02-23-2012 08:42 AM - edited 03-04-2019 03:24 PM
Hi,
First thanks for your time.
I have this output from show interfaces command for the fastethernet interface on a 2811 router.
Can any one help me find the causes of the crc and the ignored input errors on the interface?
The interface configuration is:
interface FastEthernet0/0
description VLANS_CHILE
no ip address
ip route-cache flow
duplex full
speed 100
And it's pluged to gigabit interface on a 3560 switch witth version 12.2(25r)SEE4
The interface has subinterfaces. As an aexample:
interface FastEthernet0/0.1
description Vlan Marketing & Directorio $FW_INSIDE$
encapsulation dot1Q 20
ip address 192.168.20.19 255.255.255.0
ip helper-address 192.168.23.100
ip nbar protocol-discovery
ip flow ingress
ipx encapsulation NOVELL-ETHER
ipx network 21
ipx type-20-propagation
standby 20 ip 192.168.20.1
standby 20 priority 130
standby 20 preempt
Here is the configuration of the interface on the switch:
interface GigabitEthernet0/40
description Hacia GW2_XCL
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,20-27
switchport mode trunk
speed 100
duplex full
Thanks in advance.
Regards.
Samuel.
The output from the router's interface:
GW2_XCL#sh int fas 0/0
FastEthernet0/0 is up, line protocol is up
Hardware is MV96340 Ethernet, address is 001b.d4be.66e8 (bia 001b.d4be.66e8)
Description: VLANS_CHILE
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 255/255, txload 99/255, rxload 99/255
Encapsulation 802.1Q Virtual LAN, Vlan ID 1., 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 02:34:53
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 38975000 bits/sec, 4344 packets/sec
5 minute output rate 38959000 bits/sec, 4340 packets/sec
43681411 packets input, 1886473 bytes
Received 157807 broadcasts, 8 runts, 0 giants, 0 throttles
104 input errors, 54 CRC, 0 frame, 0 overrun, 42 ignored
0 watchdog
0 input packets with dribble condition detected
43695253 packets output, 4277351296 bytes, 0 underruns
0 output errors, 0 collisions, 0 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
02-23-2012 08:44 AM
Have you tried swapping the cables?
If so, try connecting the router to another interface in the switch - it could be a bad port at either end.
02-23-2012 09:09 AM
Thanks, for your answer.
Yes I have changed cables, with the same results.
I will change to another port on the switch, later this evening (people are working now). I haven't tried that yet.
Question:
If the problem is something phisical on the router's interface, why I don't have errors on the other side, on the switch interface?, It's that normal?
Thanks.
Regards.
Samuel.
02-23-2012 10:51 AM
Hey Samuel,
CRCs are considered input errors, and usually point to an issue with the other side of the physical connection. So, to answer your question it's normal to see CRCs on only one side of a link. That's most likely why Edison suggested you try connecting to a different switch port.
If you are going to change switch ports, I would suggest making sure you are moving to a different ASIC as well. To determine port / ASIC mappings, you can do a 'show platform pm if-numbers'.
Also, have you tried using auto-negotiated speed and duplex on this links? Since they're hardcoded you shouldn't see a mismatch, but just something to try..
Hope this helps!
02-23-2012 01:56 PM
1. Remove the "speed 100" from your switch. Instead try "speed auto 10 100".
2. Remove the speed 100 from your router.
3. On your switch, try the following:
Command: test cable tdr interface
Wait for about 5 to 7 seconds;
Command: sh cable tdr interface
Post the output
02-24-2012 06:08 AM
Hi,
Here is the output:
Interface Speed Local pair Pair length Remote pair Pair status
--------- ----- ---------- ------------------ ----------- --------------------
Gi0/40 100M Pair A 2 +/- 4 meters Pair A Normal
Pair B 2 +/- 4 meters Pair B Normal
Pair C 2 +/- 4 meters Pair C Short
Pair D 2 +/- 4 meters Pair D Short
I change the cable, with identical result.
I also set speed auto in both sides as you say.
Thanks.
Regards
02-27-2012 06:50 AM
Hi,
It is normal to have pairs C and D in shoert?
I have changed cables with identical result, each time.
Thanks.
Regards
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide