Now that we covered how LISP Routing works in Part 1 and Part 2 of this series, let dig into some of the things you can do with it. I would suggest you go back and read the first two posts if you are new to LISP since I am not going to cover that material again. So, lets look at three of the most popular use cases: 1) VM mobility, 2) IPv6 migration, and 3) smarter multi-homing. I am going to cover the generic use cases, then wrap with some real-world customer use cases.
Since it seems to be the hottest topic, let start with the mobility solution. From a networking perspective, there are a couple of things that are important with a live migration (ex. VMotion): we want to try and preserve TCP sessions (note: this does not mean “packets don’t get dropped”) and we want to maintain optimal routing (note to server folks: you too care about these things). We would also like global mobility—basically the server admin should be able to move her VM wherever she want and not be constrained by IP addressing considerations.
Let’s build on the scenario we have been using in the prior posts, where we have a host 192.168.1.12 is chatting with a VM 172.16.4.7. Assume that we have gone through the whole map-request/map-reply process, so we have something that looks like this: