megaco_sdp.hrl

OTP是开放电信平台的简称

%% ``The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
%% compliance with the License. You should have received a copy of the
%% Erlang Public License along with this software. If not, it can be
%% retrieved via the world wide web at http://www.erlang.org/.
%% 
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
%% the License for the specific language governing rights and limitations
%% under the License.
%% 
%% The Initial Developer of the Original Code is Ericsson Utvecklings AB.
%% Portions created by Ericsson are Copyright 1999, Ericsson Utvecklings
%% AB. All Rights Reserved.''
%% 
%%     $Id$
%%
%%----------------------------------------------------------------------
%% Purpose: 
%%----------------------------------------------------------------------
%%
%%
%% Explanaition of the fields in the SDP body
%%   (See RFC 2327 and RFC 3266 for the complete decription)
%%
%% Session descriptions
%%
%%  v        protocol version
%%  o        owner/creator and session identifier 
%%  s        session name                          (not used)
%%  i        session information                   (not used)
%%  u        URI of description                    (not used)
%%  e        email address                         (not used)
%%  p        phone number                          (not used) 
%%  c        connection information
%%  b        bandwidth information
%%  z        time zone adjustment
%%  k        encryption key
%%  a        zero or more session attribute lines
%%  Zero or more media descriptions
%%
%% Time descriptions
%%
%%  t        time the session is active
%%  r        zero or more repeat times
%%  
%% Media descriptions
%%
%%  m        media name and transport address
%%  i        media title
%%  c        connection information - optional if included at session-level
%%  b        bandwidth information
%%  k        encryption key
%%  a        zero or more media attribute lines
%%
%% An SDP-body is a list of the folowing tuples
%%
%%   {FieldID, FieldValue} where
%%
%%   FieldID = atom()
%%   FiledValue is a term()
%%
%% FieldID    FieldValue
%% 
%% o          #megaco_sdp_o{}
%% c          #megaco_sdp_c{}
%% m          #megaco_sdp_m{}
%% a          #megaco_sdp_a_rtpmap{}  iff 'att-field'=rtpmap
%% a          #megaco_sdp_a_ptime{}   iff 'att-field'=ptime
%% <other>    string()
%%
%% An example SDP description is:
%%
%%      v=0
%%      o=mhandley 2890844526 2890842807 IN IP4 126.16.64.4
%%      s=SDP Seminar
%%      i=A Seminar on the session description protocol
%%      u=http://www.cs.ucl.ac.uk/staff/M.Handley/sdp.03.ps
%%      e=[e-mail] (Mark Handley)
%%      c=IN IP4 224.2.17.12/127
%%      t=2873397496 2873404696
%%      a=recvonly
%%      m=audio 49170 RTP/AVP 0
%%      m=video 51372 RTP/AVP 31
%%      m=application 32416 udp wb
%%      a=orient:portrait
%% 
%% 
%% An example SDP description with IPv6 addresses
%%
%%    v=0
%%    o=nasa1 971731711378798081 0 IN IP6 2201:056D::112E:144A:1E24
%%    s=(Almost) live video feed from Mars-II satellite
%%    p=[phone]
%%    c=IN IP6 FF1E:03AD::7F2E:172A:1E24
%%    t=3338481189 3370017201
%%    m=audio 6000 RTP/AVP 2
%%    a=rtpmap:2 G726-32/8000
%%    m=video 6024 RTP/AVP 107
%%    a=rtpmap:107 H263-1998/90000
%% 
%%----------------------------------------------------------------------

-ifndef(megaco_sdp_).
-define(megaco_sdp_, true).


%% ===================================================================
%% 
%% Protocol Version
%% 
%% v=0
%% 
%% This field gives the version of the Session Description Protocol.
%% There is no minor version number.
%% 

-record(megaco_sdp_v, {
	  version					% integer()
	 }
       ).




