TCP and WAN issue

Philip Lavine source_route at
Tue Mar 27 21:41:13 UTC 2007

This is the exact issue. I can only get between 5-7 Mbps. So the question is really what incremental performance gain do WAN accelerators/optimizers offer? Can registry/OS tweaks really make a significant difference because so far with all the "speed enhancements" I have deployed to the registry based on the some of the aforementioned sites I have seen no improvement.

I  guess I am looking for a product that as a wrapper can multiplex a single socket connection.


----- Original Message ----
From: Robert Boyle <robert at>
To: Philip Lavine <source_route at>; nanog <nanog at>
Sent: Tuesday, March 27, 2007 2:04:20 PM
Subject: Re: TCP and WAN issue

At 04:26 PM 3/27/2007, Philip Lavine wrote:
>I have an east coast and west coast data center connected with a 
>DS3. I am running into issues with streaming data via TCP and was 
>wondering besides hardware acceleration, is there any options at 
>increasing throughput and maximizing the bandwidth? How can I 
>overcome the TCP stack limitations inherent in Windows (registry 
>tweaks seem to not functions too well)?

You will have problems obtaining anything more than 5-7Mbit/s based 
on 1500 byte Ethernet packets and a RTT latency of 70-90ms. You can 
increase your window size or use Jumbo Ethernet frames. Almost all 
GigE gear supports jumbo frames. I'm not sure of your application, 
but without OS tweaks, each stream is limited to 5-7Mbit/s. You can 
open multiple streams between the same two hosts or you can use 
multiple hosts to transfer your data. You can utilize the entire DS3, 
but not without OS TCP stack tweaks or a move to jumbo frames. You 
can also use UDP or another connectionless packet method to move the 
data between sites. Good luck.


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