Hi Friends,
Thanks for using this blog.. Posting few more Questions from SIP.
1) Can we Send INVITE without SDP?
2) What is transaction? Will ACK is part of Transaction
3) What is the Diff between Transaction and Re-Invite?
4) What are the parameters will change in Re-Invite?
5) What is Service-info and History Info Header?
6) Expire is Header or Parameter?
7) What is Stateless Proxy? Will Transaction layer there in stateless Proxy?
8) What is Via and Route? Diff?
Thanks
Ramesh Babu
What is transaction? Will ACK is part of Transaction?
ReplyDeleteAns: Transaction in SIP will be there be in between Client and Server. It comprises all the Requests Sent from SIP Client and It receives non 200 OK response from the Server (1XX).
INVITE - 200 OK (1 Transaction)
ACK for 200 OK is also a transaction.
INVITE - (3xx,4xx,5xx,6xx) - ACK is one Transaction..
What is the Diff Between Re-transmission and Re-Invite?
ReplyDeleteAns: Re-transmission will happen when the Server didn't respond with 1XX response, In this Case Client again re-transmit the same message again to the Same server. In Re-transmission, all the earlier Content of the SIP message will be there.
But Re-Invite, Will change the SDP body when server sends re-invite. Common attributes change in Re-INVITE is, Media Attrubute (a=sendonly, a=sendrecv), Mediaport, Connection IP.