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BGP Advertised routes

vasquezwilmer
Level 1
Level 1

Dear all

I have one Router (R1) running iBGP processs with two peering. I want to advertise specfic Network to R2 and others routes
to the another Router (R3). R1 receives deafault-routes from both peeting.

R1

router bgp 65471
 bgp log-neighbor-changes
 neighbor R2 peer-group
 neighbor R2 remote-as 65472
 neighbor R2 shutdown
 neighbor R2 version 4
 neighbor R3 peer-group
 neighbor R3 remote-as 65473
 neighbor R3 version 4
 neighbor 172.16.40.37 peer-group R2
 neighbor 10.10.0.1 peer-group R3


 network 10.10.200.0 mask 255.255.255.252
 network 10.30.24.0 mask 255.255.248.0
 network 172.16.17.0 mask 255.255.255.0
 network 172.16.40.0 mask 255.255.255.0
 network 172.16.211.0 mask 255.255.255.0
 network 172.18.56.16 mask 255.255.255.248
 network 172.31.0.20 mask 255.255.255.252
 network 190.153.116.0 mask 255.255.252.0
 network 190.153.120.0 mask 255.255.252.0
 network 190.153.124.0 mask 255.255.255.0

How can I advertise only network 190.153.116.0/22 to R2 (AS6572)? and all other route to R3 (AS65473)??


R1#sh ip bgp neighbors 172.16.40.37 advertised-routes

   Network          Next Hop            Metric LocPrf Weight Path
*> 10.10.200.0/30   0.0.0.0                  0         32768 i
*> 10.30.24.0/21    172.16.40.4              0         32768 i
*> 172.16.17.0/24   172.16.40.5              0         32768 i
*> 172.16.40.0/24   0.0.0.0                  0         32768 i
*> 172.16.211.0/24  0.0.0.0                  0         32768 i
*> 172.18.56.16/29  0.0.0.0                  0         32768 i
*> 172.31.0.20/30   0.0.0.0                  0         32768 i
*> 190.153.116.0/22 172.16.40.4              0         32768 i
*> 190.153.120.0/22 172.16.40.4              0         32768 i
*> 190.153.124.0/24 0.0.0.0                  0         32768 i

R1#sh ip bgp neighbors 172.16.40.37 received-routes
BGP table version is 15732731, local router ID is 172.31.0.21
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
*>i0.0.0.0          172.16.40.37             0    100      0 i


R1#sh ip bgp neighbors 10.10.0.1 advertised-routes
BGP table version is 15732733, local router ID is 172.31.0.21
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
*> 190.153.116.0/22 172.16.40.4              0         32768 i
*> 190.153.120.0/22 172.16.40.4              0         32768 i
*> 190.153.124.0/24 0.0.0.0                  0         32768 i

 

5 Replies 5

InayathUlla Sharieff
Cisco Employee
Cisco Employee

You need to tweak parameters to send the packets.

Eg: same as local preference/MED.

 

HTH

I want to advertise only Network network 190.153.116.0 mask 255.255.252.0 to R3, how can I do ?

I am somewhat confused. In the original post you tell us that the requirement is "I want to advertise specfic Network to R2 and others routes to the another Router (R3)" . But in the following post you tell us "I want to advertise only Network network 190.153.116.0 mask 255.255.252.0 to R3". So I do not understand how to answer your specific issue but will suggest the general approach to this kind of requirement.

 

One common way to achieve the requirement that a specific route (or set of routes) is advertised to a BGP peer while other routes are advertised to another peer is to configure outbound route maps for each peer. In the route map for each peer you would specify a prefix list which would identify the routes to be advertised to that peer.

 

HTH

 

Rick

HTH

Rick

Hello

Below are a couple options:Prefix-list/Route-Map

 

ip prefix-list R3HOST sec 5 permit 190.153.116.0 /22
or
access-list 1 permit host 190.153.116.0

route-map R3 10
match ip address prefix-list R3HOST

or
match ip address 1


router bgp 65471
neighbor 10.10.0.1 prefix R3HOST out

router bgp 65471
neighbor 10.10.0.1 route-map R3HOST out


ex
clear ip bgp 10.10.0.1 out soft

res
Paul

 


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This then could assist others on these forums to find a valuable answer and broadens the community’s global network.

Kind Regards
Paul

Hello, I setup Route-Map based on IP Access-List, and it is ok. I am advertising Invalids Ips to iBGP (172.16.40.37) and Valid network to eBGP. Because I am receiving from both peering a Default Route, but internet access must go thru eBGP (190.97.254.241), for some reason I cannot reach internal network from the LAN. It is becase Local Preference is 200 and I set it up in order to use eBGP as preferred internet access.

7204VXR-SCT#sh ip bgp nei 172.16.40.37 advertised-routes    

BGP table version is 15734594, local router ID is 172.31.0.21
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          190.97.254.241                200      0 65472 i
*> 10.10.200.0/30   0.0.0.0                  0         32768 i
*> 10.30.24.0/21    172.16.40.4              0         32768 i
*> 172.16.17.0/24   172.16.40.5              0         32768 i
*> 172.16.40.0/24   172.16.40.37            10         32768 i
*> 172.16.211.0/24  0.0.0.0                  0         32768 i
*> 172.18.56.16/29  0.0.0.0                  0         32768 i
*> 172.31.0.20/30   0.0.0.0                  0         32768 i
*> 190.153.116.0/22 172.16.40.4              0         32768 i
*> 190.153.120.0/22 172.16.40.4              0         32768 i
*> 190.153.124.0/24 172.16.40.37            10         32768 i
7204VXR-SCT#sh ip bgp nei 172.16.40.37 received-routes
BGP table version is 15734594, local router ID is 172.31.0.21
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
* i0.0.0.0          172.16.40.37             0    100      0 i

Total number of prefixes 1


7204VXR-SCT#sh ip bgp nei  190.97.254.241 advertised-routes
BGP table version is 15734594, local router ID is 172.31.0.21
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
*> 190.153.116.0/22 172.16.40.4              0         32768 i
*> 190.153.120.0/22 172.16.40.4              0         32768 i
*> 190.153.124.0/24 172.16.40.37            10         32768 i

7204VXR-SCT#sh ip bgp nei  190.97.254.241 received-routes
BGP table version is 15734594, local router ID is 172.31.0.21
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          190.97.254.241                         0 65472 i

Total number of prefixes 1
7204VXR-SCT#

 

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