Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

udld

udld basic questions

1.what kind of hello packets UDLD is using? multicast?

2.only aggressive mode send hello packet? non-aggessive will detect link problem by real traffic?

Thanks

1 REPLY
Purple

Re: udld

Answers to your questions:

1. UDLD sends packets to a destination MAC address of 0100.0CCC.CCCC, which is a multicast address. It uses the following format:

UDLD SNAP format:

LLC value 0xAAAA03

Org Id 0x00000C

HDLC protocol type 0x0111

2. Both aggressive and normal mode UDLD uses UDLD messages; the difference is that the normal mode UDLD will consider the port to be in a "undetermined" state if the hellos time out. In aggressive mode, the port will be disabled ..

Hope that helps - pls do rate the post if it does.

Paresh

219
Views
0
Helpful
1
Replies
CreatePlease login to create content