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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 SIPPING D. York 3 Internet-Draft Individual 4 Intended status: Informational T. Asveren 5 Expires: March 02, 2013 Sonus 6 August 31, 2012 8 P-Charge-Info - A Private Header (P-Header) Extension to the Session 9 Initiation Protocol (SIP) 10 draft-york-sipping-p-charge-info-15 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 IMPORTANT NOTE: This version of the Internet Draft will be the last 24 with this name, as the SIPPING Working Group no longer exists. The 25 next version of this Internet Draft will be through the DISPATCH 26 Working Group and will be draft-york-dispatch-p-charge-info-00. 28 Status of this Memo 30 This Internet-Draft is submitted in full conformance with the 31 provisions of BCP 78 and BCP 79. 33 Internet-Drafts are working documents of the Internet Engineering 34 Task Force (IETF). Note that other groups may also distribute 35 working documents as Internet-Drafts. The list of current Internet- 36 Drafts is at http://datatracker.ietf.org/drafts/current/. 38 Internet-Drafts are draft documents valid for a maximum of six months 39 and may be updated, replaced, or obsoleted by other documents at any 40 time. It is inappropriate to use Internet-Drafts as reference 41 material or to cite them other than as "work in progress." 43 This Internet-Draft will expire on March 02, 2013. 45 Copyright Notice 47 Copyright (c) 2012 IETF Trust and the persons identified as the 48 document authors. All rights reserved. 50 This document is subject to BCP 78 and the IETF Trust's Legal 51 Provisions Relating to IETF Documents (http://trustee.ietf.org/ 52 license-info) in effect on the date of publication of this document. 53 Please review these documents carefully, as they describe your rights 54 and restrictions with respect to this document. Code Components 55 extracted from this document must include Simplified BSD License text 56 as described in Section 4.e of the Trust Legal Provisions and are 57 provided without warranty as described in the Simplified BSD License. 59 Table of Contents 61 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 62 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 63 3. Purpose of this Document . . . . . . . . . . . . . . . . . . . 4 64 4. Examples of the Problem . . . . . . . . . . . . . . . . . . . 4 65 4.1. Use Case - Billing Identifier . . . . . . . . . . . . . . 4 66 4.2. Use Case - ISUP Charge Number . . . . . . . . . . . . 4 67 4.3. Use Case - Distributed Enterprise . . . . . . . . . . 4 68 4.4. Use Case - Hosted Telephony Provider . . . . . . . . . 5 69 5. Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . 5 70 5.1. P-Charging-Vector . . . . . . . . . . . . . . . . . . . . 5 71 5.2. P-DCS-Billing-Info . . . . . . . . . . . . . . . . . . . . 6 72 5.3. P-Asserted-Identity . . . . . . . . . . . . . . . . . . . 6 73 6. The P-Charge-Info Header . . . . . . . . . . . . . . . . . . . 7 74 6.1. Applicability Statement for the P-Charge-Info header . . . 7 75 6.2. Usage of the P-Charge-Info header . . . . . . . . . . . . 7 76 6.2.1. Procedures at the UA . . . . . . . . . . . . . . . . . 7 77 6.2.2. Procedures at the Proxy . . . . . . . . . . . . . . . 8 78 6.3. Example of Usage . . . . . . . . . . . . . . . . . . . . . 8 79 6.4. Optional Parameters . . . . . . . . . . . . . . . . . . . 8 80 7. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 9 81 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 82 9. Security Considerations . . . . . . . . . . . . . . . . . . . 10 83 9.1. Trust Relationship . . . . . . . . . . . . . . . . . . . . 10 84 9.2. Untrusted Peers . . . . . . . . . . . . . . . . . . . . . 10 85 9.2.1. Ingress from Untrusted Peers . . . . . . . . . 10 86 9.2.2. Egress to Untrusted Peers . . . . . . . . . . . 10 87 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 10 88 11. Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 89 12. Appendix A: NPI Parameter Values . . . . . . . . . . . . . . . 13 90 13. Appendix B: NOA Parameter Values . . . . . . . . . . . . . . . 13 91 14. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14 92 14.1. Normative References . . . . . . . . . . . . . . . . . . 14 93 14.2. Informative References . . . . . . . . . . . . . . . . . 