Автор: Radhika Ranjan Roy Название: Handbook on Session Initiation Protocol: Networked Multimedia Communications for IP Telephony Издательство: CRC Press Год: 2016 ISBN: 978-1498747707 Язык: English Формат: pdf Размер: 12,1 mb Страниц: 908
Session Initiation Protocol (SIP), standardized by the Internet Engineering Task Force (IETF), has emulated the simplicity of the protocol architecture of hypertext transfer protocol (HTTP) and is being popularized for VoIP over the Internet because of the ease with which it can be meshed with web services. However, it is difficult to know exactly how many requests for comments (RFCs) have been published over the last two decades in regards to SIP or how those RFCs are interrelated.
Handbook on Session Initiation Protocol: Networked Multimedia Communications for IP Telephony solves that problem. It is the first book to put together all SIP-related RFCs, with their mandatory and optional texts, in a chronological and systematic way so that it can be used as a single super-SIP RFC with an almost one-to-one integrity from beginning to end, allowing you to see the big picture of SIP for the basic SIP functionalities.
The text of each RFC from the IETF has been reviewed by all members of a given working group made up of world-renowned experts, and a rough consensus made on which parts of the drafts need to be mandatory and optional, including whether an RFC needs to be Standards Track, Informational, or Experimental. Texts, ABNF syntaxes, figures, tables, and references are included in their original form. All RFCs, along with their authors, are provided as references. The book is organized into twenty chapters based on the major functionalities, features, and capabilities of SIP.
8.1 Introduction 351 8.2 Domain Name System 352 8.2.1 Namespace 352 8.2.2 Resource Records 353 8.2.3 Name Servers 353 8.2.4 Locating/Discovering SIP Entities 356 8.3 ENUM 361 8.3.1 DDDS Algorithm 366 8.3.2 DDDS Algorithm Application to ENUM 366 8.3.3 ENUM with Compound NAPTRs 370 8.3.4 ENUM Operations 370 8.3.5 ENUM Service Registration for SIP Addresses of Record (AORs 371 8.3.6 ENUM Services Registration in XML Chunk 372 8.3.7 Using E.164 Numbers with SIP 373 8.3.8 ENUM for SIP Services 377 8.3.9 ENUM Implementation Issues 379 8.4 DSN and ENUM Security 380 8.4.1 Cache Poisoning 380 8.4.2 Client Flooding 381 8.4.3 Dynamic Updates Vulnerability 381 8.4.4 Information Leakage 381 8.4.5 Compromising Authoritative Data 381 8.5 Summary 381
9 Routing in SIP 383
9.1 Introduction 383 9.2 SIP Registrar 383 9.3 SIP Proxy 385 9.4 Traversing a Strict-Routing Proxy 386 9.5 Rewriting Record-Route Header Field Values 387 9.5.1 Problems and Recommendation 387 9.6 Record-Routing with Globally Routable UA URI 387 9.7 Double Route-Record 388 9.8 Transport Parameter Usage Problems and Remedies 390 9.8.1 UA Implementation 390 9.8.2 Proxy Implementation 392 9.8.3 Symmetric Response Routing 392 9.9 Caller Preferences-Based Routing 394 9.9.1 Overview 394 9.9.2 Operation 395 9.9.3 UAC Behavior 395 9.9.4 UAS Behavior 396 9.9.5 Proxy Behavior 397 9.9.6 Mapping Feature Parameters to a Predicate 400 9.9.7 Header Field Definitions 401 9.9.8 Augmented BNF 402 9.10 Location-Based Routing 402 9.10.1 Overview 402 9.10.2 Basic SIP Location Conveyance Operations 403 9.10.3 Geolocation Examples 405 9.11 Loop Detection 407 9.11.1 Enhancements in Loop- Detection Algorithm 408 9.11.2 Max-Breadth Header Field 409 9.12 Summary 412
