[e2e] TCP spoofing in overlay networks

[Jon Crowcroft]

you're making lots of assumptions about how the 
software operates at the splice point. there are lots of ways to
mitigate the problems you describe - and papers about it

i think in fact we had rather more experience of this this side of the
pond than elsewhere with TCP/IP on 2Mbps X.25 nets in Europe, and, at
one point, the X.25 implemented between Cisco boxes over TCP:)
so we know the pitfalls

but a non-oblivious overlay can easily obviate this - there's ample
evidence that a p2p system is exactly that.

In missive <4225B132.60808 at reed.com>, "David P. Reed" typed:

 >>Au contraire, there has been lots of experience running TCP over 
 >>"reliable links". Lots of experience in the field with using frame relay 
 >>as a "hop", and turning on end-to-end reliability by accident, suggests 
 >>that the underlay TCP will interact with the overlay in a disastrous 
 >>postive feedback control loop creating unstable end-to-end behavior.   
 >>It is *essential* that the underlay TCP *not* try to hide congestion, 
 >>which is signaled by packet drops.   In other words if you are spoofing 
 >>IP with TCP-based links, you have to create a situation in which the 
 >>underlay does not allow its buffering to expand elasticly.

 cheers

   jon