In message <[email protected]>, Brad Smith writes:
> >
> > To provide decent service over satellite both ends need to have a
> > large buffer configured. BSD defaults to 16KB but it is typically
> > settable to 256KB without changing a constant in the kernel. Then it
> > can be set to up to 2GB.
> >
> > To what extent is sending a single TCP flow at high speed an issue in
> > non-military applications? Keeping a remote web cache synched, bulk
> > smtp relay transfer, and bulk nntp transfer can all be configured to
> > use large windows if the pair is known to have a sat link between.
> >
> > The applications that do need high speed single flows just have to
> > increase window size in the application using setsockopt. A host that
> > is dangling off a seatellite link can also change the default window
> > size in the kernel to something more appropriate.
> >
> > I suppose Windoze and NT users are out of luck.
>
> sort of.
>
> regedit Hkey_Local_Machine\System\CurrentControlSet\Services\VxD\MSTCP
> and set DefaultRcvWindow = 65536
>
> Windoze95 sat/ip (l)users are much happier with this (I am, anyway).
> M$TCP defaults to 8192.
65536 << 2GB
Microsoft does not implement RFC-1323 window scaling option that would
allow windows greater than 64K.
So Windoze and NT users *are* out of luck if they want to do even
moderate performance TCP over satellite.
Curtis
This archive was generated by hypermail 2b29 : Mon Feb 14 2000 - 16:14:32 EST