Information Technology Reference
In-Depth Information
Figure 5-2
Path Advertisement into the Network Core for 10.2.0.0/16
EIGRP 102
R5
10.2.0.0/16
R7
R6
R4
EIGRP 100
BGP 65100
R8
R3
R9
R11
The path chosen by R11 in Example 5-1, based on the BGP attributes, indicates that the
path received from R6 is the best path, because this path has a lower IGP metric.
BGP Path Information for 10.2.0.0/16 on R11
Example 5-1
R11#show ip bgp 10.2.0.0
BGP routing table entry for 10.2.0.0/16, version 3
Paths: (2 available, best #2, table Default-IP-Routing-Table)
Not advertised to any peer
Local
172.16.4.1 (metric 2323456) from 172.16.4.1 (172.16.4.1)
Origin IGP, metric 307200, localpref 100, valid, internal
Local
172.16.6.1 (metric 2297856) from 172.16.6.1 (172.16.6.1)
Origin IGP, metric 307200, localpref 100, valid, internal, best
2323456
2297856
best
From the BGP table on R3 in Example 5-2, the path chosen originates from R4. Again, the
decision is made based on the IGP metric to the next hop.
BGP Path Information for 10.2.0.0/16 on R3
Example 5-2
R3#show ip bgp 10.2.0.0
BGP routing table entry for 10.2.0.0/16, version 4
Paths: (2 available, best #1, table Default-IP-Routing-Table)
Not advertised to any peer
Local
172.16.4.1 (metric 2297856) from 172.16.4.1 (172.16.4.1)
Origin IGP, metric 307200, localpref 100, valid, internal, best
2297856
best
continues
