Comments on: Musing:How Long Does It Take to Transfer Data ? Rules of Thumb http://etherealmind.com/how-long-does-it-take-to-transfer-data-rules-of-thumb/ Network design, architecture, thinking, working. Tech. Fri, 19 Mar 2010 13:25:26 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Greg Ferro http://etherealmind.com/how-long-does-it-take-to-transfer-data-rules-of-thumb/comment-page-1/#comment-2344 Greg Ferro Thu, 12 Feb 2009 21:05:26 +0000 http://etherealmind.com/?p=1236#comment-2344 Yeah, I sort of roughed it out with an estimate. I should do a followup on this and explain it a bit more fully. Might take a while. Greg Yeah, I sort of roughed it out with an estimate. I should do a followup on this and explain it a bit more fully. Might take a while.

Greg

]]> By: Brad Hedlund http://etherealmind.com/how-long-does-it-take-to-transfer-data-rules-of-thumb/comment-page-1/#comment-2337 Brad Hedlund Tue, 10 Feb 2009 02:25:46 +0000 http://etherealmind.com/?p=1236#comment-2337 Greg, Nice post and graphics but you lost me at your last paragraph which seems to imply that a large file transfer "should" just fill the pipe without concern for TCP Windowing. With latency, TCP Windowing is a critical factor to file transfer performance, regardless of file size and bandwidth. Brad Greg,
Nice post and graphics but you lost me at your last paragraph which seems to imply that a large file transfer “should” just fill the pipe without concern for TCP Windowing.

With latency, TCP Windowing is a critical factor to file transfer performance, regardless of file size and bandwidth.

Brad

]]> By: Greg Ferro http://etherealmind.com/how-long-does-it-take-to-transfer-data-rules-of-thumb/comment-page-1/#comment-2331 Greg Ferro Thu, 05 Feb 2009 08:32:38 +0000 http://etherealmind.com/?p=1236#comment-2331 Nice! However the Google calculation doesn't account for the encapsulation of data into Layer 2 frames and Layer 3 packets. That is, 1 Megabit of data becomes, roughly, 1.4 Megabits when sent over the Internet. Nice! However the Google calculation doesn’t account for the encapsulation of data into Layer 2 frames and Layer 3 packets. That is, 1 Megabit of data becomes, roughly, 1.4 Megabits when sent over the Internet.

]]> By: Fredrik http://etherealmind.com/how-long-does-it-take-to-transfer-data-rules-of-thumb/comment-page-1/#comment-2330 Fredrik Thu, 05 Feb 2009 07:53:41 +0000 http://etherealmind.com/?p=1236#comment-2330 Google is your friend: http://www.google.co.uk/search?hl=en&q=20GB+over+10+Mbps&meta= :) Google is your friend: http://www.google.co.uk/search?hl=en&q=20GB+over+10+Mbps&meta= :)

]]> By: File Catalyst:Unlimitech Software: Pretending to be a customer | My Etherealmind http://etherealmind.com/how-long-does-it-take-to-transfer-data-rules-of-thumb/comment-page-1/#comment-2327 File Catalyst:Unlimitech Software: Pretending to be a customer | My Etherealmind Wed, 04 Feb 2009 18:42:20 +0000 http://etherealmind.com/?p=1236#comment-2327 [...] from me. So a “Mark Johnson - makr324@hotmail.com” - posts a comment on my article on How Long it Takes to transfer data : “This is the exact problem my company faced about 6 months ago. We actually looked at WAN [...] […] from me. So a “Mark Johnson — makr324@hotmail.com” — posts a comment on my article on How Long it Takes to transfer data : “This is the exact problem my company faced about 6 months ago. We actually looked at WAN […]

