VoIP Technology Briefing

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? An application – Not a network • Real-time, interactive • Delay Intolerant – delay < 150 ms • Jitter, packet loss Characteristic Issues:-

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 CO/ PBX PSTN - Analog - Digital • 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

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

9. SS7 Protocol Stack SS7 Level OSI Layer TCAP ISUP TUP Layer 5-7 Level 4 Layer 4 SCCP Layer 3 MTP Level 3 Layer 2 Level 2 Level 1 Layer 1

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? PSTN Toll Bypass V Router V IP Network Router H.323 PBX PBX

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

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 PSTN Enterprise IP Network Remote Campus PBX/ Gateway IP PBX Switch 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 Enterprise IP Network IP PBX PBX Gateway Enterprise Phone Network IP Phones Voice Mail

18. IP-Tel/VoIP at Ohio State PSTN PSTN IP T1s OSU Campus Network Remote Sites PBX IP PBXs OSU Phone Network Voice Mail Gateway 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 Enterprise IP Network Enterprise IP Network Internet2 IP PBX IP PBX

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

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 Control SS7, ISDN, Q93x H.323, SGCP, IPDC, MGCP, SIP Transport Gateways TDM, ATM, etc. RTP/UDP/IP