[c-nsp] BGP next hops in BGP not in IGP

Kamal Dissanayaka kamalasiri at gmail.com
Sun Jul 31 20:36:00 EDT 2016

HI All,

As my knowledge, BGP next hop needs to be in IGP in order to get BGP routes
in routing table.
It looks like, it may have changed ?  BGP routes populate in routing table
when the next-hp route is learned through BGP.

I tried some googling but I cannot get definite answer.

here is the scenrio

Router A (18162) Router B (65001) --- Router C (65001)

On router C,

Subnet  is learned through IBGP, As far as I remeber on my
old school this subnet should be learned through IGP to work properly.

Router C# sh ip route
Routing entry for
  Known via "bgp 65001", distance 200, metric 0, type internal
  Last update from 3w3d ago
  Routing Descriptor Blocks:
  *, from, 3w3d ago
      Route metric is 0, traffic share count is 1
      AS Hops 0

However other routes advertised from Router A is on routing table of Router
C. Is it something expected ??

Router C#sh ip route bgp is variably subnetted, 4 subnets, 2 masks
B [200/0] via, 3w3d
B [200/0] via, 3w3d
B [200/0] via, 3w3d is variably subnetted, 7 subnets, 3 masks
B [200/0] via, 2w6d
B [200/0] via, 2w6d
B [200/0] via, 3w3d

Router C #show ip bgp
BGP routing table entry for, version 48
Paths: (2 available, best #2, table Default-IP-Routing-Table)
  Advertised to update-groups:
  18162 64634, (received & used) from (
      Origin IGP, localpref 100, valid, external
  18162 64634, (received & used) from (
      Origin IGP, localpref 150, valid, internal, best
      Extended Community: RT:18162:2000430014

Best Regards


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