]]> By: Greg Ferro http://etherealmind.com/how-long-does-it-take-to-transfer-data-rules-of-thumb/comment-page-1/#comment-2326 Greg Ferro Wed, 04 Feb 2009 18:01:08 +0000 http://etherealmind.com/?p=1236#comment-2326 Yeah, BDP has an impact on the "in-flight bytes" and there are various WAN acceleration products that play with TCP Window, TCP MSS & BDP to improve TCP protocol performance (and other things of course). I haven't spent a lot of time on WAN Acceleration, but for a 'rough guess' these numbers are a good start, I think. I will research it though and see if it worth some more writing. Yeah, BDP has an impact on the “in-flight bytes” and there are various WAN acceleration products that play with TCP Window, TCP MSS & BDP to improve TCP protocol performance (and other things of course). I haven’t spent a lot of time on WAN Acceleration, but for a ‘rough guess’ these numbers are a good start, I think. I will research it though and see if it worth some more writing.

]]> By: Greg Ferro http://etherealmind.com/how-long-does-it-take-to-transfer-data-rules-of-thumb/comment-page-1/#comment-2325 Greg Ferro Wed, 04 Feb 2009 16:36:02 +0000 http://etherealmind.com/?p=1236#comment-2325 Yeah, BDP has an impact on the "in-flight bytes" and there are various WAN acceleration products that play with TCP Window, TCP MSS & BDP to imp Yeah, BDP has an impact on the “in-flight bytes” and there are various WAN acceleration products that play with TCP Window, TCP MSS & BDP to imp

]]> By: Greg Ferro http://etherealmind.com/how-long-does-it-take-to-transfer-data-rules-of-thumb/comment-page-1/#comment-2324 Greg Ferro Wed, 04 Feb 2009 16:23:28 +0000 http://etherealmind.com/?p=1236#comment-2324 My experience is little bit different, and I am really only trying to lay out some rules of thumb. Let me do a little bit of research and I will come back to you. My experience is little bit different, and I am really only trying to lay out some rules of thumb. Let me do a little bit of research and I will come back to you.

]]> By: Harold http://etherealmind.com/how-long-does-it-take-to-transfer-data-rules-of-thumb/comment-page-1/#comment-2323 Harold Wed, 04 Feb 2009 14:31:18 +0000 http://etherealmind.com/?p=1236#comment-2323 Greg, isn't important to mention the TCP window size for the case exposed above? I've heard that it's the only thing that matters in cases where TCP plays, regardless of the line rate. Greg, isn’t important to mention the TCP window size for the case exposed above? I’ve heard that it’s the only thing that matters in cases where TCP plays, regardless of the line rate.

]]> By: James Lewis http://etherealmind.com/how-long-does-it-take-to-transfer-data-rules-of-thumb/comment-page-1/#comment-2322 James Lewis Wed, 04 Feb 2009 11:21:04 +0000 http://etherealmind.com/?p=1236#comment-2322 This is really helpful Greg. I work in the file transfer industry and whilst the supply of the product is generally quite straightforward its always a little more difficult helping customers to understand the implications of their Internet connectivity and what bandwidth they should provision for. I'll be pointing customers in your general direction. Thanks! This is really helpful Greg. I work in the file transfer industry and whilst the supply of the product is generally quite straightforward its always a little more difficult helping customers to understand the implications of their Internet connectivity and what bandwidth they should provision for. I’ll be pointing customers in your general direction. Thanks!

]]> By: JohnH http://etherealmind.com/how-long-does-it-take-to-transfer-data-rules-of-thumb/comment-page-1/#comment-2320 JohnH Tue, 03 Feb 2009 23:52:56 +0000 http://etherealmind.com/?p=1236#comment-2320 Great post Greg. You should really mention the impact of the Bandwidth Delay Product at higher bandwidths and latencies. If window scaling isn't supported end-to-end your effective throughput can be hobbled by the TCP limit on the number of bytes that can be on the wire at any one time. Great post Greg. You should really mention the impact of the Bandwidth Delay Product at higher bandwidths and latencies. If window scaling isn’t supported end-to-end your effective throughput can be hobbled by the TCP limit on the number of bytes that can be on the wire at any one time.

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