Will Hill wrote: > 256k? They doubled the speed from a dismal 30 kilo-bytes/second to 60 > kilo-bytes/second. Yes, I just tested it again to verify.
60KBps = 480kbps . Still a bit off from 512kbps but round trip latencies and various other potential limiters come into play. Traffic shaping and possible MTU changes may get you a bit closer though I'd think you'd never exceed 500kbps (62KBps) on any consistent basis due to overhead. Look into wondershaper (http://lartc.org/wondershaper/ ) if your router is a linux box. Many of the linux router distributions (smoothwall, shorewall) incorporate wondershaper. Some of the netgear/linksys consumer broadband routers out now support limited traffic shaping abilities as well. Primarily those boxes prioritize VoIP over other traffic and don't do the kind of real, granular IP traffic shaping that would best benefit you. > I don't think this is a technical issue at all. At Home did just fine > without > crimps, despite Napster and the Windoze worms of the day. What's changed > between then and now? What kind of technical issues drove them to dhcp > instead of simpler static ip addresses? How about port blocking? Looks to > me like Cox has had to bow to other, stronger interests. I'm not gonna argue with you what may have changed in the past few years. I'd say a great many things have changed, but the upstream path's inherent limitation is the primary engineering problem for cable connectivity and always has been. The math involved is well understood. Customers on a single downstream connection in the US share a 6Mhz band and I'm going to surmise that Cox has gone to 256QAM modulation giving a raw throughput rate of 27Mbps on a single downstream. On the upstream side, the widest available channel width is 3.2Mhz and the most efficient available modulation scheme is 16QAM in DOCSIS 1.0/1.1 yielding 10.24Mbps raw to share amongst customers on a single upstream path.(1) DOCSIS signalling and TCP/IP overhead further erode the available bandwidth. Other factors as well will limit available bandwidth, typically on the upstream side of the equation. Getting to those maximum widths and modulations schemes for cable vendors is recent as much work had to be done to get the plant to support that without major issues. (2) A lot of companies out there are still at 64QAM on the downstream and 1.6Mhz width and QPSK on the upstream. Cox had to do a significant amount of work and buildup to support a 512kbps upstream; I talked to a couple of engineers at Cox about this, actually. The biggest improvement DOCSIS 2.0 will offer if it ever gets deployed is changes in modulation schemes on the upstream, changes in contention rules on the upstream, changes in resiliency for operating in a "noisy" RF environments, and great QoS enhancements for supporting bandwidth-intensive "real time" apps like VoIP. It's all geared towards increasing the upstream available bandwidth. (1)http://www.cisco.com/warp/public/cc/so/cuso/sp/hfcn_wp.pdf page 67, appendix table. This doc is not an easy read. http://www.cisco.com/en/US/tech/tk86/tk168/technologies_tech_note09186a0080094545.shtml "Understanding Data Throughput in a DOCSIS world" is a better read mostly for providers but there is some info on customer changes in PC's and OS that can improve throughput. http://www.cisco.com/en/US/tech/tk86/tk804/technologies_tech_note09186a00800a9702.shtml is a more "read friendly" document and though a little long in the tooth in some respects it gives a good overview of how they're making decisions. www.broadbandreports.com - the goldmine for users for information on this stuff. (2)Did Cox in BR do a good enough job cleaning up the plant, reengineering, etc is a very subjective question, of course. -- Scott Harney <[EMAIL PROTECTED]> "Asking the wrong questions is the leading cause of wrong answers" gpg key fingerprint=7125 0BD3 8EC4 08D7 321D CEE9 F024 7DA6 0BC7 94E5
