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Wireless & VoIP. Christian Huitema February 26, 2000. Wireless Voice over IP: 2 Questions. Can we make it work? Can we provide decent quality? Can we support efficient signaling? Can the telcos accept it? Loose control of voice? Loose control on “services” ?.

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Wireless voip

Wireless & VoIP

Christian Huitema

February 26, 2000


Wireless voice over ip 2 questions
Wireless Voice over IP:2 Questions

  • Can we make it work?

    • Can we provide decent quality?

    • Can we support efficient signaling?

  • Can the telcos accept it?

    • Loose control of voice?

    • Loose control on “services” ?


Interactive voice quality component 1 delay
Interactive voice quality,Component #1: delay


Components of delay
Components of delay

  • Network (delay, jitter):

    • Access Network, Uplink

    • Core Network,

    • Access Network, Downlink

  • Packetization, De-Packetization

  • Device:

    • Acquisition, Echo control, Compression,

    • Jitter, Decompression, Playback


Managing the uplink beware of contention
Managing the Uplink:beware of contention

  • Data Usage emphasizes “load”

    • Highly variable sources,

    • Contention access fits best (CSMA, TDMA-DA, slot request, etc.)

  • Contention access unfit for voice

    • Generates “large deviation”

    • Deviation => jitter => delay.

  • … Unless very low load factor


Packetization frequency size delay quality
Packetization frequency:Size => Delay => Quality


Bandwidth quality delay header payload ratio
Bandwidth => QualityDelay => Header/Payload ratio


Voice quality effects of packet losses
Voice Quality: Effects of Packet Losses

  • Loss effect aggravated by “fractal” distribution.

  • Moderate losses (1%) can be concealed.

  • Higher losses require redundancy: (standard in RTP):

    • Affects bandwidth (split / N packets)

    • affects delay (N packets) => quality…


Uplink starvation control bandwidth packet rate
Uplink Starvation => Control Bandwidth, Packet Rate

Core Network

Edge

Router,

Radio

?

Authorize

  • Signaling:

    • Voice Call ?

    • Quality ?

Network Control


Can we do efficient signaling wireless voip mobility
Can we do efficient signaling?Wireless VoIP => Mobility

  • Classic telephony approach:

    • HLR (home) /VLR (visitor)

    • Based on phone number

    • Number = Transport + User identity.

  • VoIP separates network, service

    • Network: IP address

    • Service: DNS name, e-mail, URL

  • Need clean architecture


The voip protocol soup more than one choice
The VoIP Protocol SoupMore than one choice…

  • H.323

    • ITU standard, implementations

    • Complex, heavy, hard to evolve

  • MGCP

    • Client server, “telephony device”

    • Used in Cable networks

    • Not really adequate for mobility support

    • MGCP / Megaco / H.248 debacle

  • SIP

    • Clean end-to-end architecture


Signaling mobility combine mobile ip sip

DHCP

Register

DHCP

Invite

DHCP

Register

Invite #2

Signaling & Mobility: Combine “Mobile IP”, SIP

SIP agent

Correspondent


Can the telcos accept voip wireless voip
Can the telcos accept VoIP? Wireless VoIP?

  • Special price for voice, data:

    • Wire line: price of voice is 10 x data bit

    • Wireless: data is “special service.”

  • Bundling of services:

    • Caller-ID, Call-Waiting,

    • Voice Mail,

    • 3000 “IN” services

    • 911, etc.


Wireless voip loosing control of voice
Wireless VoIP:loosing control of voice?

  • In the short term, QoS issues

    • Contention on the uplink,

    • Telco can control “voice quality IP”,

    • But “real time” is more than voice (video, games, monitoring.)

  • The end of uplink starvation?

    • High speed wireless LAN, 3GIP?

    • Need adequate “sharing” procedure.


Wireless voip becoming the infrastructure
Wireless VoIP:becoming “the” infrastructure

  • Need to be always on, meet the classic 99.999% requirement,

  • Deal with societal issues, such as wiretap, in an end-to-end environment,

  • Provide 911 like services:

    • Special signaling, no hang-up,

    • Location services, route to local 911,

    • “Emergency” level for QoS.


Wireless voip loosing control of services
Wireless VoIP:loosing control of services

  • IP signaling is end to end

    • SIP agent “outside” the network,

    • Service independent of transport.

  • State is kept in the device:

    • Local implementation of services,

    • Call waiting, multiparty call in device.

  • Empower users, unleash creativity


Wireless voip roadmap
Wireless VoIP Roadmap

  • Solve the uplink issue:

    • QoS on “first hop”, not end-to-end,

    • Independent of payload type (voice, etc.)

    • Security, authorization (DHCP, QoS).

  • Encourage competition:

    • “Secure Wireless DHCP,” Roaming

  • Concentrate signaling work on SIP:

    • Forget the ITU!


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