Subject: Re: Using DU Mode of LDP

From: Luca Martini <[email-masked]>
Date: Wed, 20 Sep 2000 16:10:54 +0000

HANSEN CHAN wrote:
> 
> Dear all,
> 
> In draft-martini-l2circuit-trans-mpls-01.txt (and also another similar
> draft draft-malis-sonet-ces-mpls-00.txt), the use of downstream
> unsolicited mode of LDP is specified to setup VC LSP. Is there any
> technical reasons that prevent using RSVP-TE or downstream on demand
> mode of LDP?
> 
> Thanks,
> Hansen
RSVP-TE would have been a poor choice because we don't want state
associated with customers to be stored in the core of the service
provider network. This also makes RSVP scale poorly. LDP-DU is used
simply because it was the most common method implemented, and there is
some advantage in having a LSR offer mappings "at it's own pace".
Assuming we have an edge LSR with 100 LDP connections, I felt that it
might be safer to avoid receiving hundreds of mapping requests ( if LDP
DoD is used ) when the LSR starts up. Otherwise both modes can be used,
and should be compatible.

Luca

-- 
Just say no to summer. Ski all year !
Luca Martini Senior Network Architect, Level 3 Communications -
Broomfield, CO
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