I have a switch that has over 21 million collisions within the last week on the vlan 1 interface. Users on this switch have been experiencing slowness for a while, and we just started monitoring the switches statistics recently. None of the physical interfaces have any collisions at all, for the last week. The switch is connected to another switch via a dot1q trunk. The neighbor switch has not collisions, or other errors, on vlan 1.
I suspect that the high number of collisions is creating some latency on the switch that is causing the slowness. Out of all 20 switches that we have, there are no VLAN interfaces with any errors, like this.
Here is the information from the offending switch:
#show interface vlan 1 VLAN1 is up, line protocol is up Hardware is CPU Interface, address is 0001.42b4.a640 (bia
0001.42b4.a640) Internet address is 192.168.253.16/24 MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set ARP type: ARPA, ARP Timeout 04:00:00 Last input 00:00:00, output 00:00:00, output hang never Last clearing of "show interface" counters never Queueing strategy: fifo Output queue 0/40, 0 drops; input queue 0/75, 0 drops 5 minute input rate 1000 bits/sec, 3 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec 2346 packets input, 173859 bytes, 0 no buffer Received 2021 broadcasts, 0 runts, 0 giants, 0 throttles 0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored 0 input packets with dribble condition detected 262 packets output, 21449 bytes, 0 underruns 0 output errors, 20763204 collisions, 0 interface resets 0 babbles, 0 late collision, 0 deferred 0 lost carrier, 0 no carrier 0 output buffer failures, 0 output buffers swapped out#show version Cisco Internetwork Operating System Software IOS (tm) C3500XL Software (C3500XL-C3H2S-M), Version 12.0(5.1)XP, MAINTENANCE INTERIM SOFTWARE Copyright (c) 1986-1999 by cisco Systems, Inc. Compiled Fri 10-Dec-99 11:16 by cchang Image text-base: 0x00003000, data-base: 0x002D84CC
ROM: Bootstrap program is C3500XL boot loader
DOM_Switch uptime is 1 hour, 57 minutes System returned to ROM by reload System image file is "flash:c3500XL-c3h2s-mz-120.5.1-XP.bin"
cisco WS-C3548-XL (PowerPC403) processor (revision 0x01) with
16384K/1024K bytes of memory. Processor board ID 0x17, with hardware revision 0x00 Last reset from warm-resetProcessor is running Enterprise Edition Software Cluster command switch capable Cluster member switch capable
48 FastEthernet/IEEE 802.3 interface(s) 2 Gigabit Ethernet/IEEE 802.3 interface(s)32K bytes of flash-simulated non-volatile configuration memory. Base ethernet MAC Address: 00:01:42:B4:A6:40 Motherboard assembly number: 73-3903-04 Power supply part number: 34-0971-01 Motherboard serial number: FAA04089M5Z Power supply serial number: PAC040802HZ Model revision number: A0 Motherboard revision number: B0 Model number: WS-C3548-XL-EN System serial number: FAA0411J015 Configuration register is 0xF