Hello all,
I have a site which has been successfully running a multilink bundle of four T1 lines for about 6 months. The remote location is a C3825 router and the central location router is a C7206. I have access to both. A few weeks ago the multilink circuit started flapping and I was able to identify one of the four T1 lines as the culprit. When I shut down the interface for that one T1 line, the multilink circuit stops bouncing. As soon as I issue a "no shut" command on that fourth T1 interface, the multilink circuit starts flapping, ping commands start to time out and I have to shut it down again. The Telco has sent a technician to both locations and reported all tests run clean. Internal wiring from the NIU to the router has also tested fine. I've tried to move the T1 lines to different ports on both routers and the problem persists. I'm out of ideas and hope someone can help. Here is the config on the router at the remote location. You will notice interface s0/1/1:0 is currently shut down. This is the problematic T1:
!
version 12.4
!
card type t1 0 0
card type t1 0 1
card type t1 0 2
card type t1 0 3
no network-clock-participate wic 0
no network-clock-participate wic 1
no network-clock-participate wic 2
no network-clock-participate wic 3
!
dot11 syslog
ip source-route
!
!
ip cef
!
!
no ip domain lookup
no ipv6 cef
!
multilink bundle-name authenticated
!
!
voice-card 0
!
!
controller T1 0/0/0
clock source internal
cablelength long 0db
channel-group 0 timeslots 1-24
!
controller T1 0/0/1
cablelength long 0db
channel-group 0 timeslots 1-24
!
controller T1 0/1/0
cablelength long 0db
channel-group 0 timeslots 1-24
!
controller T1 0/1/1
cablelength long 0db
channel-group 0 timeslots 1-24
!
interface Multilink2
bandwidth 6000
ip address a.b.c.d 255.255.255.252
no cdp enable
ppp multilink
ppp multilink group 2
!
!
interface Serial0/0/0:0
no ip address
encapsulation ppp
no fair-queue
pulse-time 3
ppp multilink
ppp multilink group 2
!
interface Serial0/0/1:0
no ip address
encapsulation ppp
no fair-queue
pulse-time 3
ppp multilink
ppp multilink group 2
!
interface Serial0/1/0:0
no ip address
encapsulation ppp
no fair-queue
pulse-time 3
ppp multilink
ppp multilink group 2
!
interface Serial0/1/1:0
no ip address
encapsulation ppp
shutdown
no fair-queue
pulse-time 3
ppp multilink
ppp multilink group 2
!
no cdp run
!
I have a site which has been successfully running a multilink bundle of four T1 lines for about 6 months. The remote location is a C3825 router and the central location router is a C7206. I have access to both. A few weeks ago the multilink circuit started flapping and I was able to identify one of the four T1 lines as the culprit. When I shut down the interface for that one T1 line, the multilink circuit stops bouncing. As soon as I issue a "no shut" command on that fourth T1 interface, the multilink circuit starts flapping, ping commands start to time out and I have to shut it down again. The Telco has sent a technician to both locations and reported all tests run clean. Internal wiring from the NIU to the router has also tested fine. I've tried to move the T1 lines to different ports on both routers and the problem persists. I'm out of ideas and hope someone can help. Here is the config on the router at the remote location. You will notice interface s0/1/1:0 is currently shut down. This is the problematic T1:
!
version 12.4
!
card type t1 0 0
card type t1 0 1
card type t1 0 2
card type t1 0 3
no network-clock-participate wic 0
no network-clock-participate wic 1
no network-clock-participate wic 2
no network-clock-participate wic 3
!
dot11 syslog
ip source-route
!
!
ip cef
!
!
no ip domain lookup
no ipv6 cef
!
multilink bundle-name authenticated
!
!
voice-card 0
!
!
controller T1 0/0/0
clock source internal
cablelength long 0db
channel-group 0 timeslots 1-24
!
controller T1 0/0/1
cablelength long 0db
channel-group 0 timeslots 1-24
!
controller T1 0/1/0
cablelength long 0db
channel-group 0 timeslots 1-24
!
controller T1 0/1/1
cablelength long 0db
channel-group 0 timeslots 1-24
!
interface Multilink2
bandwidth 6000
ip address a.b.c.d 255.255.255.252
no cdp enable
ppp multilink
ppp multilink group 2
!
!
interface Serial0/0/0:0
no ip address
encapsulation ppp
no fair-queue
pulse-time 3
ppp multilink
ppp multilink group 2
!
interface Serial0/0/1:0
no ip address
encapsulation ppp
no fair-queue
pulse-time 3
ppp multilink
ppp multilink group 2
!
interface Serial0/1/0:0
no ip address
encapsulation ppp
no fair-queue
pulse-time 3
ppp multilink
ppp multilink group 2
!
interface Serial0/1/1:0
no ip address
encapsulation ppp
shutdown
no fair-queue
pulse-time 3
ppp multilink
ppp multilink group 2
!
no cdp run
!
