I noticed a really unusual thing. When multipath is enabled between eBGP and iBGP, the AD of iBGP path also appears as 20 instead of 200. However, if eBGP path is not available and only iBGP path is available, the AD becomes 200.
This seems like a bug. Any ideas?
Here's the sample output- Notice network 10.2.2.0 in the both outputs.
PE1#sh ip route vrf CUST1
Gateway of last resort is not set
22.214.171.124/30 is subnetted, 3 subnets
C 126.96.36.199 is directly connected, Serial0/0
B 188.8.131.52 is directly connected, 00:22:35, Serial0/1
B 184.108.40.206 [200/0] via 220.127.116.11, 00:04:33
10.0.0.0/24 is subnetted, 2 subnets
B 10.2.2.0 [20/0] via 18.104.22.168 (CUST2), 00:22:35
[20/0] via 22.214.171.124, 00:00:27
B 10.1.1.0 [20/0] via 126.96.36.199, 00:22:45
PE1#sh ip bgp vpnv4 all 10.2.2.0
BGP routing table entry for 1:1:10.2.2.0/24, version 24
Paths: (2 available, best #2, table CUST1)
Advertised to update-groups:
65002, imported path from 2:2:10.2.2.0/24
188.8.131.52 (metric 11) from 184.108.40.206 (220.127.116.11)
Origin IGP, metric 0, localpref 100, valid, internal, multipath
Extended Community: RT:2:2
mpls labels in/out nolabel/20
65002, imported path from 1:2:10.2.2.0/24
18.104.22.168 from 22.214.171.124 (10.2.2.1)
Origin IGP, metric 0, localpref 100, valid, external, multipath, best
Extended Community: RT:1:2
I don't think it is a bug.
you have asked to perform iBGP and eBGP multipath if the iBGP prefix would be presented with natural AD 200 it wouldn't be installed in routing table and you would see only the eBGP path coming from CE node.
it is a way to fool IP routing table mantainer
Hope to help