Asterisk and voip

|| IT3437 Network Selected Topics Asterisk and VoIP

August 29th, 2010 060300273 Hidalgo Arellano Salvador Indra Homework:2 Team: 2

Asterisk is a free, open source software implementation of atelephone private branch exchange (PBX) originally created in 1999 by Mark Spencer of Digium. Like any PBX, it allows attached telephones to make calls to one another, and to connect to other telephoneservices including the public switched telephone network (PSTN) and Voice over Internet Protocol (VoIP) services. Its name comes from the asterisk symbol, “*”. Asterisk is released under a duallicense model, using the GNU General Public License (GPL) as a free software license and a proprietary software license to permit licensees to distribute proprietary, unpublished system components.Originally designed for Linux, Asterisk now also runs on a variety of different operating systems including NetBSD, OpenBSD, FreeBSD,Mac OS X, and Solaris. A port to Microsoft Windows is known asAsteriskWin32. 1 Asterisk protocols
Natively supported VOIP protocols:

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SIP, Session initiation protocol IAX, IAX2 - Inter Asterisk Exchange protocol (open-source trunking protocol primarily usedby Asterisk) MGCP: Media gateway control protocol, IETF H.323 (With the addition of OpenH323 )

There are third-party add-ons that greatly enhance this list, for example alternative H.323 channels,SCCP/Skinny but also for example OSP. SIP SIP, the session initiation protocol, is the IETF protocol for VOIP and other text and multimedia sessions, like instant messaging, video, online games andother services.

SIP can be regarded as the enabler protocol for telephony and voice over IP (VoIP) services. The following features of SIP play a major role in the enablement of IP telephony and VoIP: Name Translation and User Location: Ensuring that the call reaches the called party wherever they are located. Carrying out any mapping of descriptive information to

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