Team: Aaron Sproul Patrick Hamilton Wireless VoIP Team: Aaron Sproul Patrick Hamilton

Outline Context & Problem Overview of VoIP Method WinEyeQ Screenshots (QoS program) Results Demo of VoIP calls Conclusions Summary/Lessons learned/Future work

Context & Problem Context for problem Project motivation Limitations of a wireless VoIP call versus a wired VoIP call Project motivation Voice over IP is going mainstream Vonage, Skype WiFi Hotspots on the rise Greater than 100,000 Project problem definition Capacity limitation of Wireless VoIP Using 802.11b Using 802.11g Affect of WEP encryption on Calls More precise characterization of VoIP quality factors

Overview of VoIP Invite SIP – Session Initiation Protocol 200 OK ACK Application-layer control (signaling) protocol Used for creating, modifying, and terminating sessions Reduced Complexity - SIP has only six methods transport independent – used with UDP, TCP, ATM, etc. Low overhead - text based Overview of VoIP performance characteristics Jitter is an abrupt or unwanted variation of one or more signal characteristics (variation in delay) Packet loss, Delay, network latency 200 OK ACK RTP Traffic BYE 200 OK

Overview of VoIP (2) R-Factor: 0-100 (Trans. Quality Rating) MOS Factor: 1-5 (Subjective)

Method LAN Programs Used: SJPhone – PC-to-PC calling Iperf – simulates background traffic WinEyeQ - analyze and obtain VoIP QoS parameters Router: Linksys WRT54GC Compact Broadband Router Call Analysis Steps: Start WinEyeQ capturing traffic Begin call through SJPhone Begin Iperf with set number of background streams Wireless Settings Tested: 802.11b with and without WEP 802.11g with and without WEP Codec Used: G.711 A-Law Codec (64 Kbps)

Toll Quality (Normal Land Line Quality) Results: R-Factor Toll Quality (Normal Land Line Quality) 70

Results: MOS Factor Toll Quality 3.6

Results: Packet Count Fewer collisions in g only network because of increase in bandwidth throughput

Results: Average Jitter (ms) B only – randomness?? Jitter means that there is a longer delay between packet arrivals, another sign of congestion

Results: Average Packet Intervals (ms)

Results: Average Bandwidth (kbps) G maintained full bandwidth usage of ~64 kbps for more calls

Demonstration of VoIP calls B only B with WEP G only G with WEP New Iperf session added every 10 seconds

Conclusions Wireless G allows only 1 more call WEP effects: We used Highest Quality Codec (bandwidth intensive) WEP effects: Wireless B: Negative effect on call capacity and quality Wireless G: No effect on call capacity or quality

Summary Using an encrypted wireless G capable access point allows for best possible call quality and capacity. Lessons learned Booming Industry Limited Capability of single WiFi hotspot Future Work Addition of more interfaces Quality versus Bandwidth usage (codec) Better Encryption methods for VoIP

Questions?