On 9/19/05, Al Boldi <a1426z@xxxxxxxxx> wrote: > > > Pure TCP. How do you unlimit the TCP connection? You can only shape/limit connections. You can't make them go faster (unless they are slower than they should be, and then you have a tuning/equipment problem, so fix that). > > The only thing that throttles TCP throughput is packet loss, window size > > and latency. Plus host and router CPU/line card/interface utilization, device buffer sizes, link utilization, switch capacity, interrupt load, NIC quality, retransmissions, amount of RAM, etc, etc. You can get really involved if you want to. > Window size maybe. > Is this tunable per connection? Yes, but not to the level you might want. See W. Richard Stevens' UNIX Network Programming for the particular socket options that can be played with (TCP_MAXSEG and TCP_WINDOW_CLAMP, in this case; man 7 tcp will also be enlightening). > Better yet, would it be possible to auto-tune it based on system load? If you could accurately determine system load, yes, but again only to the level that is allowed in userspace (again, see Stevens). > Also, is this the only tunable? The TCP MSS (Maximum Segment Size) is also tunable, as above, with the TCP_MAXSEG socket option. You cannot change either of these values once the socket has been created. What you appear to be looking for is called TCP Rate Control. This effectively rewrites the window and MSS sizes on the return traffic (and can also induce delays on the return traffic ACKs to introduce latency when necessary) to engage or fake out the congestion control inherent in the TCP protocol. Linux does not support this, but rather supports QoS techniques such as fair queuing, token bucket filters, etc, etc. Read http://lartc.org/ for information about what it does support. If you really want it to support TCP Rate Control, you'll have to write it yourself or pay someone else to write it for you. There was one (or more?) attempt at developing this for Linux, but it was not integrated into the mainline and that code is long, long dead. -- Toby DiPasquale 0x636f6465736c696e67657240676d61696c2e636f6d - : send the line "unsubscribe linux-net" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
