Dave Martin Vice President, Product Management

Agenda  Challenges for converged networks  Quality of Service  Monitoring VoIP performance  Troubleshooting  Solutions and best practices  Deployment examples  Service Provider  Enterprise  Wrap-up/summary

Quality Of Service - Why Is It Necessary?  PSTN has set the bar - VoIP as a replacement technology must offer the same quality experience  Users will tradeoff voice quality for mobility - not true for fixed line services  VoIP has very stringent jitter, latency and packet loss requirements…best effort IP forwarding is insufficient “Becauszzzz wit_o_t it _sers w__l be unha_py!”

Ensuring A High Quality Voice Experience: Design Considerations  Prioritize voice over data traffic  Take advantage of DiffServ routing if available in the network… but remember… TOS bit setting is NOT traffic management !!  Implement traffic shaping  Provide call admission control  Route media shortest path

Pay Close Attention To Access Links T-1/E-1 Router LAN and network core tend to be over-provisioned Congestion Point OC-x Multi- Gigabit 100Mbps

Managing Access Links Traffic shaping Priority queuing Diffserv packet marking Call Admission Control Video Data T1 WAN Link 1.544Mbits/Sec Video calls established Data “shaped” New calls are blocked Data not starved completely Data allowed to consume available bandwidth as calls are completed High Priority Queue Low Priority Queue time High Priority Queue Low Priority Queue WAN/LAN Link

Route Media Shortest Path: Hosted PBX Scenario Service Provider Atlanta San Francisco Dallas Legend Signaling path Media path Softswitch

VoIP Monitoring Issues  Distributed nature of IP networking means no natural demarcation point for problem resolution  I just had a poor quality call…...but why?  Difficult to monitor long term call performance and identify consistently poor performers

Create Demarcation Points Location #1 IP network Softswitch or IP PBX IP Phone Location #2 IP Phone Signaling Media A BCD VoIP Manager Location #3  Mean Opinion Score (MOS) provides a simple listening quality scale the represents the user experience  Monitoring at points A, B, C and D provides a demarcation point between LAN and WAN

Use Call Quality Statistics To Isolate Network Problems Common causes of jitter: Ethernet link set at half duplex Ethernet link set to autonegotiate Congestion in upstream router

Provide Proactive Support  Trend analysis at the network level can spot persistent problems  Set quality thresholds for advanced notification

Deployment Examples QoS Monitoring QoS Monitoring VPN

Best Practices Summary  Quality of Service  Implement prioritization, traffic shaping, call admission control  Route calls shortest path to minimize jitter, latency, and packet loss  Monitoring  Create demarcation points  Build quality monitoring into the network  Use tools that report on the user experience and send proactive notification of VoIP quality problems

Thank You! Contact : Dave Martin Vice President, Product Management