configuration of multilink should look like this.
controller T1 0/0/0
framing esf
linecode b8zs
channel-group 0 timeslots 1-24
!
controller T1 0/0/1
framing esf
linecode b8zs
channel-group 0 timeslots 1-24
!
controller T1 0/1/0
framing esf
linecode b8zs
channel-group 0 timeslots 1-24
!
controller T1 0/1/1
framing esf
linecode b8zs
channel-group 0 timeslots 1-24
!
interface Multilink1
ip address 1.1.1.1 255.255.255.252
no cdp enable
ppp multilink
ppp multilink group 1
!
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
no fair-queue
ppp multilink
ppp multilink group 1
!
interface Serial0/1/0:0
no ip address
encapsulation ppp
no fair-queue
ppp multilink
ppp multilink group 1
!
interface Serial0/1/1:0
no ip address
encapsulation ppp
no fair-queue
ppp multilink
ppp multilink group 1
Router# show ppp multilink
Multilink1, bundle name is MY-ISP
Endpoint discriminator is MY-ISP
Bundle up for 10w0d, total bandwidth 6144, load 25/255
Receive buffer limit 48000 bytes, frag timeout 1000 ms
2/3020 fragments/bytes in reassembly list
204716 lost fragments, 310561297 reordered
474999/517174257 discarded fragments/bytes, 474999 lost received
0x256CD0 received sequence, 0x2071C9 sent sequence
Member links: 4 active, 0 inactive (max not set, min not set)
Se0/1/1:0, since 10w0d
Se0/1/0:0, since 10w0d
Se0/0/0:0, since 10w0d
Se0/0/1:0, since 10w0d
No inactive multilink interfaces
Router#
