On Fri, Dec 05, 2003 at 02:15:43AM -0500, John C Klensin wrote: > I'd also guess that, given the kind of connectivity Internet2 > implies, that you see very little mail relaying in practice > (beyond initial submission).
The backbone in question (Abilene) would see most traffic from a US research university to a US research university (for example, this message would not traverse Abilene because the IETF mail reflector does not have Abilene connectivity). Perhaps to put the fraction of traffic that is email in a better perspective, the ratio of HTTP traffic to email traffic is more than 20. (I'm not claiming that inter-university traffic is a representative sample of anything, but this might be a useful datapoint.) > But compression, properly thought out, might still be very > useful at the edges of the network with lower levels of > resources and bandwidth... I just don't know. SMTP-level email compression might very well be useful for some edges. I would think that the challenge would be to design it so that these edges could take advantage of it, while better-connected sites would not need to spend CPU cycles compressing and decompressing when exchanging email among themselves. One way to accomplish that could be to have two compression-related ESMTP options: ``support compression'' and ``prefer compression.'' Any site might support compression, while only capacity-starved edges with a large fraction of traffic that is email might prefer compression (at the site administrator's discretion). Then, message SHOULD be compressed if and only if both ESMTP peers support compression and at least one of the peers prefers compression. This way, only sites that need compression would end up using it -- for both incoming and outgoing mail. -- Stanislav Shalunov http://www.internet2.edu/~shalunov/