From: Hash!!! (hashng@gmail.com)
Date: Fri Nov 23 2007 - 12:50:14 ART
Gupta,
You will need to have the basic IP reachability for BGP peering sessions to
be established, check your frame relay configuration first and make sure you
can ping from spoke to spoke.
HTH
Hash
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Gupta, Gopal (NWCC)
Sent: Friday, November 23, 2007 6:26 PM
To: Salau, Yemi; Victor Cappuccio
Cc: Cisco certification
Subject: RE: BGP Next-Hop
No R1 cant ping R2/R3. I didn't define PVCs between spokes.
-----Original Message-----
From: Salau, Yemi [mailto:yemi.salau@siemens.com]
Sent: Friday, November 23, 2007 20:48
To: Victor Cappuccio; Gupta, Gopal (NWCC)
Cc: Cisco certification
Subject: RE: BGP Next-Hop
Just to add to Victor's comments ...
Next-hop-self is normally manually set within iBGP peers. The concept is
that my other internal neighbor doesn't know how to get to my own
external neighbor(can't ping it), so I'm telling him how to get there,
using myself as the next-hop to all routes coming from my external
neighbor.
In essense, eBGP don't need next-hop-self to be manually set as this
"should" happen within the process itself, well automatically. Hence,
"%BGP: next-hop-self is implied for an eBGP peer, there is no need to
configure it".
If it's not happening in your scenerio, then could this be down to the
NBMA setup? Can R1 ping R2/R3? etc.?
Many Thanks
Yemi Salau
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Victor Cappuccio
Sent: Friday, November 23, 2007 2:54 PM
To: Gupta, Gopal (NWCC)
Cc: Cisco certification
Subject: Re: BGP Next-Hop
Hi Gupta,
is 155.1.0.1 an external neighbor in your topology :)
Example:
WG6R3(config-router)#do show ip bgp neigh 4.4.4.4 | in external BGP
neighbor is 4.4.4.4, remote AS 4, external link
WG6R3(config-router)#!So you can not configure Next-Hop-Self here
WG6R3(config-router)#neigh 4.4.4.4 next-hop-self
%BGP: next-hop-self is implied for an eBGP peer, there is no need to
configure it WG6R3(config-router)#do show ip bgp neigh 2.2.2.2 | in
internal
EBGP next hops shall be announced using the IGP or you must Redistribute
connected interfaces into the IGP at the edge routers, or you must
Include links to EBGP neighbors into the IGP and configure them as
passive interfaces
You can configure an edge router to set its IP address as the next-hop
address even when the BGP updates are sent across IBGP sessions. As a
result, there is no need for the receiver of the IBGP information to
know how to reach the far end of the EBGP session, because that IP
address is no longer set as the next hop.
Both EBGP and IBGP sessions forward BGP updates but in slightly
different ways. BGP attributes are not changed when an update is sent
across an IBGP session unless next-hop-self is configured.
HTH
Victor Cappuccio
www.vcappuccio.wordpress.com
On Nov 23, 2007 3:03 PM, Gupta, Gopal (NWCC) <gopal.gupta@hp.com> wrote:
> 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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