From: Elias Chari (elias.chari@gmail.com)
Date: Mon Aug 21 2006 - 16:03:36 ART
Apologies, one of my statements earlier was misleading. P routers will run
RSVP if MPLS-TE is deployed.
On 8/21/06, Elias Chari <elias.chari@gmail.com> wrote:
>
> Hi Tim,
>
> Just to add add a point which may interest you. With MPLS the intelligence
> is pushed to the edge (PE routers) whilst your core (P routers) just does
> the switching. The PE and P routers will use an IGP normally ISIS (or OSPF
> in some cases) to build the Global Routing Table, which normally contains
> internal network prefixes. This means that the routing table of the core can
> be very small in comparison to the PE routers which will run MP-iBGP to
> exchange vpnv4 routes and maintain VRFs.
>
> The result of this is that the core is not overloaded with protocols such
> as MP-iBGP, RSVP (for MPLS-TE) and large routing tables as all of that is
> done at the PE level. One could argue that as less resources are consumed in
> the core, it can switch traffic more efficiently.
>
> Having said that the control and forwarding plane are separated in
> distributed architectures such as the GSR 12k, however this undoubtedly
> helps even in such cases.
>
> Rgds
> Elias
>
>
> On 8/21/06, Tim <ccie2be@nyc.rr.com> wrote:
> >
> > Hey Chris,
> >
> >
> >
> > Thanks much.
> >
> >
> >
> > I had a feeling that what you described was the case but it's great to
> > have
> > confirmation from someone who is obviously much more knowledgeable about
> > this than I am.
> >
> >
> >
> > Tim
> >
> >
> >
> > _____
> >
> > From: Chris Broadway [mailto: midatlanticnet@gmail.com ]
> > Sent: Monday, August 21, 2006 12:18 PM
> > To: Tim
> > Cc: ccielab@groupstudy.com
> > Subject: Re: MPLS speed -- switching vs IP routing
> >
> >
> >
> > Back in the old days of using the 7500s, MPLS (tag switching) was faster
> >
> > than routing due to the method of route lookups. Modern routers do not
> > look
> > up routes the same, so there is really no speed diference between layer
> > 3
> > and layer 2 lookups. But, when you read up on MPLS, they still state
> > speed
> > is a reson to use it. The real reson to use MPLS is the services that
> > you
> > would use on top of it.
> >
> >
> >
> > -Broadway
> >
> > _______________________________________________________________________
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