1. VoIP Technology Briefing
Harpal Chohan
Russell Morrison
Enterprise Networking - The Ohio State University

2. Agenda Voice as an application Overview of the PSTN VoIP toll by-pass
IP Telephony
Integrated Voice Architecture

3. Voice – What is it? Real-time, interactive
An application – Not a network
Characteristic Issues:-
Real-time, interactive
Delay Intolerant – delay < 150 ms
Jitter, packet loss

4. Constituent Pieces
Media
Signaling
Services

5. Agenda Voice as an application Overview of the PSTN VoIP toll by-pass
IP Telephony
Integrated Voice Architecture

6. Media
- Analog
PSTN
CO/
PBX
- Digital
G k (DS0)
G , 24, 32, 40 k
G k
G k
G /5.3 k Variable

7. Signaling Analog ISDN Q.930/Q.931 SS7 Signaling CO Switch CO Switch
PBX
ISDN
PSTN – SS7
PRI
Office
Media
Transport
Home

8. SS7 Elements SS7 Signaling SSP SSP Sig. & Switch Voice PBX Voice
SCP
STP
SS7 Signaling
SSP
SSP
Sig. &
Switch
Voice
PBX
Voice
Switch

9. SS7 Protocol Stack OSI Layer SS7 Level TCAP ISUP TUP SCCP MTP

10. Agenda Voice as an application Overview of the PSTN VoIP toll by-pass
IP Telephony
Integrated Voice Architecture

11. Where does IP come in? Toll Bypass V PSTN IP Network H.323 PBX PBX
Router V

12. Multi-site VoIP PSTN Gatekeeper SS7 ISDN IP WAN ISDN H.323 PBX A PBX B
PBX C

13. 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.

14. Agenda Voice as an application Overview of the PSTN VoIP toll by-pass
IP Telephony
Integrated Voice Architecture

15. IP Telephony PBX/ Gateway PSTN IP PBX Switch Enterprise IP Network
Remote
Campus
IP Phones

16. Motivators for IP Telephony
Single campus network infrastructure
Portability – easy adds/changes
IS Staff supporting voice and data??
Unified Messaging
Integrated services and features

17. IP Telephony Migration
Voice Mail
PSTN
PSTN
IP PBX
Enterprise
IP Network
PBX
Gateway
Enterprise
Phone Network
IP Phones
Voice
Mail

18. 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

19. Usual Deployment Issues
State of In-building networks
Firewalls
911
Power
Change management – record keeping
Dial Plans

20. Dial Plans Toll bypass VoIP – Phones already have E.164 identities
IP Phones – Have IP addresses, and?

21. Talking Outside Your Realm
PSTN
IP PBX
IP PBX
Internet2
Enterprise
IP Network
Enterprise
IP Network

22. Talking Outside Your Realm
PSTN
IP PBX
IP PBX
Internet2
Enterprise
IP Network
Enterprise
IP Network

23. Agenda Voice as an application Overview of the PSTN VoIP toll by-pass
IP Telephony
Integrated Voice Architecture

24. VoiP Constituent Pieces
Media, Transport & Gateways
Gateway Control and signalling
Services

25. Integrated Voice Architecture
Open Services Layer
Services
SS7, ISDN, Q93x
H.323, SGCP, IPDC, MGCP, SIP
Control
TDM, ATM, etc.
RTP/UDP/IP
Gateways
Transport