%% ===================================================================
%% 
%% Origin
%%
%% o=<username> <session id> <version> <network type> <address type>
%% <address>
%%
%% The "o=" field gives the originator of the session (their username
%% and the address of the user's host) plus a session id and session
%% version number.
%%
%% <username> is the user's login on the originating host, or it is
%% "-" if the originating host does not support the concept of user
%% ids.  <username> must not contain spaces.  <session id> is a
%% numeric string such that the tuple of <username>, <session id>,
%% <network type>, <address type> and <address> form a globally unique
%% identifier for the session.
%%
%% The method of <session id> allocation is up to the creating tool,
%% but it has been suggested that a Network Time Protocol (NTP)
%% timestamp be used to ensure uniqueness [1].
%%
%% <version> is a version number for this announcement.  It is needed
%% for proxy announcements to detect which of several announcements
%% for the same session is the most recent.  Again its usage is up to
%% the creating tool, so long as <version> is increased when a
%% modification is made to the session data.  Again, it is recommended
%% (but not mandatory) that an NTP timestamp is used.
%%
%% <network type> is a text string giving the type of network.
%% Initially "IN" is defined to have the meaning "Internet".  
%% 
%% <address type> is a text string giving the type of the address 
%% that follows. Initially "IP4" and "IP6" are defined.  
%% 
%% <address> is the globally unique address of the machine from which
%% the session was created.  For an address type of IP4, this is
%% either the fully-qualified domain name of the machine, or the
%% dotted-decimal representation of the IP version 4 address of the
%% machine.  For an address type of IP6, this is either the
%% fully-qualified domain name of the machine, or the compressed
%% textual representation of the IP version 6 address of the machine.
%% For both IP4 and IP6, the fully-qualified domain name is the form
%% that SHOULD be given unless this is unavailable, in which case the
%% globally unique address may be substituted.  A local IP address
%% MUST NOT be used in any context where the SDP description might
%% leave the scope in which the address is meaningful.
%%
%% In general, the "o=" field serves as a globally unique identifier
%% for this version of this session description, and the subfields
%% excepting the version taken together identify the session
%% irrespective of any modifications.
%% 

-record(megaco_sdp_o, {
          user_name,          % string()
          session_id,         % integer()
          version,            % integer()
          network_type = in,  % in | string()
          address_type = ip4, % ip4 | ip6 | string()
          address             % string()
         }
       ).




%% ===================================================================
%% 
%% Session Name
%%
%% s=<session name>
%%
%% The "s=" field is the session name.  There must be one and only one
%% "s=" field per session description, and it must contain ISO 10646
%% characters.
%% 

-record(megaco_sdp_s, {
	  name                                  % string()
	 }
       ).




%% ===================================================================
%% 
%% Session and Media Information
%%
%% i=<session description>
%%
%% The "i=" field is information about the session.  There may be at
%% most one session-level "i=" field per session description, and at
%% most one "i=" field per media. Although it may be omitted, this is
%% discouraged for session announcements, and user interfaces for
%% composing sessions should require text to be entered.  If it is
%% present it must contain ISO 10646 characters.
%%
%% A single "i=" field can also be used for each media definition.  In
%% media definitions, "i=" fields are primarily intended for labeling
%% media streams. As such, they are most likely to be useful when a
%% single session has more than one distinct media stream of the same
%% media type.  An example would be two different whiteboards, one for
%% slides and one for feedback and questions.
%% 

-record(megaco_sdp_i, {
	  session_descriptor                    % string()
	 }
       ).




%% ===================================================================
%% 
%% URI
%%
%% u=<URI>
%%
%% o A URI is a Universal Resource Identifier as used by WWW clients
%%
%% o The URI should be a pointer to additional information about the
%%   conference
%%
%% o This field is optional, but if it is present it should be specified
%%   before the first media field
%%
%% o No more than one URI field is allowed per session description
%% 

-record(megaco_sdp_u, {
	  uri                                   % string()
	 }
       ).




%% ===================================================================
%% 
%% Email Address and Phone Number
%%
%% e=<email address>
%% p=<phone number>
%%
%% o These specify contact information for the person responsible for
%%   the conference.  This is not necessarily the same person that
%%   created the conference announcement.
%%
%% o Either an email field or a phone field must be specified.
%%   Additional email and phone fields are allowed.
%%
%% o If these are present, they should be specified before the first
%%   media field.
%%
%% o More than one email or phone field can be given for a session
%%   description.
%%
%% o Phone numbers should be given in the conventional international
%%   format - preceded by a "+ and the international country code.