Thanks. Although they are not absolute cases, are they "typical" cases, i.e., do they apply to most of the cases? I know "typical" is not well defined, but I am kind of curious about the likelihood of the happening. A related question. Is there any sources I can look more about such issues? Chengchen 2007-11-29 ------------------------------------------------------------- From: Randy Bush Data: 2007-11-29 19:24:12 To: Chengchen Hu CC: nanog Subject: Re: Connections among ASes
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