NAME

       Net::SIP - Framework SIP (Voice Over IP, RFC3261)

SYNOPSIS

       ...

DESCRIPTION

       Net::SIP consists of packages for handling the SIP packets, for transport of the packets, for processing
       the packets and on top of all that a simplified layer for common tasks.

       Addionally Net::SIP::Util provides utility functions and Net::SIP::Debug provides a debugging layer used
       by all these packets. Especially it provides the function invoke_callback which is used for all callback
       unless otherwise in the documentation specified. This function supports a variety of different callback
       styles.

       For first and simple applications you best start with Net::SIP::Simple.  If this is no longer enough you
       might look at the details of Net::SIP::Dispatcher, Net::SIP::Endpoint, Net::SIP::Register and
       Net::SIP::StatelessProxy.  Although these packages are in itself well documented the functionality and
       the design is best understandable if you look how it gets used in tghe source of Net::SIP::Simple.

   SIP packet handling
       SIP::Net::Packet
           Is the base class for handling SIP packets and provides ways to parse, construct and manipulate SIP
           packets.

       SIP::Net::Request
           Is derived from SIP::Net::Packet and handles the request packets.  Provides ways to create special
           requests like ACK or CANCEL based on previous requests and responses, for creating responses based on
           requests, for authorization of requests.

       SIP::Net::Response
           Is derived from SIP::Net::Packet and handles the response packets.

       SIP::Net::SDP
           Handles SDP bodies from SIP packets. Provides ways to parse, construct these bodies, to get media
           information from them and to manipulate the SDP data for NAT etc.

   Transport of SIP packets
       Net::SIP::Leg
           Encapsulates socket for transport of packet. Provides way to find out, if target is reachable through
           this socket. Prepares incoming, outgoing and forwarding packets by removing or adding header like
           Via, Record-Route.

       Net::SIP::Dispatcher
           Handles new packets coming in through a Net::SIP::Leg.  Delivers outgoing packets through the
           appropriate Net::SIP::Leg.  Handles timeouts and retransmission of outgoing packets, lookup of the
           appropriate leg through DNS etc.

       Net::SIP::Dispatcher::Eventloop
           Simple implementation of an event loop for handling socket events and timers.  Can be replaced to
           integrate into other event loops, like Tk, Lib::Event or POE.

   Processing of SIP packets, application layer
       Net::SIP::Endpoint
           Implements a SIP endpoint (UAC,UAS). Provides ways to INVITE or BYE calls or to handle incoming
           calls. Calls itself will be handled by Net::SIP::Endpoint::Context.

       Net::SIP::Registrar
           Simple implementation of a registrar.

       Net::SIP::StatelessProxy
           Simple implementation of a stateless proxy. Stateful proxies should probably be implemented by
           putting multiple Net::SIP::Endpoints together.

       Net::SIP::Blocker
           Can block requests by method name with custom error code.

       Net::SIP::ReceiveChain
           Can contain various objects for processing objects. Useful in connection with Net::SIP::Authorize.

       Net::SIP::Redirect
           Works together with a registrar and redirects requests.

       Net::SIP::Authorize
           If put into a Net::SIP::ReceiveChain it requests and checks authorization and gives only authorized
           requests to the next member of the chain.

   Simplified Layer for common tasks
       Net::SIP::Simple
           Provides simple layer for common tasks and tests, like sending a voice message to somebody, receiving
           a message or even implementing an answer machine. Together with Net::SIP::Simple::RTP it is possible
           to handle simple RTP data (PCMU/8000).

   Error handling
       Unless otherwise documented the common way to propagate errors is to raise an exception, e.g. call die().
       This might especially happen when parsing packets from strings, so unless you want to crash your
       application on bad input you should catch these exceptions with eval.

EXPORTS

       By default nothing is exported. There are various arguments for exporting:

       :alias
           Exports constants as aliases for the Net::SIP::* packages, e.g.  'Simple' for 'Net::SIP::Simple',
           'Registrar' for 'Net::SIP::Registrar', 'Packet' for 'Net::SIP::Packet', 'NATHelper_Client' for
           'Net::SIP::NATHelper::Client'
            etc.

       :util
           Exports everything (tag ':all') from Net::SIP::Util.

       :debug
           Exports the default exports from Net::SIP::Debug.

       :all
           Everything from ':debug', ':util' and ':alias'.

       rtp=MINPORT-MAXPORT|rtp:MINPORT-MAXPORT
           Set the range of ports to be used for creating RTP sockets to MINPORT..MAXPORT.  This affects
           Net::SIP::Util::create_rtp_sockets.

       debug=LEVEL|debug:LEVEL
           Set Debugging level to LEVEL

       string
           Strings where the first character is upper case will be interpreted as aliases for Net::SIP::* and it
           will try to export it. If the first character is lower case it will try to import it from
           Net::SIP::Util.

   EXAMPLES
         use Net::SIP 'invoke_callback'; # use Net::SIP::Util 'invoke_callback'
         use Net::SIP ':debug';          # use Net::SIP::Debug
         use Net::SIP ':util';           # use Net::SIP::Util ':all'

         use Net::SIP ':alias';
         Packet->new( ... );             # Net::SIP::Packet->new( ... )

         # restrict rtp sockets from command line
         perl -MNet::SIP=rtp:4000-4010 program.pl

BUGS

       Support for TCP and SIPS and not or not fully implemented.

COPYRIGHT

       This module and are modules in the Net::SIP Hierarchy distributed together with this module are copyright
       (c) 2006-2013, Steffen Ullrich.  All Rights Reserved.  These modules are free software. They may be used,
       redistributed and/or modified under the same terms as Perl itself.