Re: [nsp] Cisco vs. Juniper of LSP setup

From: LU (wenxuecity2001@yahoo.com)
Date: Fri Apr 12 2002 - 16:55:20 EDT


--- Sean Crocker <crockers@mail.trinicom.com> wrote:
> >I may be missing some thing here.
> >
> >If there are multiple IGP paths and only one of
> them
> >has the bandwidth demanded from the LSP, even if
> >without TE-database, we should be able to get
> there,
> >just try them one by one till it finds it.
>
> With most (if not all) implementations, if you
> lobotomize them by
> turning CSPF off, they'll simply signal RSVP-TE
> towards the egress
> according to the RIB, and the reservation will
> either get all the way
> there because it passes admission control at every
> intermediate node,
> or a node will reject it and send back a PATHERR
> saying why it didn't
> pass... which continues every 30 seconds forever
> until someone fixes
> the issue. What you want to do is fine if you're
> playing around in
> the lab, but makes no sense in a production network.
> Cisco's CLI is
> just geared that way. It may change over time, it
> may not.

I think we are aware that's how IOS geared, but I just
do not think it is the only way.

>
> >If I want to a static LSP, I can just define the
> path
> >and bandwidth, if it can be accepted or not is
> another
> >story which depends on my estimation of the path
> >status. Is that how people calculate LSPs off-line
> in
> >stead of on-line?
>
> There may be other ways for an offline calculation
> server to get
> enough information to make smart decisions (netflow,
> etc.), but I
> believe in general offline calculation would also
> use IGP-TE. It
> could get information from the tunnel ingresses in
> some fashion, but
> how do you think they'd get their information?
> (here's a hint: IGP-TE)

IGP-TE is the only way? Can I just get some link
utilization information from, say MRTG and calculate
LSP once a week?

>
> >I think wether static is useful or not, it should
> be
> >up to the users, I guess that's why we still have
> >static and dynamic routing protocols.
>
> Sure, there's enough rope for everyone :-)
>

If the user have not other choice, sometimes I guess
it does not matter too much.

> Sean
>

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