14 94 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15 96 1. Overview 97 In certain network configurations, it is desirable to decouple the 98 identity of the caller (what is normally thought of as "Caller ID") 99 from the identity/number used for billing purposes. This document 100 records the current usage of 'P-Charge-Info', a private SIP header, 101 to provide simple billing information and requests the registration 102 of this header with IANA as required by section 4.2 of RFC 5727 103 [RFC5727]. 105 In a typical configuration, the identity of the caller, commonly 106 referred to as "Caller ID" by end users, is derived from one of the 107 following SIP headers: 109 o P-Asserted-Identity 111 o From (in the absence of P-Asserted-Identity) 113 (NOTE: Some service providers today also use the "Remote-Party-ID" 114 header but this was replaced by P-Asserted-Identity in RFC 3325 115 [RFC3325].) 117 This identity/number is typically presented to the receiving user 118 agent (UA) where it is usually displayed for the end user. It is 119 also typically used for billing purposes by the network entities 120 involved in carrying the session. 122 However, in some network configurations the "Caller ID" presented to 123 the receiving UA may be different from the number desired to be used 124 for billing purposes. 126 For example, the "Caller ID" may not reflect the actual reality of 127 the underlying network in terms of costs incurred on the PSTN. This 128 may result in excessive charging of one carrier by another based on 129 the erroneous assumption that the call was originating from a 130 different point on the PSTN. 132 Another example would be where a gateway to the Public Switched 133 Telephone Network (PSTN) receives the ISUP "Charge Number" in the 134 PSTN signaling which designates the number to be billed. The gateway 135 needs to pass this information along to a SIP entity associated with 136 billing. 138 In both these examples, there exists a need for a way to pass an 139 additional billing identifier that can be used between network 140 entities in order to correctly bill for services. 142 Several carriers and at least one equipment provider, Sonus Networks, 143 have been using the "P-Charge-Info" header for the last 7 years as a 144 simple mechanism to exchange this billing identifier. 146 2. Requirements Language 147 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 148 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 149 document are to be interpreted as described in RFC 2119. 151 3. Purpose of this Document 153 This document has been prepared to document the existing deployed 154 usage of the P-Charge-Info header and to comply with section 4 of RFC 155 5727 [RFC5727] to register this header with IANA. This document was 156 originally prepared to comply with sections 4.1 and 4.2 of the now 157 obsolete RFC 3427. It is noted that RFC 5727 specifically deprecates 158 new usage of "P-" headers, but P-Charge-Info has been in deployment 159 for over seven years now and pre-dates RFC 5727. Given this, the 160 authors request that P-Charge-Info be admitted as a "grandfathered 161 case" per section 4 of RFC 5727. 163 4. Examples of the Problem 165 4.1. Use Case - Billing Identifier 167 The simplest use case for P-Charge-Info could be an enterprise 168 environment where each SIP endpoint has a direct number that is 169 passed by the enterprise SIP proxy across to a SIP proxy at a SIP 170 Service Provider who provides PSTN connectivity. Rather than cause 171 the SIP Service Provider to have to track each individual direct 172 number for billing purposes, the enterprise SIP proxy could send in 173 the P-Charge-Info header a single billing identifier that the SIP 174 Service Provider uses for billing purposes. 176 4.2. Use Case - ISUP Charge Number 178 A second use case is one in which a PSTN gateway receives PSTN 179 signaling that includes an ISUP Charge Number parameter and the PSTN 180 gateway needs to send that ISUP Charge Number via SIP to other 181 servers. In this instance, the PSTN gateway will insert the ISUP 182 Charge Number into the P-Charge-Info SIP header. 