up and Destination Update Messages sent by a modem when 725 the credit window control defined in this document is used. Note 726 that a TID will not be used unless it is listed in a Credit Window 727 Associate Data Item. 729 The format of the Credit Window Associate Data Item is: 731 0 1 2 3 732 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 733 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 734 | Data Item Type | Length (2) | 735 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 736 |Traffic Class. Identifier (TID)| 737 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 739 Data Item Type: TBA5 741 Length: 2 743 Per [RFC8175] Length is the number of octets in the Data Item. It 744 MUST be equal to two (2). 746 Traffic Classification Identifier (TID): 748 A 16-bit unsigned integer identifying a traffic classification set 749 that has been identified in a Traffic Classification Data Item, 750 see Section 2.1. 752 A router that receives the Credit Window Associate Data Item MUST 753 locate the traffic classification information indicated by the 754 received TID. If no corresponding information can be located, the 755 Data Item MUST be treated as an error as described above. Once the 756 traffic classification information is located, it MUST be associated 757 with the destination and the router MUST ensure that any data plane 758 state, see Section 3.1, that is associated with the TID and its 759 corresponding FIDs is updated as needed. 761 3.3.3. Credit Window Grant 763 The Credit Window Grant Data Item is used by a modem to provide 764 credits to a router. One or more Credit Window Grant Data Items MAY 765 be carried in the DLEP Destination Up, Destination Announce Response, 766 Destination Update, Credit Control Messages, and Credit Control 767 Response Messages. Multiple Credit Window Grant Data Items in a 768 single message are used to indicate different credit values for 769 different credit windows. In all message types, this Data Item 770 provides an additional number of octets to be added to the indicated 771 credit window. Credit windows are identified using FID values that 772 have been previously been sent by the modem or are listed in a Credit 773 Window Initialization Data Item carried in the same messages as the 774 Data Item. 776 The format of the Credit Window Grant Data Item is: 778 0 1 2 3 779 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 780 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 781 | Data Item Type | Length (12) | 782 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 783 | Flow Identifier (FID) | Reserved | 784 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 785 | Additional Credits : 786 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 787 : Additional Credits | 788 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 790 Data Item Type: TBA6 792 Length: 12 794 Per [RFC8175], Length is the number of octets in the Data Item. 795 It MUST be equal to twelve (12). 797 Flow Identifier (FID): 799 A flow identifier as defined by the Traffic Classification Data 800 Item. The FID also uniquely identifies a credit window. 802 Additional Credit: 804 A 64-bit unsigned integer representing the credits, in octets, to 805 be added to the Credit Window. This value includes MAC headers as 806 seen on the link between the modem and router. A value of zero 807 indicates that no additional credits are being provided. 809 When receiving this Data Item, a router MUST identify the credit 810 window indicated by the FID. If the FID is not known to the router, 811 it SHOULD report or log this information and discard the Data Item. 812 It is important to note that while this Data Item can be received in 813 a destination specific message, credit windows are managed 814 independently from the destination identified in the message carrying 815 this Data Item, and the indicated FID MAY even be disjoint from the 816 identified destination. 818 Once the credit window is identified, the credit window size MUST be 819 increased by the value contained in the Additional Credits field. If 820 the increase results in a window overflow, i.e., the size of the 821 credit window after the increase is smaller than the original credit 822 window size, the Credit Window must be set to its maximum 823 (0xFFFFFFFFFFFFFFFF). 825 No response is sent by the router to a modem after processing a 826 Credit Window Grant Data Item received in a Credit Control Response 827 Message. In other cases, the receiving router MUST send a Credit 828 Window Status Data Item or items reflecting the resulting Credit 829 Window value of the updated credit window. When the Credit Grant 830 Data Item is received in a Destination Up Message, the Credit Window 831 Status Data Item(s) MUST be sent in the corresponding Destination Up 832 Response Message. Otherwise, a Credit Control Message MUST be sent. 834 3.3.4. Credit Window Status 836 The Credit Window Status Data Item is used by a router to report the 837 current credit window size to its peer modem. One or more Credit 838 Window Status Data Items MAY be carried in a Destination Up Response 839 Message or a Credit Control Response Message. As discussed above, 840 the Destination Up Response Message is used when the Data Item is 841 sent in response to a Destination Up Message, and the Credit Control 842 Response Message is sent in response to a Credit Control Message. 843 Multiple Credit Window Status Data Items in a single message are used 844 to indicate different sizes of different credit windows. Similar to 845 the Credit Window Grant, credit windows are identified using FID 846 values that have been previously been sent by the modem. 