From: Brian Dennis (brian@labforge.com)
Date: Thu Mar 13 2003 - 13:47:49 GMT-3
This doesn't mean AS1 will be the next hop for AS3 to get to AS2. This
is a multi-access network so AS1 will not alter the next hop by default.
If AS2 and AS3 were on separate IP subnets then AS1 will alter the next
hop. Here is an example:
AS3#sho run
<snip>
hostname AS3
!
interface Loopback3
ip address 3.3.3.3 255.255.255.255
!
interface Serial1/0
ip address 10.1.1.3 255.255.255.0
encapsulation frame-relay
no arp frame-relay
frame-relay map ip 10.1.1.1 301 broadcast
no frame-relay inverse-arp
!
router bgp 3
network 3.0.0.0
neighbor 10.1.1.1 remote-as 1
!
<snip>
AS3#sho ip bgp
BGP table version is 2, local router ID is 3.3.3.3
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 3.0.0.0 0.0.0.0 0 32768 i
AS3#
AS1#sho run
<snip>
!
hostname AS1
!
interface Serial0/0.1 multipoint
ip address 10.1.1.1 255.255.255.0
no arp frame-relay
frame-relay map ip 10.1.1.2 102 broadcast
frame-relay map ip 10.1.1.3 103 broadcast
no frame-relay inverse-arp
!
router bgp 1
bgp log-neighbor-changes
neighbor 10.1.1.2 remote-as 2
neighbor 10.1.1.3 remote-as 3
<snip>
AS1#sho ip bgp
BGP table version is 2, local router ID is 10.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 3.0.0.0 10.1.1.3 0 0 3 i
AS1#
AS2#sho run
<snip>
hostname AS2
!
interface Serial0/0
ip address 10.1.1.2 255.255.255.0
encapsulation frame-relay
no arp frame-relay
frame-relay map ip 10.1.1.1 201 broadcast
no frame-relay inverse-arp
!
router bgp 2
bgp log-neighbor-changes
neighbor 10.1.1.1 remote-as 1
!
<snip>
AS2#sho ip bgp
BGP table version is 2, local router ID is 10.1.1.2
Status codes: s suppressed, d damped, h history, * valid, > best, i -
internal
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
*> 3.0.0.0 10.1.1.3 0 1 3 i
AS2#
Brian Dennis, CCIE #2210 (R&S/ISP Dial/Security) CCSI# 98640
brian@labforge.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
CCIE FUN
Sent: Thursday, March 13, 2003 7:36 AM
To: Sanfilippo, Ted; 'ccielab@groupstudy.com'
Subject: Re: BGP and Multipoint interface
I don't think you would need to use next hop self on
any router.
since you are running EBGP. your next hop for any AS
would be its neighbor( specified in the neighbor
statement)
this means AS1 is next hop for AS3 to get to AS2( it
at all you are allowing AS1 to be a transit AS to get
to AS2.
--- "Sanfilippo, Ted" <Ted.Sanfilippo@PaeTec.com>
wrote:
> Does anyone know of issues with the following set-up
> fro BGP on a Frame
> Network:
>
>
>
> AS2
> /
> /
> AS1 --------
> \
> \
> AS3
>
> All sites are on a frame relay network and AS1 is
> Multipoint and AS2 and AS3
> are point-point to AS1.
>
> Do I need to use Next-hop self on AS1?AS2?AS3?
>
>
> Ted Sanfilippo
> Manager of Backbone Network Engineering
>
> PaeTec Communications
> One PaeTec Plaza
> 600 Willowbrook Office Park
> Fairport, NY 14450
>
> Tel: 585-340-2722
> Fax: 585-340-2786
> Email: ted.sanfilippo@paetec.com
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