Connections among ASes

Hi,

I am not sure about whether the following two conditions are true or not:

  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.
    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.

Thanks.

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

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