T1/E1 Bandwidth Setting ????

[enclade]

The serial module as shown below is connected to a T1 and yet the BW defaults to 2048 Kbit as opposed to 1544 Kbit as I would expect and do see on my other T1 CSU/DSU modules. Does this setting actually effect the operation of this device? I am seeing many input errors on these devices and am concerned that this setting may have something to do with it.

Thanks for any help,

Brett

Serial0/0 is up, line protocol is up

Hardware is DSCC4 with integrated T1 CSU/DSU

MTU 1500 bytes, BW 2048 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 4/255

Encapsulation HDLC, loopback not set

Keepalive set (10 sec)

Input queue: 0/75/6/0 (size/max/drops/flushes); Total output drops:

3378050

Queueing strategy: weighted fair

Output queue: 0/1000/64/3377893 (size/max total/threshold/drops)

Conversations 0/30/256 (active/max active/max total)

Reserved Conversations 0/0 (allocated/max allocated)

Available Bandwidth 536 kilobits/sec

30 second input rate 39000 bits/sec, 12 packets/sec

30 second output rate 16000 bits/sec, 14 packets/sec

331512555 packets input, 2861950734 bytes, 0 no buffer

Received 1878987 broadcasts, 0 runts, 0 giants, 0 throttles

17467 input errors, 7291 CRC, 10176 frame, 0 overrun, 0 ignored, 0

abort

314622866 packets output, 3888894327 bytes, 0 underruns

0 output errors, 0 collisions, 11 interface resets

0 output buffer failures, 0 output buffers swapped out

11 carrier transitions

DCD=up DSR=up DTR=up RTS=up CTS=up

[scottmac]

First: The "bandwidth" command / parameter has no effect on the actual transmission rate: It's only there as a parameter to determine a metric for (some) routing protocols.

Next: reset your counters and give us the output and note how long it took to get the stats. Just having a bunch of errors noted doesn't help; you need to indicate the time period measured.

It would also help (a little) to know what's on the other end: the Internet, another site that's running at the same speed, or another site that's running slower (especially over Frame Relay) - you may want to add some traffic shaping.

Reset your counters, measure for an hour, several hours, a day, several days ... whatever it takes to get a good error count, then repost your new stats.

Good Luck

Scott

[dgahm]

The bandwidth setting is used to determine routing metrics, and for queuing. You should change it to 1536, but this is not causing your errors.

A more likely issue is the clocking. One router on the T1 (or the carrier) needs to be providing clock (internal clock), and the other end should be loop timed (line clock).

A 'show service-module s0/0' will provide some more clues. It will tell you the clock source, as well as show if you seeing layer 1 errors like line code violations which might indicate wiring problems.

You should also clear your counters to be sure that the errors are still accumulating.