10 User and Netw]ork- Asserted Identity in SIP 415
10.1 Introduction 415 10.2 Multiple User Identities 415 10.3 Public User Identity 416 10.4 Private User Identity 416 10.4.1 P-Asserted-Identity 417 10.4.2 P-Preferred-Identity 417 10.4.3 Identity 417 10.4.4 Recommended Use of Asserted Identity with SIP Messages 418 10.5 Network-Asserted Identity 420 10.5.1 Overview 420 10.5.2 Trust Domain Identities, NAI, and Trust Domain Specification 421 10.5.3 Generation of NAI 422 10.5.4 Transport of NAI 422 10.5.5 Parties with NAIs 422 10.5.6 Types of NAI 422 10.6 Summary 423
11 Early Media in SIP 425
11.1 Introduction 425 11.2 Early Media and Session Establishment in SIP 425 11.3 Early-Media Solution Models 426 11.4 Early-Media Solution Model with Disposition-Type: Early-Session 426 11.4.1 Overview 426 11.4.2 Issues Related to Early-Media Session Establishment 427 11.4.3 Early-Session Disposition Type 427 11.4.4 Preconditions 428 11.4.5 Option Tag 428 11.4.6 Example 428 11.4.7 Early-Media Solution with Application Server and Gateway Model 428 11.5 Early-Media Solution Model with P-Early-Media Header 432 11.5.1 Early-Media Policy 432 11.5.2 Early-Media Application Environments 432 11.5.3 Early-Media Authorization 432 11.5.4 Applicability of Content-Disposition and Application/Gateway Model 433 11.5.5 Operation 434 11.5.6 Limitations of the P-Early-Media Header Field 434 11.5.7 P-Early-Media Header Field 435 11.6 Summary 436
12 Service and Served-User Identity in SIP 437
12.1 Introduction 437 12.2 Communications Service ID 438 12.2.1 Derived Service ID 438 12.2.2 SIP’s Expressiveness for Negotiation 438 12.2.3 Presence 438 12.2.4 Intradomain 438 12.2.5 Device Dispatch 439 12.3 Asserted- and Preferred-Service ID 439 12.3.1 Overview 439 12.3.2 Applicability Statement 440 12.3.3 Header Fields 440 12.3.4 Usage of Header Fields in Requests 442 12.3.5 Usage of Header Fields in Responses 442 12.3.6 Examples of Usage 442 12.4 Served-User ID for Handling Services 444 12.4.1 P-Served-User Header 444 12.4.2 Application Service Invocation 445 12.4.3 P-Served-User Header Field Usage, Definition, and Syntax 447 12.4.4 Proxy Behavior: Generating the P-Served-User Header 447 12.4.5 Proxy Behavior: Consuming the P-Served-User Header 447 12.4.6 Applicability and Limitations 448 12.5 Summary 448
13 Connections Management and Overload Control in SIP 449
13.1 Introduction 449 13.2 Connections Management in SIP Network 449 13.2.1 Overview 449 13.2.2 Flow-Based Connections Setup 450 13.2.3 Keep-Alive Mechanisms 450 13.2.4 Grammar 451 13.2.5 Connections Management Procedures for SIP Entities 451 13.2.6 Keep-Alive Mechanisms in SIP Network 460 13.2.7 Connection Management Example 463 13.2.8 Connection Reuse in SIP 467 13.3 Loss-Based Overload Control in SIP Network 472 13.3.1 Overview 472 13.3.2 Operations 472 13.3.3 Via Header Parameters for Overload Control 473 13.3.4 General Behavior 474 13.3.5 Loss-Based Overload Control Scheme 478 13.3.6 Relationship with Other SIP Load Control Schemes 480 13.3.7 Syntax 480 13.3.8 Design Considerations for Overload Control 480 13.3.9 Salient Features of Overload Control 482 13.4 Rate-Based Overload Control in SIP Network 483 13.4.1 Overview 483 13.4.2 Rate-Based Algorithm Scheme 483 13.4.3 Example 487 13.4.4 Syntax 487 13.5 Summary 487 References 488
