input error

[Danilo Dy]

Hi,

My C7507 Router FastEthernet Interface is receiving a lot of "input error" as shown below. What could be the cause of this? The interface is configured Full-Duplex.

FastEthernet4/0/0 is up, line protocol is up

Hardware is cyBus FastEthernet Interface, address is 00d0.066a.8480 (bia 00d0.066a.8480)

Description: 100Mbps link to APOLLO-II

Internet address is 202.90.16.105/29

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

reliability 255/255, txload 7/255, rxload 2/255

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 00:00:19, output 00:00:03, output hang never

Last clearing of "show interface" counters 00:02:51

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 1003000 bits/sec, 697 packets/sec

5 minute output rate 2778000 bits/sec, 582 packets/sec

119027 packets input, 21617396 bytes, 0 no buffer

Received 6 broadcasts, 0 runts, 0 giants, 0 throttles

594 input errors, 594 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog

0 input packets with dribble condition detected

97893 packets output, 54687022 bytes, 0 underruns

[jolmo · Accepted solution]

Your router's input errors are CRC errors. This can indicate excessive noise or transmission problems on the LAN or the LAN bus itself. A high number of CRCs is usually the result of collisions or a station transmitting bad data.

Check cables to determine whether any are damaged. Also ensure Category 5 cabling is being used and not another type, such as Category 3.

HTH

[a.grauso · Accepted solution]

You have 594 input errors = 594 CRC

CRC= Cyclic redundancy checksum generated by the originating LAN station or far-end device does not match the checksum calculated from the data received. On a LAN, this usually indicates noise or transmission problems on the LAN interface or the LAN bus itself. A high number of CRCs is usually the result of collisions or a station transmitting bad data.

Check endpoint is configured 100/full, try to replace cable. An extended ping will help you to check connection sanity.

Alex

[Danilo Dy]

Actually the connection is this;

C10000<---->PacketShaper<---->C7500

Both routers have "input error" on its FastEthernet Interface. No "output error".

I thought it's the PacketShaper problem, so I checked on the PacketShaper Interface. The interface facing C7500 have "input error", I was expecting "output error" but nothing. The interface facing C10000 doesn't have any error at all. I shutdown the PacketShaper (so it become just a piece of wire), but the "input error" in both routers are still accumulating very fast.

I did suspect it as a cabling problem, but I need a second opinion.