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New Member

UDLD on routed ports

We have bunch of 3550 access switches connected to two 6500 switches running IOS. The links between 3550 and 6500 are gigabut using multimode fibres. We use routed links instead of switched to the access-level.

This is the config on one of the 6500's:

interface GigabitEthernet3/6

description XXXXXXXXXXXXXXXXXX

ip address X.X.X.X X.X.X.X

no ip redirects

ip pim sparse-mode

udld disable

standby 1 priority 253 preempt

standby 1 ip X.X.X.X

and on the 3550:

interface GigabitEthernet0/1

description XXXXXXXXXXXXXXXX

switchport mode access

no ip address

spanning-tree portfast

Is it possible to turn on UDLD for these links? All UDLD-documents I can find only mention switched networks and gains regaring avoiding spanning-tree loops. We dont use spannig-tree to the access-level.

I'd appreciate if someone using the similar setup could enlighen me...

Thanks

2 REPLIES
New Member

Re: UDLD on routed ports

Although UDLD is a layer 2 protocol that helps you detect layer 1 faults, it can be used on pure layer 3 ports.

The reason it's often mentioned in connection with layer 2 networks and Spanning Tree loops is that UDLD can cut off a unidirectional link before you end up with a Spanning Tree loop.

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/12_1e/swconfig/udld.htm

New Member

Re: UDLD on routed ports

Thanks!

So....the recommendation would be to use it in this kind of setup? :)

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