[nsp] Inter-Vlan Routing Problem

Oreste Dimaggio oreste.dimaggio at clio.it
Fri Nov 7 06:03:02 EST 2003


I'm getting some strange performance issues with inter vlan routing
on a 802.1q FastEthernet Trunk between a Catalyst 2950 and 7206.

We have about 10 vlan configured on 2950 and 10 subinterfaces on 7206.
File transfers between PC of these vlans are very slow (about 120k/s).

I checked port speed, duplex on both end of trunk and they are 100fdx.
I tried a filetransfer between 2 PC in the same vlan, and it was FAST.
Trunk is near empty (no traffic).
I get slow file transfers only if both ends are on different vlans,
no matter what vlans are.

Ios on 7206: c7200-ik9o3s-mz.122-19a.bin  IP PLUS/FW/IDS 3DES
Ios on 2950: c2950-i6q4l2-mz.121-13.EA1c.bin  Standard Image

A piace of 7200 configuration

interface FastEthernet5/1
 description "Trunk verso core1.sw porta 24"
 no ip address
 no ip redirects
 no ip proxy-arp
 duplex full
 no cdp enable
interface FastEthernet5/1.2
 encapsulation dot1Q 2 
 ip address
 no cdp enable

A piece of 2950 configuration

interface FastEthernet0/23
 switchport access vlan 2
 switchport mode access
 no ip address
interface FastEthernet0/24
 switchport mode trunk
 no ip address
 duplex full
 speed 100

Any suggestions on how to solve or trace this mess?


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