15 Resource Priority and Quality of Service in SIP 505
15.1 Introduction 505 15.2 Communications Resource Priority in SIP 506 15.2.1 Overview 506 15.2.2 Resource-Priority SIP Header Field 507 15.2.3 Behavior of SIP Elements That Receive Prioritized Requests 508 15.2.4 UAC Behavior 510 15.2.5 UAS Behavior 511 15.2.6 Proxy Behavior 511 15.2.7 Third-Party Authentication 511 15.2.8 Backwards Compatibility 511 15.2.9 Examples 512 15.2.10 Handling Multiple Concurrent Namespaces 513 15.2.11 Registering Namespaces 514 15.2.12 Namespace Definitions 515 15.3 Preemption Events in SIP 516 15.3.1 Overview 516 15.3.2 Access Preemption Events 517 15.3.3 Network Preemption Events 518 15.3.4 Hybrid Infrastructure Preemption Events 520 15.3.5 Preemption Reason Header Cause Codes and Semantics 520 15.4 QOS in SIP 524 15.4.1 Overview 524 15.4.2 SDP Parameters 525 15.4.3 Usage of Preconditions with Offer–Answer 525 15.4.4 Suspending and Resuming Session Establishment 527 15.4.5 Status Confirmation 528 15.4.6 Refusing an Offer 528 15.4.7 Unknown Precondition Type 529 15.4.8 Multiple Preconditions per Media Stream 529 15.4.9 Option Tag for Preconditions 529 15.4.10 Indicating Capabilities 529 15.4.11 Examples 529 15.4.12 Enhancements in Precondition Procedures and Use in Session Mobility 532 15.4.13 SIP Performance Metrics 535 15.5 SDP Media Streams Mapping to QOS Flows 538 15.5.1 Overview 538 15.5.2 SRF Semantics 538 15.5.3 Applicability Statement 538 15.5.4 Examples 538 15.5.5 IANA Registration: SDP Attribute for Group 538 15.6 QOS Mechanism Selection in SDP 539 15.6.1 Overview 539 15.6.2 SDP Attribute Definitions 539 15.6.3 Offer–Answer Behavior 539 15.6.4 Example 540 15.6.5 IANA Registration: SDP Attribute and Token for QOS 540 15.7 SIP Signaling Compression 540 15.8 Summary 541 References 542
16 Call Services in SIP 543
16.1 Introduction 543 16.2 Call Transfer and Related Call Services 544 16.2.1 Overview 544 16.2.2 Actors and Roles 544 16.2.3 Requirements 544 16.2.4 Using REFER to Achieve Call Transfer 544 16.2.5 Basic Transfer 545 16.2.6 Transfer with Consultation Hold 549 16.2.7 Transfer with Referred-By 562 16.2.8 Transfer as an Ad Hoc Conference 564 16.2.9 Transfer with Multiple Parties 564 16.2.10 Gateway Transfer Issues 565 16.2.11 Call Services with Shared Appearances of a SIP AOR 567 16.2.12 Completion of Call Services in SIP 570 16.3 Call Diversion Indication 575 16.3.1 Overview 575 16.3.2 Diversion and History-Info Header Interworking in SIP 576 16.4 Call Services Using Session Border Controller 582 16.4.1 Overview 582 16.4.2 Distributed SBC Architecture 583 16.4.3 Conclusion 587 16.5 Referring Call to Multiple Resources 588 16.5.1 Overview 588 16.5.2 Operation 588 16.5.3 Multiple-Refer SIP Option Tag 588 16.5.4 Suppressing REFER’s Implicit Subscription 588 16.5.5 URI-List Format 589 16.5.6 Behavior of SIP