184 4.3. Use Case - Distributed Enterprise 186 A third and common use case is a large enterprise with a widely 187 distributed SIP network to designate the specific point at which PSTN 188 interconnection occurs. Consider an enterprise with a work force and 189 offices distributed over a wide geographic area and linked by a 190 common internal network over which voice traffic is sent. Users 191 across the network may be able to contact each other directly via SIP 192 sessions, but there may only be a relatively few points in the 193 network where interconnection occurs to the PSTN. Consider this 194 case: 196 o A branch office in Massachusetts has a series of IP phones that 197 are connected via SIP to systems in the main office in Colorado 198 and from there via SIP connections to the PSTN through a SIP 199 service provider. 201 o The phones in the Massachusetts office have each been assigned a 202 direct, local phone number in the US area code of 617. 204 o This local 617 phone number is presented to callers on the PSTN as 205 the "Caller ID" based on its inclusion in the From and/or P 206 -Asserted-Identity SIP headers. 208 o This local 617 phone number may also be used by the SIP service 209 provider as the billing identifier and the call will be charged to 210 the enterprise according to the relevant rates. 212 o However, the call actually connected to the PSTN via the SIP 213 connection in the Colorado office where the USA area code is 303. 215 Rather than use the direct numbers of each SIP endpoint for 216 generating the billing information, the enterprise might choose to 217 instead pass the SIP URI of the PSTN interconnection point in the P 218 -Charge-Info header, either for simplicity or potentially to obtain 219 better rates from the SIP service provider. 221 4.4. Use Case - Hosted Telephony Provider 223 Similar to the third use case of a large enterprise, a hosted 224 telephony provider or hosted voice application provider may have a 225 large SIP network with customers distributed over a very large 226 geographic area using local market PSTN numbers but with only a very 227 few actual PSTN interconnection points. 229 As with the branch office earlier, the customer may have all local 230 phone numbers yet outgoing calls are actually being routed across a 231 SIP network and out specific PSTN gateways or across specific SIP 232 connections to SIP service providers. The hosted provider may want 233 to pass a billing identifier to its SIP service providers again 234 either for the purpose of simplicity in billing or to obtain better 235 rates from the SIP service providers. 237 5. Alternatives 239 5.1. P-Charging-Vector 240 P-Charging-Vector is defined in section 4.6 of RFC 3455 [RFC3455] and 241 used by the 3GPP to carry information related to the charging of a 242 session. There are, however, some differences in the semantics 243 associated with P-Charging-Vector and P-Charge-Info. P-Charging- 244 Vector is mainly used to carry information for correlation of 245 multiple charging records generated for a single session. On the 246 other hand, P-Charge-Info is used to convey information about the 247 party to be billed for a call. Furthermore, P-Charging-Vector has a 248 mandatory icid-value parameter which is a globally unique value to 249 identify the session for which the charging information is generated. 250 Such a globally-unique identifier is not necessary when carrying 251 information about the user to be billed when it is attached to the 252 corresponding session-related signaling. 254 5.2. P-DCS-Billing-Info 256 P-DCS-Billing-Info is defined in section 7 of RFC 3603 [RFC3603] and 257 used for passing billing information between trusted entities in the 258 PacketCable Distributed Call Signaling Architecture. For many 259 billing situations, particularly the very large-scale residential 260 telephone networks for which this header is designed, P-DCS-Billing- 261 Info is an excellent solution. However, this ability to address a 262 range of situations adds complexity. According to RFC 3603, each use 263 of the P-DCS-Billing-Info header MUST include in the header the 264 following: 266 o Billing-Correlation-ID, a globally unique identifier 268 o Financial-Entity-ID 270 o RKS-Group-ID (record keeping server) 272 and may include a variety of additional parameters. 274 While this may work well in many billing scenarios, there are other 275 billing scenarios that do not at all need this level of complexity. 276 In those simpler scenarios all that is needed is simply a number to 277 use for billing. P-Charge-Info provides this simple solution for 278 simple billing scenarios. 