Router BGP Policy Interesting Packets Settings

The scenario is like this R7 as the CPE router and has default route towards R2. In R5 there are two loopbacks as the server. (5.5.5.5 and 50.50.50.50). R2 must use R3 to reach 5.5.5.5 and R2 must use R4 to reach 50.50.50.50
The topology is like this :

In R2, we configure bgp attributes using weight :

Router bgp 7
 no synchronization
 bgp log-neighbor-changes
 network 7.7.23.0 mask 255.255.255.0
 network 7.7.24.0 mask 255.255.255.0
 redistribute connected
 neighbor 7.7.23.3 remote-as 33
 neighbor 7.7.23.3 soft-reconfiguration inbound
 neighbor 7.7.23.3 route-map A in
 neighbor 7.7.24.4 remote-as 44
 neighbor 7.7.24.4 soft-reconfiguration inbound
 neighbor 7.7.24.4 route-map B in
 no auto-summary

Match loopback in R5

access-list 101 permit ip host 5.5.5.5 any

access-list 102 permit ip host 50.50.50.50 any

Creating Route-map to set weight and match loopback

route-map A permit 10
 match ip address 101
 set weight 1000
!
route-map A permit 20 // match others ip addresses
!
route-map B permit 10
 match ip address 102
 set weight 1000
!
route-map B permit 20 // match others ip addresses

This is what we get in R2

R2#sh ip bgp
BGP table version is 18, local router ID is 20.20.20.20
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
*  2.2.2.2/32       7.7.24.4                 0             0 44 ?
*                   7.7.23.3                 0             0 33 ?
*>                  0.0.0.0                  0         32768 ?
*  5.5.5.5/32       7.7.24.4                               0 44 55 i
*>                  7.7.23.3                            1000 33 55 i
*  7.7.23.0/24      7.7.23.3                 0             0 33 i
*>                  0.0.0.0                  0         32768 i
*  7.7.24.0/24      7.7.24.4                 0             0 44 i
*>                  0.0.0.0                  0         32768 i
*  7.7.27.0/24      7.7.24.4                 0             0 44 ?
*                   7.7.23.3                 0             0 33 ?
*>                  0.0.0.0                  0         32768 ?
*  7.7.35.0/24      7.7.24.4                               0 44 55 i
*>                  7.7.23.3                 0             0 33 i
*> 7.7.45.0/24      7.7.24.4                 0             0 44 i
*                   7.7.23.3                               0 33 55 i
*  20.20.20.20/32   7.7.24.4                 0             0 44 ?
   Network          Next Hop            Metric LocPrf Weight Path
*                   7.7.23.3                 0             0 33 ?
*>                  0.0.0.0                  0         32768 ?
*> 50.50.50.50/32   7.7.24.4                            1000 44 55 i
*                   7.7.23.3                               0 33 55 i

if we do traceroute, this is what we get in R7 :



It moves to R3 then to R5

R7#traceroute 5.5.5.5

Type escape sequence to abort.
Tracing the route to 5.5.5.5

  1 7.7.27.2 4 msec 4 msec 8 msec
  2 7.7.23.3 4 msec 12 msec 8 msec
  3 7.7.35.5 8 msec *  32 msec

It flows from R4 to R5

R7#traceroute 50.50.50.50

Type escape sequence to abort.
Tracing the route to 50.50.50.50

  1 7.7.27.2 4 msec 4 msec 4 msec
  2 7.7.24.4 8 msec 12 msec 8 msec
  3 7.7.45.5 8 msec *  12 msec

This is according to the requirements from R2 point of view. We will explore more in the next posting. I have attached the gns3 file and initial configuration in here :

http://www.4shared.com/rar/uTg2U06B/BGP_Policy.html

Happy labbing