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Voice and Desktop Video Teleconferencing over IP

Voice and Desktop Video Teleconferencing over IP. Willis Kim 9 July 2005. Wideband. PSTN/PBX. G.722 64-256k. G.711 64k. G.729a 8k. G.723.1 6.3k. Application Voice Quality. Only Level Possible in a PBX. DSP. DSP. IP Telephony (and Video) Enablers. Data. Voice. Data. Voice.

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Voice and Desktop Video Teleconferencing over IP

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  1. Voice and Desktop Video Teleconferencing over IP Willis Kim 9 July 2005

  2. Wideband PSTN/PBX G.722 64-256k G.711 64k G.729a 8k G.723.1 6.3k Application Voice Quality Only Level Possible in a PBX

  3. DSP DSP IP Telephony (and Video) Enablers Data Voice Data Voice Network Consolidation Usage Costs Trunk Charges Data Exceeds VoiceOver Voice Net Bigger,Cheaper Bandwidth QoS Advances Open Telephony Standards H.323/MGCP/SGCP/SIP FRF.11/12 AAL1/2/5 Digital Signal Processor Advances IP Precedence, 802.1p, IntServ/RSVP, DiffServ

  4. Reason for Convergence on IP • Convergence Delivers • Reduced maintenance costs via common infrastructure • Increased productivity & Decreased Time-to-Deploy • Better leverage of capital across multiple organizations • Greater administration and operation efficiencies

  5. Multiservice Networks Data Single Infrastructure Packet-BasedMultiservice Network Voice Video Internet • Integration of data, voice, and video services into a single packet-based infrastructure using IP • Both in enterprise and public service provider networks infrastructure

  6. Open Standards • H.323 - An International Telecommunications Union (ITU) interoperability protocol enabling cross-communication of multimedia products and applications over packet-based networks. Under H.323, multimedia products offered by one vendor can work with those of another, regardless of hardware compatibility. For example, a PC can share audio and video streams over either an intranet or the Internet. Applications are thus network-, platform-, and application-independent. Extension of ITU-T standard H.320 that enables videoconferencing over LANs and other packet-switched networks, as well as video over the Internet. • SIP - Session Initiation Protocol (SIP) is a peer-to-peer, multimedia signaling protocol developed in the IETF. SIP is ASCII-based, resembling HTTP, and reuses existing IP protocols (DNS, SDP, etc.) to provide media setup and teardown. Since its first publication in 1999, SIP has generated a high level of interest in the VoIP industry, and many people believe that SIP will become the de facto standard protocol for future voice networks.

  7. Non-Open Standards • SCCP (Skinny Call Control Protocol) - Skinny gateways are a series of digital gateways that include the DT-24+, the DT-30+, and the WS-X6608-x1 Catalyst voice module.

  8. PSTN Switch Connectivity PSTN WAN PSTN Switch Switch Call Processing Cluster Call Processing Cluster PSTN – Public Switched Telephone Network

  9. How can I check my Internet connection?

  10. Typical Application QoS Requirements Voice Data Low toModerate Moderateto High Bandwidth Random Drop Sensitive Low High Delay Sensitive High Low Jitter Sensitive High Low

  11. Firewall and NAT Refresher Connection Table Connection Connection Connection Connection Connection Connection Connection Connection Connection requests Connection replies Network Address Translation (Overloading)

  12. Why do firewalls or NAT cause problems? • With H.323, SIP and SCCP heavily use dynamically allocated ports • Egress is ok, but igress is not

  13. Why is QoS Important? • In an Agency Network QoS: • Ensures that real-time traffic gets priority • Ensures that ERP/business-critical traffic is serviced appropriately • Ensures that non-critical traffic (Napster, Gnotella, etc.) does NOT consume valuable bandwidth • Protects against denial of service attacks!

  14. IP V4 Packet – IP Precedence 4 4 8 16 16 3 13 8 8 16 32 32 bits Hdr Total Header Source Destination Vers Len TOS Length ID Flags Offset TTL Prot Chksum Address Address Data... bits 3 1 1 1 2 Precedence D T R Unused IP V4 Packet - IETF DiffServ 4 4 8 16 16 3 13 8 8 16 32 32 bits Hdr Total Header Source Destination Vers Len DS Length ID Flags Offset TTL Prot Chksum Address Address Data... 6 2 bits DSCP Unused Packet Labeling - Layer 3 3 bits = 8 values; 0-7 6 bits = 64 values; 0-63

  15. VoIP and Video Demonstration • Cisco IP Phone • Configuration • Unity Call Manager Express on Cisco 3825 (gateway) • IP Phone – 7960 and 7920 • Call and Analysis • Video • End-points • TANGBERG 1500 • D-Link DVC-1000

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