1. An investigation into the provision of video capabilities in iLanga Fred Otten Supervisors: Prof Alfredo Terzoli Prof Peter Clayton

2. Outline Demonstration iLanga user interface and expansions Channels H323 What I have achieved

3. Statement of Problem Channel-based architecture of Asterisk, the core of iLanga, provides a means to bridge the transport of voice between various protocols In principle the architecture should allow the transport of video with relative ease

4. SIP Video Using Windows Messenger as a client

5. Demonstration Demonstration of Call Transfer of video using Asterisk and the Manager interface

6. Call Transfer Dragging round ball when busy (red) or clicking on a person activates call transfer

7. Call Transfer Confirmation of request

8. Call Parking Activated by clicking on the red ball Confirmation request. Transfers to extension 400

9. Call Parking Status button on the bottom changes to Orange while there is a parked call

10. The Asterisk User Interface

11. Channels Provide the possibility of interoperability An abstraction of each end Operates by passing frames between the Asterisk core

12. Inheritance of features Call transfer works fine (as we have seen) Call parking works fine, plays music on hold, and leaves the last video frame frozen until you unpark the call Conference rooms claim to support video, however this is not the case they do not work for video conferences

13. Channel Modules Compiled as an system object file Contains functions to process a request, set up a channels and provide interpretation, signalling and media transfer to end points Created in the same manner as any other Asterisk module

14. Channel API Contains functions for –Registering a channel with Asterisk –Un-registering a channel with Asterisk –Calling a channel (using a function within the relevant channel) –Channel masquerading

15. The dial application Important to understand how channels are used within Asterisk, and hence the dial application is highly applicable Process involved in the dial application 1.Parsing the dial arguments, setting options and creating a list of channels 2.Waiting for an answer from one of the channels 3.Bridging the channels 4.Closing of the application, updating varibles and killing the channels

16. Example Channel Asterisk 1.0.9, Copyright (C) 1999-2004 Digium. Written by Mark Spencer ========================================================================= Connected to Asterisk 1.0.9 currently running on g02z0525-1 (pid = 30823) == Creating a new Example Channel :) == == Initiating a new call to the example channel == Oct 31 22:45:30 WARNING[30824]: channel.c:2127 ast_channel_make_compatible: No path to translate from EG/5555-ec4c(0) to SIP/600-ca00(2) g02z0525-1*CLI> show channels Channel (Context Extension Pri ) State Appl. Data EG/5555-ec4c (default s 1 ) Up AppDial (Outgoing Line) SIP/600-ca00 (local-from-sip 5555 1 ) Ring Dial EG/5555 2 active channel(s)

17. VoIP Protocols SIP H.323 IAX All are provided with Asterisk

18. H.323 There are a few different channels available for H.323 –OpenH323 –OOH323 –H323 Have installed and tested all of them None of them natively support video

19. H.323 OOH323 driver is only available in the development version (now beta) 1.2 It uses the OOH323 stack, which is still young, and not nearly as good as the OpenH323 stack The channel driver only supports a few audio codecs and does not support video OpenH323 and H323 drivers use the OpenH323 stack, however this is written in C++, and the interface in C which speaks to OpenH323 does not support video

20. What I have achieved Video using the SIP channel Understanding of the channel structure, and producing documentation for the channel API and its relevant functions Built an example channel Used the manager interface to do call parking and call transfer Extended the user interface to provide facilities for call parking and call transfer Taking a look at the H.323 channels available, and discovering their lack of video support

21. Questions ?