TCP and WAN issue

Joe Maimon jmaimon at ttec.com
Tue Mar 27 22:36:44 UTC 2007


Philip Lavine wrote:

> I have 2 data transmission scenarios:
> 
> 1. Microsoft MSMQ data using TCP
> 2. "Streaming" market data stock quotes transmitted via a TCP sockets
> 
> Philip

TCP stack tuning works very well for applications with large sized 
network reads and writes.

Applications that will only write X and then will wait to read Y do not 
gain from tweaks when Y or X are not large enough to fill a significant 
portion of the pipe end to end. IOW, the chattiness of the protocol 
multiplied by the rtt equals delay.

Applications that open and close sockets to chat are even worse.

The only real thing that can cure this other than a rewrite of the 
applications behavior, is a application layer proxy that "chats on 
behalf of"

This is part of the wan optimization space from what I understand.


> 
> 
> ----- Original Message ----
> From: William F. Maton Sotomayor <wmaton at ryouko.imsb.nrc.ca>
> To: Philip Lavine <source_route at yahoo.com>
> Sent: Tuesday, March 27, 2007 2:50:44 PM
> Subject: Re: TCP and WAN issue
> 
> 
> Hi Philip,
> 
>      We've run across this problem from one end of Canada to the other. 
> As others have alluded to, the best you can hope for is to tweak the TCP 
> window sizes up and increase the socket buffers to suit.  However, if 
> you're doing something over NetBIOS, it's turned out to be a total lost 
> cause.  Right now we're looking at the Steelheads from Riverbed to solve 
> the NetBIOS problem.  (The Steelheads do the dirty work of TCP tweaking on 
> your behalf, so you don't have to, besides cacheing.)
> 
>      BTW, when you say stream, you're saying transfer of data other 
> than a webcast, correct?
> 
> On Tue, 27 Mar 2007, Philip Lavine wrote:
> 
> 
>>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.
>>
>>Philip
>>
>>----- Original Message ----
>>From: Robert Boyle <robert at tellurian.com>
>>To: Philip Lavine <source_route at yahoo.com>; nanog <nanog at merit.edu>
>>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.
>>
>>-Robert
>>
>>
>>
>>Tellurian Networks - Global Hosting Solutions Since 1995
>>http://www.tellurian.com | 888-TELLURIAN | 973-300-9211
>>"Well done is better than well said." - Benjamin Franklin
>>
>>
>>
>>
>>
>>
>>
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> 
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