Trunk ports are not passing traffic through correctly

Unanswered Question
Aug 17th, 2007

We have a Cisco 2801 plugged in to a CAT2950 switch. The router IOS is c2801-advipservicesk9-mz.124-8c.bin and the switch IOS is c2950-i6q4l2-mz.121-22.EA9.bin.

When the devices are reset/reloaded the state of the link between the devices comes up but CRC errors are shown on the switch port and there is 80-90% packet loss.

If a different switch port is used the problem still occurs. The router interface is fastethernet0/1 and the switch interface is fastethernet0/3.

The only way to stop the errors is to manually shutdown and then open the interfaces.

Switch Port

interface FastEthernet0/3

description **** Trunk link to router FastEthernet0/1 ****

switchport trunk allowed vlan X,X,X

switchport mode trunk

speed 100

duplex full

Router port

interface FastEthernet0/1

description Trunk to Switch FastEthernet 0/3

no ip address

no ip route-cache cef

no ip route-cache

no ip split-horizon

speed 100



I have this problem too.
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ankbhasi Fri, 08/17/2007 - 01:05

Hi Friend,

You have configured trunk on switch but have you configured any subinterfaces on routers with encapsulation and dot1q? Also can you remove manual speed and duplex settings and keep them as auto auto?



flashsplash Sun, 08/19/2007 - 16:43

hi mayam can u post the output of the show interface trunk command?

bye flash


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