From: Dwi C Taniel (dc@dwichandra.info)
Date: Fri Feb 23 2007 - 02:15:15 ART
... and here is the example if you needed it (at least I got the idea
better with this example)
R1 (AS1) --- R2 (AS2) --- R3 (AS2) --- R4 (AS2) --- R5 (AS3)
The 'neighbor x.x.x.x next-hop-self' would need to be in R2 and R4 for
their neighbourship with R3 (yes, in some countries they spelled it
'neighbour', which give me problem in configuring bgp in the past.
Thanks to the 'neigh' shortcut that remove this problem)
Thus, R3 would be informed by R2 and R4 for reachability to R1 (AS1)
and R5 (AS3).
Without 'next-hop-self', R3 would receive the NLRI (CMIIW for the
terms as I am still a barbaric network engineer) but did not have the
'best' selected (the one with symbol '>' from 'show ip bgp' in R3)
Hope it helps ;)
DC
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dc@dwichandra.info
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On 02/23/2007, "Schulz, Dave" <DSchulz@dpsciences.com> wrote:
> Dennis -
>
> When a route is received via ebgp, and passed into ibgp....the next hop
> is not manipulated. Therefore, the routers within the AS will not know
> how to reach this next hop (learned by ebgp).
>
> By using the next-hop-self command, the AS border router is set as the
> next hop. This allows the other routers within the AS reachability,
> since the border router knows how to reach the route on the next AS.
>
>
> Dave Schulz,
> Email: dschulz@dpsciences.com
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> dennis lin
> Sent: Thursday, February 22, 2007 10:13 PM
> To: ccielab@groupstudy.com
> Subject: BGP --neighbor x.x.x.x next-hop-self
>
> I am quite confused about this BGP command: neighbor
> x.x.x.xnext-hop-self Do you know under what situation I have to
> issue this
> command? Thanks
>
>
> Dennis
>
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