excessive collisions


I have a cisco 2600 series router that has been functioning quite normally for a couple of years. Within the last 2-3 weeks, I've been getting %AMDP2_FE-5-EXCESSCOLL: Ethernet0/0 TDR=1, TRC=0 errors sent to my syslog. My sho int ethernet0/0 is as follows:

Ethernet0/0 is up, line protocol is up Hardware is AmdP2, address is 0002.16bb.64a0 (bia 0002.16bb.64a0) Internet address is MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, reliability 255/255, txload 1/255, rxload 1/255 Encapsulation ARPA, loopback not set Keepalive set (10 sec) 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, 137 drops; input queue 0/75, 30 drops 5 minute input rate 58000 bits/sec, 31 packets/sec 5 minute output rate 29000 bits/sec, 28 packets/sec 117808771 packets input, 2851115318 bytes, 0 no buffer Received 194097 broadcasts, 0 runts, 0 giants, 0 throttles 11226 input errors, 0 CRC, 0 frame, 0 overrun, 11226 ignored 0 input packets with dribble condition detected 105960040 packets output, 441677166 bytes, 0 underruns 449 output errors, 622296 collisions, 1 interface resets 0 babbles, 0 late collision, 1019742 deferred 0 lost carrier, 0 no carrier 0 output buffer failures, 0 output buffers swapped out

I have googled this, and read that excessive collisions is often caused by bad cabling/connectors. I also read that the TDR can be used to pinpoint where along the cabling the fault may lie. There is supposedly an equation that will help me figure out what the TDR=1 means as far as where a cable fault might be but I can't find that equation. Can someone help?


Lisa Casey

Reply to
Lisa Casey
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Hi Lisa,

Cisco Error Message:


Ethernet or Fast Ethernet is seeing multiple collisions.

This condition may occur under heavy loads.

If an interface fails to allocate a slot in which it can transmit its frame without another collision for 16 times, it will not retry the operation.

The frame is not transmitted and is marked as an excessive collision.


Cisco's Recommended Action:

The system should recover.

No action is required.


Hope this helps.

Brad Reese BradReese.Com - Cisco Repair

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Hendersonville Road, Suite 17 Asheville, North Carolina USA 28803 USA & Canada: 877-549-2680 International: 828-277-7272 Fax: 775-254-3558 AIM: R2MGrant BradReese.Com - Cisco Power Supply Headquarters
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Reply to

You can also get excessive collisions if the duplex settings do not match between the E0./0 port and whatever you are attached to. Beware the low end switches produced by Linksys,etc. I have had to power cycle the cheap and expensisve swithes to get duplex settings to match.

Years ago one of my occasional customers spent in excess of 100K reprogramming their apps, because data transfer was taking over 9 hours on a

100Mbps ethernet.

I found a duplex mis-match and resolved it. The transfer then took 8 minutes. Do not trust auto sensing equipment-CHECK both ends and if possible manually set the duplex and speed settings.

Digital Doug Systems Analyst

Reply to
Houston SBC

Good point. Auto negotiating has been a big problem for us too and we tpyically will set it specifically on all our cisco gear.

Reply to
Todd H.

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