Information Technology Reference
In-Depth Information
Figure 11-24 shows an RPF check that fails.
Figure 11-24
MSDP SA RPF Fails Without Matching the BGP Session
Source
ISP 3
ISP 2
R2
R1
BGP Peer
MSDP Peer
ISP 5
ISP 4
SA Message
R3
R4
R5
ISP 1
R6 RP
The MSDP SA for group 224.1.1.1 originated by the RP 10.1.0.1 is also received by R6
from R3 in AS 5. The MSDP debugs for the SA reception are shown in Example 11-17,
where the RPF check fails. The SA is received from MSDP peer 10.1.0.3, for which R6 has
no matching BGP session. The first AS in the AS_PATH for the originating RP (10.1.0.1)
is AS 4, as shown in Example 11-16. The originating AS for MSDP peer 10.1.0.3 is AS 5.
These do not match, which results in the RPF check's failing.
