07-08-2013 01:13 PM - edited 03-07-2019 02:17 PM
Hello ,
I have been observing high amount of Late Collisions on Ethernet 0 interface for a Cisco 1721 Router (LOL EOL for sure )
The internet line terminates on the interface
#sh int e0
6640 output errors, 5677 collisions, 0 interface resets
0 babbles, 6454 late collision, 10467 deferred
#sh controllers | i single
4304 single collisions, 1373 multiple collisions
For LAN Access ,the router has GRE IPSec Tunnels which forms EIGRP Neighborship with Remote end Router
Due to this issue , lately the GRE IPsec Tunnels flaps causing EIGRP Neighborship to get disrupted often resulting in connectivity loss
As late collssions can mostly be caused by Duplex mismatch , I checked the duplex settings and that seems to be fine
(https://supportforums.cisco.com/thread/9246)
1. The LAN has around 200 nodes connected via Fa0 intreface , Can the Speed mismatch ( 10Mbps and 100 Mbps ) cause bottle necks and be the reason for Late collissions ?
2. Are Late collissions bad ?
3. What are the options ahead of me to try and resolve this issue ?
Please Help !
Regards,
Anup
Solved! Go to Solution.
07-08-2013 04:04 PM
Can the Speed mismatch ( 10Mbps and 100 Mbps ) cause bottle necks and be the reason for Late collissions ?
No. Speed mismatch gives you CRC or FCS. Collisions, as a whole, means you're interface is set up for HALF duplex.
Post the complete output to the command "sh interface
Ethernet0? I believe this interface can only negotiate HALF duplex.
07-08-2013 04:04 PM
Can the Speed mismatch ( 10Mbps and 100 Mbps ) cause bottle necks and be the reason for Late collissions ?
No. Speed mismatch gives you CRC or FCS. Collisions, as a whole, means you're interface is set up for HALF duplex.
Post the complete output to the command "sh interface
Ethernet0? I believe this interface can only negotiate HALF duplex.
07-08-2013 04:06 PM
Troubleshooting Switch Port and Interface Problems and go to Table 1.
07-08-2013 04:32 PM
Hi Leo ,
It 's Half Duplex itself !
Sorry I checked the Fa0 port and found it to be Full Duplex
For E0
Ethernet0 is up, line protocol is up
Hardware is PQUICC Ethernet, address is 000d.28db.6d26 (bia 000d.28db.6d26)
Description: == Public IP ==
Internet address is 1.2.3.4/24
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)
Half-duplex, 10BaseT
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
Input queue: 0/75/351/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 3000 bits/sec, 3 packets/sec
5 minute output rate 3000 bits/sec, 3 packets/sec
3962930 packets input, 1547443857 bytes, 640 no buffer
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
6677 input errors, 0 CRC, 0 frame, 5 overrun, 6666 ignored
0 input packets with dribble condition detected
5588762 packets output, 1453864156 bytes, 0 underruns
6666 output errors, 5697 collisions, 0 interface resets
0 babbles, 6480 late collision, 10494 deferred
186 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
Regards,
Anup
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