06-12-2014 09:06 PM - edited 03-07-2019 07:43 PM
Hi everybody
This is what I observed at work
This is my understanding
Let say R1 is receiving a prefix( via BGP) 1.0.0.0/8 from two ISP, Isp1 and ISP2, both routes will be installed in RIB, R1 finds the the route through ISP1 as the best and installs it in routing table.
However, I am seeing a strange implementation to save memory ( i think) at my work. Our core folks make some kind of configurations changes which cause R1 only to have the best route in RIB even though R1 may be receiving a prefix from many sources.
Is there any command I can use to display those routes?
Thanks
Solved! Go to Solution.
06-13-2014 12:54 AM
06-13-2014 01:22 AM
Hi Sara,
Can you do check with show ip route repair-path??
Regards
Karthik
06-13-2014 12:54 AM
show ip bgp <the remote routes>
Regards
Prajith
06-13-2014 01:22 AM
Hi Sara,
Can you do check with show ip route repair-path??
Regards
Karthik
06-13-2014 03:51 PM
Hi everybody
Thanks all you guys who responded also who did not :)
This is what I found.
IP core is not doing anything special.
What I observed is typical BGP behaviour
R1 is learning the prefixes from both ISP say isp1 and isp2, R1 selects the route through ISP1 as best and installs it in routing table. R1 then advertises it its IBGP peer say R3. R1 only advertises the best route.
R3 's RIB shows one route ( as it should as R3 is not learning the same prefix only from R1)
On the contrary R1 Rib shows two routes one via ISP1, ISP2 as it is receiving them from two sources .
Simple thing but I did not realize that.
Thanks for your help
Have a great weekend.
06-13-2014 01:52 AM
Hello
Not sure I understand, do you mean what prefixes that are being accepted that are advertised to you from either ISP?
sh ip bgp neighour x.x.x.x routes
res
Paul
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