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Checking references for intended status: Informational ---------------------------------------------------------------------------- -- Obsolete informational reference (is this intentional?): RFC 3455 (Obsoleted by RFC 7315) -- Obsolete informational reference (is this intentional?): RFC 3603 (Obsoleted by RFC 5503) -- Obsolete informational reference (is this intentional?): RFC 2234 (Obsoleted by RFC 4234) Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 4 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 DISPATCH D. York 3 Internet-Draft DisTel Research 4 Intended status: Informational T. Asveren 5 Expires: December 12, 2015 Sonus 6 June 10, 2015 8 P-Charge-Info - A Private Header (P-Header) Extension to the Session 9 Initiation Protocol (SIP) 10 draft-york-dispatch-p-charge-info-05 12 Abstract 14 This text documents 'P-Charge-Info', an existing private Session 15 Initiation Protocol (SIP) header (P-header) used to convey billing 16 information about the party to be charged. This P-Header is 17 currently in production usage by a number of equipment vendors and 18 carriers and this document is submitted to request the registration 19 of this header with IANA. This P-Header may also be used in some 20 situations to carry the ISUP Charge Number parameter for PSTN 21 interconnection. 23 NOTE: This document has been in development since 2008 under the name 24 draft-york-sipping-p-charge-info. This -05 document is identical to 25 draft-york-sipping-p-charge-info-15 except for edits to the text to 26 indicate this is now for the DISPATCH working group as the SIPPING 27 working group no longer exists. 29 Status of This Memo 31 This Internet-Draft is submitted in full conformance with the 32 provisions of BCP 78 and BCP 79. 34 Internet-Drafts are working documents of the Internet Engineering 35 Task Force (IETF). Note that other groups may also distribute 36 working documents as Internet-Drafts. The list of current Internet- 37 Drafts is at http://datatracker.ietf.org/drafts/current/. 39 Internet-Drafts are draft documents valid for a maximum of six months 40 and may be updated, replaced, or obsoleted by other documents at any 41 time. It is inappropriate to use Internet-Drafts as reference 42 material or to cite them other than as "work in progress." 44 This Internet-Draft will expire on December 12, 2015. 46 Copyright Notice 48 Copyright (c) 2015 IETF Trust and the persons identified as the 49 document authors. All rights reserved. 51 This document is subject to BCP 78 and the IETF Trust's Legal 52 Provisions Relating to IETF Documents 53 (http://trustee.ietf.org/license-info) in effect on the date of 54 publication of this document. Please review these documents 55 carefully, as they describe your rights and restrictions with respect 56 to this document. Code Components extracted from this document must 57 include Simplified BSD License text as described in Section 4.e of 58 the Trust Legal Provisions and are provided without warranty as 59 described in the Simplified BSD License. 61 Table of Contents 63 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 3 64 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4 65 3. Purpose of this Document . . . . . . . . . . . . . . . . . . 4 66 4. Examples of the Problem . . . . . . . . . . . . . . . . . . . 4 67 4.1. Use Case - Billing Identifier . . . . . . . . . . . . . . 4 68 4.2. Use Case - ISUP Charge Number . . . . . . . . . . . . 4 69 4.3. Use Case - Distributed Enterprise . . . . . . . . . . 5 70 4.4. Use Case - Hosted Telephony Provider . . . . . . . . 5 71 5. Alternatives . . . . . . . . . . . . . . . . . . . . . . . . 6 72 5.1. P-Charging-Vector . . . . . . . . . . . . . . . . . . . . 6 73 5.2. P-DCS-Billing-Info . . . . . . . . . . . . . . . . . . . 6 74 5.3. P-Asserted-Identity . . . . . . . . . . . . . . . . . . . 7 75 6. The P-Charge-Info Header . . . . . . . . . . . . . . . . . . 7 76 6.1. Applicability Statement for the P-Charge-Info header . . 7 77 6.2. Usage of the P-Charge-Info header . . . . . . . . . . . . 7 78 6.2.1. Procedures at the UA . . . . . . . . . . . . . . . . 8 79 6.2.2. Procedures at the Proxy . . . . . . . . . . . . . . . 8 80 6.3. Example of Usage . . . . . . . . . . . . . . . . . . . . 9 81 6.4. Optional Parameters . . . . . . . . . . . . . . . . . . . 9 82 7. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 9 83 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 84 9. Security Considerations . . . . . . . . . . . . . . . . . . . 10 85 9.1. Trust Relationship . . . . . . . . . . . . . . . . . . . 10 86 9.2. Untrusted Peers . . . . . . . . . . . . . . . . . . . . . 