I have an intermittent problem on a network at a remote site. The problem is
the network seems slow going out over wan. The gateway router does not seem
to be the problem, so I wanted to run something by the group. I did a sh int
gi4/1, the interface that connects our switch to the router.

Description: uplink from att router
MTU 1500 bytes, BW 100000 Kbit, DLY 10 usec,
reliability 251/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
-snip-

Full-duplex, 100Mb/s, link type is auto, media type is 10/100/1000-TX

-snip-
input flow-control is off, output flow-control is off
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output never, output hang never
Last clearing of "show interface" counters 3d22h
Input queue: 0/2000/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)j
5 minute input rate 334000 bits/sec, 78 packets/sec
5 minute output rate 220000 bits/sec, 96 packets/sec
19830905 packets input, 7253560574 bytes, 0 no buffer
Received 15303 broadcasts (0 multicast)
0 runts, 0 giants, 0 throttles
1 input errors, 1 CRC, 0 frame, 0 overrun, 0 ignored
0 input packets with dribble condition detected
21201894 packets output, 6978548159 bytes, 0 underruns
405163 output errors, 19018 collisions, 0 interface rese
0 babbles, 367194 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out

I am confused on the line reading 'full duplex...', does the auto mean set
to an auto condition? Should I set this to 'full/100'? What I see is a lot
of collisions and late collisions.

L

"Branigan" <lgovedich@yahoo.com> wrote in message
news:89Odnfa9IKaoeajfRVn-gQ@giganews.com...
it sounds like the switch and whatever is at the other end of the link
disagree about the duplex settings - the effect would be that the error rate
increases very rapidly once the port comes under a high load of data in both
directions.

the golden rule is to be consistent. possible settings are:
both ends set to full duplex
both ends set to auto
both ends set to 1/2 duplex
1 end auto and the other 1/2 duplex, or not capable of auto negotiate.
Regards

Stephen Hope - return address needs fewer xxs

Branigan wrote:

Either this...

or this is lying to you. When the port is running full-duplex, it won't
show collisions, and when it shows collisions, it's running half duplex.

If the 'collisions' and especially the 'late collisions' counter is
going up, it means it's running half duplex and the other end is running
full duplex.

Try fixing the port at 100/Full and also check the other end.

Regards,

Marco.