6500, sup2, msfc2 and WS-X6516-GE-TX

[roadhouse1387]

Hi,

Just finished sorting out a routing problem which I traced back to a routed port on a WS-X6516-GE-TX. The port had a 100meg LES circuit attached to it, with the speed and duplex set to 100meg/FD.

However, the interface (on sh interface command) was still showing a bandwidth of 1gig preventing EIGRP from calculating the expected metric for the link. Simply setting the bandwidth statement on the interface to match the configured line rate sorted the problem out.

What I would like to know is given that we have a number of 6500 with sup720's, some cat 4500's and some 3550's all routing and they all show the correct linerate based on the speed settings, without the need to set the bandwidth command on each interface.

Is this something peculiar to sup2's/msfc2's ? I cant find any mention of this on tac or the knowledge base, or is this something new ?

Cheers

Shaun

[eofelt]

Is it auto-negotiation/sensing you are asking about or default settings on the sup?

[roadhouse1387]

Hi, Thanks for the reply.

Its to do with the bandwidth value which EIGRP takes from the interface in order to calulate the feasable distance for routes dependant on that particular interface.

To illustrate..in this configuration..

interface GigabitEthernet5/1

description L3-LES-To-JCH

ip address 192.168.0.9 255.255.255.248

speed 100

duplex full

mls qos trust dscp

end

The line rate is set to 100meg. But if you do a show interface command....you get this...

CIVCOR001#sh int gig5/1

GigabitEthernet5/1 is up, line protocol is up (connected)

Hardware is C6k 1000Mb 802.3, address is 000a.8b9d.2c0a (bia 000a.8b9d.2c0a)

Description: L3-LES-To-JCH

Internet address is 192.168.0.9/29

MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,.....truncated...

Notice how the BW parameter is displaying 1000000 (1gig) despite the line rate being configured to 100 meg.

To fix it, I applied 'Bandwidth 100000' to the interface. This had the desired effect and changed the BW parameter in the show interface output. Subsequently, EIGRP calculated the metrics I was expecting to see.

On every other switching platform I have used, this happens automatically. Even the 6500's we have with SUP720's. I have never had to manually set the bandwidth parameter of an interface to ensure the correct linerate reporting before.

I am wondering if anyone else has seen this ?or knows if it is a documented problem/feature ?

Cheers

Shaun

[eofelt]

I understand now. It's an interesting issue but I have not seen this yet, maybe others will reply.