11 87 9.2.1. Ingress from Untrusted Peers . . . . . . . . . 11 88 9.2.2. Egress to Untrusted Peers . . . . . . . . . . 11 89 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11 90 11. Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 91 12. Appendix A: NPI Parameter Values . . . . . . . . . . . . . . 15 92 13. Appendix B: NOA Parameter Values . . . . . . . . . . . . . . 15 93 14. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 94 14.1. Normative References . . . . . . . . . . . . . . . . . . 16 95 14.2. Informative References . . . . . . . . . . . . . . . . . 16 96 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 98 1. Overview 100 In certain network configurations, it is desirable to decouple the 101 identity of the caller (what is normally thought of as "Caller ID") 102 from the identity/number used for billing purposes. This document 103 records the current usage of 'P-Charge-Info', a private SIP header, 104 to provide simple billing information and requests the registration 105 of this header with IANA as required by section 4.2 of RFC 5727 106 [RFC5727]. 108 In a typical configuration, the identity of the caller, commonly 109 referred to as "Caller ID" by end users, is derived from one of the 110 following SIP headers: 112 o P-Asserted-Identity 114 o From (in the absence of P-Asserted-Identity) 116 (NOTE: Some service providers today also use the "Remote-Party-ID" 117 header but this was replaced by P-Asserted-Identity in RFC 3325 118 [RFC3325].) 120 This identity/number is typically presented to the receiving user 121 agent (UA) where it is usually displayed for the end user. It is 122 also typically used for billing purposes by the network entities 123 involved in carrying the session. 125 However, in some network configurations the "Caller ID" presented to 126 the receiving UA may be different from the number desired to be used 127 for billing purposes. 129 For example, the "Caller ID" may not reflect the actual reality of 130 the underlying network in terms of costs incurred on the PSTN. This 131 may result in excessive charging of one carrier by another based on 132 the erroneous assumption that the call was originating from a 133 different point on the PSTN. 135 Another example would be where a gateway to the Public Switched 136 Telephone Network (PSTN) receives the ISUP "Charge Number" in the 137 PSTN signaling which designates the number to be billed. The gateway 138 needs to pass this information along to a SIP entity associated with 139 billing. 141 In both these examples, there exists a need for a way to pass an 142 additional billing identifier that can be used between network 143 entities in order to correctly bill for services. 145 Several carriers and at least one equipment provider, Sonus Networks, 146 have been using the "P-Charge-Info" header since at least 2007 as a 147 simple mechanism to exchange this billing identifier. 149 2. Requirements Language 151 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 152 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 153 document are to be interpreted as described in RFC 2119. 155 3. Purpose of this Document 157 This document has been prepared to document the existing deployed 158 usage of the P-Charge-Info header and to comply with section 4 of RFC 159 5727 [RFC5727] to register this header with IANA. This document was 160 originally prepared to comply with sections 4.1 and 4.2 of the now 161 obsolete RFC 3427. It is noted that RFC 5727 specifically deprecates 162 new usage of "P-" headers, but P-Charge-Info has been in deployment 163 for over seven years now and pre-dates RFC 5727. Given this, the 164 authors request that P-Charge-Info be admitted as a "grandfathered 165 case" per section 4 of RFC 5727. 167 4. Examples of the Problem 169 4.1. Use Case - Billing Identifier 171 The simplest use case for P-Charge-Info could be an enterprise 172 environment where each SIP endpoint has a direct number that is 173 passed by the enterprise SIP proxy across to a SIP proxy at a SIP 174 Service Provider who provides PSTN connectivity. Rather than cause 175 the SIP Service Provider to have to track each individual direct 176 number for billing purposes, the enterprise SIP proxy could send in 177 the P-Charge-Info header a single billing identifier that the SIP 178 Service Provider uses for billing purposes. 180 4.2. Use Case - ISUP Charge Number 182 A second use case is one in which a PSTN gateway receives PSTN 183 signaling that includes an ISUP Charge Number parameter and the PSTN 184 gateway needs to send that ISUP Charge Number via SIP to other 185 servers. In this instance, the PSTN gateway will insert the ISUP 186 Charge Number into the P-Charge-Info SIP header. 