REFER-Issuers 590 16.5.7 Behavior of REFER-Recipients 590 16.5.8 Example 590 16.6 Call Services with Content Indirection 591 16.6.1 Overview 591 16.6.2 Use-Case Examples 592 16.6.3 Requirements 593 16.6.4 Application of MIME-URI Standard to Content Indirection 593 16.6.5 Examples 596 16.7 Transcoding Call Services 596 16.7.1 Transcoding Services Framework 596 16.7.2 Third-Party Transcoding Services 597 16.7.3 Conference Bridging Transcoding Call Control Flows 604 16.8 INFO Method—Mid-Call Information Transfer 607 16.8.1 Overview 607 16.8.2 Motivation 607 16.8.3 UAs Are Allowed to Enable Both Legacy INFO Usages and Info 608 16.8.4 INFO Method 608 16.8.5 INFO Packages 609 16.8.6 Formal INFO Method Definition and Header Fields 611 16.8.7 INFO Package Considerations 611 16.8.8 Alternative Mechanisms 611 16.8.9 INFO Package Requirements 612 16.8.10 Examples 614 16.9 SIP Call Control UUI Transfer Services 616 16.9.1 Overview 616 16.9.2 Requirements for UUI Transport 616 16.9.3 Possible Approaches for UUI Transport in SIP 617 16.9.4 SIP Extensions for UUI Transport 619 16.9.5 Normative Definition 619 16.9.6 Guidelines for UUI Packages 621 16.9.7 Use Cases 622 16.10 Call Services Using DTMF 623 16.11 Emergency Call Services in SIP 624 16.11.1 Overview 624 16.11.2 Emergency Services Uniform Resource Name 625 16.11.3 Multilevel Precedence and Preemption 625 16.12 Summary 626 References 627
17 Media Server Interfaces in SIP 629
17.1 Introduction 629 17.2 SIP Interface to VoiceXML Media Server 630 17.2.1 Overview 630 17.2.2 Use Cases 630 17.2.3 VoiceXML Session Establishment and Termination 632 17.2.4 Media Support 637 17.2.5 Returning Data to the Application Server 639 17.2.6 Outbound Calling 640 17.2.7 Call Transfer 640 17.3 Summary 642 References 643
18 Multiparty Conferencing in SIP 645
18.1 Introduction 645 18.2 Multiparty Multimedia Conferencing 645 18.3 Third-Party Multiparty Conferencing 646 18.3.1 3PCC Call Establishment 646 18.3.2 Recommendations for 3PCC Call Setups 649 18.3.3 Multiparty Call Establishment Error Handling 649 18.3.4 Continued Call Processing in 3PCC 650 18.3.5 3PCC and Early Media 650 18.3.6 3PCC and SDP Preconditions 651 18.3.7 3PCC Service Examples 652 18.3.8 3PCC Implementation Recommendations 654 18.3.9 Concluding Remarks 654 18.4 Summary 654
19 Security Mechanisms in SIP 657
19.1 Introduction 657 19.2 Multilevel Security Characteristics in SIP 658 19.2.1 Overview 658 19.2.2 Session-Level Security 658 19.2.3 Media-Level Security 672 19.3 Security Mechanisms Negotiation 679 19.3.1 Security Mechanisms Negotiation 680 19.3.2 Backwards Compatibility 683 19.3.3 Security Algorithms Negotiation Example 683 19.3.4 Security Considerations 684 19.3.5 Syntax of IPsec–3GPP Security Headers 685 19.4 Authentication in SIP 686 19.4.1 Background 686 19.4.2 Framework 687 19.4.3 User-to-User Authentication 688 19.4.4 Proxy-to-User Authentication 689 19.4.5 Digest Authentication Scheme 690 19.4.6 Domain Certificates over TLS for Authentication in SIP 690 19.4.7 Authenticated Identity Body Format in SIP 697 19.4.8 Cryptographic Authentication Scheme 701 19.4.9 HTTP Digest Authentication Using AKA in SIP 716 19.4.10 Key-Derivation Authentication Scheme in SIP 