User's Manual

Appendix A: Basic call flows 105
Copyright © 2003, Nortel Networks MCP SIP Application Module Basics
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Figure 5 Failed call transfer call flow
Client B
SIP
Module
Application
Client A Client C
Call established between A and B
2. Invite (hold)
3. 200 OK
5. Ack
8. Refer (to C)
10. 202 (accepted)
11. Invite (to C)
15. Ack
19. 200 OK
1. Invite (hold)
4. 200 OK
6. Ack
7. Refer (to C)
9. 202 (accepted)
12. Invite (to C)
13. 486 Busy Here
20. 200 OK
17. Notify (486 Busy Here)
16. Ack
21. Invite (Unhold) or Bye
25. Ack
24. 200 OK
26. Ack
14. 486 Busy Here
18. Notify (486 Busy Here)
23. 200 OK
22. Invite (Unhold)