WIC 1DSU T1 puzzler

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Jul 21st, 2008
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I have a 1721 router with at WIC 1DSU T1(version 1) card. The router is running a static VPN tunnel to another site. With all of the IP services running and traffic the router is hitting 90% and dropping VOIP traffic. I upgraded the router to a 2811 with a WIC 1DSU T1 V2 card. The router dropps every other ping and traffice but it doesn't sho up in a <sho int> command. I upgraded to IOS version c2800nm-advsecurityk9-mz.124-15.T5.bin. Is there a compatibility with the DSLAM? The routers have somewhat of the same config on them. Any suggestions? BTW I think that the ISP us spoofing a frame-relay connection and it is really ATM.

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Giuseppe Larosa Sat, 07/26/2008 - 13:01
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Hello Jason,

you should provide more information in order to get some help.

Interface configuration

sh frame-rel pvc

sh frame-rel lmi

Your provider can give you a FR PVC that is switched to an ATM pvc by using service interworking.

Your interface should be a serial interface with FR encapsulation not an ATM T1.

If the interface isn't up/up the router can't use it for traffic.

On the CO side there is a FR switch not a DSLAM.

Give a look at the following:


Notice there are some new commands about physical layer


The following are prerequisites to enable the T1 CSU WIC:

•Leased line from your telephone company

•Configuration parameters as specified by your telephone company. For most connections, the following default settings should suffice:

-service-module t1 clock source line

-service-module t1 data-coding normal

-service-module t1 timeslots all speed 64

-service-module t1 framing esf

-service-module t1 lbo none

-service-module t1 linecode b8zs

-no service-module t1 remote-alarm-enable

-no service-module t1 fdl

Hope to help



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