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APPENDIX A
SIP Compliance
This appendix describes Cisco SIP proxy server (Cisco SPS) compliance with the Internet Engineering
Task Force (IETF) definition of Session Initiation Protocol (SIP) as described in the following RFCs.
1
RFC Title
2543 SIP: Session Initiation Protocol (March 1999)
3261 SIP: Session Initiation Protocol (June 2002)
3263 SIP: Locating SIP Servers (June 2002)
1. Not all supported RFCs are listed.
Contents
• RFC 2543 and RFC 3261
– SIP Functions, page A-2
– SIP Methods, p
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Appendix A SIP Compliance RFC 2543 and RFC 3261 RFC 2543 and RFC 3261 SIP Functions Table A-1 SIP Functions Function Supported? Proxy server Yes (transaction stateful, parallel forking, and recursive) Redirect server Yes Registrar server Yes SIP Methods Cisco SPS supports five of the six methods used by SIP. It handles unknown methods such as NEWMETHOD in the same manner as known methods such as OPTIONS and REFER. Table A-2 SIP Methods Method Supported? Cisco SPS Action 1 ACK Yes Forwar
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Appendix A SIP Compliance RFC 2543 and RFC 3261 � 5xx Response—Server Failure Responses � 6xx Response—Global Responses Table A-3 SIP Responses SIP Response Meaning Supported? Cisco SPS Action 1xx Response—Information Responses 100 Trying Action is being taken on behalf of the Yes Generates and forwards this caller, but the called party is not yet response for an incoming located. INVITE. Upon receiving this response, waits for a 180 Ringing, 183 Session progress, or 200 OK response.
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Appendix A SIP Compliance RFC 2543 and RFC 3261 Table A-3 SIP Responses (continued) SIP Response Meaning Supported? Cisco SPS Action 4xx Response—Request Failure Responses 400 Bad Request Request can not be understood because Yes Generates and forwards this of an illegal format. response. 401 Unauthorized Request requires user authentication. Yes Forwards this response. If it is configured as a registrar and authentication is enabled, generates this response. 402 Payment required Paym
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Appendix A SIP Compliance RFC 2543 and RFC 3261 Table A-3 SIP Responses (continued) SIP Response Meaning Supported? Cisco SPS Action 415 Unsupported media Server refuses to process the request Yes Forwards this response. because the format of the body is not supported by the destination endpoint. 420 Bad extension Server cannot understand the protocol Yes Generates and forwards this extension indicated in the Require response. header. 480 Temporarily Called party was contacted but is Ye
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Appendix A SIP Compliance RFC 2543 and RFC 3261 Table A-3 SIP Responses (continued) SIP Response Meaning Supported? Cisco SPS Action 5xx Response—Server Failure Responses 500 Server internal error Server or gateway encountered an Yes Generates and forwards this unexpected error that prevents it from response. processing the request. 501 Not implemented Server or gateway does not support the functions required to complete the request. 502 Bad gateway Server or gateway received an invali
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Appendix A SIP Compliance RFC 2543 and RFC 3261 Table A-4 SIP Header Fields Header Field Supported? Header Field Supported? Accept Yes Organization Yes Accept-Encoding Yes MIME-Version Yes Accept-Language Yes Priority Yes Alert-Info Yes Proxy-Authenticate Yes Allow Yes Proxy Authorization Yes Also Yes Proxy-Require Yes Authorization Yes Record-Route Yes Call-ID Yes Require Yes Call-Info Yes Response-Key Yes Contact Yes Retry-After Yes Content-Disposition Yes Route Yes Content-Encoding Yes
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Appendix A SIP Compliance RFC 3263 SIP Security Table A-6 SIP Security Mode Supported? Encryption Mode End-to-end No Hop-by-Hop Yes Authentication Mode 1 Basic Yes Digest Yes Proxy Yes 1. Due to its weak security, basic authentication has been deprecated. This is a change from RFC 2543. It is not disabled or removed from Cisco SPS, but will no longer be supported or extended to interwork with new or modified functionality. We strongly discourage the use of basic authentication. RFC 326
