 This topic has 10 replies, 1 voice, and was last updated 2 years, 9 months ago by Mahmoud.

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Manoj Kumar C.Guest
Gents,
I am on an effort to find out a genuine formula to calculate the time needed to transfer certain amount of data (say 200MB) across a 64K leased line ( terrestrial). The formula should also include the actual delay and stuff like that. Is there any? or can you help me to find it out.
Thanks & Cheers,
Manoj Kumar
Anwer JalilGuestHi,
A leased line of 64 kilobit per second can carry 64/8 kilobytes per second for bytes consisting of 8 bits. Therefore, a file of 200MB data will take 200,000/8/60/60 hours i.e. about 7 hours. However, please keep in mind that a leased line of 64kb/s never delivers true 64k, so you should put some margin for thatThanks
Anwer Jalil
Manoj Kumar C.GuestAnwar,
Many Thanks for the information.
Note that in an actual scenario it took around 12.5 hours to complete this transfer. Do you think the margin should be that big?Thanks & Cheers,
Manoj Kumar
Don McKGuestThe 64kb is the speed of the data on the line and it should be a true 64kb, after all, that is what you are paying for.
You are probably using a networking protocol which places some overheads on the data, for exaple both IP and Frame relay add additional data packets (for addressing, error detection etc). You may also be using a file transfer application which does its own error detection and asks for some data to be resent.
This additional data is an overhead on your file, but it must be included in the total data transmitted. For instance a 20% overhead adds 40Mb or approximately an additional 84 minutes.
The transfer speed will also depend upon the efficiency of the network at either end, (getting from PC to router and router to PC) and the efficiency of the router (It may be operating at near capacity and queuing data)
There are lots of areas where delays can be introduced, it can be a very specialised task to actually find the cause and a very expensive exercise to ‘fix’ it.
Good Luck.
Don McK
ZahidGuestOne more thing I mean question in the same context, how MRTG shows the bandwidth utilization??
Need HelpGuestAppreciate it you could help me to calculate the time needed to transfer the amount of data 24KB across a 16Kbps analog line with 16Bytes CIR. Please show the geneine formula on the calculation.
Thanks in advance.
MarlonGuestWould appreciate for an answer about a calculation that I am not sure of.
Case:
I have 2Mbps leased line to access the internet.I have a network that allows many computers to access the internet via my leased line using dialup networking.
Question:
What is the maximum number of dialup computers that can connect with a minimum speed of 32Kbps?Should I just divide the 2MB to the number of dial up computers and come up with 32Kbps?
Thank you.
dmckGuestMarlon, your calculation assumes that all computers are using 32Kb continuously whilst connected to the internet. IN fact they are using the 32Kb or more for only relatively short durations (sometimes only seconds)usually during upload/download. Down loads are usually bigger files. To calculate the maximum number you need to know the average time they are downloading data and divide this into 1 hour or find the average download file size (in bits) and divide into 2M x 3600 (bits per hour).
These calcs wil more closely approximate the max number of PC’s to connect.
samir p vyasGuesthow to calculate 10 MBPS leased line , If i download one file and so me as a 1280 KBPS. Then it is Correct or Not ?
AjitGuestHow much bandwidth is sufficient to cater to normal internet surfing by 150 users plus uploading video data 12 cameras?
MahmoudGuesti have a daily transaction of 4GB from 200 concurrent users, so what is the leased line bandwidth i will required ?

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