Quote:
Originally Posted by Rathji
I have no idea what jutter is. Jitter on the other hand is the variance that you have between packets arriving. It can be caused by packets taking different routes, or by a piece of equipment (router, switch etc) that is sending the packet out sending them at strange times for a variety of reasons. As I understand it, and I really don't because it isn't a level of networking I ever deal with, it is bad because packets usually need to be assembled in order as they come in, so if you have a delay then the processor needs to wait to put the next packet in. Also if jitter is really bad, over 50%, you can get packets coming in the wrong order, which can slow things down getting them put back together.
|
To further elaborate on this...
The world of TCP/IP is different from most means of communication that we are used to. We are used to receiving information in chronological order from beginning to end. When we communicate with one another -- whether by spoken or written word -- we form our sentences in a manner that our peer can understand them. sentence senseless up in a inherently -- sentence while the become the same Mixing -- can cause words message to.
Downloading large files best describes how data transmission over TCP/IP works, particularly when using a bittorrent program. Most bittorrent programs I'm aware of allow you to see not just a progress bar, but also a pictograph depicting what data you have thus far. Every single time, you will notice that you have packets all over the place, rather than arriving in sequential, chronological order. It's like a jigsaw puzzle that your PC is slowly putting together as it receives all the pieces, except your computer uses the overhead data sent with each packet to determine where in the file each and every packet is expected to go. Jitter has little to no effect on this.
However, when the IP world is used for real-time communications -- i.e. live streaming video or voice communication -- suddenly there is a restriction put in place. Data must be sent and received in the same order between peers, otherwise the message will not be understood by the receiving peer. These scenario's are the most adversely affected by jitter, as there is no lee-way in the sending and receiving of packets. System B cannot ask system A to resend lost packets, because by the time it takes to request a retransmit, process the request, resend the packet, receive it and process it, is too long. It is already too late; the puck is in the net. Now you'll have to wait to see it on the slo-mo replay because you missed it live.