Adtran 908e 2nd Gen Dual PRI Failover Issue

908e 2nd Gen Dual PRI Failover Issue

In testing the 908e 2nd Gen I discovered a problem with the ability to route inbound calls to the second PRI when the first one was unplugged. If you did a shutdown ("admin down") on the T1 for that PRI it would send the calls to the second one. If you just unplugged the cable and it became "DOWN", inbound calls would not complete. 

Support articles showed possible problems with the A2.X release of the AOS. I opened a ticket with Adtran support to discuss further. It was confirmed that the A2.x release had a problem with how it handled this. there is a work around for this, but the A2.x version is no longer supported by Adtran. The suggested fix was to leave the config the same as I had it and upgrade AOS to R10.9.5. After the upgrade, and reboot, the testing completed successfully. Now when I unplugged the cable from PRI 1 inbound calls got sent to PRI 2.

The AOS file I used is labeled for the 900e 2nd Gen series, not the 900 series.

AOS version used in upgrade is R10.9.5:

https://www.adtran.com/web/page/portal/Adtran/wp_support_productdownloads_landin

Document for this upgrade:

https://supportforums.adtran.com/docs/DOC-1672

This AOS release allows for a single SIP trunk, Two T1's/PRI's, and single ISDN-group with both PRI's in the group. Example:

interface t1 0/3
  description T1 to PBX
  lbo long -7.5
  tdm-group 1 timeslots 1-24 speed 64
  no shutdown
!
interface t1 0/4
  description T1 to Vanna PBX
  lbo long -7.5
  tdm-group 1 timeslots 1-24 speed 64
  no shutdown

!

interface pri 1
  description PRI to PBX
  role network b-channel-restarts enable
  isdn name-delivery setup
  connect t1 0/3 tdm-group 1
  no shutdown
!

!
interface pri 3
  description PRI to Vanna PBX
  role network b-channel-restarts enable
  isdn name-delivery setup
  connect t1 0/4 tdm-group 1
  no shutdown
!

isdn-group 1
  connect pri 1
  connect pri 3
!
!
voice trunk T01 type sip
  description "SIP-Trunk"
  sip-server primary xxx.cableone.net
  registrar primary xxx.cableone.net
  outbound-proxy primary x.x.x.x
  domain "xxx.cableone.net"
  sip-keep-alive options 3600
  register 6026000000
  register 6026000001
  authentication username "xxx" password "xxx"
!
voice trunk T02 type isdn
  description "PRI-Trunk"
  resource-selection circular descending
  connect isdn-group 1
  rtp delay-mode adaptive
!
!
voice grouped-trunk SIP
  trunk T01
  accept $ cost 0
!
!
voice grouped-trunk ISDN
  trunk T02
  accept $ cost 0