Outing TDM Circuit during a SIP outage?

[Anonymous]

I have a customer running a 908e Gen 3 Adtran and using it for a SIP to TDM conversion.  The customer has had a couple of network outages which have disrupted their SIP service.  This wouldn't normally be too big of a deal for the customer as they have secondary routes that are automatically used in the event of a TDM outage.  Of course, when an outage occurs on the SIP side, the TDM circuits remain in service which prevents the PBX from recognizing a failure and invoking the backup paths.  So, I'm wondering if there is a method to monitor SIP connectivity and automatically shut down a T1 port in the event of a failure?

[jayh · Accepted solution]

Not directly. However, you can hairpin the backup PRI to the PBX through another T1 port on the TA908 (configure it for role user and be mindful of clocking) and then build a voice grouped-trunk out that trunk with a higher cost than SIP. The PBX will send the calls to the TA908 which will try SIP first, then use the PRI after a brief post-dial delay. You'll likely want 9-1-1 to prefer the PRI as well as possibly other service codes that are handled locally like Dig-Alert, 3-1-1, etc.

[Anonymous · Accepted solution]

What is the TDM connection? PRI, RBS, or FXS?

If PRI, you could busy out the PRI trunk using Network Monitor. Here is config guide: Configuring Network Monitor in AOS

Here is an example of setting up a ping probe on the sip server. If the wan goes down, it will busy out the PRI trunk. You apply the track under the PRI voice trunk as shown in config.

!

probe FAILOVER icmp-echo

  destination <IP of SIP Server or Internet address that replies to pings>

  period 5

  tolerance consecutive fail 5 pass 2

  no shutdown

!

track WANTRACK

  snmp trap state-change

  test if probe FAILOVER

  no shutdown

!

voice trunk T02 type isdn

  description "PRI Trunk"

  busy-out monitor track WANTRACK

!

Let me know if you have questions.

-Mark