The MPLS WG Archive

["Gopal@Yahoo" <gnaganab@yahoo.com>]

Sachin, You wrote "...As NHS is disabled on PE2, the
new route will have CE's address as "BGP Next Hop"....

That is not right. On remote-PE vpn-v4 route will not
have another vpnv4 addr as the next-hop. On PE-1
next-hop addr for vpnv4 routes will not be the CE
addr. The next-hop addr would some ipv4 addr of PE-2.

There is only one bgp session btw PE1 and PE2. For
ipv4 and vpn-v4 address family routes, the next-hop is
going to be a ipv4 address. If next-hop-self is
disabled, you need to config some ipv4 addr as the
next-hop. PE1 will use this ipv4 next-hop's label as
the outer label.
Does it answer your q?
cheers,
Gopal

--- Sachin Kalra <skalra@opnet.com> wrote:
> Dear MPLS Community:
> 
> I would appreciate if someone can answer the
> following question about 
> BGP-MPLS VPNs.
> 
> Lets say we have the following topology:
> 
> [CE1]                                               
>               [CE11]
>          \                                          
>                  /
>          
> [PE1]-----------------[Rtr1]-------------------[PE2]
>          /                                          
>                  \
> [CE2]                                               
>              [CE22]
> 
> 
> 1. Running IBGP between PE1 and PE2.
> 2. Running EBGP between all PEs and CEs.
> 3. BGP "Next Hop Self (NHS)" option is disabled on
> PEs.
> 
> Now, when PE1 receive a route from PE2, how will PE1
> know "BGP Next Hop" 
> address for that route? As NHS is disabled on PE2,
> the new route will have 
> CE's address as "BGP Next Hop", and PE1 will not be
> able to find any LSP 
> going to that CE.
> 
> Is this correct?
> 
> I appreciate your response.
> Thanks,
> Sachin Kalra
> 


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