Rfc3261 and rfc3262 define CSeq and rack respectively, but they often do not understand their meaning during the application process, leading to errors. The call-ID of the request must be set to the call-ID of the dialog.
Requests within a dialog must contain strictly monotonically
Increasing and contiguous CSeq sequence numbers (increasing-by-one)
In each direction (sort ting ack and cancel of course, whose numbers
Equal the requests being acknowledged or canceled). These are rfc3261 requirements for CSeq in a request. For a session, CSeq on the UAC side and the UAS side are incremented by 1, but except for cancel and ACK, The CSeq of both is consistent with that of invite. Example: --> invite CSeq: 1 invite <-- 100 CSeq: 1 invite <-- 183 CSeq: 1 invite --> prack CSeq: 2 prack <-- 200 (prack) CSeq: 2 prack --> cancel CSeq: 1 cancel <-- 200 (cancel) CSeq: 1 cancel <-- 487 CSeq: 1 invite --> ack CSeq: 1 ack UAC side and UAS side CSeq are independent and unrelated, but for response, its CSeq needs to be consistent with its corresponding request. Two examples are listed: --> invite CSeq: 1 invite <-- 100 CSeq: 1 invite <-- 183 CSeq: 1 invite --> prack CSeq: 2 prack <-- 200 (prack) CSeq: 2 prack --> Update CSeq: 3 Update <-- 200 (update) CSeq: 3 Update <-- 200 (invite) CSeq: 1 invite --> ack CSeq: 1 ack --> bye CSeq: 4 bye <-- 200 (bye) CSeq: 4 Bye --> invite CSeq: 1 invite <-- 100 CSeq: 1 invite <-- 183 CSeq: 1 invite --> prack CSeq: 2 prack <-- 200 (prack) CSeq: 2 prack --> Update CSeq: 3 UPD Ate <-- 200 (update) CSeq: 3 Update <-- 200 (invite) CSeq: 1 invite --> ack CSeq: 1 ack <-- invite CSeq: 14 invite --> 200 (invite) CSeq: 14 invite <-- ack CSeq: 14 ack <-- bye CSeq: 15 Bye --> 200 (bye) CSeq: 15 bye prack contains the rack header, which is also confusing. The Rack header is sent in a prack request to support reliability
Provisional responses. It contains two numbers and a method tag.
The first number is the value from the rseq header in the provisional
Response that is being acknowledged. The next number, and
Method, are copied from the CSeq in the response that is being
Acknowledged. The method name in the rack header is case sensitive. Example: Rack: 776656 1 invite
The above is the definition of rack in rfc3262. The Rack format is: Rack: rseq CSeq methodrseq is the rseq in 183, and CSeq is the CSeq in 183, that is, the CSeq of invite. The method is invite. In addition, the rseq value increases by 1 at 183 resend. Example: --> invite CSeq: 1 invite <-- 100 CSeq: 1 invite <-- 183 CSeq: 1 invite rseq: 100 --> prack CSeq: 2 prack Rack: 100 1 invite <-- 200 (prack) CSeq: 2 prack <-- 183 CSeq: 1 invite rseq: 101 --> prack CSeq: 3 prack Rack: 101 1 invite <-- 200 (prack) CSeq: 3 prack --> cancel CSeq: 1 cancel <-- 200 (cancel) CSeq: 1 cancel <-- 487 CSeq: 1 invite --> ack CSeq: 1 ack from: http://fypz.spaces.live.com/blog/cns! 32be3d7e15d984f4! 462. Entry
The content source of this page is from Internet, which doesn't represent Alibaba Cloud's opinion;
products and services mentioned on that page don't have any relationship with Alibaba Cloud. If the
content of the page makes you feel confusing, please write us an email, we will handle the problem
within 5 days after receiving your email.
If you find any instances of plagiarism from the community, please send an email to:
info-contact@alibabacloud.com
and provide relevant evidence. A staff member will contact you within 5 working days.
