Common use of SIP Request Headers Clause in Contracts

SIP Request Headers. All SIP requests shall support the following headers :- REQ-URI, TO, FROM, CALL-ID, CSEQ & CONTENT-LENGTH. In addition, the following table describes the salient headers which are supported in the various requests:- Content Type C O O O O M M Contact M O O N/A N/A O N/A Supported M N/A O O O O N/A Rack N/A N/A M N/A N/A N/A N/A Require M N/A N/A N/A N/A N/A N/A Content Disposition C N/A N/A N/A N/A N/A M Record Route M N/A N/A N/A N/A N/A N/A Route O O N/A O O O O Session Expires O N/A N/A N/A N/A N/A O Min-SE O N/A N/A N/A N/A N/A N/A Allow M (note) N/A N/A N/A N/A N/A N/A Resource Priority O O O O O O O Accept Resource Priority O O O O O O O Note – Used to advertise support of UPDATE. Key :- M – Mandatory, O – Optional, C – Conditional (i.e. if message body not empty, then M), N/A – Not applicable. Embedded ISUP messages may be present in the following Methods :- INVITE IAM Always present. ACK None Never present BYE REL Always present CANCEL REL Always present PRACK None PRACK used to acknowledge early bearer info (e.g. in 18X). INFO RES, SUS UPDATE None UPDATE used for mid call bearer change or session timer update. None ▇▇▇ ▇/A since en-bloc working assumed.

SIP Request Headers. All SIP requests shall support the following headers :- REQ-URI, TO, FROM, CALL-ID, CSEQ & CONTENT-LENGTH. In addition, the following table describes the salient headers which are supported in the various requests:- Content Type C O O O O N/A M M Contact M O O N/A N/A O O N/A Supported M N/A O O O O O N/A Rack N/A N/A M N/A N/A N/A N/A N/A Require M N/A N/A N/A N/A N/A N/A Content Disposition C N/A N/A N/A N/A N/A M Record Route M N/A N/A N/A N/A N/A N/A N/A Route O O N/A O O O O O O Session Expires O N/A N/A N/A N/A N/A N/A O Min-SE O N/A N/A N/A N/A N/A N/A N/A Allow M (note) O N/A N/A N/A N/A N/A N/A Resource Priority P- O N/A N/A N/A O O O N/A Asserted Identity Max- Forwards O O N/A O O O O O O O Accept Refer-To N/A N/A N/A N/A N/A M N/A N/A Referred- By N/A N/A N/A N/A N/A M N/A N/A Subscript ion State N/A N/A N/A N/A N/A N/A M N/A Resource Priority M M M O O O O O O O M Note – Used to advertise support of certain Methods – e.g. UPDATE. Key :- M – Mandatory, O – Optional, C – Conditional (i.e. if message body not empty, then M), N/A – Not applicable. Embedded ISUP messages may be present in the following Methods :- INVITE IAM Always present. ACK None Never present BYE REL Always present CANCEL REL Always present PRACK None PRACK used to acknowledge early bearer info (e.g. in 18X). INFO RES, SUS UPDATE None UPDATE used for mid call bearer change or session timer update. None ▇▇▇ ▇/A since en-bloc working assumed.