Re: TCP Window Optiimization with LFN.

We tried that also :)

Didn't help...

Only effects router generated traffic :y

Ha ha - read the doc cd...

Riverbed is like the IRS - sooner or later - you need to pay them :y

From: JB Poplawski [mailto:jb.poplawski_at_gmail.com]
Sent: Thursday, August 16, 2012 04:37 PM
To: Joseph L. Brunner
Cc: Dan Shechter <danshtr_at_gmail.com>; ccielab_at_groupstudy.com <ccielab_at_groupstudy.com>
Subject: Re: TCP Window Optiimization with LFN.

TAC is having me give this a whirl.

Global
ip tcp window-size 8625000

Config on L2 Interfaces
hold-queue 4096 in
hold-queue 4096 out

I calc-ed the estimated Window via this link.
  http://bradhedlund.com/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links/

It's amazing I get a good 30MB from a 3GB ISO off of a Server08 box. From a Server 03, I'm lucky to get 85bytes on a 22MB file.

SE and AM are getting some WAAS and ASR quotes together. *Puts on nut cup*

Thanks guys,
JB

On Thu, Aug 16, 2012 at 3:27 PM, Joseph L. Brunner <joe_at_affirmedsystems.com<mailto:joe_at_affirmedsystems.com>> wrote:
We tried that extensively in windows 2003 and other things - never worked or made a difference....

-----Original Message-----
From: nobody_at_groupstudy.com<mailto:nobody_at_groupstudy.com> [mailto:nobody_at_groupstudy.com<mailto:nobody_at_groupstudy.com>] On Behalf Of Dan Shechter
Sent: Thursday, August 16, 2012 4:12 PM
To: JB Poplawski
Cc: ccielab_at_groupstudy.com<mailto:ccielab_at_groupstudy.com>
Subject: Re: TCP Window Optiimization with LFN.

It depends on what you are looking for: High BW, Latency issues or both.

For a large window size,
http://en.wikipedia.org/wiki/TCP_window_scale_option should do it. As long as there are no CRC errors on the path, there is no much harm enabling it by default.

For latency issues of chatty protocols, we will all have to wait for the results of CERN experiments to see if we can send packets faster then the speed of light... ;) . For some applications, WAAS "reducing" the latency is much more important than BW.

HTH,
Dan #13685 (RS/Sec/SP)
 The CCIE troubleshooting blog: http://dans-net.com Bring order to your Private VLAN network: http://marathon-networks.com

On Thu, Aug 16, 2012 at 9:07 PM, JB Poplawski <jb.poplawski_at_gmail.com<mailto:jb.poplawski_at_gmail.com>>wrote:

> Good afternoon,
>
> My token question out to the group as I await TAC.
>
> I have a network with Gb links between sites. Connected like such:
> Site A < 7ms > Site B < 71ms > Site C <9ms> Site D
>
> End to end latency between Site A and Site D is 69ms. My numbers
> above are the average given from CLI.
>
> I've been reading on LFNs (Long Fat Networks) and basically I need to
> optimize the TCP Window size (calculated to 8625KB).
>
> My question, where do I implement it?
> Site A and Site D? Or Site B and Site C?
>
> If I implement on Site B and Site C, how does that impact Site C to
> Site D, etc?
>
> Any ideas?
>
> We previously had MPLS connection with WAAS which optimized traffic.
> Now since we're running Gb, we removed WAAS (our WAAS boxes were only
> rated to 50Mbps).
>
> Any suggestions? Am I on the right path?
>
> Any help is greatly appreciated.
> JB
>
>
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Received on Thu Aug 16 2012 - 20:41:40 ART