2. PTCL Training & Development1 H.323 Terminals

3. Client end points on the network IP phones, PCs having own OS Terminals running an H.323 protocols and the multimedia applications. Must support audio G.711 (64 kb/s). Several compression coders G.723.1, g.729, GSM & others Should also have support for Video, data Support for RTP used for packet media flow 2 H.323 Terminals

4. 3 Terminal Call Manager RTCP H225 Call Sig H225 RAS H245 Call Cont RTP Audio appls video appls G.771 G.729 G.723.1 H261 H263 T120 Data Transport Protocols & Network Interface

5. Gateway provides connectivity between an H.323 network and a non-H.323 network by translating protocols for call setup and release Converting media formats between different networks Transferring information between the networks connected by the gateway. A gateway is not required, however, for comn. b/w two terminals on an H.323 network 4 H.323 Gateways

6. On the H.323 side, a gateway runs H.245 control signaling for exchanging capabilities H.245 call signaling for call setup and release H.225 registration, admissions, and status (RAS) for registration with the gatekeeper On the SCN (switched circuit network) side, a gateway runs SCN- specific protocols (e.g., ISDN and SS7 protocols) Translation between audio, video, and data formats may also be performed by the gateway 5 H.323 Gateways

7. 6 Interworking Call Control Gateway Call Manager PSTN/ISDN Signaling Call contro l PSTN/ISDN Signaling Link Control Physical Interface H245 Control Sign RTP RTCP H225 RAS H225 Call Sign Transport Protocol & Network Interface

8. Considered brain of H.323 network It is the focal point for all calls within the H.323 network Provide services such as addressing, authorization and authentication of terminals and gateways bandwidth management and call-control services for H.323 endpoints An optional feature--Call-signaling routing. Endpoints send call-signaling messages to Gatekeeper which are routed to destination endpoints 7 H.323 Gatekeepers

9. Gatekeeper provides bandwidth control by using messages, bandwidth request (BRQ), confirm (BCF), and reject (BRJ) For instance: A threshold for simultaneous connections in H.323 network is specified Gatekeeper can refuse for any more connections once the threshold is reached. The result is to limit the total allocated bandwidth to some fraction of the total available, leaving the remaining bandwidth for data applications. 8 H.323 Gatekeepers

10. 9 Gatekeeper Manager H225 RAS H245 Control Sign H225 Call Sign Billing Services Directory Services Security Services Policy/Call Mgt. Services Transport Protocols & Network Interface

11. MCUs provide support for conferences of three or more H.323 terminals All terminals participating in the conference establish a connection with the MCU MCU manages conference resources, negotiates between terminals in determining (CODEC) to use Handle the media stream Gatekeepers, Gateways, and MCUs are logically separate components of the H.323 standard but can be implemented as a single physical device 10 H.323 Multi-point Control Units

12. MCU has two Logical entities: Multipoint Controller Multipoint Processor Multipoint Controller: Controls conference call for a Multicast(many users) or Unicast (to single user) Multipoint Processor: provides advanced functions in H323 like video mixing, audio mixing or video switching 11 H.323 Multi-point Control Units