ISR 4K NIM 4MFT-T1/E1 - no "interface Serial"

[njsanders1]

I'm configuring a new 4K router with a 4MFT-T1/E1, with the intent of using it as a branch router connected to a 2xT1 MPLS link.  I followed the instructions found on on this Cisco page to the letter, but something's still not right.  I had no issues defining the card type or the controllers, nor did I have a problem creating the Multilink interface.  However, I cannot configure the serial interfaces - "serial" is not an option under the "interfaces" command context.

R4261-1(config)# int serial ?

% Unrecognized command

The card does appear when I do a "show inventory."  Also, the T1s appear in a "show controllers" command output.

[eric.ahernandez · Accepted solution]

Hi,

You need to define the channel-group with the timeslots in the controller (in case you're using that T1 as a Data Interface):

channel group channel-group-number {timeslots range [speed kbps ] | unframed }

Or in case you're using it for voice you define it as a ds0-group or pri-group:

ds0-group ds0-group-number timeslots timeslot-list type {e&m-delay-dial | e&m-immediate-start | e&m-wink-start | fxo-ground-start | fxo-loop-start | fxs-ground-start | fxs-loop-start

Both configuration examples are on that same link you posted. When you do this it will create the interface you need with the channel-group / ds0-group number, for example:

If you create channel-group 1 and your card is on slot 0/0/0 it will create a Serial 0/0/0:1 Interface

If you create ds0-group 2 and your card is on slot 0/1/0 it will create a voice-port 0/1/0:2 Interface

Hope that helps

[njsanders1]

If both T1s are going to be part of the same multilink bundle, do I use the same channel-group number under both controllers?

[eric.ahernandez]

It's really not necessary to do that, as it's only for your serial interfaces identification purposes, it does not affect the multilink bundling.

So if you have 2 different cards for example you can use the same channel-number and have 2 serials like Serial 0/0/0:1 and Serial 0/1/0:1, or use any other number you like (I've seen people use channel-group 17 and stuff) and there should be no problem with the multilink.

[njsanders1]

Thanks, Eric.  "It's been too long since I've done this." :)