The Broadband Guide
search advanced
FAQs Categories:

16. What RWIN (TCP Receive Window) value should I use ?

The TCP Receive Window (RWIN) value depends on two main factors:

1. The speed of your internet connection (bandwidth).
2. The maximum anticipated latency on the line (pings).

There is a BDP (bandwidth * delay product) formula that gives the approximate RWIN you should use for a given throughput and latency...

The Analyzer and the Optimizer go a couple of steps further in optimizing RWIN:

3. The recommended values for RWIN are multiple of MSS
4. The recommended numbers use large unscaled RWIN values

After all those calculations, here is a very rough breakdown of the Analyzer recommended values... Assuming land lines (satellite should use larger RWIN values because of the high latency), and 1492 MTU:

511104 -- works for ~8 to ~30 Mbps
255552 -- 2 to 14 Mbps
127776 -- 1 to 5 Mbps
63888 -- works well up to ~2 Mbps.

  User Reviews/Comments:
by branoox - 2007-08-27 07:12
How Do I Change The RWIN Value On Vista.
by anonymous - 2007-10-01 11:11
From what I was reading about vista, you dont. It has an Automatic RWIN feature. It can be read about in great detail from the MS site themselves. Looks like you should probably enable the stuff in vista, that comes with longhorn, the server version, if you are serving files, or concerned about sending at a higher rate.

From what I read though, its automatic!
News Glossary of Terms FAQs Polls Cool Links SpeedGuide Teams SG Premium Services SG Gear Store
Registry Tweaks Broadband Tools Downloads/Patches Broadband Hardware SG Ports Database Security Default Passwords User Stories
Broadband Routers Wireless Firewalls / VPNs Software Hardware User Reviews
Broadband Security Editorials General User Articles Quick Reference
Broadband Forums General Discussions
Advertising Awards Link to us Server Statistics Helping SG About