Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

7206 router and channel-groups

I have a 7206 router with 6 T1 lines bound together in a multilink.

3 are on a 4 port T1 controller card, the other three are on a serial port card with CSU/DSUs.

I am going to change out the CSU/DSUs for another T1 controller card.

The existing T1 controller has all three T1s on channel-group 0.

When installing the additional T1 controller, do I create a new channel-group or can I add the new T1 controllers to the same channel group?

All six T1s need to bind together

Hall of Fame Super Gold

Re: 7206 router and channel-groups


You need to create a new channel-group. This will create a new serial interface that you will add to the multilink bundle.

Hope this helps please rate post if it does!

New Member

Re: 7206 router and channel-groups


on the existing controller, three T1s are being used and all three have the same channel-group number(channel-group 0).

Do I give all the additional three T1s the same channel-group number of 1?

Hall of Fame Super Gold

Re: 7206 router and channel-groups

Hi Wilson,

The channel-group ID can be replicated as many times you want in the router, and using 0 for all controllers is correct.

The resulting serial interface will be differentiated anyway by the slot/port number, even if the last digits will always be ":0".

Thanks for the nice rating and good luck!

New Member

Re: 7206 router and channel-groups

Yea, thanks, it hit me after I wrote that that it was per interface.

One thing though, after the module swap and all six T1s are back part of the multilink, I see the old interfaces showing up as "inactive" when I do a "sh ppp multilink"

6 active

3 inactive

How can that be if the interfaces do not exist any longer?, I replaced the serial port module with the T1 controller module in the same slot.

How do I remove them from the multilink?

Re: 7206 router and channel-groups

Mostly this happens when you do not remove the old interface configuration and just swap the modules.

The interfaces go to deleted state which can be seen from the sh ip int brief command.

It would require a reboot to clear these interfaces

HTH, rate if it does