Download VoIP Technology Briefing

VoIP Technology Briefing
Harpal Chohan
Russell Morrison
Enterprise Networking - The Ohio State University
9 Dec 99
© 1999, The Ohio State University
1
Agenda
• Voice as an application
• Overview of the PSTN
• VoIP toll by-pass
• IP Telephony
• Integrated Voice Architecture
The Ohio State University
2
Voice – What is it?
An application – Not a network
Characteristic Issues:-
• Real-time, interactive
• Delay Intolerant – delay < 150 ms
• Jitter, packet loss
The Ohio State University
3
Constituent Pieces
• Media
• Signaling
• Services
The Ohio State University
4
Agenda
• Voice as an application
• Overview of the PSTN
• VoIP toll by-pass
• IP Telephony
• Integrated Voice Architecture
The Ohio State University
5
Media
- Analog
CO/
- Digital
PBX
PSTN
• G.711
64 k (DS0)
• G.726
16, 24, 32, 40 k
• G.729
8k
• G.728
16 k
• G.723.1
6.3/5.3 k Variable
The Ohio State University
6
Signaling
• Analog
• ISDN Q.930/Q.931
• SS7
PBX
CO
Switch
ISDN
PRI
Office
Signaling
CO
Switch
PSTN – SS7
Media
Transport
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Home
SS7 Elements
SCP
SCP
STP
STP
SS7 Signaling
SSP
SSP
STP
STP
Sig. &
Switch
Voice
PBX
Voice
Switch
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8
SS7 Protocol Stack
SS7 Level
OSI Layer
Layer 5-7
TCAP
ISUP
Layer 4
TUP
SCCP
Layer 3
Layer 2
Level 4
Level 3
MTP
Level 2
Level 1
Layer 1
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9
Agenda
• Voice as an application
• Overview of the PSTN
• VoIP toll by-pass
• IP Telephony
• Integrated Voice Architecture
The Ohio State University
10
Where does IP come in?
PBX
PBX
PSTN
Toll Bypass
V
IP Network
V
Router
Router
H.323
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11
Multi-site VoIP
PBX A
PSTN
Gatekeeper
SS7
PBX B
PBX
ISDN
IP WAN
ISDN
H.323
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PBX C
Motivators for Enterprise VoIP
• Toll bypass – of course.
• Single wide area infrastructure – gotta have data
connectivity anyway. Right?
• Consolidation of long distance volume.
• Custom dial plan (5 digit across all locations).
• Network Consolidation.
The Ohio State University
13
Agenda
• Voice as an application
• Overview of the PSTN
• VoIP toll by-pass
• IP Telephony
• Integrated Voice Architecture
The Ohio State University
14
IP Telephony
PBX/
Gateway
IP PBX
PSTN
Switch
Enterprise
IP Network
Remote
Campus
IP Phones
The Ohio State University
15
Motivators for IP Telephony
• Single campus network infrastructure
• Portability – easy adds/changes
• IS Staff supporting voice and data??
• Unified Messaging
• Integrated services and features
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IP Telephony Migration
Voice Mail
PSTN
PSTN
IP PBX
Enterprise
IP Network
PBX
Gateway
Enterprise
IP Phones
Phone Network
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Voice
Mail
IP-Tel/VoIP at Ohio State
PBX
PSTN
PSTN
IP PBXs
OSU Phone Network
Voice Mail
Gateway
OSU Campus
Network
IP T1s
Remote
Sites
IP Phones
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Usual Deployment Issues
• State of In-building networks
• Firewalls
• 911
• Power
• Change management – record keeping
• Dial Plans
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Dial Plans
• Toll bypass VoIP – Phones already
have E.164 identities
• IP Phones – Have IP addresses, and?
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20
Talking Outside Your Realm
PSTN
IP PBX
Enterprise
IP Network
IP PBX
Internet2
The Ohio State University
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Enterprise
IP Network
Talking Outside Your Realm
PSTN
IP PBX
Enterprise
IP Network
IP PBX
Internet2
The Ohio State University
22
Enterprise
IP Network
Agenda
• Voice as an application
• Overview of the PSTN
• VoIP toll by-pass
• IP Telephony
• Integrated Voice Architecture
The Ohio State University
23
VoiP Constituent Pieces
• Media, Transport & Gateways
• Gateway Control and signalling
• Services
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24
Integrated Voice Architecture
Services
Open Services Layer
SS7, ISDN, Q93x
H.323, SGCP, IPDC, MGCP, SIP
TDM, ATM, etc.
RTP/UDP/IP
Gateways
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25
Control
Transport