Protocol
This is probably the most important term to understand as you can probably tell from a lot of the abbreviations below (most have a reference to protocol). A protocol is where two devices use a standard set of commands to communicate and process tasks. Let's say computer A wants to say 'hello' to computer B. When computer A sends the word 'hello' over to computer B, computer B needs to know the word is a greeting; if computer B has been programmed with the English language (the protocol), it will know what the message means. Computer B will also be able to reference the protocol on how it should respond; computer A is probably waiting for a 'hello' back as an acknowledgement, just like you and I would when engaging in conversation.
Around the world, different people use different languages to communicate; or in other words, they use different protocols. The German's use German as their protocol, the Swiss use French, English, Italian and / or German depending on which part of Switzerland they come from. The same is true for computers, networks and communications.
In the world of information technology, there are many bodies that set standards and protocols. Sometimes they are just agreed upon by various manufacturers in a specific market segment and then this standard can be ratified by another external body.
- Wikipedia - Protocol (Computing)
- Wikipedia - Communications Protocol I think this had a better description than the computing one.
- IEEE - Institute of Eletrical and Electronics Engineers One of the main standards bodies for technology.
VoIP (Voice Over Internet Protocol)
Voice was traditionally carried over copper wires. Now it is carried with lots of other data on networks such as the Internet. (The Internet now carries emails, web pages, video clips, large photographs, files between corporate sites, voice conversations, faxes and lots of other 'stuff' although it originally only carried one thing: text.) Since equipment such as servers, telephones, routers and gateways all need to know what to do with voice traffic, a protocol was devised to make sure voice traffic is kept separate from data traffic, and is processed in the correct way. For example, voice traffic is often moved along data networks whilst being given priority, where as other data (just using the internet protocol) waits for spare capacity. This ensures that your voice is not broken up when it arrives at the other side.
- Wikipedia - VoIP
- cnet.com.au - VoIP In Australia Provides some interesting insites into VoIP and our Internet infrastructure.
SIP (Session Initiation Protocol)
Used by many services including MSN Messenger, SIP negotiates between two parties the various protocol requirements of both sides and then matches whatever options it can. For example, in telephony, SIP can negotiate which codec (voice compression standard) is used between phones and / or the server and lets each device know where the traffic between the two end points should be routed.
- Wikipedia - Session Initiation Protocol A very informative and in-depth article.
- SIPForum - Promoters of the SIP protocol.
Codec
Stands for COde, DECode or COmpression, DECrompression. When sending data from one point to another, you need to split it into little blocks and they need to be wrapped in certain ways. A codec defines this. When two devices start communicating (assuming they are SIP devices) they agree on the codec to be used which allows both devices to send and receive data using the same standard for splitting and wrapping the 'data packets'. If both sides don't use the same codec, the data when it reaches the other end will be un-intelligible.
- voip-info.org - Codec Choices voip-info.org is my favourite site and has lots of information about VoIP solutions.