andrew.clayba...@securian.com wrote: > Hello - my company currently has two connections with a single tier 1 ISP. > We are using the AS from our ISP at this time. In the next month we will > be implementing a third connection with a second tier 1 ISP, so we will now > be using our own AS number on all three routers. My question is when we > implement the new connection and update our existing connections to use are > own AS number, how much downtime will there be? So far the second ISP has > only said that it could be hours for BGP to fully converge. We are looking > for more detail about how long the outage will be and how widespread.
Hours? No way. It's more like minutes. > Will it be relatively short to our customers that are on one of the ISPs we > are directly connected to? Is downtime less for customers on other tier 1 > ISPs versus tier 2, etc. ISPs? Doesn't matter. > We will only be receiving a default route on each of the three connections. > Our routers will be advertising a small number of routes - 6 to 8. > I strongly encourage you to reconsider and take more than a default if you're multihoming and your routers have enough memory. Remember to create a full mesh on your BGP routers. And as already said, if you're totally new to BGP and multihoming, hire someone with experience in such matters to set it up. ~Seth
