> 1) there is no such a direct link between two routers located in two > Internet eXchange Points-IXPs (even in same city) if they are from > different ASes. For example, a router A belongs to AS x located in > IXP1, and router B belongs to AS y located in IXP2, there is no link > between A and B.
it is not safe to assume that routers A & B, each belonging to a different isp and each in a different colo in the same city are not otherwise interconnected. > 2) small AS will not use one router to connect to 2 different > providers in differnet IXPs. It is much cheaper using one router to > connect with different ASes in a same IXP. what if the two providers to which i want to connect are not at the same ix but i can get a cheap L2 transport to the second ix? randy