188 4.3. Use Case - Distributed Enterprise 190 A third and common use case is a large enterprise with a widely 191 distributed SIP network to designate the specific point at which PSTN 192 interconnection occurs. Consider an enterprise with a work force and 193 offices distributed over a wide geographic area and linked by a 194 common internal network over which voice traffic is sent. Users 195 across the network may be able to contact each other directly via SIP 196 sessions, but there may only be a relatively few points in the 197 network where interconnection occurs to the PSTN. Consider this 198 case: 200 o A branch office in Massachusetts has a series of IP phones that 201 are connected via SIP to systems in the main office in Colorado 202 and from there via SIP connections to the PSTN through a SIP 203 service provider. 205 o The phones in the Massachusetts office have each been assigned a 206 direct, local phone number in the US area code of 617. 208 o This local 617 phone number is presented to callers on the PSTN as 209 the "Caller ID" based on its inclusion in the From and/or P- 210 Asserted-Identity SIP headers. 212 o This local 617 phone number may also be used by the SIP service 213 provider as the billing identifier and the call will be charged to 214 the enterprise according to the relevant rates. 216 o However, the call actually connected to the PSTN via the SIP 217 connection in the Colorado office where the USA area code is 303. 219 Rather than use the direct numbers of each SIP endpoint for 220 generating the billing information, the enterprise might choose to 221 instead pass the SIP URI of the PSTN interconnection point in the P- 222 Charge-Info header, either for simplicity or potentially to obtain 223 better rates from the SIP service provider. 225 4.4. Use Case - Hosted Telephony Provider 227 Similar to the third use case of a large enterprise, a hosted 228 telephony provider or hosted voice application provider may have a 229 large SIP network with customers distributed over a very large 230 geographic area using local market PSTN numbers but with only a very 231 few actual PSTN interconnection points. 233 As with the branch office earlier, the customer may have all local 234 phone numbers yet outgoing calls are actually being routed across a 235 SIP network and out specific PSTN gateways or across specific SIP 236 connections to SIP service providers. The hosted provider may want 237 to pass a billing identifier to its SIP service providers again 238 either for the purpose of simplicity in billing or to obtain better 239 rates from the SIP service providers. 241 5. Alternatives 243 5.1. P-Charging-Vector 245 P-Charging-Vector is defined in section 4.6 of RFC 3455 [RFC3455] and 246 used by the 3GPP to carry information related to the charging of a 247 session. There are, however, some differences in the semantics 248 associated with P-Charging-Vector and P-Charge-Info. P-Charging- 249 Vector is mainly used to carry information for correlation of 250 multiple charging records generated for a single session. On the 251 other hand, P-Charge-Info is used to convey information about the 252 party to be billed for a call. Furthermore, P-Charging-Vector has a 253 mandatory icid-value parameter which is a globally unique value to 254 identify the session for which the charging information is generated. 255 Such a globally-unique identifier is not necessary when carrying 256 information about the user to be billed when it is attached to the 257 corresponding session-related signaling. 259 5.2. P-DCS-Billing-Info 261 P-DCS-Billing-Info is defined in section 7 of RFC 3603 [RFC3603] and 262 used for passing billing information between trusted entities in the 263 PacketCable Distributed Call Signaling Architecture. For many 264 billing situations, particularly the very large-scale residential 265 telephone networks for which this header is designed, P-DCS-Billing- 266 Info is an excellent solution. However, this ability to address a 267 range of situations adds complexity. According to RFC 3603, each use 268 of the P-DCS-Billing-Info header MUST include in the header the 269 following: 271 o Billing-Correlation-ID, a globally unique identifier 273 o Financial-Entity-ID 275 o RKS-Group-ID (record keeping server) 277 and may include a variety of additional parameters. 279 While this may work well in many billing scenarios, there are other 280 billing scenarios that do not at all need this level of complexity. 281 In those simpler scenarios all that is needed is simply a number to 282 use for billing. P-Charge-Info provides this simple solution for 283 simple billing scenarios. 