Transcript Voice over IP - Asia Pacific Advanced Network

Voice over IP
Interconnect
Stephen Kingham
John Barlow
Project Manager and
Consulting Engineer,
Voice and Video over IP
AARNet and CSIRO
Network Engineer
AARNet
[email protected]
Ph +61 2 6276 6223
[email protected]
Ph +61 2 6276 6903
Who is AARNet and CSIRO
• CSIRO
Is Australia’s premier government
research organisation, only partially
government funded.
http://www.csiro.au
• AARNet
Is the Australian Academic Research
Network, linking Australia’s Universities,
premier research and cultural centres to
the internet.
http://www.aarnet.edu.au
AARNet Topology
http://www.aarnet.edu.au
AARNet VOIP Building Blocks
Reliability QoS
Monitor
PABX
VoIP
GATEWAY
GATEKEEPER
Translate telephone numbers to IP
addresses
IP Telephone
H.323 Terminal
AARNet
Internet with
QoS bandwidth
H.323
PROXY
Billing
System
VoIP
GATEWAY
PSTN
Carrier
H.323
PROXY
Other
advanced IP
network
Based on ITU H.323 standards
AARNet VoIP Service, Now
• Supports all telephony destinations, Toll-by-pass
and feature transparency is core business.
• Savings range up to 90% off RRP.
• Traffic: connects around 16,000 telephone calls
per day, and growing.
• Uses a root Gatekeeper and some feeders.
• AARNet backbone supports QoS.
• QoS is policed at ingress – accesslist (yuk).
• VoIP hackers are policed – accesslist (yuk).
• Billing system, based on calling IP address.
• QoS network management actively changes
H.323 routing around problems.
• Test lab
Test Call Scenarios
• Test key call scenarios and
• PABX/IP Telephone alternate route under
all failure conditions
PABX
VoIP
GATEWAY
AARNet
Internet with
QoS bandwidth
IP Telephone
H.323 Terminal
PSTN
Carrier
In dial exchange
lines or CAS
GATEKEEPER
Translate telephone numbers to IP
addresses
VoIP
GATEWAY
H.323
PROXY
PABX
“TOLL BYPASS” Business Model
First
choice
PABX
Se
ch co
oi nd
ce
AARNet
Internet
Public Switched
Telephone Network
Carrier
PABX
Hop off points for AARNet
Members
PSTN
Brisbane
Gatekeeper
PSTN
CSIRO
USQ
QUT
Perth
AARNet
ACU
UQ
Sydney
CSIRO
Uni WA
CSIRO
PSTN
Sydny
ACU
CSIRO
Adelaide
CSIRO
Melbourne
Canberra
PSTN
Ade Uni
La Trobe
Flinders
Uni Mel
CSIRO
Ballarat
Canberra
VUT
ANU
PSTN
Deakin
Swinburne
PSTN
AARNet VoIP, Tomorrow
 Research VoIP interconnects between carriers.
 VoIP interconnect pilots with research institutions in US,
Korea, Singapore, Czech Republic, Brazil.
 VoIP interconnect with two Australian Carriers.
 Implement a smarter Gatekeeper.
 Get H.323 proxies working in production.
 Change method of policing QoS.
 Change method of authorising VoIP calls.
 Change billing system to be based on bytes rather than
time (both ends pay …).
 Support IP Telephones.
 Support VIDEO as well as audio (native as well
conferencing and gateways back to ISDN).
Some key lessons
• Resource QoS implementation and support as
much as the VoIP.
• Use VoIP to switch call, do not use PABXs.
• Reduces faults in private telephone networks.
• VoIP using G.729 is resilient against packet
loss.
• Enabling QoS to get over the brief periods of
congestion is needed, even on Gigabit.
• Billing model need to change from traditional
telephony to data constructs.
Basis of the Charging Model
See http://voip.aarnet.net.au/AARNet
On-net
Rx data
charge 1c/min
CALLING
Member
PABX
Hop-off
Rx data
charge 1c/min
ANSWERING
Member
PABX
AARNet
Rx data charge and
the call charge
Rx data
charge
CALLING
Member
PABX
Rx data
charge
AARNet
Local Call
Charge
AARNet transit
VoIP router
Public
Telephone
Carrier
Some key lessons
• Although peak bandwidth per call is 24kbps,
in practice it is on average 5kbps (using
G.729), do your own maths on the cost!
• Huge changes looming for management of
basic telephony. AARNet has started a
working group to assist migration from PABX
to IP Telephones.
VoIPMonitor TOPOLOGY
•
•
•
•
Monitor links to each RNO, and
Links to each member.
Shutdown destinations that fail.
http://lattice.aarnet.net.au/VoIPMonitor
Member
RNO
TEST
RNO
TEST
Member
TEST
TEST
Member
RNO
• Client only tests local
Member
links
Some key issues for VoIP
interconnect.
• H.323 proxies appear to be the answer for
solving these key issues:
• Providing access between domains, or Internet
into LAN based IP telephones.
• Policing use of QoS.
• Authenticating who is making the VoIP call.
• Gateways need to authenticate VoIP calls
through an intelligent Gatekeeper or a
clearing house sever using OSP.
VoIP Carrier Interconnection
PSTN
VoIP
Proxy
ITU-T
SS No 7
PSTN
VoIP
•Signalling system number 7 is
not appropriate for VoIP
Outgoing calls from site
PABX
First
ce
choi
Extension
Second
choice
Interconnection
Gateway
d
n
o e
c
c
e
i
S ho
c First
choice
IP Telephone
PSTN
First
choice
Proxy
AARNet
Internet
Safety of Life
• Emergency Service providers rely on
knowing WHERE someone is, not who.
How do we do it????
Questions
Contact Details, and Thank you
URL: http://www.aarnet.edu.au/
[email protected]
Phone +61 2 6276 6223
Mobile +61 419 417 471
[email protected]
Phone +61 2 6276 6690