=====datacomm Keyword 1=====
asterisk

====Definition====
A programming language to communicate and execute the basic functions of telephony services.

=====datacomm Keyword 1 Phase 2=====
SIP - Session Initiation Protocol

====Definition====
SIP is a signalling protocol.  I would guess that that means it is a certain method of having machines communicate.  It is typically used for voice and video communication.  SIP can be used for two-party (unicast) and multiparty (multicast).

You can modify IPs and ports, invite more people, and add/delete media streams.

SIP can take care of 5 things:

  * User Location      - Figures out what system will be used for the call.
  * User Availability  - Determining the availability of the user.
  * User Capabilities  - Determining how the call will be made (voice, video, etc).
  * Session Setup      - The making of the session, making the ringing happen.
  * Session Management - Transferring, terminating, and modifying the call.

At first I had no idea what SIP was all about and had difficulty understanding it. Now I have a pretty good understanding, I think.  I'll probably ask about it next class to make sure I am right, but I feel like SIP is basically just a 'code' of how machines communicate. Just like how humans use English, or Spanish, or Arabic. Computers can use SIP.

On further research, the analogy is fairly sound, but needs a little bit more to it.  SIP is basically a specific format that machines can use to communicate.  It's a set of certain things that need to be done while communicating.  It's not like a language.... it's more like the RULES behind a language.
====References====
http://www.voipmechanic.com/sip-basics.htm \\
http://en.wikipedia.org/wiki/Communications_protocol
====Demonstration====
A demonstration of SIP would be the conversation with another sip registered member and its options. The options/steps are as follows:

**INVITE** - invites another registered sip to the call with your registered sip.

**ACK** - acknowledges the request and sends a retrieval of the request acknowledgement.

**BYE** - ends the conversation between the two sip registered members of the call.

__Other things that can happen during a sip situation include but are not limited to:__

**CANCEL** - requesting information about the remote server you are contacting.

**OPTIONS** - requesting to be registered with the remote server you are trying to contact.