On Fri, 26 Mar 1999, Oskar Pearson wrote:
> Assumptions: a cache digest is 200 000 bytes (a large peer may exceed
> this quite easily, though). This is equivalent to 3333 ICP packets
> (200000/60). If you retrieve the cache digest every 10 minutes
> (600 seconds), you need to be sending 5 1/2 icp queries a second to
> make cache digests worthwhile (3333/600). For ISP caches, cache
> digests make sense. For ISP customers, you almost certainly want to
> use ICP.
Oscar,
I am afraid this math (and the conclusion) is somewhat misleading
even with the current [ugly] Digest implementation. Please correct me if I
misinterpreted your example. Receiving a digest every ten minutes implies
that you have 6 peers. Sending 6 ICP queries per second if you have 6
peers means one query per second per peer. That is a very low rate for
most configurations with large number of peers.
Also, using as many as 6 peers with ICP often implies noticeable delays.
Finally, our initial experiments with "deltas" or "diffs" indicate that we
can further [drastically] reduce bandwidth requirements for digests.
Alex.
