APPENDIX A Cisco SIP Proxy Server (CSPS) Compliance Information This appendix describes how the CSPS complies with the IETF definition of SIP (Internet Draft draft-ietf-sip-rfc2543bis-04.txt, based on RFC 2543). It also provides an overview of SIP services. SIP Compliance with RFC 2543 This section contains compliance information on the following: SIP Functions, page A-1 SIP Methods, page A-1 SIP Responses, page A-2 SIP Header Fields, page A-6 Transport Layer Protocols, page A-8 SIP Security, page A-8 SIP Functions Function Proxy Server Redirect Server Registrar Server (Transaction stateful, parallel forking, and recursive) SIP Methods Five of the six methods used by the SIP are supported: Method Comments INVITE The CSPS proxies SIP INVITE requests. ACK The CSPS proxies the SIP ACK method. 1 A-1
SIP Compliance with RFC 2543 Appendix A Method Comments OPTIONS The CSPS proxies the OPTIONS and BYE BYE methods. CANCEL The CSPS proxies the SIP CANCEL method. 2 REGISTER The CSPS supports both user and device registration. 1. The CSPS can generate a local ACK for a non-200 OK final response to an INVITE request. 2. The CSPS can generate a local CANCEL for a pending branch when it receives a 200 OK or 6xx response from the branch. SIP Responses The CSPS supports the following SIP responses: 1xx Response Information Responses, page A-3 2xx Response Successful Responses, page A-3 3xx Response Redirection Responses, page A-4 4xx Response Request Failure Responses, page A-4 5xx Response Server Failure Responses, page A-6 6xx Response Global Responses, page A-6 A-2
Appendix A SIP Compliance with RFC 2543 1xx Response Information Responses 1xx Response Comments 100 Trying The CSPS generates and proxies this response for an incoming INVITE. Upon receiving this response, the server waits for a 180 Ringing, 183 Session progress, or 200 OK response. 180 Ringing None 181 Call is being The CSPS proxies these responses. forwarded 182 Queued 183 Session Progress The CSPS does not generate this message. Upon receiving this message, the proxy server forwards the message upstream. 2xx Response Successful Responses 2xx Response Comments 200 OK The CSPS can generate a 200 OK response to a REGISTER or CANCEL request. The CSPS proxy 200 OK responses to other requests. A-3
SIP Compliance with RFC 2543 Appendix A 3xx Response Redirection Responses 3xx Response Supported Comments 300 Multiple Choices 301 Moved Permanently 302 Moved Temporarily 305 Use Proxy None. 380 Alternate No None. Service When in Redirect mode, the CSPS can only generate the 300 Multiple Choices response. When in Proxy mode, the CSPS can generate or proxy this response. The CSPS can proxy this response. When in Redirect mode, the CSPS can only generate the 302 Moved Temporarily response when a matching registration is located. When in Proxy mode, the CSPS can generate or proxy this response. 4xx Response Request Failure Responses 4xx Response Comments 400 Bad Request The proxy server can generate and proxy a 400 Bad Request response. 401 Unauthorized This response is proxied by the CSPS. If the CSPS is configured as a registrar and authentication is turned on, the proxy server generates this response. 402 Payment Required 403 Forbidden These responses are generated if the CSPS is in registrar mode and is proxied by the proxy server. 404 Not Found These responses are generated and proxied by the CSPS. 405 Method Not Allowed 406 Not Acceptable 407 Proxy Authentication Required 408 Request Timeout 409 Conflict These responses are proxied in this release. This response is proxied by the CSPS. If authentication is turned on, the CSPS generates this response. These responses are generated and proxied by the CSPS. A-4
Appendix A SIP Compliance with RFC 2543 4xx Response Comments 410 Gone This response is only proxied by the CSPS in this release. The 410 Gone response indicates that a resource is no longer available at the server and no forwarding address is known. 411 Length Required 413 Request Entity Too Large 414 Request URL Too Long 415 Unsupported Media This response is proxied in this release. This response indicates that the user refuses to accept the request without a defined content length. This response is only proxied by the CSPS in this release. If a retry after header field is contained in this response, then the user can attempt the call once again in the retry time provided. This response is generated and proxied by the CSPS. This response is proxied in this release. 420 Bad Extension This response is generated and proxied by the CSPS. 480 Temporarily Unavailable 481 Call Leg/Transaction Does Not Exist 482 Loop Detected 483 Too Many Hops 484 Address Incomplete This response is proxied by the CSPS in this release. It is generated if pre-authentication is enabled and fails. These responses are generated and proxied by the CSPS. This response is proxied by the CSPS. 485 Ambiguous This response is only proxied by the 486 Busy Here 487" ; Request No CSPS in this release. Terminated 488" ; Not Acceptable Here This response is proxied by the CSPS. A-5
SIP Compliance with RFC 2543 Appendix A 5xx Response Server Failure Responses 5xx Response Comments 500 Internal Server Error 501 Not Implemented These responses are generated and proxied by the CSPS. 502 Bad Gateway This response is only proxied by the CSPS in 503 Service Unavailable 504 Gateway Timeout 505 Version Not Supported this release. 6xx Response Global Responses 6xx Response Comments 600 Busy Everywhere 603 Decline 604 Does Not Exist Anywhere 606 Not Acceptable These responses are only proxied by the CSPS in this release. SIP Header Fields Note All SIP header fields that concern the CSPS are correctly handled and parsed except for the Hide and Encryption header fields. Header fields that do not directly affect the CSPS or are unknown to the CSPS are passed unaltered in the SIP request. Header Field Accept Accept-Encoding Accept-Language Alert-Info Allow Also Authorization Call-ID Call-Info A-6
Appendix A SIP Compliance with RFC 2543 Header Field Contact Content-Encoding Content-Disposition Content-Length Content-Type Cseq Date Encryption 1 Error-Info Expires From In-Reply-To Max-Forwards Organization MIME-Version Priority Proxy-Authenticate Proxy-Authorization Proxy-Require Record-Route Require Response-Key Retry-After Route Server Subject Supported Timestamp To Unsupported User-Agent Via Warning WWW-Authenticate No 1. When a SIP message is received that contains this header field, the message is processed with the field ignored. A-7
Transport Layer Protocols Appendix A Transport Layer Protocols Protocol Unicast UDP Multicast UDP TCP No SIP Security Authentication Basic Authentication Digest Authentication Proxy Authentication PGP No SIP DNS Records Usage DNS Resource Record Type Type A Type SRV. A-8