We are migrating from a single router single internet GW, to dual router/dual gateway setup. We're aiming for chassis redundancy, with the accepted risk that we'll need smart hands to physically move the southern cloud connection in the event the eastern router fails. We would split our network announcements over BGP across both transit links for load balancing. Communities are available to AS path pre-pend so that the networks are advertised on both links, but half would only be preferred if the other link failed (hopefully that makes sense to you my dear reader!). So in essense, network 2.2.2.0/24 is advertised on the west transit link, but with a as prepend community so it won't become a real route unless the east path fails. We are currently only receiving a default route from our transit provider, so my question is, how can i route egress traffic from the bottom "cloud" out the appropriate path, so that 1.1.1.0/24 routes out west, and 2.2.2.0/24 routes out east? Our SE thinks we'll have to take full routes on our transit and use BGP to manipulate the routing to achieve this. This might also be possible with VRFs or EVPNs but he thinks would need two links towards the bottom cloud. With our current architecture, the 1.1.1.0/24 would ingress on the western transit link, but egress on the eastern transit link due to the preferred default gateway (asymmetric routing). Multipath and a route map weighting the western default route the same as the eastern would result in the asymmetric traffic as well, but traffic could flow out the east and west at least.
What should I look at implementing here, networkers of reddit?
No comments:
Post a Comment