[cisco-voip] help with modem calls going PRI -> 2811 -> PRI?

[Norton, Mike]

How about "show controllers T1" - any errors?

Maybe the two PRIs coming in on 0/0/0 and 0/1/0 don't share the same clock. If I understand your intentions correctly, you're not planning to keep the second PRI if this all works out. So rather than introduce 0/1/0 as a potential source of trouble, why not just get calls working from 0/0/0 to 0/1/1 and leave 0/1/0 out of the picture. Might mean having to schedule some downtime around the transition, but retraining 10 times then failing isn't exactly uptime anyway.

--
Mike Norton
I.T. Support
Peace Wapiti School Division No. 76
Helpdesk: 780-831-3080
Direct: 780-831-3076



From: cisco-voip-bounces at puck.nether.net [mailto:cisco-voip-bounces at puck.nether.net] On Behalf Of John Callahan
Sent: September-08-11 5:01 PM
To: cisco-voip at puck.nether.net
Subject: [cisco-voip] help with modem calls going PRI -> 2811 -> PRI?


Help!  I have a single telco PRI terminated in a RAS (dial-up V.90 modems) that is only serving a few users at this point, but they don't have any other access options (other than satellite) so we continue to run it...

I would like to move the access numbers to our main PRI that terminates in an MGCP gateway on a Cisco 2811 and then provide a "network side" PRI from that same 2811 to the RAS box so I don't have to pay for a full PRI for just a few concurrent users.

Everything seems to work except when I route the PRI through the 2811, negotiated speeds drop way down and retrains go way up.  Often a modem will retrain 10 times and just give up.

The incoming PRI (from telco) and the outgoing PRI (towards RAS) are both on the same 2811, so I presume packet loss and jitter shouldn't be an issue -- I am wondering if it is somehow a clock issue?  Do I just give up because this is unrealistic?

Here is the relevant IOS config - 0/0/0 is my normal voice PRI, 0/1/0 is the PRI normally going directly to the RAS , 0/1/1 is the PRI provided to the NAS (note the isdn protocol emulate network)

========================================================
network-clock-participate wic 0
network-clock-participate wic 1
network-clock-select 1 T1 0/0/0

controller T1 0/1/0
 framing esf
 linecode b8zs
 cablelength short 133
 pri-group timeslots 1-24 service mgcp
!
controller T1 0/1/1
 framing esf
 linecode b8zs
 cablelength short 133
 pri-group timeslots 1-24 service mgcp
!
interface Serial0/1/0:23
 no ip address
 encapsulation hdlc
 isdn switch-type primary-ni
 isdn incoming-voice voice
 isdn bind-l3 ccm-manager
 no cdp enable
!
interface Serial0/1/1:23
 no ip address
 encapsulation hdlc
 isdn switch-type primary-ni
 isdn protocol-emulate network
 isdn incoming-voice voice
 isdn bind-l3 ccm-manager
 no cdp enable
!
mgcp modem passthrough voip mode nse






-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://puck.nether.net/pipermail/cisco-voip/attachments/20110908/f53a9f7c/attachment.html>