285 Additionally, section 7.3 of RFC 3603 mandates that a UA MUST create 286 a Billing-Correlation-ID and insert this into the P-DCS-Billing-Info 287 header (along with the other required information) sent in the 288 initial SIP INVITE. This again makes sense for the residential 289 telephone service environment for which this header is designed. In 290 contrast, P-Charge-Info is designed to be used among proxies and not 291 to be used at all by normal user agents. (P-Charge-Info may, though, 292 by used by user agents associated with PSTN gateways.) 294 5.3. P-Asserted-Identity 296 Early reviewers of this document asked why the "P-Asserted-Identity" 297 header documented in RFC 3325 [RFC3325] could not be used. As 298 mentioned in the use case example above, P-Asserted-Identity is used 299 to indicate the identity of the calling party. However, in this 300 instance, the requirement is to provide an additional identity of the 301 SIP-to-PSTN interconnect point. 303 It would be typical to find both P-Asserted-Identity and P-Charge- 304 Info used in a SIP exchange. P-Asserted-Identity would be used to 305 provide the caller identity which would be displayed to the end user 306 as "Caller ID" while P-Charge-Info would provide the billing 307 identifier used for the billing associated with the call. 309 6. The P-Charge-Info Header 311 6.1. Applicability Statement for the P-Charge-Info header 313 The P-Charge-Info header is applicable within a single private 314 administrative domain or between different administrative domains 315 where there is a trust relationship between the domains. 317 6.2. Usage of the P-Charge-Info header 319 The P-Charge-Info header is used to convey information about the 320 identity of the party to be charged. The P-Charge-Info header is 321 typically inserted by one of the following: 323 o the SIP proxy on the originating network; 325 o a PSTN gateway acting as a SIP UA; or 327 o an application server generating billing information. 329 P-Charge-Info is to be consumed by the SIP entity that provides 330 billing services for a session. This could be an entity generating 331 billing records or an entity interacting with another enitity 332 generating billing records. Upon receipt of an INVITE request with 333 P-Charge-Info header, such an entity SHOULD use the value present in 334 the P-Charge-Info as indicating the party responsible for the charges 335 associated with the session. 337 6.2.1. Procedures at the UA 339 The P-Charge-Info header may be inserted by PSTN gateways or 340 application servers acting as a SIP UA, either through local policy 341 or as a result of information received via PSTN signaling, e.g. the 342 Charge Number parameter in an ISUP IAM message. 344 The P-Charge-Info header is not used/interpreted by a regular UA and 345 should not normally be seen by such a UA. If the header is 346 transmitted to such a UA, the UA SHOULD ignore the header. 347 Similarly, a regular UA originating a SIP message should not insert 348 this header. 350 A PSTN gateway or application server acting as a UA MAY use the 351 content of the P-Charge-Info header present in an INVITE request it 352 received for billing related procedures, e.g. in a billing record or 353 during interaction with another entity generating billing records, as 354 the identity of the party to be charged for the session. A PSTN 355 gateway or application server acting as a UA MAY use the content of 356 the P-Charge-Info header to populate information about the identity 357 of the party to charge in another type of signaling, e.g. ISUP. 359 6.2.2. Procedures at the Proxy 361 A SIP proxy that supports this extension and receives a request, 362 typically a SIP INVITE, without the P-Charge-Info header MAY insert a 363 P-Charge-Info header. The contents of the inserted header may be 364 decided based on local policy or by querying an external entity to 365 determine the identity of the party to be charged. 367 A proxy MAY use the content of the P-Charge-Info header present in an 368 INVITE request it received for billing related procedures, e.g. in a 369 billing record or during interaction with another entity generating 370 billing records. 372 A SIP proxy that does not support this extension will pass any 373 received P-Charge-Info header unmodified in compliance with RFC 3261. 375 A proxy supporting this extension SHOULD remove the P-Charge-Info 376 header before sending a request to a UA that is not acting as a PSTN 377 gateway or appropriate application server. 