848 The format of the Credit Window Status Data Item is: 850 0 1 2 3 851 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 852 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 853 | Data Item Type | Length (12) | 854 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 855 | Flow Identifier (FID) | Reserved | 856 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 857 | Credit Window Size : 858 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 859 : Credit Window Size | 860 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 862 Data Item Type: TBA7 864 Length: 12 866 Per [RFC8175] Length is the number of octets in the Data Item. It 867 MUST be equal to twelve (12). 869 Flow Identifier (FID): 871 A flow identifier as defined by the Traffic Classification Data 872 Item. The FID also uniquely identifies a credit window. 874 Credit Window Size: 876 A 64-bit unsigned integer, indicating the current number of 877 credits, in octets, available for the router to send to the modem. 878 This is referred to as the Modem Receive Window in 879 [I-D.ietf-manet-credit-window]. 881 When receiving this Data Item, a modem MUST identify the credit 882 window indicated by the FID. If the FID is not known to the modem, 883 it SHOULD report or log this information and discard the Data Item. 884 As with the Credit Window Grant Data Item, the FID MAY be unrelated 885 to the Destination indicated in the message carrying the Data Item. 887 Once the credit window is identified, the modem SHOULD check the 888 received Credit Window Size field value against the outstanding 889 credit window's available credits at the time the most Credit Window 890 Initialization or Grant Data Item associated with the indicated FID 891 was sent. If the values significantly differ, i.e., greater than can 892 be accounted for based on observed data frames, then the modem SHOULD 893 send a Credit Window Initialization Data Item to reset the associated 894 credit window size to the modem's current view of the available 895 credits. As defined above, Credit Window Initialization Data Items 896 are sent in Session Update Messages. When multiple Data Items need 897 to be sent, they SHOULD be combined into a single message when 898 possible. Alternatively, and also in cases where there are small 899 differences, the modem MAY adjust the values sent in Credit Window 900 Grant Data Items to account for the reported Credit Window. 902 3.3.5. Credit Window Request 904 The Credit Window Request Data Item is used by a router to request 905 additional credits for particular credit windows. Credit Window 906 Request Data Items are carried in Credit Control Messages, and one or 907 more Credit Window Request Data Items MAY be present in a message. 909 Credit windows identified using a FID as defined above in 910 Section 3.3.1. Multiple FIDs MAY be present to allow for the case 911 where the router identifies that credits are needed in multiple 912 credit windows. A special FID value, as defined below, is used to 913 indicate that a credit request is being made across all queues. 915 The format of the Credit Window Request Data Item is: 917 0 1 2 3 918 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 919 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 920 | Data Item Type | Length | 921 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 922 | Flow Identifier (FID) | ... : 923 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 924 : ... | Flow Identifier (FID) | 925 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 927 Data Item Type: TBA8 929 Length: Variable 931 Per [RFC8175] Length is the number of octets in the Data Item, 932 excluding the Type and Length fields. It will equal the number of 933 FID fields carried in the Data Item times 2 and MUST be at least 934 2. 936 Flow Identifier (FID): 938 A flow identifier as defined by the Traffic Classification Data 939 Item. The FID also uniquely identifies a credit window. The 940 special value of 0xFFFF indicates that the request applies to all 941 FIDs. 943 A modem receiving this Data Item MUST provide a Credit Increment for 944 the indicated credit windows via Credit Window Grant Data Items 945 carried in a new Credit Control Message. Multiple values and queue 946 indexes SHOULD be combined into a single Credit Control Message when 947 possible. Unknown FID values SHOULD be reported or logged and then 948 ignored by the modem. 950 3.4. Management Considerations 952 This section provides several network management guidelines to 953 implementations supporting the credit window mechanisms defined in 954 this document. 956 Modems MAY support the configuration of the number of credit windows 957 (queues) to advertise to a router. 959 Routers may have limits on the number of queues that they can support 960 and, perhaps, even limits in supported credit window combinations, 961 e.g., if per destination queues can even be supported at all. When 962 modem-provided credit window information exceeds the capabilities of 963 a router, the router MAY use a subset of the provided credit windows. 964 Alternatively, a router MAY reset the session and indicate that the 965 extension is not supported. In either case, the mismatch of 966 capabilities SHOULD be reported to the user via normal network 967 management mechanisms, e.g., user interface or error logging. 969 4. Compatibility 971 The data items defined in this document will only be used when 972 extensions require their use. 974 5. Security Considerations 976 This document introduces credit window control and flow mechanisms to 977 DLEP. These mechanisms do not inherently introduce any additional 978 threats above those documented in [RFC8175]. The approach taken to 979 Security in that document applies equally to the mechanism defined in 980 this document. 