North American Network Operators Group
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Re: Satellite latency

  • From: Hank Nussbacher
  • Date: Tue Mar 05 01:47:35 2002 
New 12.2(8)T feature in Cisco IOS called TCP Windows Scaling:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t8/tcpwslfn.htm

Specifically made for satellite networks:
ip tcp window-size 750000

-Hank


On Wed, Feb 27, 2002 at 11:01:04PM -0500, Mark Allman wrote:
> > The receiver is the one that informs the sender how large of a
> > window it can accept, so it can be practical for a subscriber
> > installation. It wouldn't be a good idea to park a bunch of
> > servers behind one of these links, but any receiving node that set
> > its TCP receive window to 2x the byte/sec capacity of the link
> > should see decent throughput.
>
> No, you need to set things on both sides.  The sender has to buffer
> data until it is ACKed in case it needs to retransmit.  So, its
> buffer needs to be as big as the advertised window or the sender
> buffer will effectivly limit the advertised window.

What do you need to set on the send side? If the receiver tells the
sender "my acceptable window is 512k", the sender knows how much it
has to buffer.

-c