280 Additionally, section 7.3 of RFC 3603 mandates that a UA MUST create 281 a Billing-Correlation-ID and insert this into the P-DCS-Billing-Info 282 header (along with the other required information) sent in the 283 initial SIP INVITE. This again makes sense for the residential 284 telephone service environment for which this header is designed. In 285 contrast, P-Charge-Info is designed to be used among proxies and not 286 to be used at all by normal user agents. (P-Charge-Info may, though, 287 by used by user agents associated with PSTN gateways.) 289 5.3. P-Asserted-Identity 290 Early reviewers of this document asked why the "P-Asserted-Identity" 291 header documented in RFC 3325 [RFC3325] could not be used. As 292 mentioned in the use case example above, P-Asserted-Identity is used 293 to indicate the identity of the calling party. However, in this 294 instance, the requirement is to provide an additional identity of the 295 SIP-to-PSTN interconnect point. 297 It would be typical to find both P-Asserted-Identity and P-Charge- 298 Info used in a SIP exchange. P-Asserted-Identity would be used to 299 provide the caller identity which would be displayed to the end user 300 as "Caller ID" while P-Charge-Info would provide the billing 301 identifier used for the billing associated with the call. 303 6. The P-Charge-Info Header 305 6.1. Applicability Statement for the P-Charge-Info header 307 The P-Charge-Info header is applicable within a single private 308 administrative domain or between different administrative domains 309 where there is a trust relationship between the domains. 311 6.2. Usage of the P-Charge-Info header 313 The P-Charge-Info header is used to convey information about the 314 identity of the party to be charged. The P-Charge-Info header is 315 typically inserted by one of the following: 317 o the SIP proxy on the originating network; 319 o a PSTN gateway acting as a SIP UA; or 321 o an application server generating billing information. 323 P-Charge-Info is to be consumed by the SIP entity that provides 324 billing services for a session. This could be an entity generating 325 billing records or an entity interacting with another enitity 326 generating billing records. Upon receipt of an INVITE request with P 327 -Charge-Info header, such an entity SHOULD use the value present in 328 the P-Charge-Info as indicating the party responsible for the charges 329 associated with the session. 331 6.2.1. Procedures at the UA 333 The P-Charge-Info header may be inserted by PSTN gateways or 334 application servers acting as a SIP UA, either through local policy 335 or as a result of information received via PSTN signaling, e.g. the 336 Charge Number parameter in an ISUP IAM message. 338 The P-Charge-Info header is not used/interpreted by a regular UA and 339 should not normally be seen by such a UA. If the header is 340 transmitted to such a UA, the UA SHOULD ignore the header. 342 Similarly, a regular UA originating a SIP message should not insert 343 this header. 345 A PSTN gateway or application server acting as a UA MAY use the 346 content of the P-Charge-Info header present in an INVITE request it 347 received for billing related procedures, e.g. in a billing record or 348 during interaction with another entity generating billing records, as 349 the identity of the party to be charged for the session. A PSTN 350 gateway or application server acting as a UA MAY use the content of 351 the P-Charge-Info header to populate information about the identity 352 of the party to charge in another type of signaling, e.g. ISUP. 354 6.2.2. Procedures at the Proxy 356 A SIP proxy that supports this extension and receives a request, 357 typically a SIP INVITE, without the P-Charge-Info header MAY insert a 358 P-Charge-Info header. The contents of the inserted header may be 359 decided based on local policy or by querying an external entity to 360 determine the identity of the party to be charged. 362 A proxy MAY use the content of the P-Charge-Info header present in an 363 INVITE request it received for billing related procedures, e.g. in a 364 billing record or during interaction with another entity generating 365 billing records. 367 A SIP proxy that does not support this extension will pass any 368 received P-Charge-Info header unmodified in compliance with RFC 3261. 370 A proxy supporting this extension SHOULD remove the P-Charge-Info 371 header before sending a request to a UA that is not acting as a PSTN 372 gateway or appropriate application server. 