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Home > Archive > CCNP > June 2003 > Collisions And Deffered On 3600 Router Interface
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Collisions And Deffered On 3600 Router Interface
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| haseeb_eng 2003-06-04, 3:33 am |
| my 3600 series router is showing me collisions and deffered . To troubbleshoot it i had tried to changed the cable , change the speed and duplex modes but none of them worked . Collisions are not happening very fast . What else could be the problem ?
PIC-SSB-RAS3640#sh int eth 0/0
Ethernet0/0 is up, line protocol is up
Hardware is AmdP2, address is 0007.eb1e.31c0 (bia 0007.eb1e.31c0)
Internet address is x.x.x.x/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)
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 4w4d
Queueing strategy: fifo
Output queue 0/40, 0 drops; input queue 0/75, 610 drops
5 minute input rate 48000 bits/sec, 16 packets/sec
5 minute output rate 6000 bits/sec, 7 packets/sec
44133874 packets input, 2467861701 bytes, 0 no buffer
Received 14709200 broadcasts, 0 runts, 0 giants, 0 throttles
4 input errors, 0 CRC, 0 frame, 0 overrun, 4 ignored
0 input packets with dribble condition detected
25652806 packets output, 127957916 bytes, 0 underruns
0 output errors, 91958 collisions, 0 interface resets
0 babbles, 0 late collision, 91011 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out | |
| Yankee 2003-06-04, 3:48 am |
| You have approx 3.6% collision rate which many senior techs would not trouble shoot especially if the router is connected to a hub. Deferred simply means that the frame waited in queue (was delayed) mostly because the wire was busy or a collision had occured, so it is not an error I pay much attention to.
I don't believe you have a real problem, but if you have more info making you think you do I would be happy to look at it.
Yankee | |
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| haseeb
I found a very good article on the Cisco web site, the link is:
http://www.cisco.com/en/US/partner/...
8009446d.shtml
Note that I have logged in with my CCO login, so you may have to modify the link; otherwise do a search on 'deferred collisons' and look for the article
'ethernet - troubleshooting ethernet collisions'. And then bookmark it for future reference.
Cheers
Hippo | |
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| Is this going to the same switch as in your other post??
The port doesn't have a lot of activity at 16 packets a second, it also looks like you haven't cleared the counters recently?? The 3.6% may be a red herring if were working on old data??
Clear your counters and watch it for a few hours. | |
| haseeb_eng 2003-06-04, 4:09 am |
| thanks yankee and hippo for your reply . Router is not having any delay but the customer need to know why these collisions are there . Last time clear counters was issued 1 months back . Mat it is not connected to the same switch . Now i will clear the counters again and will see the time between every collision | |
| forbdnlovr 2003-06-04, 5:41 am |
| Hmmm... according to Cisco site, if it's full duplex ethernet, collision detection should be disabled. It should be considering that full duplex ethernet should not have collisions at all. What are you connecting to that interface? Could it be worn out cabling? Well, as Yankee has said, it is insignificant percentage of collisions but if both this interface and the one device it's connecting to is full duplex, collisions should be out of the question. | |
| anchor40 2003-06-04, 9:16 am |
| A couple of things need clarification, haseeb -
1) Is the router connected to a switch or a hub?
2) What duplex is it set for? Your post did not state what it was left at.
3) What protocols are running on that segment?
If there is a duplex mis-match, you'd see runts (there are none, so duplex is probably fine), but if there's a device that is broadcasting a lot, or a LAN protocol that relies on broadcasts, maybe the network segment size could be reduced. Or, if this really is a RAS concentrator, it should be on its own segment, like a DMZ to protect the internal network.
Food for thought... | |
| cloudd 2003-06-04, 10:52 am |
| Noticed the same thing happening for all eth interfaces, even though the corresponding port to the other router / switch is a Fast Eth port regardless of the duplex settings.
I guess if you want to totally eliminate that, you could try change your connection to a spare Fast Eth port. That should solve your problem. However, we haven't had any user complaining about slow transfer or anything like that. | |
| Yankee 2003-06-04, 12:15 pm |
| If the collisions are incrementing on E0/0 as he indicated, the router side must be set to half duplex. You won't see runts if router is set to full and the other is half, but you will see CRC and frame errors if this was the case.
Collisions are expected in half-duplex. They are simply a fact of life, though you should watch the percent of collisions in that enviroment.
If the customer is so concerned about a low level of collisions then they don't know anything and you can make them happy by changing both sides to full duplex if they both support it.
10 or 100M is not an issue for this site unless it was 10M and attempting to pass over 3M of traffic over a sustained period of time (30% utilization is the key). If that were happening you would need to look for more bandwidth.
In my opinion what I have seen is not an issue and the best answer may be educating the customer.
Yankee |
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