User's Manual

Appendix D: PSTN example call flow
During normal operation, calls made by a survivable extension are received by the Avaya Aura
®
Session
Manager and passed to the extension's Communication Manager Feature Server. The Communication
Manager Feature Server then sends the call back to the Avaya Aura
®
Session Manager for routing
elsewhere in the Avaya Aura
®
network.
In this example, a survivable extension at branch 811 dials an external number in local area code 908.
This happens to be local to branch 811, so we want Avaya Aura
®
Session Manager and Communication
Manager Feature Server to route the call to that branch to be dialed as a local PSTN call.
For this example, the call routing is as follows:
1. The survivable extension co-located at branch 811 dials 9-1908-555-1111 (A).
2. This sends a SIP INVITE to the Avaya Aura
®
Session Manager. The B5800 Branch Gateway
system at branch 811 is not involved.
3. The Avaya Aura
®
Session Manager identifies that the call is from an extension that matches
an assigned Communication Manager Feature Server extension and so forwards the SIP
INVITE to the Communication Manager Feature Server.
4. The Communication Manager Feature Server receives the SIP INVITE from Avaya Aura
®
Session Manager on a SIP trunk group number (for this example 42).
5. The Communication Manager Feature Server identifies the IP address of the extensions as an
IP address mapped to IP Network Region 11 and Location 11.
6. The leading 9 in the dialed digit string matches the ARS Access Code. The 9 is removed from
the dialed digit string.
7. The ARS Digit Analysis Table for Location 11 is queried for a match on the remaining digits
19085551111.
8. A match on 1908 is found, specifying Route Pattern 11.
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