Simple BGP Multipath Test in Packet Tracer 5.3

This is another simple BGP test file in Packet Tracer 5.3. We can see selection of the best route by AS_PATH.

• BGP-Multipath-Test.zip, (Backup Link)

I changed the topology a bit from previous BGP sample, so that we can see different paths to the same destination network in the BGP table (the output of "show ip bgp").

In addition, the output of "show ip bgp" would now have meaningful "best route" selected, according to each possible path's AS_PATH length.

AS1>show ip bgp 
BGP table version is 11, local router ID is 11.0.0.1
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
*> 11.0.0.0/24       0.0.0.0                  0     0 32768 i
*> 12.0.0.0/24       1.1.2.2                  0     0     0 2 i
*                    1.1.3.3                  0     0     0 2 3 i
*                    1.1.4.4                  0     0     0 2 3 4 i
*  13.0.0.0/24       1.1.2.2                  0     0     0 3 2 i
*                    1.1.4.4                  0     0     0 3 4 i
*>                   1.1.3.3                  0     0     0 3 i
*> 14.0.0.0/24       1.1.4.4                  0     0     0 4 i
*                    1.1.2.2                  0     0     0 4 2 i
*                    1.1.3.3                  0     0     0 4 3 i
AS1>

In this example, at AS1's point of view, the best route for destination 14.0.0.0/24 is going via 1.1.4.4 at AS4. This is correct and can be verified on the diagram.

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Cheers!

Reference:
"BGP Best Path Selection Algorithm" documentation on Cisco.com