How to calculate exact time required to send image files over a WAN link?

[pankajs]

While undergoing a project, I have come a situation where I need to calculate time required to send a specific format of image file (70KBytes) over different WAN speeds (128,256, 2Mbps....).

There is no current setup in place to experiment and I have to submit a report on theoritical basis.

If I am correct then I understand that time required to send a specific amout of data is different for text and image files. But I don't know what parameters decide this. Also I have to submit the report taking in account all the practical factors like physical signaling overhead (i.e. the available transfer speed on a T1 is not 1536 Kbps since 192 Kbps is usually tied up in the T1 signaling protocol), layer 4 transport and transmission protocol overhead (i.e. TCP overhead, error checking, or protocol headers. For example each IPv4 header is 160 bits, each UDP header is 64 bits, etc.

Please suggest if there is any literature available to get the details.

Thanks

[rgodden]

http://www.t1shopper.com/tools/calculate/downloadcalculator.shtml

[frenzeus]

Hehe.. i think he might have already been to the url u pasted above. Quoting from the exact words from the url.. "(i.e. the available transfer speed on a T1 is not 1536 Kbps since 192 Kbps is usually tied up in the T1 signaling protocol), layer 4 transport and transmission protocol overhead (i.e. TCP overhead, error checking, or protocol headers. For example each IPv4 header is 160 bits, each UDP header is 64 bits, etc. Add all this up and you can loose over 10% of the total line capacity for just this one step.),"

[pankajs]

:-D.....any more ideas????

[frenzeus]

There is a good topic that explains how calculations are done for the various delays, ie. serialization delays, propagation delays, queueing delays etc.

You can read all about it from Cisco Press: IP Telephony Self-Study, Cisco QoS Exam Certification Guide, 2nd Edition by Wendell Odom & Michael J Cavanaugh.