721 19.4.11 DNS-Based Authentication for TLS Sessions in SIP 723 19.5 Authorization in SIP 725 19.5.1 Trait-Based Authorization in SIP 725 19.5.2 Authorization through Dialog Identification in SIP 732 19.5.3 Media Authorization in SIP 737 19.5.4 Early-Media Authorization in SIP 742 19.5.5 Framework for Session Setup with Media Authorization 742 19.6 Integrity and Confidentiality in SIP 743 19.6.1 S/MIME Certificates 743 19.6.2 S/MIME Key Exchange 743 19.6.3 Securing MIME Bodies 744 19.6.4 SIP Header Confidentiality and Integrity Using S/MIME: Tunneling SIP 745 19.7 Security for SIP URI-List Services 748 19.7.1 Objective 748 19.7.2 Requirements 748 19.7.3 Framework 748 19.7.4 Security Considerations 749 19.8 Consent-Based Communications for Enhancing Security in SIP 750 19.8.1 Objective 750 19.8.2 Definitions and Terminology 751 19.8.3 Relays and Translations 751 19.8.4 Architecture 752 19.8.5 Framework Operations 754 19.8.6 Security Considerations 761 19.9 SIP Forking Proxy Security 762 19.9.1 Overview 762 19.9.2 Vulnerability: Leveraging Forking to Flood a Network 762 19.9.3 Security Considerations 764 19.10 Nonrepudiation Services in SIP 764 19.11 Call Flows Explaining SIP Security Features 765 19.11.1 Registration 765 19.11.2 Session Setup 765 19.12 Threat Model and Security Usage Recommendations in SIP 767 19.12.1 Attacks and Threat Models 768 19.12.2 Security Mechanisms 769 19.12.3 Implementing Security Mechanisms 771 19.12.4 Limitations 774 19.13 Summary 775 References 777
20 Privacy and Anonymity in SIP 779
20.1 Introduction 779 20.2 Privacy Mechanism in SIP 780 20.2.1 Background 780 20.2.2 Varieties of Privacy 781 20.2.3 UA Behavior 782 20.2.4 UA Behavior Constructing Private Messages 782 20.2.5 UA Behavior Expressing Privacy Preferences 783 20.2.6 UA Behavior Routing Requests to Privacy Services 784 20.2.7 UA Behavior Routing Responses to Privacy Services 784 20.2.8 Privacy Service Behavior 785 20.2.9 Location Information Privacy 787 20.2.10 Security Considerations 787 20.3 Asserted and Preferred Identity for Privacy in SIP 788 20.3.1 Background 788 20.3.2 P-Asserted-Identity and P-Preferred-Identity for Privacy 788 20.3.3 Proxy Behavior 789 20.3.4 Hints for Multiple Identities 789 20.3.5 Requesting Privacy 789 20.3.6 UAS Behavior 790 20.3.7 Examples 790 20.3.8 Example of Spec(T 792 20.3.9 Security Considerations 792 20.4 Connected Identity for Privacy in SIP 793 20.4.1 Overview 793 20.4.2 Terminology 793 20.4.3 Overview of Solution 793 20.4.4 UA Behavior outside the Context of an Existing Dialog 794 20.4.5 Behavior of a UA Whose Identity Changes 794 20.4.6 General UA Behavior 795 20.4.7 Authentication Service Behavior 795 20.4.8 Verifier Behavior 795 20.4.9 Proxy Behavior 795 20.4.10 Examples 796 20.4.11 Security Considerations 800 20.5 Guidelines for Using Privacy Mechanism in SIP 801 20.5.1 Definition 801 20.5.2 Semantics of Existing Priv-Values 801 20.5.3 Target for Each Priv-Value 801 20.5.4 Recommended Treatment of User Privacy-Sensitive Information 803 20.6 Anonymity in SIP 810 20.6.1 Overview 810 20.6.2 UA-Driven Anonymity 810 20.6.3 Rejecting Anonymous Requests 813 20.7 Summary 814
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