H.323 mengatur.. Video Codec (H.261 dll). Audio Codec (G.711, G.723 dll). Data channel (T.120 dll) e-board dll. System Ctrl Unit (H.245, H.225.0 dll). H.225.0 layer – error detection, error correction and frame sequencing.
Komponen H.323 Terminal Gateway Gatekeeper Multipoint Control Unit (MCU)
Terminal H.323 Provide Real-Time. Provide Two-way communications. H.245 – nego channel usage & capabilities. Q.931 – Registration/Admission/Status (RAS). T.120 – Data Conferencing Protocols.
Komponen H.323 H.323 Gateway Interface H.323 terminal – WAN terminal. H.323 Gatekeeper Address Translation (E.164 – IP) Admission Control. Authentication. Bandwidth Control. Zone Management. Call Control & Management (e.g. VoIP – PSTN)
H.323 Gateway Optional! Translation function between H.323 conferencing endpoints and other terminal types. Translation between transmission formats (i.e. H.225.0 to H.221). Translation between communications procedures (i.e. H.245 to H.242). Translation between audio and video codecs. Performs call setup and clearing on both the LAN side and the PSTN side.
Gatekeeper The most important component asct as a virtual switch of an H.323 enabled network. It acts as the central point for all calls within its zone and provides call control services to registered endpoints.
Gatekeeper Address translation from LAN aliases for terminals and gateways to IP or IPX addresses (e.g E.164 – IP) Bandwidth management. Route H.323 calls. Bill for calls.
Isu Quality of Service (QoS) Kekurangan Bandwidth Delay terlalu lama. Jitter / Variasi delay.
QoS Resource Reservation Protocol (RSVP) Real Time Protocol (RTP) Compressed Real Time Protocol (CRTP) Traffic Shaping Queuing: Custom Queuing, Weighted Fair Queuing. Congestion Control: Random Early Detection. Effisiensi Jaringan: link fragmentation & interleaving.
Philosophy The old world Box reliability The new world Network availability
Redudancy at many levels. Advanced Layer 3 Protocols: Hot Standby Routing Protocol (HSRP). Open Shortest Path First (OSPF). Enhanced Interior Gateway Routing Protocol (EIGRP). Multicast Routing: Protocol Independent Multicast (PIM). Distance Vector Multicast Routing Protocol (DVMRP).
How? – Detailed..
Open Architecture H.323 Simple Gateway Control Protocol (SGCP) Media Gateway Control Protocol (MGCP) Session Initiation Protocol (SIP) Telephony Application Programmable Interface (TAPI) Java Telephony Application Programmable Interface (JTAPI)
Low Cost of Ownership
Hierarchical WAN Design the network must support and supply the prerequisite QoS features. Hierarchical model to allow the most cost- effective platforms. As the requirements for data traffic outstrip those of voice, voice bandwidth decreases & lowering costs. WAN links to support the minimum requirements for data + voice and video. When other applications are quiescent, the bandwidth is available for data.
WAN QoS-Enabling Tech.
Classification Layer 3 (IP) IP Precedence; VoIP 5. Differentiated Services Code Point (DSCP) Layer 2 (MAC) schemes Voice RTP Voice UDP Voice Port 16383 - 32767
Traffic Shaping Multiple access nonbroadcast media such as ATM and Frame Relay where the physical access speed varies between two end points.
Issue QoS - Campus Network Aggregation points where many links aggregate into an uplink. aggregation points where speed mismatches occur.
QoS Campus Network The primary concern is buffer management and the ability to provide the required queuing schemes to ensure voice gets the appropriate bounds for loss, delay, and jitter.
QoS – Strategies Classification is a key attribute. Queuing techniques. Buffer management is also used to ensure that excess jitter is not added for voice traffic. To combat this, the multilayer LAN switches provide either two queues or a single queue with definable drop thresholds to bound delay.
Application IP Telephony Unified Messaging IP Contact Center