Hello Everyone,
I have been working through an issue the past few weeks and I was curious if anyone had any suggestions on it. We have a point to point t1 connecting our 2 sites. Occassionally (2-3 times a week) we have an issue where the t1 flaps for a second. It's just a second, but we have some applications that get disconnected and we get interface resets, carrier transitions on the interfaces of the routers. I have been round-and-round with Cisco TAC and the ISP. Both keep sending me to the other. Router at City1 is a 2821. router at City2 is a 2811. the flap occurs at all times of the day. Sometimes, it happens during the least busiest hours and sometimes it happens during the most busiest hours.
Can you look at these configurations and let me know if you see anything unusual? one suggestion is the clocking configuration, but I think the config is fine. It was suggested to try to reverse the configuration. I believe that is just a matter of taking the service-module t1 clock source internal off of one interface and putting it on the other.
Any suggestion would be great.
Thanks,
Ben
So this is what the interface configurations look like:
Router @ City 1:
Serial0/3/0 is up, line protocol is up
Hardware is GT96K with integrated T1 CSU/DSU
Description: Connection to city2 72HCGS434178PN
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 255/255, txload 69/255, rxload 33/255
Encapsulation PPP, LCP Open, multilink Open
Link is a member of Multilink bundle Multilink2, loopback not set
Keepalive set (10 sec)
Last input 00:00:00, output 00:00:04, output hang never
Last clearing of "show interface" counters 4d23h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 150
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 200000 bits/sec, 448 packets/sec
5 minute output rate 418000 bits/sec, 447 packets/sec
42748791 packets input, 2202424607 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
56 input errors, 56 CRC, 48 frame, 10 overrun, 0 ignored, 47 abort
34638955 packets output, 3456742347 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 output buffer failures, 0 output buffers swapped out
2 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up
interface Serial0/3/0
description Connection to city2
no ip address
encapsulation ppp
service-module t1 clock source internal
no fair-queue
ppp multilink
ppp multilink group 2
end
interface Multilink2
ip address 172.26.100.2 255.255.255.0
ip nbar protocol-discovery
ppp multilink
ppp multilink group 2
service-policy output llq-t1
Router at City2
Serial0/3/0 is up, line protocol is up
Hardware is GT96K with integrated T1 CSU/DSU
Description: Connection to City1
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 255/255, txload 37/255, rxload 84/255
Encapsulation PPP, LCP Open, multilink Open
Link is a member of Multilink bundle Multilink2, loopback not set
Keepalive set (10 sec)
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 2d21h
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 159
Queueing strategy: weighted fair [suspended, using FIFO]
FIFO output queue 0/40, 159 drops
5 minute input rate 509000 bits/sec, 451 packets/sec
5 minute output rate 228000 bits/sec, 445 packets/sec
27315388 packets input, 2215104027 bytes, 0 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
34091757 packets output, 68135486 bytes, 0 underruns
0 output errors, 0 collisions, 1 interface resets
0 output buffer failures, 0 output buffers swapped out
2 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up
interface Serial0/3/0
description Connection to City1
no ip address
encapsulation ppp
ppp multilink
ppp multilink group 2
end
interface Multilink2
ip address 172.26.100.1 255.255.255.0
ppp multilink
ppp multilink group 2
service-policy output llq-t1
