input errors and crc errors counter are same

Vishnu Reddy · ‎01-15-2015

Hello,

This is a 2621XM router with 12.2(7r) version.

FastEthernet0/1 is up, line protocol is up
Hardware is AmdFE, address is 000d.bdc7.3fe1 (bia 000d.bdc7.3fe1)
Internet address is xx.xxx.22.254/26
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
     reliability 252/255, txload 3/255, rxload 6/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Full-duplex, 100Mb/s, 100BaseTX/FX
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 00:17:53
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: fifo
Output queue: 0/40 (size/max)
5 minute input rate 2554000 bits/sec, 423 packets/sec
5 minute output rate 1290000 bits/sec, 399 packets/sec
     419355 packets input, 334462917 bytes
     Received 49 broadcasts, 0 runts, 0 giants, 0 throttles
     9760 input errors, 9760 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog
     0 input packets with dribble condition detected
     383155 packets output, 143958497 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets

Both router FA0/1 interface and ASA 5510-k8 version 7.2(2) with e0/0 with IP: ip address xx.xxx.22.230 255.255.255.128

And speed and duplex is set manually to 100 and full.

ASA was giving late collisions after setting the speed and duplex to 100 and manual. Late collisions stopped.

I also noticed that the subnet masks are different i.e. 26 and 25. Does this make a difference? This is causing a headache.

Not sure if there are any devices in between or distance between the 2 devices. I verified that cable from ASA to going to internet gateway at coloc.

Need help to figure of what could be a problem.......!

AllertGen · ‎01-16-2015

Hello, vreddy002.

CRC is used at Ethernet frames to check that the packets that you're sending/getting is Ok (http://en.wikipedia.org/wiki/Ethernet_frame). All your errors means that all your input error packets was damaged. The collisions is not only one source of such problems.

Subnet mask don't has any effect to CRC because subnet mask is L3 (CRC is L2).

If interface at your side configured at auto/auto state what type of speed and duplex are you getting?

Vishnu Reddy · ‎01-16-2015

I didn't tried auto on both sides. Initially ASA was set to Auto and other end was set to 100 and full manual. ASA was showing late collisions which now stopped completey after setting it to full duplex and speed to 100Mbps manual. Now I am thinking it has to do with bad cable or bad port.

AllertGen · ‎01-18-2015

Hi, vreddy002.

Yes, usually CRC errors happens because of the physical problems. It can be a cable or the port problems. You can try check cable with the Lan tester. Also it'd be good to check the length of the UTP cable (and checking the cable category would be good too).

Also for a testing you can try this IOS tools: http://www.cisco.com/c/en/us/td/docs/ios/fundamentals/command/reference/cf_book/cf_t1.html But the lan tester will be better.

milan.kulik · ‎01-18-2015

Hi, as you said "Not sure if there are any devices in between or distance between the 2 devices." in your original post, I believe this is the crucial question to answer. It makes a sense to configure duplex/speed the same way, but you need to be sure the devices are directly connected each to the other. In a case you would configure both the ASA and router to 100/Full manually while there would be a switch between them configured to auto (and finished the autonegotiation in 100/Half duplex) you would see no collisions on your devices (as Full duplex simply does not check for collisions anymore) but still there would be framed damaged by duplex mismatch on the switch. And finally you would see CRC errors on your devices - as you are seeing currently. Best regards, Milan

Vishnu Reddy · ‎01-19-2015

Thanks for your reply.

Yes you are right as it sounds to me. Since its very difficult for me since cdp neighbors won't show any devices. So as far as my understanding when I set the ASA to full and 100Meg manual and the router to auto for speed and duplex it doesn't give any CRC errors this does prove that the packets are not getting damaged and there might be switch in the middle but its difficult for me to trace the cable. Also I am getting the some input errors and overruns which i suspect this is because of over bursting then the agreed bandwidth which is 10meg.

milan.kulik · ‎01-19-2015

Hi, yes, it's possible there is some Cisco switch with CDP disabled in the middle and that's why you don't see any neighbors via CDP. Best regards, Milan

Leo Laohoo · ‎01-19-2015

reliability 252/255, txload 3/255, rxload 6/255

CRC errors you are seeing is caused by a faulty cable. The value highlighted above should NEVER fall below 255. It should always be 255/255 for reliability and X/255 for txload and rxload respectively.

milan.kulik · ‎01-20-2015

Hi, I've seen CRC errors caused by duplex mismatch several times. So it may be a faulty cable or duplex mismatch causing all the trouble. Best regards, Milan

Leo Laohoo · ‎01-20-2015

Hi, I've seen CRC errors caused by duplex mismatch several times.

That is correct, Milan. There are a lot of causes for CRC errors, however, in this particular case we can't "drill down" the specific cause of the errors because there is no commands that I know of to do so on a router. If this was on a switch, you could use the command "sh controller ethernet <PORT>" (or "sh counter interface <PORT>" for a 6500".

So it may be a faulty cable or duplex mismatch causing all the trouble.

Maybe, but in this case, I'm very certain it's caused by a cable fault.