A P P E N D I X 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.
RFC1 |
Title |
2543 |
SIP: Session Initiation Protocol (March 1999) |
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3261 |
SIP: Session Initiation Protocol (June 2002) |
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3263 |
SIP: Locating SIP Servers (June 2002) |
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1. Not all supported RFCs are listed.
•RFC 2543 and RFC 3261
–SIP Functions, page A-2
–SIP Methods, page A-2
–SIP Responses, page A-2
–SIP Header Fields, page A-6
–SIP Transport Layer Protocols, page A-7
–SIP Security, page A-8
•RFC 3263
–SIP DNS Records Usage, page A-8
Cisco SIP Proxy Server Administrator Guide
A-1
Appendix A SIP Compliance
RFC 2543 and RFC 3261
RFC 2543 and RFC 3261
Table A-1 |
SIP Functions |
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Function |
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Supported? |
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Proxy server |
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Yes (transaction stateful, parallel forking, and |
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recursive) |
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Redirect server |
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Yes |
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Registrar server |
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Yes |
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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 |
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Method |
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Supported? |
Cisco SPS Action |
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ACK |
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Yes |
Forwards ACK requests.1 |
BYE |
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Yes |
Forwards BYE requests. |
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CANCEL |
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Yes |
Forwards CANCEL requests.2 |
INFO |
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Yes |
Forwards INFO requests. |
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INVITE |
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Yes |
Forwards INVITE requests. |
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NOTIFY |
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Yes |
Forwards NOTIFY requests. |
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OPTIONS |
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Yes |
Responds to OPTIONS requests. |
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REFER |
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Yes |
Forwards REFER requests. |
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REGISTER |
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Yes |
Supports both user and device registration. |
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SUBSCRIBE |
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Yes |
Forwards SUBSCRIBE requests. |
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UPDATE |
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Yes |
Forwards UPDATE requests. |
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1.The SPS can generate a local ACK for a non-200 OK final response to an INVITE request.
2.The SPS can generate a local CANCEL for a pending branch when it receives a 200 OK or 6xx response from the branch.
Cisco SPS supports the following SIP responses:
•1xx Response—Information Responses
•2xx Response—Successful Responses
•3xx Response—Redirection Responses
•4xx Response—Request Failure Responses
Cisco SIP Proxy Server Administrator Guide
A-2
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 |
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1xx Response—Information Responses |
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100 |
Trying |
Action is being taken on behalf of the |
Yes |
Generates and forwards this |
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caller, but the called party is not yet |
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response for an incoming |
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located. |
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INVITE. Upon receiving this |
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response, waits for a 180 |
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Ringing, 183 Session progress, |
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or 200 OK response. |
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180 |
Ringing |
Called party is located and is being |
Yes |
Forwards this response. |
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notified of the call. |
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181 |
Call is being forwarded |
Call is being rerouted to another |
Yes |
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destination. |
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182 |
Queued |
Called party is not currently available or |
Yes |
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elects to queue the call rather than reject |
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it. |
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183 |
Session progress |
System performs inband alerting for the |
Yes |
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caller. |
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2xx Response—Successful Responses
200 OK |
Request has been successfully |
Yes |
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processed. The action taken depends on |
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the request made. |
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Generates this response to a REGISTER or CANCEL request. Otherwise forwards this response.
3xx Response—Redirection Responses |
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300 |
Multiple choices |
Address resolves to more than one |
Yes |
Does not generate this response. |
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location. All locations are provided and |
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If recursive is enabled, recurses |
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the user or UA can select which location |
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on all contacts; otherwise |
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to use. |
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forwards this response. |
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301 |
Moved permanently |
User is no longer available at the |
Yes |
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specified location. An alternate location |
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is included in the header. |
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302 |
Moved temporarily |
User is temporarily unavailable at the |
Yes |
In redirect mode, generates this |
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specified location. An alternate location |
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response when it locates one or |
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is included in the header. |
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more contacts. In proxy mode, if |
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recursive is enabled, recurses on |
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all contacts; otherwise forwards |
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this response. |
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305 |
Use proxy |
Caller must use a proxy to contact the |
Yes |
Does not generate this response. |
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called party. |
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If recursive is enabled, recurses |
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on all contacts; otherwise |
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380 |
Alternative service |
Call is unsuccessful, but alternative |
Yes |
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forwards this response. |
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services are available. |
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Cisco SIP Proxy Server Administrator Guide
A-3