379 6.3. Example of Usage 381 The content of the P-Charge-Info header is typically simply a SIP URI 382 used as a billing indicator. As such, an example would be as simple 383 as one of: 385 P-Charge-Info: 387 P-Charge-Info: 389 P-Charge-Info: 391 P-Charge-Info: 393 Any other applicable SIP URI could be used. 395 6.4. Optional Parameters 397 P-Charge-Info optionally includes the additional parameters of 399 o Numbering Plan Indicator (NPI) 401 o Nature of Address (NOA) 403 These are used when the ISUP Charge Number value needs to be passed 404 as part of P-Charge-Info. For instance, this might be required in a 405 SIP message for scenarios where SIP is used to connect two PSTN 406 segments and needs to pass charging information between them. 408 An example of the usage of the optional parameters is: 410 P-Charge-Info: 412 Values passed in the "npi" and "noa" parameters are expressed as 413 decimal numbers and possible values are defined in Appendices A and 414 B. 416 7. Formal Syntax 418 The Private Header specified in this document is described in both 419 prose and an augmented Backus-Naur Form (BNF) defined in RFC 2234. 420 Further, several BNF definitions are inherited from SIP and are not 421 repeated here. Implementors need to be familiar with the notation 422 and contents of SIP [RFC3261] and RFC 2234 [RFC2234] to understand 423 this document. 425 The syntax of the P-Charge-Info header is described as follows: 427 P-Charge-Info = "P-Charge-Info" HCOLON (name-addr / addr-spec) 428 ; name-addr and addr-spec are specified in RFC 3261 429 charge-param = npi-param / noa-param / generic-param 430 npi-param = ";npi" EQUAL npi-value 431 ; generic-param is specifed in RFC 3261 432 npi-value = gen-value 433 noa-param = ";noa" EQUAL noa-value 434 noa-value = gen-value 436 The SIP URI contained in the name-addr/addr-spec is the billing 437 indicator that is passed between the parties. 439 charge-param is used as a userinfo parameter in P-Charge-Info. 441 The two optional parameters for PSTN interoperability are mentioned 442 in the previous section and are: 444 o npi = "Numbering Plan Indicator" 446 o noa = "Nature of Address" 448 Typical values for the "npi-value" are listed in Appendix A. 450 Typical values for the "noa-value" are listed in Appendix B. 452 8. IANA Considerations 454 This document defines a private SIP extension header field. 456 The extension is registered as a private extension field: 458 RFC Number: RFCXXXX [Note to IANA: Please fill in with the RFC number 459 of this specification. 461 Header Field Name: P-Charge-Info 463 Compact Form: none 465 9. Security Considerations 467 9.1. Trust Relationship 469 Given that the information contained in the P-Charge-Info header will 470 be used for billing purposes the proxies and other SIP entities that 471 share this information MUST have a trust relationship. 473 If an untrusted entity were inserted between the trusted entities, it 474 could potentially interfere with the billing records for the call. 476 If the SIP connections are not made over a private network, a 477 mechanism for securing the confidentiality and integrity of the SIP 478 connection should be used to protect the information. One such 479 mechanism could be TLS-encryption of the SIP signaling stream. 481 9.2. Untrusted Peers 483 9.2.1. Ingress from Untrusted Peers 485 If the P-Charge-Info header was accepted by a SIP entity from an 486 untrusted peer, there is the potential for fraud if the untrusted 487 entity sent incorrect information, either inadvertently or 488 maliciously. 490 Therefore a SIP entity MUST remove and ignore the P-Charge-Info 491 header when it is received from an untrusted entity. 493 9.2.2. Egress to Untrusted Peers 495 If the P-Charge-Info header was sent by a SIP entity to an untrusted 496 peer, there is the potential exposure of network information that is 497 internal to a trust domain. For instance, the untrusted entity may 498 learn the identities of public SIP proxies used within the trust 499 domain which could then potentially be directly attacked. 501 Therefore a SIP entity MUST remove the P-Charge-Info header when it 502 is sent to an untrusted entity. 504 10. Acknowledgements 506 The authors thank the following people for their comments, criticism, 507 suggestions and assistance with ABNF notation: Keith Drage, Miguel 508 Garcia, Christer Holmberg, Paul Kyzivat, Jonathan Rosenberg, Juha 509 Heinanen, Sumit Garg and Tom Taylor. The authors thank Glen Wang for 510 helping clarify the NPI parameter values with the reference to ANSI 511 T1.113. 513 The authors want to specificially thank John Haluska for a great 514 range of comments and specific information related to interworking 515 with the ISUP Charge Number. 517 11. Changes 519 NOTE TO RFC EDITOR - Please remove this "Changes" section prior to 520 publication. Thank you. 522 Revision -05 is a refresh as -04 expired. Several small tweaks were 523 also made to narrative text. 525 Revision -04 is purely a refresh as -03 expired. 