Comments on: How to Calculate TCP throughput for long distance WAN links http://www.internetworkexpert.org/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links/ Studies in Data Center Networking, Virtualization, Computing Wed, 10 Mar 2010 19:34:35 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: slimer http://www.internetworkexpert.org/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links/comment-page-1/#comment-685 slimer Tue, 26 Jan 2010 21:07:07 +0000 http://www.internetworkexpert.org/?p=74#comment-685 Brad, Thanks for the very interesting explanation here! I have a question and hope you can help. We want to perform a data consolidation for some of our application whereby we already know the number of server and we will be able to get the volume of traffic. However, we are not sure how much WAN bandwidth needed in the data center that we will do the data consolidation. Let's say, I have the following parameters: - 120GB of aggregated traffic over the LAN (this is the server/client traffic) - WAN latency is 75ms (RTD-150ms) Objective: To know the WAN bandwidth to be used Thanks...Slimer Brad,

Thanks for the very interesting explanation here! I have a question and hope you can help.

We want to perform a data consolidation for some of our application whereby we already know the number of server and we will be able to get the volume of traffic. However, we are not sure how much WAN bandwidth needed in the data center that we will do the data consolidation.

Let’s say, I have the following parameters:
- 120GB of aggregated traffic over the LAN (this is the server/client traffic)
- WAN latency is 75ms (RTD-150ms)

Objective: To know the WAN bandwidth to be used

Thanks…Slimer

]]> By: Blog | jim80.net » Why 100Mbps Does Not Mean 100Mbps Transfer Rates http://www.internetworkexpert.org/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links/comment-page-1/#comment-681 Blog | jim80.net » Why 100Mbps Does Not Mean 100Mbps Transfer Rates Fri, 22 Jan 2010 16:11:32 +0000 http://www.internetworkexpert.org/?p=74#comment-681 [...] http://www.internetworkexpert.org/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links...for a more in-depth discussion on [...] [...] http://www.internetworkexpert.org/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links…for a more in-depth discussion on [...]

]]> By: Brad Hedlund http://www.internetworkexpert.org/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links/comment-page-1/#comment-678 Brad Hedlund Wed, 13 Jan 2010 02:11:15 +0000 http://www.internetworkexpert.org/?p=74#comment-678 Jorge, I found this formula in my files: <img src="http://internetworkexpert.s3.amazonaws.com/2008/12/tcp-throughput-calc-with-packet-loss.png" alt="tcp calc with packet loss" /> Hope this helps. Cheers, Brad Jorge,

I found this formula in my files:

tcp calc with packet loss

Hope this helps.

Cheers,
Brad

]]> By: jorge luis obregon http://www.internetworkexpert.org/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links/comment-page-1/#comment-677 jorge luis obregon Mon, 11 Jan 2010 20:24:07 +0000 http://www.internetworkexpert.org/?p=74#comment-677 Hi Brad: Could you help me with a model that calculated the throughput, included loss. I need a formula for estimated a throughput with loss with the same topology. Please help me if you can. Hi Brad:
Could you help me with a model that calculated the throughput, included loss. I need a formula for estimated a throughput with loss with the same topology. Please help me if you can.

]]> By: TQ http://www.internetworkexpert.org/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links/comment-page-1/#comment-676 TQ Mon, 11 Jan 2010 15:44:52 +0000 http://www.internetworkexpert.org/?p=74#comment-676 Brad Hedlund, I just wanted to thank you for your effort in publishing this article. Regards Brad Hedlund,
I just wanted to thank you for your effort in publishing this article.

Regards

]]> By: dheeraj http://www.internetworkexpert.org/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links/comment-page-1/#comment-670 dheeraj Wed, 30 Dec 2009 11:16:36 +0000 http://www.internetworkexpert.org/?p=74#comment-670 dear Brad i am doing research on multipath routing how can we prove that throughput of multipath routing is better than single path routing thanks and regards dear Brad
i am doing research on multipath routing
how can we prove that throughput of multipath routing is better than single path routing

thanks and regards

]]> By: Andy http://www.internetworkexpert.org/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links/comment-page-1/#comment-663 Andy Mon, 21 Dec 2009 17:17:12 +0000 http://www.internetworkexpert.org/?p=74#comment-663 Hi Brad, This is continuation of my Previous Post. Throughput is RWIN/Latency is Sec say I have a 2Mbps link and as per the throughput calulation ,i get a throughput of 1Mbps ,Can i get a trasfer ratefor 1mbps for all file trasfer like FTP traffic,http traffic,MS-DS traffic ,MRDP traffic etc. How this can be decided? Please help I am desperately looking for an Answer... Hi Brad,

This is continuation of my Previous Post.

