Information Technology Reference
In-Depth Information
Example 8-14
BGP RIB on R6 as a Client of R4 (Continued)
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* i172.16.0.0 192.168.100.1 0 100 0 200 i
*>i 192.168.100.1 0 100 0 200 i
* i192.168.200.0 192.168.100.3 0 100 0 i
*>i 192.168.100.3 0 100 0 i
*> 192.168.201.0 0.0.0.0 0 32768 i
* i192.168.202.0 192.168.100.7 0 100 0 i
*>i 192.168.100.7 0 100 0 I
The direct path is selected as the best path because the reflected path has a longer cluster
list.
NOTE
Step 4: Move the Other Core Router to RR, and Add Access Routers as Clients
Repeat Steps 2 and 3 for R5. As soon as both R4 and R5 are RRs for R6 and R7, even more
paths appear on clients. Example 8-15 shows the BGP RIB on R7. For each prefix that is
not locally generated, R7 receives three paths: one from the originator, and one each from
the two RRs.
Example 8-15
BGP RIB on R7 After Both R4 and R5 Are Migrated to RRs
R7#show ip bgp
BGP table version is 5, local router ID is 192.168.100.7
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
r RIB-failure
Origin codes: i - IGP, e - EGP, ? - incomplete
Network Next Hop Metric LocPrf Weight Path
* i172.16.0.0 192.168.100.1 0 100 0 200 i
* i 192.168.100.1 0 100 0 200 i
*>i 192.168.100.1 0 100 0 200 i
* i192.168.200.0 192.168.100.3 0 100 0 i
* i 192.168.100.3 0 100 0 i
*>i 192.168.100.3 0 100 0 i
* i192.168.201.0 192.168.100.6 0 100 0 i
* i 192.168.100.6 0 100 0 i
*>i 192.168.100.6 0 100 0 i
*> 192.168.202.0 0.0.0.0 0 32768 i
Example 8-16 shows the detail path information for 192.168.201.0/24. The first path is
reflected from R5, the second path is reflected from R4, and the third path is from R6
directly. The third path is selected as the best path.
