1 © 1999, the ohio state university 9 dec 99 voip technology briefing harpal chohan russell...
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1© 1999, The Ohio State University 9 Dec 99
VoIP Technology Briefing
Harpal ChohanRussell Morrison
Enterprise Networking - The Ohio State University
The Ohio State UniversityThe Ohio State University
2
AgendaAgenda
• Voice as an application
• Overview of the PSTN
• VoIP toll by-pass
• IP Telephony
• Integrated Voice Architecture
The Ohio State UniversityThe Ohio State University
3
Voice – What is it?Voice – What is it?Voice – What is it?Voice – What is it?
• Real-time, interactive
• Delay Intolerant – delay < 150 ms
• Jitter, packet loss
An application – Not a network
Characteristic Issues:-Characteristic Issues:-
The Ohio State UniversityThe Ohio State University
4
Constituent PiecesConstituent Pieces
• Media
• Signaling
• Services
The Ohio State UniversityThe Ohio State University
5
AgendaAgenda
• Voice as an application
• Overview of the PSTN
• VoIP toll by-pass
• IP Telephony
• Integrated Voice Architecture
The Ohio State UniversityThe Ohio State University
6
MediaMedia
• G.711 64 k (DS0)
• G.726 16, 24, 32, 40 k
• G.729 8 k
• G.728 16 k
• G.723.1 6.3/5.3 k Variable
- Analog- Analog
- Digital- DigitalPSTN
CO/CO/
PBXPBX
The Ohio State UniversityThe Ohio State University
7
SignalingSignaling
• Analog
• ISDN Q.930/Q.931
• SS7
PBXPBX
MediaTransport
Signaling
PSTN – SS7
COSwitch
COSwitch
ISDNPRI
HomeHomeOfficeOffice
The Ohio State UniversityThe Ohio State University
8
SS7 ElementsSS7 Elements
VoiceSig. &
VoiceVoice
SS7 SignalingSS7 Signaling
SSP SSPSSP
STP STPSTP
STPSTP STPSTP
Switch
SwitchSwitch
PBX
SCPSCPSCP
The Ohio State UniversityThe Ohio State University
9
SS7 Protocol StackSS7 Protocol Stack
SS7 LevelOSI Layer
Level 1Level 1
Level 2Level 2
Level 3Level 3
Level 4Level 4
Layer 1Layer 1
Layer 2Layer 2
Layer 3Layer 3
Layer 4Layer 4
Layer 5-7Layer 5-7
MTPMTP
TUPISUP
SCCP
TCAP
The Ohio State UniversityThe Ohio State University
10
AgendaAgenda
• Voice as an application
• Overview of the PSTN
• VoIP toll by-pass
• IP Telephony
• Integrated Voice Architecture
The Ohio State UniversityThe Ohio State University
11
Where does IP come in?Where does IP come in?
PBXPBX
PSTN
IP NetworkRouter
V
Router
V
H.323H.323
Toll BypassToll Bypass
The Ohio State UniversityThe Ohio State University
12
Multi-site VoIPMulti-site VoIP
PBX
IP WAN
PBX APSTN
H.323H.323
PBX B
PBX C
ISDNISDN
ISDNISDN
SS7SS7
GatekeeperGatekeeper
The Ohio State UniversityThe Ohio State University
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Motivators for Enterprise VoIPMotivators 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 UniversityThe Ohio State University
14
AgendaAgenda
• Voice as an application
• Overview of the PSTN
• VoIP toll by-pass
• IP Telephony
• Integrated Voice Architecture
The Ohio State UniversityThe Ohio State University
15
RemoteCampus
IP TelephonyIP Telephony
EnterpriseIP Network
IP PhonesIP Phones
IP PBXIP PBX
GatewayPBX/PBX/
Switch
PSTN
The Ohio State UniversityThe Ohio State University
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Motivators for IP TelephonyMotivators for IP Telephony
• Single campus network infrastructure
• Portability – easy adds/changes
• IS Staff supporting voice and data??
• Unified Messaging
• Integrated services and features
The Ohio State UniversityThe Ohio State University
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Voice MailVoice Mail
IP Telephony MigrationIP Telephony Migration
EnterpriseIP Network
IP PhonesIP Phones
IP PBXIP PBX
Gateway
PBXPBX
PSTN
VoiceMailVoiceMail
Enterprise
Phone Network
Enterprise
Phone Network
PSTN
The Ohio State UniversityThe Ohio State University
18
PSTN
IP-Tel/VoIP at Ohio StateIP-Tel/VoIP at Ohio State
OSU CampusNetwork
IP PhonesIP Phones
IP PBXsIP PBXs
Gateway
PBXPBXPSTN
OSU Phone Network
Voice Mail
IP T1sIP T1s
RemoteSites
The Ohio State UniversityThe Ohio State University
19
Usual Deployment IssuesUsual Deployment Issues
• State of In-building networks
• Firewalls
• 911
• Power
• Change management – record keeping
• Dial Plans
The Ohio State UniversityThe Ohio State University
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Dial PlansDial Plans
• Toll bypass VoIP – Phones already have E.164 identities
• IP Phones – Have IP addresses, and?
The Ohio State UniversityThe Ohio State University
21
Internet2
Talking Outside Your RealmTalking Outside Your Realm
EnterpriseIP Network
IP PBXIP PBX
PSTN
EnterpriseIP Network
IP PBXIP PBX
The Ohio State UniversityThe Ohio State University
22
Talking Outside Your RealmTalking Outside Your Realm
EnterpriseIP Network
IP PBXIP PBX
PSTN
EnterpriseIP Network
IP PBXIP PBX
Internet2
The Ohio State UniversityThe Ohio State University
23
AgendaAgenda
• Voice as an application
• Overview of the PSTN
• VoIP toll by-pass
• IP Telephony
• Integrated Voice Architecture
The Ohio State UniversityThe Ohio State University
24
VoiP Constituent PiecesVoiP Constituent Pieces
• Media, Transport & Gateways
• Gateway Control and signalling
• Services
The Ohio State UniversityThe Ohio State University
25
Integrated Voice ArchitectureIntegrated Voice Architecture
TDM, ATM, etc.TDM, ATM, etc.
SS7, ISDN, Q93xSS7, ISDN, Q93x
RTP/UDP/IP Gateways
H.323, SGCP, IPDC, MGCP, SIP
Open Services LayerOpen Services Layer
TransportTransport
ControlControl
ServicesServices
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