nanog mailing list archives
RE: Satellite latency
From: "David Luyer" <david () luyer net>
Date: Wed, 6 Mar 2002 16:53:26 +1100
Tony Rall wrote:
Specifically made for satellite networks: ip tcp window-size 750000I don't understand the benefit of this on a router. Except for connections where the router itself is an endpoint (telnet to the
router,
for example), the router has no need to even be aware of window size. Perhaps the router's window size comes into play if the router is performing advanced functions such as NAT or IPSEC?
I don't expect the router would do anything in the NAT case, but a transparent proxy used to work magic in the satellite days in Australia (before Southern Cross). A SOCKS proxy would do the same but be far more intrusive. Basically a customer accessing a US web site ends up looking like this (many hops deliberately missed): DIAL CUSTOMER (customer tcp stack) | medium latency hop (modem) | layer 4 switch or router with WCCP or policy routing | PROXY FARM (good tcp stack with good window sizes) | high latency hop (satellite) | US internet | US WEBSITE (server tcp stack) Often the server TCP stack and the customer TCP stack may be dodgy and sometimes even unable to directly communicate, but the good TCP stack in the middle can communicate to both of the dodgy TCP stacks at either end as well as providing a good window size to receive from the server and splitting the latency in half on each TCP connection leg as to a direct connection. David. -- David Luyer Phone: +61 3 9674 7525 Network Development Manager P A C I F I C Fax: +61 3 9699 8693 Pacific Internet (Australia) I N T E R N E T Mobile: +61 4 1111 BYTE http://www.pacific.net.au/ NASDAQ: PCNTF
Current thread:
- Re: Satellite latency Hank Nussbacher (Mar 04)
- Re: Satellite latency Richard A Steenbergen (Mar 05)
- Re: Satellite latency Clayton Fiske (Mar 05)
- Re: Satellite latency Richard A Steenbergen (Mar 05)
- Re: Satellite latency Clayton Fiske (Mar 05)
- <Possible follow-ups>
- Re: Satellite latency Tony Rall (Mar 05)
- RE: Satellite latency David Luyer (Mar 05)
- Re: Satellite latency Joe Abley (Mar 05)
- RE: Satellite latency David Luyer (Mar 05)
- Re: Satellite latency Richard A Steenbergen (Mar 05)