[cisco-voip] Generating PRI for Cisco-Tandberg-Codian 3241 ISDN gateway

[Robert Kulagowski]

If anyone remembers the saga of using a Cisco router as H.320 to H.323 
gateway, after 2 years I've pretty much given up.  Even with IOS 15.0, it's 
very unreliable.  The TAC guy that I've been working with has been helpful, 
but it always seems to be one thing or another with H.320 or H.323 low 
level parameters, and "the other end" not doing something correct with 
regards to call setup or whatever.

Since I can't change the rest of the planet and get them to do it "The 
Cisco Way", I'm going to approach my issue differently.

I have Codian 3241 ISDN gateways.  They work just fine in allowing H.323 to 
H.320 calls, so Codian has got it figured out, even if Cisco isn't there yet.

Should it be possible to connect a 3241 to a 2851 over ISDN PRI (back to 
back) and be able to place video calls?  I'd like to peel off portions of 
my existing DID range and make them available for video calls.

In my lab I've got a 3241 connected via T1 crossover and have the serial 
port on the 2851 configured for isdn network-protocol-emulate.  The PRI is up.

Outbound calls from the 3241 are hitting the router and going out to the 
telco.  I can see in the q.931 debugs that 6 b-channels are brought up, but 
then the calls drop about 17 seconds later.

Is there anything "special" I need to do on the 2851 to allow it to work?

I've got:
network-clock-participate wic 0
network-clock-participate wic 1
network-clock-select 1 T1 0/0/0
network-clock-select 2 T1 0/1/0

controller T1 0/0/0
! To the Telco
  cablelength long 0db
  pri-group timeslots 1-24
!
controller T1 0/1/0
! To the Codian 3241
  cablelength short 110
  pri-group timeslots 1-24
!

interface Serial0/0/0:23
  no ip address
  encapsulation hdlc
  isdn switch-type primary-ni
  isdn supp-service name calling
  isdn integrate calltype all
  no cdp enable
!
interface Serial0/1/0:23
  no ip address
  encapsulation hdlc
  isdn switch-type primary-ni
  isdn protocol-emulate network
  isdn integrate calltype all
  no cdp enable
!

dial-peer voice 100 pots
  description Connection to Codian 3241
  incoming called-number .T
  direct-inward-dial
  port 0/1/0:23
!
dial-peer voice 300 pots
  description Connection to Telco
  destination-pattern 1..........
  forward-digits 11
  port 0/0/0:23