527 Revision -03 is purely a refresh as -02 expired. 529 Revision -02 is purely a refresh as -01 expired. My hope is to move 530 this document forward soon to put closure on it. 532 Revision -01 is purely a refresh as -00 expired. Only a few minor 533 tweaks to this "Changes" section of the document. 535 Revision -00 is the initial release of "draft-york-dispatch-p-charge- 536 info" and is identical to "draft-york-sipping-p-charge-info-15" 537 except for changes to wording to reflect the change to the DISPATCH 538 working group. The "organization" name for Dan York was also changed 539 from blank to "DisTel Research" to remove the confusion that it 540 looked like he was also employed by Sonus Networks. 542 NAME CHANGE - The document is now "draft-york-dispatch-p-charge-info" 543 to reflect the fact that the SIPPING Working Group no longer exists. 545 Revision -15 simply fixes a wording error in the abstract in the 546 previous revision. This will also be the last version of 'draft- 547 york-sipping-p-charge-info'. The next version will be 'draft-york- 548 dispatch-p-charge-info'. 550 Revision -14 incorporates the following changes: 552 o Two examples were updated to include a "+1" at the beginning of 553 the SIP URI. 555 o An example was changed to use "example.net" to be compliant with 556 RFC 2606. 558 o Dan York's organization was updated to "Individual" (from empty) 559 to indicate that his involvement with this draft is purely as an 560 individual with no connection to his employer. 562 o The length of time the header has been used in the Introduction 563 was changed to 7 years, to reflect the first usage around 2005. 565 o A note was added to the abstract indicating that this is expected 566 to be the last version using the name 'draft-york-sipping-p- 567 charge-info'. 569 o Informative references were added to RFC 3261 and RFC 2234 to 570 address missing references in the text. 572 o Numerous other tweaks to the text for readability. 574 Revision -13 has no changes to content and was issued as -12 expired. 575 Discussions are under way coming out of IETF 83 on a plan to move 576 this draft forward. As the SIPPING working group no longer exists, 577 the draft name needs to change and there are a couple of other 578 required changes. 580 Revision -12 included the following modifications based on feedback 581 from John Haluska and Glen Wang: 583 o Modification of Appendix B to reflect ANSI T1.113 values. 585 Revision -11 represents a fairly significant revision responding to a 586 solid review by Paul Kyzivat and providing additional explanation. A 587 major shift was the move to using decimal values for the npi-value 588 parameter versus the text values of previous drafts. Changes 589 include: 591 o ABNF definition updated to indicate that npi is now a number vs 592 text. 594 o The "npi" and "noa" acronyms were expanded and stated near the 595 formal syntax definition. 597 o New section created explicitly mentioning the optional parameters. 599 o Example of optional parameters updated to have npi use a number vs 600 text. 602 o Appendix B added to give examples of NOA parameter. 604 o Overview text updated to indicate that P-Charge-Info was been in 605 use now for over 5 years (given that the draft has been in 606 development for 3 years). 608 o Several small fixes for readability. 610 Revision -10 included the following modifications: 612 o Formal ABNF definition updated. 614 o In formal syntax, semicolons added to npi-param and noa-param 615 definitions. 617 o npi-param changed to a 'gen-value' to use digits vs text. Values 618 npi-param are shown in Appendix A. 620 o Corrected example to show proper use of parameters. 622 o Updated references to RFC 3427 and RFC 3968 to reference RFC 5727. 624 Revision -09 included the following modifications: 626 o Re-submitted with only a date change. Discussions are ongoing to 627 finalize this draft and submit it for expert review. 629 Revision -08 included the following modifications: 631 o The ABNF for the "npi-value" was modified to conform to the 632 sequence of possible values stated in ANSI T1.113. 634 o An Appendix A was created listing the values from ANSI T1.113. 636 Revision -07 was updated to the "trust200902" IPR statement and added 637 references to RFC 3968. At this point all comments have been 638 incorporated and publication will be requested. 640 Revision -06 had only a minor correction to the second usage example. 641 The IPR statement was also updated to comply with RFC 5378. 