Hello folks,
quick background of network. 2 edge Routers that each have a total of 3 BGP peerings each. 1 eBGP with ISPA, 1 eBGP with ISPB, and 1 iBGP with eachother edge routers. Getting a default route only.
I have a question about iBGP neighborship that I have never seen in action on this network. So right now, we peer to 2 ISPs as you can see in the pic.
Both ISPs give us a default route only. ISPA LP of 200, ISPB LP of 150. When I look into the configs, I can also see that we have an iBGP neighborship
between our edge routers. And both these Routers learn a default-route from eachother at LP 200 which in turn is learnt from ISPA. I'm wondering what would happen if Router 5
for example loses its eBGP neighborship with ISPA because of a pysical problem with Router 5 but Router 10 does not lose it's eBGP peering with ISPA.
I'm guessing this is just as simple as Router 5 just shooting the traffic over to iBGP link to to Router 10 as its deafult route.
But Now I'm wondering what would happen if both routers lose their eBGP neighbroship to ISPA because ISPA goes down....since the LP to their corresponding iBGP neighbors is better then ISPB(LP150)
, would both Routers just shoot the default traffic over to eachother, and then to ISPB...or would they just go directly to ISPB? I can't quite wrap my head around it.
Thank you
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