Re: BGP LABEL LSP

Read up on PHP, this might help.

JS

On Mon, Dec 10, 2012 at 8:00 PM, Routing Freak <routingfreak_at_gmail.com>wrote:

> Anybody get this ? ANy thoughts on this ?
>
>
>
>
> On Mon, Dec 10, 2012 at 10:41 PM, Routing Freak <routingfreak_at_gmail.com
> >wrote:
>
> > Hi
> >
> > I have a topology like this
> >
> > ____________ibgp______________
> >
> > R5------------------R1-------------------R2-----------------------R3
> > ibgp ebgp ebgp
> >
> >
> > R1 and R3 are running iBGP in AS 100 and R1 and R2 are running eBGP with
> > R2 in AS 200 and respectively R2 and R3 are eBGP neighbors.
> >
> > There is no physical connection between R1 and R3 . There is an iBGP peer
> > between R1 and R3 via R2 which is a eBGP peer with both R1 and R3
> >
> > Now R1 is a RR and R5 and R3 are clients
> >
> > MPLS is enabled between R1 and R2 and R2 and R3. But there is no LDP or
> > RSVP enabled on those interfaces.I have just enabled the forwarding place
> > saying that this interface can receive labelled packets.
> >
> > R3 is learning R5's routes via R1's iBGP connection with a next hop as
> R5.
> >
> > R5's loopback is advertised as ebGP route to R2 from R1 and it is passed
> > to R3 from R2 as eBGP route.
> >
> > Now when R1 is sending as Ipv4 Unicast routes with Labels on it. ( with
> > Send label option ) to R2.
> >
> > R2 is also having the send label in the eBGP peering with R3 .
> >
> > So now for R3 to reach R5s loopback there it should use a label sent from
> > eBGP neighbor R2.
> >
> > So now here is the problem part. I dont have a label for the prefixes (
> ie
> > R5 advertised prefixes ) and i only have the next hop which is R5
> loopback
> > label ( ie advertised by R2 to R3 ) .
> >
> > So when R3 is sending traffic to R5's prefixes, will it use the BGP label
> > to R2 and R2 will use the BGP label to reach R1 and then R1 will strip
> the
> > label and do a normal routing lookup to send traffic to R5
> >
> > Will BGP label forms an LSP ?. When a next hop in a BGP table is again
> > learned by BGP, will it use the BGP label to send the traffic ?
> >
> > Without the prefix label , will only the next hop BGP label will work to
> > form LSP ?
>
>
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Received on Tue Dec 11 2012 - 14:43:48 ART