643 Revision -05 included the following modifications: 645 o The usage of P-Charge-Info for carrying the ISUP Charge Number 646 parameter was formally incorporated into the draft. Previous 647 revisions had mentioned it as a possible use case but had not 648 really explicitly included it. 650 o The examples/use cases section was expanded to include further 651 examples of where P-Charge-Info may be used. 653 o The original use case which discussed inter/intra-state billing 654 practices was changed as the geographical references were clouding 655 the more fundamental issue. 657 o The "UNKNOWN" value was added to the ABNF for the "npi-value" 658 parameter as that was identified as missing but required for ISUP 659 interworking. 661 o The optional "Nature of Address" parameter was added to support 662 interworking with the ISUP Charge Number. 664 Revision -04 corrected a major error in the example where the 665 parameter was placed inside the angle brackets. The P-DCS-Billing- 666 Info header was also added as an alternative and a few minor edits 667 were made. 669 12. Appendix A: NPI Parameter Values 671 To better understand the possible values for the optional NPI 672 parameter, ANSI T1.113 states that the 'numbering plan indicator' may 673 contain the following values: 675 000 unknown (no interpretation) 676 001 ISDN (Telephony) numbering plan (Recommendation E-164) 677 010 spare (no interpretation) 678 011 reserved (CCITT Data numbering plan) 679 100 reserved (CCITT Telex numbering plan) 680 101 Private numbering plan 681 110 spare (no interpretation) 682 111 spare (no interpretation) 684 Note that the values shown here are in binary notation per ANSI 685 T1.113, but when the values are passed in the NPI parameter of P- 686 Charge-Info they are represented in decimal notation. 688 13. Appendix B: NOA Parameter Values 690 To better understand the possible values for the optional NOA 691 parameter, ANSI T1.113 states that the 'nature of address indicator' 692 may contain the following values: 694 0 0 0 0 0 0 0 spare 695 0 0 0 0 0 0 1 ANI of the calling party; subscriber number 696 0 0 0 0 0 1 0 ANI not available or not provided 697 0 0 0 0 0 1 1 ANI of the calling party; national number 698 0 0 0 0 1 0 0 spare 699 0 0 0 0 1 0 1 ANI of the called party; subscriber number 700 0 0 0 0 1 1 0 ANI of the called party; no number present 701 0 0 0 0 1 1 1 ANI of the called party; national number 702 0 0 0 1 0 0 0 703 to 704 1 1 1 0 1 1 1 spare 706 1 1 1 1 0 0 0 707 to 708 1 1 1 1 1 1 0 reserved for network specific use 710 1 1 1 1 1 1 1 spare 712 Note that the values shown in the table here are in binary notation 713 per ANSI T1.113. However, when the values are passed in the NOA 714 parameter of P-Charge-Info they are represented in decimal notation. 716 As examples of values in the "reserved for national use" block, the 717 following values have been defined by ANSI for North American use: 719 113 subscriber number, operator requested 720 114 national number, operator requested 721 115 international number, operator requested 722 116 no number present, operator requested 723 117 950+ call from local exchange carrier public station, 724 hotel/motel, or non-exchange access end office 725 118 test line test code 727 14. References 729 14.1. Normative References 731 [RFC5727] Peterson, J., Jennings, C., and R. Sparks, "Change Process 732 for the Session Initiation Protocol (SIP) and the Real- 733 time Applications and Infrastructure Area", BCP 67, RFC 734 5727, March 2010. 736 14.2. Informative References 738 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, 739 A., Peterson, J., Sparks, R., Handley, M., and E. 740 Schooler, "SIP: Session Initiation Protocol", RFC 3261, 741 June 2002. 743 [RFC3455] Garcia-Martin, M., Henrikson, E., and D. Mills, "Private 744 Header (P-Header) Extensions to the Session Initiation 745 Protocol (SIP) for the 3rd-Generation Partnership Project 746 (3GPP)", RFC 3455, January 2003. 748 [RFC3325] Jennings, C., Peterson, J., and M. Watson, "Private 749 Extensions to the Session Initiation Protocol (SIP) for 750 Asserted Identity within Trusted Networks", RFC 3325, 751 November 2002. 753 [RFC3603] Marshall, W. and F. Andreasen, "Private Session Initiation 754 Protocol (SIP) Proxy-to-Proxy Extensions for Supporting 755 the PacketCable Distributed Call Signaling Architecture", 756 RFC 3603, October 2003. 758 [RFC2234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax 759 Specifications: ABNF", RFC 2234, November 1997. 761 Authors' Addresses 763 Dan York 764 DisTel Research 765 Keene, NH 766 USA 768 Phone: +1-802-735-1624 769 Email: dyork@lodestar2.com 771 Tolga Asveren 772 Sonus Networks 773 3 Paragon Way 774 Freehold, NJ 07728 775 USA 777 Email: tasveren@sonusnet.com