Throughput is RWIN/Latency is Sec

say I have a 2Mbps link and as per the throughput calulation ,i get a throughput of 1Mbps ,Can i get a trasfer ratefor 1mbps for all file trasfer like FTP traffic,http traffic,MS-DS traffic ,MRDP traffic etc.
How this can be decided?
Please help
I am desperately looking for an Answer…

]]> By: Munir K http://www.internetworkexpert.org/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links/comment-page-1/#comment-662 Munir K Mon, 21 Dec 2009 14:11:19 +0000 http://www.internetworkexpert.org/?p=74#comment-662 Hi Brad, Thanks a lot for this. I have already lined up with Cisco for POC. I will surely share the results with you on this forum. Regards, Munir K. Hi Brad,

Thanks a lot for this. I have already lined up with Cisco for POC. I will surely share the results with you on this forum.

Regards,

Munir K.

]]> By: Brad Hedlund http://www.internetworkexpert.org/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links/comment-page-1/#comment-659 Brad Hedlund Sat, 19 Dec 2009 05:15:10 +0000 http://www.internetworkexpert.org/?p=74#comment-659 Munir, In your case, I would recommend that you look at deploying a Cisco WAAS appliance at each end of the link. The Cisco 3745 router does not support WAAS modules, but I think the performance profile of an appliance would be better for you anyway ... such as the Cisco WAVE-674. You can simply place the WAAS appliance inline between your 3745 and LAN switch. http://www.cisco.com/go/waas Munir,
In your case, I would recommend that you look at deploying a Cisco WAAS appliance at each end of the link. The Cisco 3745 router does not support WAAS modules, but I think the performance profile of an appliance would be better for you anyway … such as the Cisco WAVE-674. You can simply place the WAAS appliance inline between your 3745 and LAN switch.

http://www.cisco.com/go/waas

]]> By: Andy http://www.internetworkexpert.org/2008/12/19/how-to-calculate-tcp-throughput-for-long-distance-links/comment-page-1/#comment-657 Andy Wed, 16 Dec 2009 17:07:52 +0000 http://www.internetworkexpert.org/?p=74#comment-657 Hi Brad, Thanks a lot for your excellent post here. I am facing a very critical issue.Need your help(all r welcome to help me) I am in China and my company has a WAN link to US (4*T1-Bundled) and then we have a IPSEC tunnel to our Customer network through Internet.We use MRDP to access the Customer's VM and access some applications.This application is based on Flash and its extremely slow as we are working on MRDP. The utilization on our WAN link is not above 30%. Latency is 300ms beween the Client and Server. Changing the Window size is going to help us Most of our desktops in my companies are Vista and i read we can tune the TCP by setting netsh int tcp set global autotuninglevel=experimental so that the window size can be upto 16MB. After setting this ,we are dont see any performance difference. I am really being screwed because of this issue.Kindly suggest a suitable solution. I want to know how we can change the Window Size?is it by creating a new Reg Value ? These are the parameters on my Windows XP MSS: 1440 MTU: 1480 TCP Window: 17280 (multiple of MSS) RWIN Scaling: 2 bits (2^2=4) Unscaled RWIN : 4320 Recommended RWINs: 63360, 126720, 253440, 506880, 1013760 BDP limit (200ms): 691kbps (86KBytes/s) BDP limit (500ms): 276kbps (35KBytes/s) Please help Andy Hi Brad,

Thanks a lot for your excellent post here.
I am facing a very critical issue.Need your help(all r welcome to help me)

I am in China and my company has a WAN link to US (4*T1-Bundled) and then we have a IPSEC tunnel to our Customer network through Internet.We use MRDP to access the Customer’s VM and access some applications.This application is based on Flash and its extremely slow as we are working on MRDP.
The utilization on our WAN link is not above 30%.
Latency is 300ms beween the Client and Server.

Changing the Window size is going to help us
Most of our desktops in my companies are Vista and i read we can tune the TCP by setting
netsh int tcp set global autotuninglevel=experimental so that the window size can be upto 16MB.
After setting this ,we are dont see any performance difference.
I am really being screwed because of this issue.Kindly suggest a suitable solution.
I want to know how we can change the Window Size?is it by creating a new Reg Value ?

These are the parameters on my Windows XP

MSS: 1440
MTU: 1480
TCP Window: 17280 (multiple of MSS)
RWIN Scaling: 2 bits (2^2=4)
Unscaled RWIN : 4320
Recommended RWINs: 63360, 126720, 253440, 506880, 1013760
BDP limit (200ms): 691kbps (86KBytes/s)
BDP limit (500ms): 276kbps (35KBytes/s)

Please help

Andy

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