I am currently using a very simple eBGP and iBGP configuration in my network to route out through a single ISP. This diagram gives a rough idea of what I currently have in operation:
I am running out of capacity through ISP 1 and would like to add an additional ISP and create a dual homed setup. I have a /20 from ARIN that I am advertising to ISP1.
This is the setup I would like to end up with:
I know that I can use local-pref to control which of my two edge routers customer traffic should exit through. However, inbound route control is more difficult.
I would like to advertise my same /20 to both ISP 1 and ISP 2. Is there any way I can load-balance incoming traffic into my network? I know there are tricks such as as-path prepending, etc…
I don't want to run into a situation where all inbound traffic is taking preference through ISP 1, to the point where I'm maxing out the 1G connection, while ISP 2 sits idle.
I use VyOS on my edge routers.
Best Answer
Understatement of the century. Just as you can use local-pref to push traffic out which ever pipe you wish, others can as well. As a result, you have little control over how traffic reaches you. AS-PATH is the only sure-fire way to remotely influence route preference (and the local network admin can still override it, but my experience says that's rare.) Depending on your two ISPs, there may be various communities that can limit where your routes go.