I am seeing input and CRC errors on WAN interface at one of branch router. Topology overview is : WAN----> Adtran 3430 (eth 0/1) -------> Juniper 2200 (LAN via eth 0/2).
We are using site to site VPN at this router.
show run int eth 0/1
interface eth 0/1
description Spectrum IP is ************
ip address *************** 255.255.255.252
ip access-policy Public
ip crypto map VPN
no lldp send-and-receive
Here is details output for interface:
sh int eth 0/1
eth 0/1 is UP, line protocol is UP
Description: Spectrum IP is ************
Hardware address is **************
Ip address is **********, netmask is 255.255.255.252
IP MTU is 1500 bytes
BW is 100000 Kbit
ARP type: ARPA; ARP timeout is 20 minutes
Last clearing of "show interface" counters: 02:51:50
5 minute input rate 138080 bits/sec, 29 packets/sec
5 minute output rate 72320 bits/sec, 36 packets/sec
Queueing method: fifo
Output queue: 0/256/0 (size/max total/drops)
Interface Shaper: NOT ENABLED
426676 packets input, 238919227 bytes
426620 unicasts, 56 broadcasts, 0 multicasts input
0 unknown protocol, 0 symbol errors, 0 discards
3731 input errors, 0 runts, 0 giants
0 no buffer, 0 overruns, 0 internal receive errors
0 alignment errors, 3731 crc errors
463362 packets output, 131887741 bytes
463362 unicasts, 0 broadcasts, 0 multicasts output
0 output errors, 0 deferred, 0 discards
0 single, 0 multiple, 0 late collisions
0 excessive collisions, 0 underruns
0 internal transmit errors, 0 carrier sense errors
0 resets, 0 throttles
Please suggest me some troubleshooting tips.
You probably have a duplex mismatch. When you specify "speed 100" that turns off auto-negotiation. The other side will then fall back to half-duplex. I would suggest that you remove the "speed 100" statement in the interface configuration. This will probably cause the interface to bounce. Then clear counters and see if the errors continue to increment.
If this doesn't fix it or the interface doesn't recover, you may need to use a crossover cable if the other side doesn't do auto-MDI-X.
If it still doesn't want to behave, you may need to go to the connected device on eth 0/1 and configure both sides to 100Mbits and full duplex. I bet simply removing the "speed 100" statement will fix it.
interface eth 0/1
no speed 100
clear counter eth 0/1
show int eth 0/1
[wait a couple of minutes]
show int eth 01
Look for incrementing errors.