Cisco 7960G Administrator's Manual page 105
Sip
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Also See for 7960G:
- Administration manual (184 pages) ,
- User manual (122 pages) ,
- Phone manual (74 pages)
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Appendix B
SIP Call Flows
Figure B-4
SIP IP
Phone User A
Step
Action
INVITE—Phone A to Phone B
1.
180 Ringing—Phone B to Phone A
2.
Simple Call Hold
IP
1. INVITE B
2. 180 RINGING
3. 200 OK
4. ACK
2-way RTP channel
5. INVITE (c=IN IP4 0.0.0.0)
6. 200 OK
7. ACK
A is on hold. The RTP channel between A and B is torn down.
8. INVITE (c=IN IP4 IP-User B)
9. 200 OK
10. ACK
A is taken off hold. The RTP channel between A and B is reestablished.
Description
Phone A sends a SIP INVITE request to Phone B. The request is an invitation
to User B to participate in a call session. In the INVITE request:
The phone number of User B is inserted in the Request-URI field in the
•
form of a SIP URL. The SIP URL identifies the address of User B and
takes a form similar to an e-mail address (user@host, where user is the
telephone number and host is either a domain name or a numeric network
address). For example, the Request-URI field in the INVITE request to
User B appears as "INVITE sip:555-0199@companyb.com; user=phone."
The "user=phone" parameter distinquishes that the Request-URI address
is a telephone number rather than a username.
Phone A is identified as the call session initiator in the From field.
•
A unique numeric identifier is assigned to the call and is inserted in the
•
Call-ID field.
•
The transaction number within a single call leg is identified in the CSeq
field.
•
The media capability User A is ready to receive is specified.
Phone B sends a SIP 180 Ringing response to Phone A.
Call Flow Scenarios for Successful Calls
IP Network
Cisco SIP IP Phone Administrator Guide, Release 6.x and 7.x
SIP IP
Phone User B
IP
B-9
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