For almost a year my server is colocated at the non-profit association ColoClue. I had my own vlan with my own ip space and it worked well. I have also colocated the server of a friend of my, in the same vlan/ip space.
Previous weekend I colocated my second server in an another datacenter used by ColoClue, now it becomes a little bit tricky. At ColoClue lans only exists in 1 location and do not extend to the other. With my IP space in 1 location I had to reinvent my own network. What made it complicater was that I want to run my systems on both servers at the same time, which is anycast.
There is a wonderfull solution that can be used, which is use network protocols such as BGP. Per server I announce with BGP to the ColoClue routers which IP addresses of my range I want to terminate at that server. Since you can see this, you can conclude it works like a charm.