1. Evaluation and Comparison of Real-time Network Latency
Phillip Marlow
KoolSpan Inc.
TJHSST Computer Systems Lab

2. What is Network Latency?

3. How is Data Transported?
Link Layer
General Packet Radio Service (GPRS)
Ethernet
Wifi
Internet Layer
Internet Protocol (IP)
Transport Layer
Transmission Control Protocol (TCP)
User Datagram Protocol (UDP)
Application Layer
Security (KoolSpan TrustChip)
Message Packing

4. What Causes Network Latency?
Collisions
Ordering
Encryption/Decryption
Packing/Unpacking
Link
Internet
Transport
Application
Speed of Light
Routing

5. Why Does Network Latency Matter?
User Experience
Delays on voice data are especially noticeable
Excellent  < 300 ms
Good  < 600 ms
Poor  < 900 ms
Unacceptable  > 900 ms

6. How is Network Latency Measured?

7. How is Network Latency Measured?
SYN

8. How is Network Latency Measured?
ACK

9. Link Layer

10. Transport Layer

11. Application Layer

12. Results GPRS is unfit for voice communication UDP is faster than TCP
Security doesn't make a serious impact on overall latency

13. Suggestions for Future Research
3G Network
Time of Day
Network Load

14. Evaluation and Comparison of Real-time Network Latency
Special Thanks To:
Anthony Fascenda - KoolSpan Inc
Randy Latimer - TJHSST
Matthew Pearce - TJHSST