Hi Everyone,

I figured this little configuration snippet may help someone some day. I had to configure an MPLS circuit today for a customer who had a 2851 ISR router, with an MPLS circuit. The circuit featured 3 T1's that were to be bonded together for a 4.5 meg circuit.

For brevity sake I am only showing what is needed on the interfaces and for basic routing.

!
card type t1 0 0
card type t1 0 1
card type t1 0 2
card type t1 0 3
!
controller T1 0/0/0
framing esf
linecode b8zs
cablelength short 110
channel-group 0 timeslots 1-24
!
controller T1 0/0/1
framing esf
linecode b8zs
cablelength long 0db
channel-group 0 timeslots 1-24
!
controller T1 0/1/0
framing esf
linecode b8zs
cablelength long 0db
channel-group 0 timeslots 1-24
!
!
interface Multilink1
ip address x.x.x.x x.x.x.x
no peer neighbor-route
no cdp enable
ppp multilink
ppp multilink links minimum 1
ppp multilink group 1
ppp multilink fragment disable
!
interface GigabitEthernet0/0
description Inside LAN Interface
ip address y.y.y.y y.y.y.y
duplex auto
speed auto
!
!
interface Serial0/0/0:0
no ip address
encapsulation ppp
no fair-queue
ppp multilink
ppp multilink group 1
!
interface Serial0/0/1:0
no ip address
encapsulation ppp
ppp multilink
ppp multilink group 1
!
interface Serial0/1/0:0
no ip address
encapsulation ppp
ppp multilink
ppp multilink group 1
!
ip route 0.0.0.0 0.0.0.0 x.x.x.x
!

Now, just because you have that in the router, make sure you NO SHUT the interfaces, you will also need to look at each of the controllers to see if there are any errors. I would recommend something like the following:

!
hostname (enable)# clear counters
hostname (enable)# show controller t1 x/x/x
!

Also, you should be able to ping the IP address the carrier is using in the cloud. More than likely you will get a 255.255.255.252 subnet so do your subnet calculations.

There is an excellent article I dug up on the subject here:

http://blogs.techrepublic.com.com/networking/?p=498