Presentation on theme: "CSG mini-Workshop Voice over IP Jim Jokl – Virginia Susan DeLellis – Harvard May, 2001."— Presentation transcript:
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 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
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
Packet Voice: What is different? Traditional Phone SwitchVoice over IP (VoIP) Phone Switch Phone PSTN Campus Network Routers, hubs, switches PSTN Gateway Call Manager
Network Infrastructure for Voice over IP Support Low latency Low loss Predictable packet arrival High availability Minimal capacity
Network Quality of Service (QoS) Goal: provide better service for some Build lots of network capacity Layer 3 QoS Layer 2 QoS
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
Personal Computer IP Phone 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 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
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?
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?
Preparations at Virginia The 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?
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
VoIP at Virginia Siemens HiPath 5500 One dozen phones PRI connection to Hicom PBX CorNet features Nortel Business Communications Manager Planned for summer Symbol?
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
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?