Util on a 100 Mb/s WAN Link for Lotus Notes

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Apr 23rd, 2009
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Hi to all,

my question:


i have a 100Mb/s Link with a Delay of about 15 ms.

There is a Lotus Notes Client-Server communication running and i am not able to fill up this connection because of delay and windowsize of notes.


does anybody know if there is a kind of windowsize in notes in a way that notes waits until it gets an ack from the other side befor it continous sending?


if yes, whats the "windowsize/blocksize" in notes and how to adjust/increase it?


would it be a good idea to e.g. double it?


Thanks for any answer

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Joseph W. Doherty Thu, 04/23/2009 - 16:08
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If your Lotus Notes is using TCP, TCP's "ideal" receive window is the BDP (bandwidth delay product). For your 100 Mbps and 15 ms, that would be 187,500 bytes. How to adjust it, if it can be adjusted, depends on the host OS. (NB: many hosts default TCP receive window size is often less that 16 KB. Also older TCP implementations don't support TCP receive windows larger than 64 KB.)


PS:

BTW, this is only important for large data transfers. Client-server applications can be latency bound.

rabeder Thu, 04/23/2009 - 22:49
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Hi,

thank you for your answer.


Yes it uses TCP.

I think i do not have problems with the TCP-Windowsize.

Is it possible, that e.g notes for itself uses a kind of blocksize, which is independent from tcp-winsize and is smaller and so the whole communication (filetransfer) is slower, than it would be if it would use the whole tcp-windowsize.

Joseph W. Doherty Fri, 04/24/2009 - 03:13
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It it possible Lotus Notes uses a blocksize that impedes its network performance? Sure, although I don't know if that's the case. Additionally, many client-server applications weren't designed for WAN latencies, and perform poorly across WANs. Lotus Notes might be such an application and there might not be anything that you can "tune" to improve.

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