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CSG mini-Workshop Voice over IP

CSG mini-Workshop Voice over IP. Jim Jokl – Virginia Susan DeLellis – Harvard May, 2001. VoIP Systems: Lots of definitions. PBX VoIP line or trunk card - A Call path between IP phones via PBX Initial releases by Lucent, NEC, others PBX VoIP line or trunk cards - B

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CSG mini-Workshop Voice over IP

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  1. CSG mini-WorkshopVoice over IP Jim Jokl – Virginia Susan DeLellis – Harvard May, 2001

  2. VoIP Systems: Lots of definitions • PBX VoIP line or trunk card - A • Call path between IP phones via PBX • Initial releases by Lucent, NEC, others • PBX VoIP line or trunk cards - B • Call path between IP phones via LAN • Nortel, Siemens, others have systems • Most PBX manufacturers working towards this type of functionality • Major advantage: phone features

  3. More VoIP System Definitions • LAN-based Systems • Call setup via LAN call processing server • Call path between all peripherals via LAN • Cisco Call Manager • Siemens HiPath Xpress • Nortel Business Communications Manager • Others • LAN-based systems generally limited • ACD, console, call center applications

  4. Campus Network Routers, hubs, switches Packet Voice: What is different? Traditional Phone Switch Voice over IP (VoIP) PSTN PSTN Call Manager Gateway Phone Phone Switch Phone Phone Phone Phone Phone

  5. Network Capacity for Multimedia Applications

  6. Network Capacity for Packet Voice Services

  7. Network Infrastructure for Voice over IP Support • Low latency • Low loss • Predictable packet arrival • High availability • Minimal capacity

  8. Network Quality of Service (QoS) • Goal: provide better service for some • Build lots of network capacity • Layer 3 QoS • Layer 2 QoS

  9. QoS: Useful for? • Have we seen the light? • Solving capacity problems? • Protect voice traffic? • Need a way to remap QoS parameters where traffic enters the network

  10. IP Phones and QoS • IP phone generates 802.1p CoS = 5 and IP precedence = 5 • Switch in phone can clear PC’s QoS header settings • Phone and PC can be in different VLANs Switched Network Wall Jack IP Phone Personal Computer

  11. IP Telephones and Power • Powering options • Via Ethernet cable • Via wall power transformer • Phone power consumption • Tested Cisco and Nortel phones • Between 4 and 6.5 watts/phone • Large wiring closet • 250 phones, 75% efficiency • Closet power: 400 Watts • Powering phones – no worse than 72 switch ports

  12. My Other Wireless Phone

  13. Wireless Data VoIP • Symbol NetVision Phone • H.323 on 802.11 • But no DSSS yet (summer) • Spectralink NetLink Phone System • VoIP-based • Both FHSS and DSSS available • Proprietary adapter  integration • Killer App: 802.11b/PCS dual mode phone?

  14. Wireless & QoS • Challenge: protect voice traffic • Wireless LANs low bandwidth • Easy to overload • SpectraLink Voice Priority (SVP) • Retransmission modification • Priority queuing in base station • Symbol • Similar capabilities • Standards?

  15. Preparations at VirginiaThe Network • New backbone this summer • Layer 3 switching • IP Precedence • Wiring Closet • 802.1p/Q • New edge switches will reclassify traffic • Policy management, multicast • Closet UPS and cooling work • Are these VoIP costs?

  16. VoIP at Virginia • Initial application: toll bypass • AS-5300 Gateway – T1 to PBX • 2600/3600/3810 at remote location • Analog interface to remote PBX • Added Cisco Call Manager • Couple dozen phones • Voice mail issues • Number portability

  17. VoIP at Virginia • Siemens HiPath 5500 • One dozen phones • PRI connection to Hicom PBX • CorNet features • Nortel Business Communications Manager • Planned for summer • Symbol?

  18. Next Steps • Continue to prepare network for converged applications • Select a VoIP system for larger pilots • Harvest some low hanging fruit • Safe areas • Telecommuters • Wireless? • Solve the wired/wireless VoIP question • Continue to watch technology

  19. Issues: Financial Model • Converged networks, especially VoIP, break most existing funding models • What to bill for • Wall outlet? • MAC Address? • IP phone or soft phone? • A tax based on headcount or NASF? • Central funding?

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