thank you ! I will post all my results... regards. -> -> hi andres, -> -> i re-read your question and now that i have a bit more time, i'll try to -> respond to it more carefully: -> -> On Fri, 2004-02-13 at 21:37, ThE LinuX_KiD wrote: -> > Hi, -> > -> > I'm trying to setting a very low bandwidth -> > VSAT connection (90 kbits download / 20kbits upload) -> > -> > I'm looking for best kernel SYSCTL parameters for this -> > -> > Have someone a sysctl configuration for this ? -> -> your question implies that the vsat system that you're currently using -> is un-optimized by the provider -- i'll try to explain. -> -> here in europe, the two principal providers Eutelsat and Satlynx both -> offer true two-way satellite service that are asymmetrical in bandwidth. -> -> the eutelsat d-start product as well as the satlynx 360e are both -> optimized by the provider, that is to say, that both re-negotiate the -> layer 4 tcp connection parameters for each tcp session. if you take the -> time to try to reset the tcp parameters, it is really unnecessary as -> they are thrown out and replaced by the providers variables (performed -> by the indoor unit). -> -> the exceptions are the astra bbi platform and other "pure" vsat -> platforms that do not perform layer 4 renegotiation or ack spoofing and -> the like. at this point, tweaking the sysctl parameters helps -> enormously, however, it is noteworthy that a client passing its traffic -> via your linux router, will not inherit the router's parameters: each -> client will setup its own tcp parameters during the handshake. -> -> so, here's a brief summary: -> -> squid and/or another http proxy: -> a http proxy server is recommended in all cases. setup a large cache, -> good memory and cache object size. avoid using the bandwidth if you do -> not have to. -> -> satlynx 360e: -> no need to much here with your router, excepting that you should really -> try to make use of the http proxy port (9877) provided by the indoor -> unit. you can setup a transparent squid proxy (or regular) and put a -> line in the squid.conf like: -> -> cache_peer $GILAT_INDOOR_IP parent 9877 0 no-query -> -> when squid doesn't find the cache object, it will send the http request -> through their proxy port and you will enjoy the benefits of their -> caching and acceleration. -> -> -> eutelsat d-star: -> like the gilat, eutelsat has optimized their backbone with ack spoofing -> and tcp layer renegotiation. no need to worry about clients behind this -> idu either. -> -> astra bbi and other "pure" vsat connections: -> here you will want to do your maximum effort to tweak sysctl and use a -> proxy so that the linux router will use its tcp paramters at layer 4. -> here's a few suggestions for sysctl.conf, your mileage may vary: -> -> net.core.wmem_max = 8388608 -> net.core.rmem_max = 8388608 -> net.ipv4.tcp_wmem = 4096 200000 250000 -> net.ipv4.tcp_rmem = 4096 200000 250000 -> net.ipv4.tcp_dsack = 1 -> net.ipv4.tcp_sack = 1 -> net.ipv4.tcp_fack = 1 -> #net.ipv4.tcp_wmem = 4096 87380 4194304 -> #net.ipv4.tcp_wmem = 4096 250000 300000 -> #net.ipv4.tcp_rmem = 4096 87380 4194304 -> #net.ipv4.tcp_rmem = 4096 150000 200000 -> -> the # statements were taken from several howtos and you should give them -> a try to see if your getting improvements. remember again that using -> squid will cause these parameters to be used as opposed to a client -> behind that does its own layer 4 negotiation. iptables patches may be of -> help as well to get a clients tcp negotiation to support better -> congestion window size. older ip stacks (i.e. win 95 and nt 40) can be -> problematic as these paramters cannot be changed (as far as i know). -> -> patience, testing, and let us know! -> -> cheers -> -> charles -> -> -> -> -> _______________________________________________ -> LARTC mailing list / LARTC@xxxxxxxxxxxxxxx -> http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/ -> _______________________________________________ LARTC mailing list / LARTC@xxxxxxxxxxxxxxx http://mailman.ds9a.nl/mailman/listinfo/lartc HOWTO: http://lartc.org/
