	SIP Reference Guide
Table Of Contents
DNS Example
Elements and Architectures
Header Fields
Header Fields – Compact Forms
Header Parameters & Values
INVITE Client Transaction
INVITE Server Transaction
INVITE/200
Mapping Between SS7 USI and the SIP SDP (SS7 Origination)
Mapping Between the SIP SDP and SS7 USI/HLC (SIP Origination)
Mapping ISUP Cause Codes to SIP-I/SIP-T Responses
Mapping SIP-T Responses to ISUP Cause Codes
Mechanics: Location
Mechanics: Registration
Namespaces and Priority Values for the Resource Priority Header Field
NAPTR Records
Non-INVITE Client Transaction
Non-INVITE Server Transaction
Option Tags for SIP Extensions
Response Code
Security Mechanism Names
Session Description Protocol
SIP Events
SIP Methods
SIP Response to a Call Progress (CPG) Message
SIP Timers
SIP/SIPS URI Parameters
SIP-I Responses - ISUP Cause Codes
SIPS's Use of DNS
SRV Records
Types of DNS Resource Records
URI Purposes
Warning Codes
Glossary of SIP Acronyms
SIP References

Mapping SIP-I Responses to ISUP Cause Codes

Other SIP Resources

	SIP Pocket Guide
	SIP Signaling Router Use Cases Multimedia
	SIP Sessions Blog
	SIP Signaling Router Application Handbook
	SIP Signaling Router (SSR) Use Cases Application Guide

ITU-T Q.1912.5

SIP-I Response	ISUP Cause Code	Remarks
400 Bad Request	127 Interworking
401 Unauthorized	127 Interworking	Note 1
402 Payment Required	127 Interworking
403 Forbidden	127 Interworking
404 Not Found	1 Unallocated number
405 Method Not Allowed	127 Interworking
406 Not Acceptable	127 Interworking
407 Proxy Authentication Required	127 Interworking	Note 1
408 Request Timeout	127 Interworking
410 Gone	22 Number changed (without diagnostic)
413 Request Entity Too Long	127 Interworking	Note 1
414 Request-URI Too Long	127 Interworking	Note 1
415 Unsupported Media Type	127 Interworking	Note 1
416 Unsupported URI Scheme	127 Interworking	Note 1
420 Bad Extension	127 Interworking	Note 1
421 Extension Required	127 Interworking	Note 1
423 Interval Too Brief	127 Interworking
480 Temporarily Unavailable	20 Subscriber absent
481 Call/Transaction Does Not Exist	127 Interworking
482 Loop Detected	127 Interworking
483 Too Many Hops	127 Interworking
484 Address Incomplete	28 Invalid number format	Note 1
485 Ambiguous	127 Interworking
486 Busy Here	17 User busy
487 Request Terminated	127 Interworking or no mapping (Note 3)	Note 2
488 Not Acceptable Here	127 Interworking
491 Request Pending	No Mapping	Note 2
493 Undecipherable	127 Interworking
500 Server Internal Error	127 Interworking
501 Not Implemented	127 Interworking
502 Bad Gateway	127 Interworking
503 Service Unavailable	127 Interworking	Note 1
504 Server Timeout	127 Interworking
505 Version Not Supported	127 Interworking	Note 1
513 Message Too Large	127 Interworking
580 Precondition Failure	127 Interworking	Note 1
600 Busy Everywhere	17 User busy
603 Decline	21 Call rejected
604 Does Not Exist Anywhere	1 Unallocated number
606 Not Acceptable	127 Interworking

NOTE 1 – This response may be handled entirely on the SIP side; if so, it is not interworked.

NOTE 2 – This response does not terminate a SIP dialog, but only a specific transaction within it.

NOTE 3 – No mapping if the O-IWU previously issued a CANCEL request for the INVITE.

Mapping SIP-I Responses to ISUP Cause Codes

ITU-T Q.1912.5

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