We are pleased to share with you all an interesting article contributed by Abdul Aziz Khan who is a Telecom Professional having more than 18 years of diverse Telecom Experience of Planning, Project Management, Optimization and Operations, he is currently working in Network Optimization team of Mobily KSA.
Abdulaziz Khan Technical Consultant at Mobily
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Latency is quite a new word for a common user and for some of the experienced users as well. We generally know about the goodness of a communication link with its speed in Mbps only.
If we want to have a good connection at our home or office where we have number of devices then we would like to go with a connection of a high Mbps value like 30, 50 or 100Mbps as per our anticipated usage based on our daily experience.
The only test carried out on the day of installation is a speed test, which shows a downlink close to the rate of our acquired connection rate.
So if we are generally fine with a high speed link then from where Latency comes in the picture, let me take you through an example of a of a user who uses an app for Stock trading and he finds a stock trading on a very low rate and he tries to buy this stock at his desired price, however the app responds that his request is rejected as the stock price has changed; even though the user is connected to the internet with a 30Mbps link and the request that he has sent to the network is in kbps only but his request still failed as it was not able to reach the destination in the required time.
Take another example of network based game, where multiple players are contesting with each other and one specific player is continuously getting his connection lost to the game server even though he has a big 100Mbps connection to the internet but still he got disconnected time and again.
These and similar are the places where Latency sweeps in, latency is the time which is required by your data to reach from one point to another point in the network, generally speaking it is the time difference when the data leaves the application server and reach to your device or vice versa. Also in some cases Round Trip Time or RTT which is the time that is taken by a data packet to leave a user and come back to him after having a round trip to a destination, both scenarios are depicted in the picture below:
Practically speaking no server can wait forever for you to complete any transaction and if your response is not received within a fixed time then it assumes that you are not interested in the transaction and rejects it, for example in our stock trading app example, once you query the price of a specific stock it will show you but the price will not be fixed forever as the prices are constantly changing, the app does not know that either your request has reached late due to network issues or you have send the response late, hence it rejects your order if it is not reached on time.
What is the solution to it?
If you are a home user then there are no good solutions to it as the Internet Service Providers do not guarantee a minimum or average Latency for a normal user, most of the apps do take this into account that there may be a variable latency on the network and you have to depend on it.
However if you are a IT Manager for an organization and you are negotiating to get a good Internet connection for your organization then you must add Latency in your service contract and should ask the Service provider to guarantee some minimum average latency for your connection.
Thanks a lot for reading the article; I am sure that this article should have put some questions in your mind, please leave your questions in form of a comment that can be answered by me or someone else reading it. |
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IS there any formula to calculate average latency on any network?
Dear, there is no simple formula as the live network has always changing parameters, it is better to use some sort of testing, for example speedtest in case of websites or use ping, these test also provide the latency at that specific time, it may change even in two consecutive tests
Dear All,
Kindly visit to below site for Calculating the letency.
http://wintelguy.com/wanlat.html
Hi aazizk,
Can you post an article about the RFC 2544 suite in which the latency tests are run to check for conformance of L2/L3 devices ?!
It would be very helpful. I've worked with IXIA and Spirent and i would like to go down the memory lane as i do not have any documents regarding the same !
I know about latency. Thank you very much.