374 6.3. Example of Usage 376 The content of the P-Charge-Info header is typically simply a SIP URI 377 used as a billing indicator. As such, an example would be as simple 378 as one of: 380 P-Charge-Info: 382 P-Charge-Info: 384 P-Charge-Info: 386 P-Charge-Info: 388 Any other applicable SIP URI could be used. 390 6.4. Optional Parameters 392 P-Charge-Info optionally includes the additional parameters of 394 o Numbering Plan Indicator (NPI) 395 o Nature of Address (NOA) 397 These are used when the ISUP Charge Number value needs to be passed 398 as part of P-Charge-Info. For instance, this might be required in a 399 SIP message for scenarios where SIP is used to connect two PSTN 400 segments and needs to pass charging information between them. 402 An example of the usage of the optional parameters is: 404 P-Charge-Info: 406 Values passed in the "npi" and "noa" parameters are expressed as 407 decimal numbers and possible values are defined in Appendices A and 408 B. 410 7. Formal Syntax 412 The Private Header specified in this document is described in both 413 prose and an augmented Backus-Naur Form (BNF) defined in RFC 2234. 414 Further, several BNF definitions are inherited from SIP and are not 415 repeated here. Implementors need to be familiar with the notation 416 and contents of SIP [RFC3261] and RFC 2234 [RFC2234] to understand 417 this document. 419 The syntax of the P-Charge-Info header is described as follows: 421 P-Charge-Info = "P-Charge-Info" HCOLON (name-addr / addr-spec) 422 ; name-addr and addr-spec are specified in RFC 3261 423 charge-param = npi-param / noa-param / generic-param 424 npi-param = ";npi" EQUAL npi-value 425 ; generic-param is specifed in RFC 3261 426 npi-value = gen-value 427 noa-param = ";noa" EQUAL noa-value 428 noa-value = gen-value 430 The SIP URI contained in the name-addr/addr-spec is the billing 431 indicator that is passed between the parties. 433 charge-param is used as a userinfo parameter in P-Charge-Info. 435 The two optional parameters for PSTN interoperability are mentioned 436 in the previous section and are: 438 o npi = "Numbering Plan Indicator" 440 o noa = "Nature of Address" 442 Typical values for the "npi-value" are listed in Appendix A. 444 Typical values for the "noa-value" are listed in Appendix B. 446 8. IANA Considerations 447 This document defines a private SIP extension header field. 449 The extension is registered as a private extension field: 451 RFC Number: RFCXXXX [Note to IANA: Please fill in with the RFC 452 number of this specification. 454 Header Field Name: P-Charge-Info 456 Compact Form: none 458 9. Security Considerations 460 9.1. Trust Relationship 462 Given that the information contained in the P-Charge-Info header will 463 be used for billing purposes the proxies and other SIP entities that 464 share this information MUST have a trust relationship. 466 If an untrusted entity were inserted between the trusted entities, it 467 could potentially interfere with the billing records for the call. 468 If the SIP connections are not made over a private network, a 469 mechanism for securing the confidentiality and integrity of the SIP 470 connection should be used to protect the information. One such 471 mechanism could be TLS-encryption of the SIP signaling stream. 473 9.2. Untrusted Peers 475 9.2.1. Ingress from Untrusted Peers 477 If the P-Charge-Info header was accepted by a SIP entity from an 478 untrusted peer, there is the potential for fraud if the untrusted 479 entity sent incorrect information, either inadvertently or 480 maliciously. 482 Therefore a SIP entity MUST remove and ignore the P-Charge-Info 483 header when it is received from an untrusted entity. 485 9.2.2. Egress to Untrusted Peers 487 If the P-Charge-Info header was sent by a SIP entity to an untrusted 488 peer, there is the potential exposure of network information that is 489 internal to a trust domain. For instance, the untrusted entity may 490 learn the identities of public SIP proxies used within the trust 491 domain which could then potentially be directly attacked. 493 Therefore a SIP entity MUST remove the P-Charge-Info header when it 494 is sent to an untrusted entity. 496 10. Acknowledgements 497 The authors thank the following people for their comments, criticism, 498 suggestions and assistance with ABNF notation: Keith Drage, Miguel 499 Garcia, Christer Holmberg, Paul Kyzivat, Jonathan Rosenberg, Juha 500 Heinanen, Sumit Garg and Tom Taylor. The authors thank Glen Wang for 501 helping clarify the NPI parameter values with the reference to ANSI 502 T1.113. 