982 6. IANA Considerations 984 This document requests the assignment of several values by IANA. All 985 assignments are to registries defined by [RFC8175]. 987 6.1. Message Values 989 This document requests 2 new assignments to the DLEP Message Registry 990 named "Message Values" in the range with the "Specification Required" 991 policy. The requested values are as follows: 993 +-----------+-------------------------+ 994 | Type Code | Description | 995 +-----------+-------------------------+ 996 | TBA2 | Credit Control | 997 | | | 998 | TBA3 | Credit Control Response | 999 +-----------+-------------------------+ 1001 Table 1: Requested Message Values 1003 6.2. Data Item Values 1005 This document requests the following new assignments to the DLEP Data 1006 Item Registry named "Data Item Type Values" in the range with the 1007 "Specification Required" policy. The requested values are as 1008 follows: 1010 +-----------+------------------------------+ 1011 | Type Code | Description | 1012 +-----------+------------------------------+ 1013 | TBA1 | Traffic Classification | 1014 | | | 1015 | TBA4 | Credit Window Initialization | 1016 | | | 1017 | TBA5 | Credit Window Association | 1018 | | | 1019 | TBA6 | Credit Window Grant | 1020 | | | 1021 | TBA7 | Credit Window Status | 1022 | | | 1023 | TBA8 | Credit Window Request | 1024 +-----------+------------------------------+ 1026 Table 2: Requested Data Item Values 1028 6.3. DLEP Sub Data Item Registry 1030 Upon approval of this document, IANA is requested to create a new 1031 DLEP registry, named "Sub Data Item Type Values". The registry shall 1032 identify the type code value, the Data Item which may use the value, 1033 and a description of the value. While the same value may be reused 1034 in different Data Items, this is not recommended at this time. 1036 The following table provides initial registry values and the 1037 [RFC8126] defined policies that should apply to the registry: 1039 +-------------+--------------------------+--------------------------+ 1040 | Type Code | Valid Data Items | Description | 1041 +-------------+--------------------------+--------------------------+ 1042 | 0 | N/A | Reserved | 1043 | | | | 1044 | 1 | N/A | Reserved (for pause sub- | 1045 | | | DI) | 1046 | | | | 1047 | 2 | DiffServ Traffic | DiffServ Traffic | 1048 | | Classification | Classification | 1049 | | | | 1050 | 3 | Ethernet Traffic | Ethernet Traffic | 1051 | | Classification | Classification | 1052 | | | | 1053 | 4-65407 | | Specification Required | 1054 | | | | 1055 | 65408-65534 | | Private Use | 1056 | | | | 1057 | 65535 | | Reserved | 1058 +-------------+--------------------------+--------------------------+ 1060 Table 3: Initial Registry Values 1062 7. References 1064 7.1. Normative References 1066 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1067 Requirement Levels", BCP 14, RFC 2119, 1068 DOI 10.17487/RFC2119, March 1997, 1069 . 1071 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 1072 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 1073 May 2017, . 1075 [RFC8175] Ratliff, S., Jury, S., Satterwhite, D., Taylor, R., and B. 1076 Berry, "Dynamic Link Exchange Protocol (DLEP)", RFC 8175, 1077 DOI 10.17487/RFC8175, June 2017, 1078 . 1080 7.2. Informative References 1082 [I-D.ietf-manet-credit-window] 1083 Ratliff, S., "Credit Windowing extension for DLEP", draft- 1084 ietf-manet-credit-window-07 (work in progress), November 1085 2016. 1087 [I-D.ietf-manet-dlep-da-credit-extension] 1088 Cheng, B., Wiggins, D., and L. Berger, "DLEP DiffServ 1089 Aware Credit Window Extension", draft-ietf-manet-dlep-da- 1090 credit-extension-04 (work in progress), March 2018. 1092 [I-D.ietf-manet-dlep-pause-extension] 1093 Cheng, B., Wiggins, D., and L. Berger, "DLEP Control Plane 1094 Based Pause Extension", draft-ietf-manet-dlep-pause- 1095 extension-03 (work in progress), March 2018. 1097 [IEEE.802.1Q_2014] 1098 IEEE, "IEEE Standard for Local and metropolitan area 1099 networks--Bridges and Bridged Networks", IEEE 802.1Q-2014, 1100 DOI 10.1109/ieeestd.2014.6991462, December 2014, 1101 . 1104 [RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black, 1105 "Definition of the Differentiated Services Field (DS 1106 Field) in the IPv4 and IPv6 Headers", RFC 2474, 1107 DOI 10.17487/RFC2474, December 1998, 1108 . 1110 [RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z., 1111 and W. Weiss, "An Architecture for Differentiated 1112 Services", RFC 2475, DOI 10.17487/RFC2475, December 1998, 1113 . 1115 [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for 1116 Writing an IANA Considerations Section in RFCs", BCP 26, 1117 RFC 8126, DOI 10.17487/RFC8126, June 2017, 1118 . 1120 Appendix A. Acknowledgments 1122 The sub Data Item format was inspired by Rick Taylor's "Data Item 1123 Containers". He also proposed the separation of credit windows from 1124 traffic classification at IETF98. Many useful comments were received 1125 from contributors to the MANET working group. This document was 1126 derived from [I-D.ietf-manet-dlep-da-credit-extension] as a result of 1127 discussions at IETF101. 1129 Authors' Addresses 1130 Bow-Nan Cheng 1131 Lincoln Laboratory 1132 Massachusetts Institute of Technology 1133 244 Wood Street 1134 Lexington, MA 02421-6426 1136 Email: bcheng@ll.mit.edu 1138 David Wiggins 1139 Lincoln Laboratory 1140 Massachusetts Institute of Technology 1141 244 Wood Street 1142 Lexington, MA 02421-6426 1144 Email: David.Wiggins@ll.mit.edu 1146 Lou Berger 1147 LabN Consulting, L.L.C. 1149 Email: lberger@labn.net