VoIP Architectures Standards and Issues

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VoIP ArchitecturesStandards and Issues

• R. Brough Turner
• October 5, 2004

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NMS at a Glance

• Communications technologies and solutions
• Founded 1983, publicly traded since 1994
• 300 employees, 130 RD
• Products in 90 countries

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TDM Voice vs. Packet Data
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Consumer VoIP

• Vonage, ATT CallVantage, SIPphone, Free World
  Dialup, Skype,
• Verizon, MCI, BellSouth and other majors making
  consumer VoIP announcements

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Softswitch vs Peer-to-Peer
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Softswitch vs Peer-to-Peer
SIP Invite
Register
Redirect
SIP Invite
SIP Invite
Peer-to-Peer
Peer-to-Peer
Caller
Called Party
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Protocol Wars
Softswitch
Peer-to-Peer

• MGCP
• Media Gateway Control Protocol
• Being replaced by
• H.248 (MEGACO)
• But
• Proprietary dominates
• Cisco Skinny
• Every other majorIP-PBX vendor

• H.323
• Integrated, overly complex ?, ITU
• Being replaced by
• Session Initiation Protocol (SIP)
• Modular, from IETF
• And
• Some proprietary
• e.g. Skype

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Real-Time Transport Protocol
But all sides agree media goes over RTP
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VoIP Impairments

• Packet Loss
• Audible gaps in speech
• Bigger problem for mobiles driving research
• Error correction packet loss concealment
• Delay
• Talkers interrupt each other echo is annoying
• Echo cancellation
• Jitter
• Requires buffering causing extra delay

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Quality of Service (QoS)

• QoS for bandwidth bottlenecks
• Most data networks lightly loaded
• Internet backbone
• Private networks 3-5
• LANs negligible
• Access links a problem
• When needed, simple schemes best
• Gold brown bits
• L2 - Ethernet 802.1p
• L3 - DiffServ

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Wideband Audio

• VoIP can be better than PSTN quality
• Dramatically improve quality of conversation
• Improved intelligibility, reduced fatigue,
  understand accented speech like being there !
• Video conferencing experience
• 128 Kbps ISDN video telephony gear sacrificed
  video bits for wideband audio
• Improved perception of video
• Also improves speech reco
• Helps w/letters c, e, g...

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New User Interfaces

• Presence you know whos available
• AOL, MSN, ICQ Yahoo all adding audio and video
  to Instant Messengers
• Skype providing VoIP telephony with an IM
  interface and voice conferencing

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Peer-to-Peer Service Providers

• Ever more powerful devices
• Open Internet fosters innovation
• Peer-to-peer fosters products over service
• e.g. Fax is a products business, not a service
• But still need
• PSTN connectivity
• Directories
• 7x24 handling of incoming calls
• Need simplicity
• Phone just works no IT hassles, no super user

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Enormous Opportunity Ahead

• Telecom is fundamental
• Fills basic human need
• Supported by rapidly evolving technologies
• Silicon, fiber, wireless
• Transformational change
• Fixed to mobile, TDM to IP, closed to open
• Change is Opportunity

Have Fun, Make Money !
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