Voice over IP

As computer and telephony integration proceeds, it has been predicted that present voice and data networks will combine to become a single organisational resource. The ability to route voice traffic over an IP network will result in major cost savings as separate network functions are combined within one multi-purpose entity. This includes traditional telephony (voice over IP) and the interworking with legacy telephony systems.

This two-day, technically based course examines the issues and defines the potential of Voice over Internet Protocol.

An in-depth instructor led course with practical exercises:

  • Networking With TCP/IP (DCTCPIP)
  • Network and LAN Implementation (NELANIM)
  • Next Generation Networks (DCNGN)
  • Implementing MPLS (DCIMPLS)


Upon completion students will be able to:

  • Describe the underlying protocols used in Voice over IP
  • Make informed choices within network design to migrate towards a converged future
  • Describe some of the design elements in order to implement networks that save cost
  • Make rational and cost effective purchasing decisions
  • Describe the differences between H.323 and SIP and other VoIP protocols
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Introduction to VoIP (5 topics)

  • Voice and Data convergence, VoIP implementations
  • Telephony Overview
  • Analogue bandwidth, Codecs, Telephone numbering, Delay & Echo, Circuit Switched Networks, Time Division Multiplexing, Digital signalling
  • Packet Switching Overview
  • Local Area Networks, Ethernet, Internet Protocol, IP routing, TCP, UDP, Ports

VoIP Overview (7 topics)

  • Standards & protocols, Speech coding & compression, Network loading
  • Voice Quality & Qos Issues
  • Delay & jitter, Packet loss, Echo cancellation, Packet size, IEEE 802.p/q, IP precedence
  • The RTP header, RTCP packet types, SDES, RTSP, Mixers and Translators
  • H.323
  • H.323 versions & features, The H.323 protocol stack, H.323 Architecture, Terminals, Gateways, Gatekeepers, MCU's, Directory services, H.323 conferencing, Registration, Administration, Status, H.323 Call establishment

Session Initiation Protocol (5 topics)

  • The SIP protocol stack, SIP Architecture, User Agents, Proxy Servers, Registrar Servers, Gateways, SIP Addressing, SIP Messages, SIP Call establishment, Session Description Protocol, SIP-T, ENUM, Comparison between SIP and H.323
  • MGCP
  • The Protocol stack, Gateways, Endpoints and Connections, Call establishment, Interworking between MGCP and SIP
  • H.248/MEGACO
  • The Protocol stack, Gateways, Terminations and Contexts, Call establishment, Interworking between H.248/MEGACO and SIP

VoIP Security (1 topic)

  • Security issues, DOS attacks , eavesdropping, spoofing, Firewalls

Network Planners, Designers and Engineers requiring an understanding of Voice over IP. Those requiring a comprehensive overview of how voice may be integrated into IP networks An understanding of TCP/IP would be an advantage but is not essential as basic TCP/IP is discussed