Developer Forum

Dont know what to try next.

Configured a point to point T1 between two 3640s. Ping times are erratic.
Looks fine for a few seconds then jumps to 1500 - 3600 then normal again.

No errors, drops, resets what so ever.

Ive currently got them sitting next to each other with same issue: Cisco1 >
CSU > Cable > CSU > Cisco 2
Ive replaced everything: cables, CSUs, Serial cards...
Any ideas what to try?

TIA


interface Serial0/0
description Router1
ip address x.x.x.1 255.255.255.252
no ip route-cache
no ip mroute-cache
no fair-queue
serial restart-delay 0
no cdp enable
------------------------------------------------
Router1#show int serial0/0
Serial0/0 is up, line protocol is up
Hardware is DSCC4 Serial
Description: Router 1
Internet address is x.x.x.1/30
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation HDLC, loopback not set
Keepalive set (10 sec)
Restart-Delay is 0 secs
Last input 00:00:00, output 00:00:00, output hang never
Last clearing of "show interface" counters 00:09:56
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 1000 bits/sec, 3 packets/sec
5 minute output rate 1000 bits/sec, 3 packets/sec
2326 packets input, 187763 bytes, 0 no buffer
Received 60 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
2293 packets output, 186881 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions
=============================================
interface Serial1/1
description Router2
ip address x.x.x.2 255.255.255.252
no ip route-cache
no ip mroute-cache
no fair-queue
serial restart-delay 0
no cdp enable
--------------------------------------------

Router2#show int serial1/1
Serial1/1 is up, line protocol is up
Hardware is DSCC4 Serial
Description: Router2
Internet address is x.x.x.2./30
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation HDLC, loopback not set
Keepalive set (10 sec)
Restart-Delay is 0 secs
Last input 00:00:08, output 00:00:00, output hang never
Last clearing of "show interface" counters 00:09:57
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 2000 bits/sec, 3 packets/sec
5 minute output rate 1000 bits/sec, 3 packets/sec
2289 packets input, 187183 bytes, 0 no buffer
Received 59 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
2323 packets output, 187607 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 output buffer failures, 0 output buffers swapped out
0 carrier transitions

ypical pingtimes:
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=53ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=53ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=53ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=54ms TTL=249
Reply from x.x.x.2: bytes=32 time=389ms TTL=249
Reply from x.x.x.2: bytes=32 time=392ms TTL=249
Reply from x.x.x.2: bytes=32 time=53ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=391ms TTL=249
Reply from x.x.x.2: bytes=32 time=395ms TTL=249
Reply from x.x.x.2: bytes=32 time=394ms TTL=249
Reply from x.x.x.2: bytes=32 time=402ms TTL=249
Reply from x.x.x.2: bytes=32 time=403ms TTL=249
Reply from x.x.x.2: bytes=32 time=410ms TTL=249
Reply from x.x.x.2: bytes=32 time=3591ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=1406ms TTL=249
Reply from x.x.x.2: bytes=32 time=414ms TTL=249
Reply from x.x.x.2: bytes=32 time=51ms TTL=249
Reply from x.x.x.2: bytes=32 time=51ms TTL=249
Reply from x.x.x.2: bytes=32 time=50ms TTL=249
Reply from x.x.x.2: bytes=32 time=1046ms TTL=249
Reply from x.x.x.2: bytes=32 time=1010ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=989ms TTL=249
Reply from x.x.x.2: bytes=32 time=989ms TTL=249
Reply from x.x.x.2: bytes=32 time=935ms TTL=249
Reply from x.x.x.2: bytes=32 time=990ms TTL=249
Reply from x.x.x.2: bytes=32 time=991ms TTL=249
Reply from x.x.x.2: bytes=32 time=999ms TTL=249
Reply from x.x.x.2: bytes=32 time=53ms TTL=249
Reply from x.x.x.2: bytes=32 time=51ms TTL=249
Reply from x.x.x.2: bytes=32 time=992ms TTL=249
Reply from x.x.x.2: bytes=32 time=521ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=354ms TTL=249
Reply from x.x.x.2: bytes=32 time=51ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms TTL=249
Reply from x.x.x.2: bytes=32 time=53ms TTL=249
Reply from x.x.x.2: bytes=32 time=50ms TTL=249
Reply from x.x.x.2: bytes=32 time=999ms TTL=249
Reply from x.x.x.2: bytes=32 time=838ms TTL=249
Reply from x.x.x.2: bytes=32 time=1012ms TTL=249
Reply from x.x.x.2: bytes=32 time=502ms TTL=249
Reply from x.x.x.2: bytes=32 time=66ms TTL=249
Reply from x.x.x.2: bytes=32 time=106ms TTL=249
Reply from x.x.x.2: bytes=32 time=51ms TTL=249
Reply from x.x.x.2: bytes=32 time=51ms TTL=249
Reply from x.x.x.2: bytes=32 time=51ms TTL=249
Reply from x.x.x.2: bytes=32 time=995ms TTL=249
Reply from x.x.x.2: bytes=32 time=52ms T

Jake" < XXXX@XXXXX.COM > wrote in message
news:7f888$426e57a1$8b37d4f5$ XXXX@XXXXX.COM ...
erratic.
again.
Cisco1


Try putting a bandwidth monitor on there as well. You'll probably notice
that the ping times go up as there is more traffic going across the network.
Also, run the ping from 3640 to 3640, as you don't want other sections of
the network to get in the way of your response times. Ping is a great tool,
but I've found many people misunderstand how to use it.

The bigger concern for me would be that your BEST response is 50ms. I would
expect to have < 1ms on an empty P2P network.

Hope that helps,

Jim

>>

Thanks Jim,

The pings were done from my PC over my DSL to the router(s) in a different
state so thats why the longer times.

I was able to locate an old 2500 and swapped out each side and when
connected to the far end 3640, the pings between them were perfect (100%,
1/2/4) so that points to a bad serial card or slot in Router 1. Looking for
spares now.

Thanks again!

~ >>
~ >
~ >
~ > Try putting a bandwidth monitor on there as well. You'll probably notice
~ > that the ping times go up as there is more traffic going across the
~ > network.
~ > Also, run the ping from 3640 to 3640, as you don't want other sections of
~ > the network to get in the way of your response times. Ping is a great
~ > tool,
~ > but I've found many people misunderstand how to use it.
~ >
~ > The bigger concern for me would be that your BEST response is 50ms. I
~ > would
~ > expect to have < 1ms on an empty P2P network.
~ >
~ > Hope that helps,
~ >
~ > Jim
~ >
~
~ Thanks Jim,
~
~ The pings were done from my PC over my DSL to the router(s) in a different
~ state so thats why the longer times.
~
~ I was able to locate an old 2500 and swapped out each side and when
~ connected to the far end 3640, the pings between them were perfect (100%,
~ 1/2/4) so that points to a bad serial card or slot in Router 1. Looking for
~ spares now.
~
~ Thanks again!

If you are seeing spikes in ping latency between routerA and routerB,
and if routerA and routerB are configured by a direct point-to-point
circuit, and if that circuit does not do any layer-2 error correction,
then I would tend to suspect intermittent/periodic excessive CPU load
in routerA and/or routerB.

If the problem is seen with a pair 3640s but is not seen with a pair
of 2500s, then I would bet a nickel that the problem is not in the
3640 hardware but in the 3640 software and/or configuration.

"show proc cpu" while the problem is occuring may help to explain
the phenomenon.

Aaron

Swapped out serial cards and now functioning fine.

Thanks all!