Transcript Voice over IP

VoIP Overview and Futures
Topics to Cover
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AARNet background
Peering
H.323 & SIP
Soft PaBX
Video Conference
Multipoint Control Unit
AARNet background
• About 20,000 VoIP calls each day
• Over 15 (almost half) Australian
universities use VoIP for toll-bypass
• One university purely VoIP
• Over 3000 VoIP handsets (all H.323)
• Billing, QoS, monitoring
• http://voip.aarnet.net.au/AARNet/
Peering
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Proxy
Firewall
QoS
Billing/settlement
International peering project
Proxy
PABX
VoIP
GATEWAY
GATEKEEPER
Translate telephone numbers to IP
addresses
IP Telephone
H.323 Terminal
AARNet
Internet with
QoS bandwidth
H.323
PROXY
H.323
PROXY
Other
advanced IP
network
Firewall
• Difficult to find a firewall product that allows
H.323 and SIP through securely
• Use of a proxy would help
Quality of Service
• QoS is required – we can not afford to “throw
bandwidth at the problem”
• Examples of QoS include H.323 video
conferencing to this meeting – it is required,
and we should all provide it
• QoS is difficult due to potential for a DOS
attack – need proxy and QoS rate limiting ?
Billing
• Within your group you may have to perform
“cost recovery” of your IP telephony
equipment (central gatekeeper, etc.)
• Outside your group you might choose no
cost peering relationship
• Next step may include access to “call hopoff” in remote countries, possibly requiring
more cost recovery
International Peering Project
• Using H.323 there are “world root
gatekeepers” (much like root DNS
servers).
• http://www.vide.net/workgroups/nasm/re
sources/vrla.shtml
Dial Plan
Egon Verharen has written up a great primer on the
Global Dialing Scheme (GDS) which is enormously
helpful for video conferencing.
In Australia we can call people on the GDS but they can
not call us. In Australia today we support the
international dialplan and the Australian dialplan, ie
just the <OP><EN> or the <CC><OP><EN> (see
below). Trying to support both is a problem!
Sometime in the new year we will be publishing a
discussion paper and organising a virtual conference
so that we can discuss what we should have as a
dialplan "within" Australia.
Root Gatekeepers
International
numberplan
International
numberplan
International
numberplan
International
numberplan
H.323 & SIP
• Different protocols to achieve the same goal
• Reasonably easy to translate between them
• Expect proxy/translation units to be common
H.323
VoIP
Network
H.323/SIP
converter
SIP
Soft PaBX
• New features and functionality now possible
• Voice mail Available via email
• Soft phone (eg: receive a call on my laptop)
• Extra features easily added (unlike PaBX)
• LDAP/X.500 directory service
Video Conference
• This is H.323 – not just VoIP, but video
conferencing
Multipoint Control Unit
• Allows multiple people in a conference
(where H.323 is normally point-to-point).
• Blends Video over IP, Voice over IP, ISDN
video and PSTN voice conferencing.
• One way to easily handle remote teaching