India Broadband Forum

Luke Skywalker

What is latency?
It is a measure of abilty of a medium to transverse( transport) a given data i.e. it is the amount of time in which it transfers the data.

I have speed of 200 mbps . So, is my speed greater than one having connection of 56baud(bps)?
No. Bps is not unit of the speed but bandwidth.
Two ananlogies by me to explain :
1.Sunlight , tubelight & laser . All have same speed =c. But a laser can give more energy than sunlight which in turn give more energy than light. Laser takes same time to travel.
2.Sonic booms wave can destroy glass. But sunlight can't. It carries less heat. But sunlight is faster than sonic boom. Sunlight takes less time to travel.
If latency is time9 which depends upon speed) here & data download speed( bandwidth) is heat or energy , then you can see that they are not dependent on each other.

What determines latency?
Latency is determine by velocity factor (respect to spped of light)) if we are talking about a medium. Also it depends upon routers , attenuation e.t.c. if we are talking about overall latency not just of a medium.

What does latency determines?
It only determines the rate at which data comes to you not how much data comes to you.

What is rank of varoius medium in terms of latency?
Vaccum vf nearly 1.0
Copper wires of v.f 0 .9
Cable .7-.4
Optic fibres 0.66
You can't do ping to determine this.


A medium had better latency . So a it is better than others?
Yes, theoritically it is better but when you talk about when you are taking them in use you will also have to take into account SNR, attenuation, fidelity, sensitivity , selectivity image rejection ratio when technology used.
Practically you are now getting :
Copper( upto a fixed distance)
Cable
Optics
Wireless

I am using a certain technology which use a certain medium but I am not getting requisite latency as specified theoritically by you, L.S.?
It is because that tech. Had still much to improve. Take example of wimax. Currently wimax in used is of older defination by IEEE & it is being used all over the world. But newer defination which is also called wimax-m will improve latency & bandwidth (upto 1 gBps download for fixed & far better latency than currently offered by various wireless technologies).


Still the practical latency rank given by you L.S. Is not correct for me. Why?
Because your ISP had not better infrastructure.

Is a medium having better latency is better for mass transferring of data?
No, that is a different situation. The list I have given is for you to station. If you use cable to your station then it will have lower latency then copper.

Lower latency means better environment for gaming?
Yes, it is so. But not always. Some time other factors are also there which I have mentioned above.


Latency is not a measure of how good a technology is but how fast it is.
A good technology should give you lower attenation, higher bandwidth, high SNR, good fidelity( ability to reproduce signals). Cost is also a factor. You can search out countless factors.

mickey

great Info Luke... you rock ... :rock on:

meetdilip

Good one Luke.