504 The authors want to specificially thank John Haluska for a great 505 range of comments and specific information related to interworking 506 with the ISUP Charge Number. 508 11. Changes 510 NOTE TO RFC EDITOR - Please remove this "Changes" section prior to 511 publication. Thank you. 513 Revision -15 simply fixes a wording error in the abstract in the 514 previous revision. This will also be the last version of 'draft- 515 york-sipping-p-charge-info'. The next version will be 'draft-york- 516 dispatch-p-charge-info'. 518 Revision -14 incorporates the following changes: 520 o Two examples were updated to include a "+1" at the beginning of 521 the SIP URI. 523 o An example was changed to use "example.net" to be compliant with 524 RFC 2606. 526 o Dan York's organization was updated to "Individual" (from empty) 527 to indicate that his involvement with this draft is purely as an 528 individual with no connection to his employer. 530 o The length of time the header has been used in the Introduction 531 was changed to 7 years, to reflect the first usage around 2005. 533 o A note was added to the abstract indicating that this is expected 534 to be the last version using the name 'draft-york-sipping-p 535 -charge-info'. 537 o Informative references were added to RFC 3261 and RFC 2234 to 538 address missing references in the text. 540 o Numerous other tweaks to the text for readability. 542 Revision -13 has no changes to content and was issued as -12 expired. 543 Discussions are under way coming out of IETF 83 on a plan to move 544 this draft forward. As the SIPPING working group no longer exists, 545 the draft name needs to change and there are a couple of other 546 required changes. 548 Revision -12 included the following modifications based on feedback 549 from John Haluska and Glen Wang: 551 o Modification of Appendix B to reflect ANSI T1.113 values. 553 Revision -11 represents a fairly significant revision responding to a 554 solid review by Paul Kyzivat and providing additional explanation. A 555 major shift was the move to using decimal values for the npi-value 556 parameter versus the text values of previous drafts. Changes 557 include: 559 o ABNF definition updated to indicate that npi is now a number vs 560 text. 562 o The "npi" and "noa" acronyms were expanded and stated near the 563 formal syntax definition. 565 o New section created explicitly mentioning the optional parameters. 567 o Example of optional parameters updated to have npi use a number vs 568 text. 570 o Appendix B added to give examples of NOA parameter. 572 o Overview text updated to indicate that P-Charge-Info was been in 573 use now for over 5 years (given that the draft has been in 574 development for 3 years). 576 o Several small fixes for readability. 578 Revision -10 included the following modifications: 580 o Formal ABNF definition updated. 582 o In formal syntax, semicolons added to npi-param and noa-param 583 definitions. 585 o npi-param changed to a 'gen-value' to use digits vs text. Values 586 npi-param are shown in Appendix A. 588 o Corrected example to show proper use of parameters. 590 o Updated references to RFC 3427 and RFC 3968 to reference RFC 5727. 592 Revision -09 included the following modifications: 594 o Re-submitted with only a date change. Discussions are ongoing to 595 finalize this draft and submit it for expert review. 597 Revision -08 included the following modifications: 599 o The ABNF for the "npi-value" was modified to conform to the 600 sequence of possible values stated in ANSI T1.113. 602 o An Appendix A was created listing the values from ANSI T1.113. 604 Revision -07 was updated to the "trust200902" IPR statement and added 605 references to RFC 3968. At this point all comments have been 606 incorporated and publication will be requested. 608 Revision -06 had only a minor correction to the second usage example. 609 The IPR statement was also updated to comply with RFC 5378. 611 Revision -05 included the following modifications: 613 o The usage of P-Charge-Info for carrying the ISUP Charge Number 614 parameter was formally incorporated into the draft. Previous 615 revisions had mentioned it as a possible use case but had not 616 really explicitly included it. 618 o The examples/use cases section was expanded to include further 619 examples of where P-Charge-Info may be used. 621 o The original use case which discussed inter/intra-state billing 622 practices was changed as the geographical references were clouding 623 the more fundamental issue. 