tdp ldp confusion

Unanswered Question
Aug 30th, 2007


There are many very similar cmd for ldp and tdp..e.g

no tag-switching propogate-ttl forwrd

no mpls propogate-ttl forward

Can we use the commdnas interchangebly or it depends on whcih protocol is in use..



I have this problem too.
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mheusing Thu, 08/30/2007 - 23:33


The main commands to choose LDP vs. TDP are

1) Router(config)#mpls label protocol [ldp|tdp]

2) Router(config-if)#mpls label protocol [ldp|tdp|both]

where 1) sets the global default and 2) sets the protocol per interface, even allowing to turn on both at the same time.

Besides the two commands above, all other commands do not indicate LDP vs. TDP, i.e. the commands are the same whether LDP or TDP is activated (or both).

Depending on your IOS "mpls" and "ldp" are used in the CLI parser or "tag-switching" and "tdp". The CLI parser expects different ASCI strings, but the underlying functionality is the same. A little confusing, I agree.

So in brief as a rule of thumbs: Whatever command you use they work for both, LDP and TDP with one exception: "mpls label protocol [ldp|tdp]" lets you decide, which one is used.

It is always possible to check, which protocol is used, by executing f.e. a "show mpls ldp discovery". This one will show you on a per interface basis, if LDP or TDP or even both are enabled.

Hope this helps! PLease rate all posts.

Regards, Martin


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