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RE: Home media servers, AUPs, and upstream bandwidth utilization.
Chris mentioned: #it might also be interesting to know how tcp-stack differences affect some #of the usage patterns as well. With the now widely deployed win* platform #tcp stach respecting tcp-reno things work according to well #understood/accepted models. Mac OSX, linux and Vista seem to NOT respect #tcp-reno, and may change the models somewhat... Will this cause more #spikiness on individual links? will this change in behaviour on a wide #scale (vista rollout to new computers or to existing platforms) causing #folks capacity planning models to fail? Capacity planning is a very important issue, but for other folks capacity *under*utilization is the flip side of that issue. For example, there are still scientific researchers who continue to be puzzled by low throughput for bulk data transfers, even with clean fast ethernet (or gig ethernet!) connections end-to-end. For example, looking at table 1 of http://netflow.internet2.edu/weekly/20061218/ we can see that on I2 95% of all bulk TCP data transfers are ~25Mbps or less -- however the top 1/10th of 1% successfully demonstrate 1Gbps throughput. The question then becomes one of "How do we help bridge that 'wizard gap' or transfer that expertise (of those who are demonstrably able to fully utilize the connections at their disposal) to all the other well-connected researchers out there?" Things like Web100, see http://www.web100.org/download/ are intended to help automate this for Linux users, although clearly there are still issues with applications (if you're curious, you can see the sort of improvements to SSH that were made by the folks at PSC at: http://www.psc.edu/networking/projects/hpn-ssh/ and there's a lot of fascinating empirical work that's been done with applications such as GridFTP (where encryption is not the bottleneck). So what about Vista? Well, it has (or should have, I'll withold any final assertions until I see what actually finally gets shipped to consumers) a number of TCP performance enhancements which are described at http://www.microsoft.com/technet/community/columns/cableguy/cg1105.mspx (last updated September 22nd, 2006). If the network traffic load feels different post-Vista, well, it very well may *be* different. :-) But that's all host-based -- what about at the network level? I'm intrigued to see things like jumbo frames accounting for a non-negligible fraction of traffic on Internet2 (e.g., roughly 7% or so of octets, see http://netflow.internet2.edu/weekly/longit/perc-b-jumbo-packets.png ), and I also notice that at least one alternative TCP/IP implementation has elected to commercialize in the form of a 1U gateway appliance that does its mojo network wide, rather than working to retrofit individual hosts with high performance TCP stacks on a host-by-host basis. I think those sort of things have tremendous potential to change the aggregate network behavior we all see over time. Regards, Joe St Sauver ([email protected]) http://www.uoregon.edu/~joe/ Disclaimer: all opinions strictly my own.