Re: BGP- Conditional attribute

Hi,

I'm not sure if I understand the scenario exactly.

But here is a conditional scenario where 7.7.7.7 will be in the AS300
bgp table but won't be advertised to AS200 if there is no default
route. The conditional syntax determines whether a network is
announced or withdrawn from the neighbor in question.

-Rich

>>>>>>>>>>no default route<<<<<<<<<<<<<<<<<
Router R1

router bgp 200
 no synchronization
 bgp log-neighbor-changes
 neighbor 9.9.12.2 remote-as 300
 default-information originate
 no redistribute static
 no auto-summary
!
ip forward-protocol nd
ip route 0.0.0.0 0.0.0.0 Null0

R1#sh ip bgp
BGP table version is 2, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network Next Hop Metric LocPrf Weight Path
*> 8.8.8.8/32 9.9.12.2 0 0 300 i
R1#

Router R2

router bgp 300
 no synchronization
 bgp log-neighbor-changes
 network 7.7.7.7 mask 255.255.255.255
 network 8.8.8.8 mask 255.255.255.255
 neighbor 9.9.12.1 remote-as 200
 neighbor 9.9.12.1 advertise-map PC exist-map DEFAULT
 no auto-summary
!

!
ip prefix-list DEFAULT seq 5 permit 0.0.0.0/0
!
ip prefix-list PC seq 5 permit 7.7.7.7/32

!
!
!
!
route-map PC permit 10
 match ip address prefix-list PC
!
route-map DEFAULT permit 10
 match ip address prefix-list DEFAULT
!

R2#sh ip bgp
BGP table version is 7, local router ID is 8.8.8.8
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network Next Hop Metric LocPrf Weight Path
*> 7.7.7.7/32 0.0.0.0 0 32768 i
*> 8.8.8.8/32 0.0.0.0 0 32768 i
R2#

>>>Now if default is available from AS200<<<<

R1#sh ip bgp
BGP table version is 4, local router ID is 1.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network Next Hop Metric LocPrf Weight Path
*> 0.0.0.0 0.0.0.0 0 32768 ?
*> 7.7.7.7/32 9.9.12.2 0 0 300 i
*> 8.8.8.8/32 9.9.12.2 0 0 300 i
R1#

'
R2#sh ip bgp
BGP table version is 9, local router ID is 8.8.8.8
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network Next Hop Metric LocPrf Weight Path
*> 0.0.0.0 9.9.12.1 0 0 200 ?
*> 7.7.7.7/32 0.0.0.0 0 32768 i
*> 8.8.8.8/32 0.0.0.0 0 32768 i
R2#

On Sun, Mar 6, 2011 at 6:51 AM, sameer inam <i_sameer_at_hotmail.com> wrote:
> Dear expert,
> I m trying to implement the conditional attribute Via EBGP . I put the
> condition on router which has AS300 and other side is AS200 , its like that
> there is one PC connected in to AS300 network which has IP of 7.7.7.7 .
>
> condition is if AS200 router has default route then 7.7.7.7 network can show
> into BGP routing table of that router otherwise NO . after I put the condition
> on AS300 router I cannot see 7.7.7.7 route on AS200 router BGP routing table
> but issue is when I m trying to define the default route on AS200 router its
> show as static on normal routing table not in BGP routing table .
> AS200 R2 > AS300 R3 >PC 7.7.7.7
> can any one help me on that .
> kind regards,
> Sameer
>
>
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Received on Sun Mar 06 2011 - 18:51:59 ART