3.8 wording
I'm little confused on 3.8 :
Modify the R1’s policy routing so that if R1 loses R5 as a CDP neighbor
traffic from R3 to R4’s Loopback0 network is rerouted directly to R4.
Okay traffic direction could be manipulated with PBR/route-map/access-list... now Can some1 care to explain this game of words on CDP and how to use EOT tracking on that ?
P.S Just read this in soultion guide, thanks INE - I've read 3 books+DOCCD and could not find CDP correlation when it comes to PBR.
With CDP tracking for policy routing R1 looks into the CDP table to see if there is a neighbor installed with IP address that matches the next-hop value being set in the route-map. In this case the syntax
set ip next-hop 155.1.0.5
set ip next hop verify-availability
set ip default next-hop 155.1.146.4
means if there is no CDP neighbor with IP address 155.1.0.5 traffic that matches this sequence will be routed to 155.1.146.4
Comments
is triggered. Then next-hop (of 155.1.0.5) is set only if there is
such cdp neighbor, this is due to (next-hop verify-availability). If
no - then routing table is check, is there is no such route in RT -
"default next-hop" of 155.1.146.4 is chosen.
route-map RELIABLE_POLICY_ROUTING permit 10
match ip address FROM_R3_TO_R4_LOOPBACK
set ip next-hop 155.1.0.5
set ip next-hop verify-availability
set ip default next-hop 155.1.146.4
Andrius
Hi unsobill,
The CDP thing on tracking is explained in the Command Reference Guide.
Good luck with your studies!
This is referring to set ip next-hop verify-availability which uses CDP to verify if the neighbor is active or not.