I think its b/c they have like a couple or however many "SUPER" Ultrapeers that handle all of fasttrack's traffic in a whole. While a gnutella host's horizon is only a portion of all the gnutella hosts.

For example

Fasttrack:

as where hosts A, B, C, D, and E can talk to each other in x amount hops..

While gnutella

A, C, and E can talk to each

and

C, D and A can talk to each

but E is x+1 hops away from C, and C can only go x hops away. So E is too far to reach.


So theres a little segmentation of the network.