625 o The "UNKNOWN" value was added to the ABNF for the "npi-value" 626 parameter as that was identified as missing but required for ISUP 627 interworking. 629 o The optional "Nature of Address" parameter was added to support 630 interworking with the ISUP Charge Number. 632 Revision -04 corrected a major error in the example where the 633 parameter was placed inside the angle brackets. The P-DCS-Billing- 634 Info header was also added as an alternative and a few minor edits 635 were made. 637 12. Appendix A: NPI Parameter Values 639 To better understand the possible values for the optional NPI 640 parameter, ANSI T1.113 states that the 'numbering plan indicator' may 641 contain the following values: 643 000 unknown (no interpretation) 644 001 ISDN (Telephony) numbering plan (Recommendation E-164) 645 010 spare (no interpretation) 646 011 reserved (CCITT Data numbering plan) 647 100 reserved (CCITT Telex numbering plan) 648 101 Private numbering plan 649 110 spare (no interpretation) 650 111 spare (no interpretation) 652 Note that the values shown here are in binary notation per ANSI 653 T1.113, but when the values are passed in the NPI parameter of P 654 -Charge-Info they are represented in decimal notation. 656 13. Appendix B: NOA Parameter Values 657 To better understand the possible values for the optional NOA 658 parameter, ANSI T1.113 states that the 'nature of address indicator' 659 may contain the following values: 661 0 0 0 0 0 0 0 spare 662 0 0 0 0 0 0 1 ANI of the calling party; subscriber number 663 0 0 0 0 0 1 0 ANI not available or not provided 664 0 0 0 0 0 1 1 ANI of the calling party; national number 665 0 0 0 0 1 0 0 spare 666 0 0 0 0 1 0 1 ANI of the called party; subscriber number 667 0 0 0 0 1 1 0 ANI of the called party; no number present 668 0 0 0 0 1 1 1 ANI of the called party; national number 669 0 0 0 1 0 0 0 670 to 671 1 1 1 0 1 1 1 spare 673 1 1 1 1 0 0 0 674 to 675 1 1 1 1 1 1 0 reserved for network specific use 677 1 1 1 1 1 1 1 spare 679 Note that the values shown in the table here are in binary notation 680 per ANSI T1.113. However, when the values are passed in the NOA 681 parameter of P-Charge-Info they are represented in decimal notation. 683 As examples of values in the "reserved for national use" block, the 684 following values have been defined by ANSI for North American use: 686 113 subscriber number, operator requested 687 114 national number, operator requested 688 115 international number, operator requested 689 116 no number present, operator requested 690 117 950+ call from local exchange carrier public station, 691 hotel/motel, or non-exchange access end office 692 118 test line test code 694 14. References 696 14.1. Normative References 698 [RFC5727] Peterson, J., Jennings, C. and R. Sparks, "Change Process 699 for the Session Initiation Protocol (SIP) and the Real- 700 time Applications and Infrastructure Area", BCP 67, RFC 701 5727, March 2010. 703 14.2. Informative References 705 [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, 706 A., Peterson, J., Sparks, R., Handley, M. and E. Schooler, 707 "SIP: Session Initiation Protocol", RFC 3261, June 2002. 709 [RFC3455] Garcia-Martin, M., Henrikson, E. and D. Mills, "Private 710 Header (P-Header) Extensions to the Session Initiation 711 Protocol (SIP) for the 3rd-Generation Partnership Project 712 (3GPP)", RFC 3455, January 2003. 714 [RFC3325] Jennings, C., Peterson, J. and M. Watson, "Private 715 Extensions to the Session Initiation Protocol (SIP) for 716 Asserted Identity within Trusted Networks", RFC 3325, 717 November 2002. 719 [RFC3603] Marshall, W. and F. Andreasen, "Private Session Initiation 720 Protocol (SIP) Proxy-to-Proxy Extensions for Supporting 721 the PacketCable Distributed Call Signaling Architecture", 722 RFC 3603, October 2003. 724 [RFC2234] Crocker, D.Ed., and P. Overell, "Augmented BNF for Syntax 725 Specifications: ABNF", RFC 2234, November 1997. 727 Authors' Addresses 729 Dan York 730 Individual 731 Keene, NH 732 USA 734 Phone: +1-802-735-1624 735 Email: dyork@lodestar2.com 737 Tolga Asveren 738 Sonus Networks 739 3 Paragon Way 740 Freehold, NJ 07728 741 USA 743 Email: tasveren@sonusnet.com