From: Gupta, Gopal (NWCC) (gopal.gupta@hp.com)
Date: Fri Nov 23 2007 - 12:49:09 ART
Thanks for your inputs,
Till here its fine, but i would like to know why we cant we use neighbor
x.x.x.x next-hop-self command in this case, why to set next-hop
manually; this is waht my concern is.
Thanks
Gops
________________________________
From: Joel Amao [mailto:femmy79@hotmail.com]
Sent: Friday, November 23, 2007 21:14
To: Gupta, Gopal (NWCC); Cisco certification
Subject: RE: BGP Next-Hop
Hello Gupta,
what you are seeing is normal and expected.
There is an exception to egbg next hop modification in broadcast and
NBMA mode called third-party next hop modification.
The normal rule regarding next-hop modification is below;
1. If the route is locally originated set the NEXT-HOP to the peering
ip address (even if sent to an IBGP peer)
2. If the route is propagated to an eBGP peer, set the NEXT-HOP to our
peering ip address
3. If the route is propagated to an iBGP peer, do not change the
NEXT-HOP
**exception to this rule **When two peers are in a multiaccess network
(Frame Relay multipoint interface, Ethernet, etc) we dont change the
next-hop.
thanks,
Joel Amao
CCIE#18128
> Subject: BGP Next-Hop
> Date: Fri, 23 Nov 2007 19:33:56 +0530
> From: gopal.gupta@hp.com
> To: ccielab@groupstudy.com
>
> Hi Folks,
>
> I am facing issue with BGP..
>
> R1 , R2, R3 are spokes connected to hub R5 throgh Frame relay .... all
> with the major interface.
> having subnet 155.1.0.0/24 and all are in their own individual AS ; R1
> is in AS1, R2 in 2, R3 in 3, R5 in 5.
>
> when routes originated by R2 are sent to R5 and then R5 in turn sends
> that route to R3 or R1, the next hop doesn't change which should be
> changed coz of EBGP connections and should not be changed coz of
> Frame-relay NBMA on same subnet.
>
> and if i try to set next-hop-self under neighbor stement on R5 for
> R1,R2&R3..i get an error message
>
> R5(config-router)#neighbor 155.1.0.1 next-hop-self
> %BGP: next-hop-self is implied for an eBGP peer, there is no need to
> configure it
> R5(config-router)#neighbor 155.1.0.2 next-hop-self
> %BGP: next-hop-self is implied for an eBGP peer, there is no need to
> configure it
> R5(config-router)#neighbor 155.1.0.3 next-hop-self
> %BGP: next-hop-self is implied for an eBGP peer, there is no need to
> configure it
>
> I know i can set it manually throgh Route-map, is this the only way we
> can have workaround or i am missing something.....not sure.
>
> Any Comments please !!!!!!
>
> Best Regards,
> Gops
>
>
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