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Highlighted
Beginner

Channelized T1 on 2821 to Service module T1 2801 config

I have a 2821 at central site with a channelized T1 on a Network Module NM-2CE1T1-PRI. I've configured a channel group 2 with timeslots 7-8 on this central site router(not a big science). On the remote site I have a 2801 with a service module WIC-1DSU-T1 with the command service-module t1 timeslots 1-2. The situation is that the interfaces are up, protocol down at both sites and it seems to be all well configured, no alarms, the cd green light, Controllers up, etc... We connect the T1 to the 3com routers we are looking to substitute and it will come up without any problem. This 3com have the same channels T1 settings. I'm sending the configs to see if there's any special configuration that I'm missing. Thanks in advance:

Central site 2821 with NM-2CE1T1-PRI:

Controller T1 1/1

framing esf

linecode b8zs

channel-group 2 timeslots 7-8

int serial 1/1:2

ip address 192.168.100.x 255.255.255.252

description T1 P2P 128K

no ip redirects

no ip proxy-arp

======================================

Remote site 2801 with WIC-1DSU-T1:

interface Serial0/3/0

description ** Point to Point connection to 2821 Central **

ip address 192.168.100.x 255.255.255.252

no ip redirects

no ip proxy-arp

no fair-queue

service-module t1 timeslots 1-2

6 REPLIES 6
Highlighted
Advisor

Re: Channelized T1 on 2821 to Service module T1 2801 config

Hi,

You need to use the same timeslots at each end, not just the same number of timeslots.

Can you give that a go ?

Pls do remember to rate posts.

Paresh

Highlighted
Beginner

Re: Channelized T1 on 2821 to Service module T1 2801 config

Thanks for your response on this. Are you 100% sure about this? I'm almost sure I did this with the same results. And the 3com with it's external csu/dsu is configured using channels 1-2 at the remote site.

Highlighted
Advisor

Re: Channelized T1 on 2821 to Service module T1 2801 config

Yes I am. If you don't use the same timeslot numbers at each end then how will the router at each end know which timeslots are used by the other end for a particular serial interface. They need to be the same.

Pls do remember to rate posts...

Paresh.

Highlighted
Beginner

Re: Channelized T1 on 2821 to Service module T1 2801 config

Hello Paresh. A curious note. In this NM when you create a channel-group the speed it gets per channel default is 56K. See the BW parameter at the show interface newly created:

2821-Catec-GWY(config-controller)#channel-group 7 timeslots 19-20

2821-Catec-GWY(config-controller)#

2821-Catec-GWY#sh int ser 1/0:7

Serial1/0:7 is reset, line protocol is down

Hardware is M32X with CSU/DSU

MTU 1500 bytes, BW 112 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation HDLC, loopback not set

You have to put the speed 64 statement after the channel-group 7 timeslots 19-20 command:

2821-Catec-GWY(config-controller)#channel-group 7 timeslots 19-20 speed 64

2821-Catec-GWY(config-controller)#

2821-Catec-GWY#sh int ser 1/0:7

Serial1/0:7 is reset, line protocol is down

Hardware is M32X with CSU/DSU

MTU 1500 bytes, BW 128 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation HDLC, loopback not set

I'm gonna try this and let you know. But definitely will not work without the "speed" statement on this Network module. Spread the word :-)

Highlighted
Advisor

Re: Channelized T1 on 2821 to Service module T1 2801 config

Yeah, I've actually seen this before and it's really irritating when you've got a card at the other end which defaults to 64k.

Paresh

Highlighted
Beginner

Re: Channelized T1 on 2821 to Service module T1 2801 config

Nope. Doesn't work either. I've tried using the same channels with the same result. I'll have to open a TAC case. :-(