1. GH Telstra Internet 1 Capacity Measurement for IP Networks Geoff Huston Technical Manager Telstra Internet

2. GH Telstra Internet 2 TCP/IP Protocol Issues TCP/IP is NOT a flow damped protocol TCP/IP is NOT a flow damped protocol end to end flow management end to end flow management sliding window protocol sliding window protocol adaptive flow rate designed to probe and use max available end to end bandwidth adaptive flow rate designed to probe and use max available end to end bandwidth only limited by end system buffering size only limited by end system buffering size bandwidth x delay bandwidth x delay

3. GH Telstra Internet 3 TCP/IP Protocol Issues TCP/IP Data Flow Rate Adaptation Time Data Flow Rate Steady State Available Bandwidth

4. GH Telstra Internet 4 TCP/IP Protocol Issues No network-based flow control mechanism No network-based flow control mechanism Network-based packet loss signals end systems to collapse window size Network-based packet loss signals end systems to collapse window size Varying window size allows adaptive flow metrics to adapt to changing maximum available capacity Varying window size allows adaptive flow metrics to adapt to changing maximum available capacity Sustained insufficient capacity leads to congestion induced collapse of data throughput Sustained insufficient capacity leads to congestion induced collapse of data throughput

5. GH Telstra Internet 5 TCP/IP Protocol Issues TCP/IP efficiency under congestion load Traffic Level Data Throughput 33% 66%

6. GH Telstra Internet 6 TCP/IP Protocol Issues TCP vs UDP TCP vs UDP UDP-based applications UDP-based applications Internet Phone, Video, Workgroup Internet Phone, Video, Workgroup UDP Issues UDP Issues no flow control mechanism no flow control mechanism sustained use forces precedence over TCP flows sustained use forces precedence over TCP flows increasing use of flow bandwitdh negotiated protocols for these applications (RTP) increasing use of flow bandwitdh negotiated protocols for these applications (RTP)

7. GH Telstra Internet 7 TCP/IP Protocol Issues Damping network capacity is not a demand management tool Damping network capacity is not a demand management tool Network capacity must be available to meet peak demand levels without congestion loss Network capacity must be available to meet peak demand levels without congestion loss

8. GH Telstra Internet 8 Usage Profile Two major Internet use profiles: Two major Internet use profiles: Business use profile Business use profile peak at 1500 - 1600 peak at 1500 - 1600 plateau 1000 - 1730 plateau 1000 - 1730 Residential dial profile Residential dial profile peak at 2030 - 2330 peak at 2030 - 2330 plateau 1900 - 2400 plateau 1900 - 2400

9. GH Telstra Internet 9 Usage Profile Distance profiles Distance profiles 30% Local 40% Domestic Trunk 30% International Traffic mix due to: Traffic mix due to: Distance invisible applications without user control Distance invisible applications without user control Distance independent tariff Distance independent tariff

10. GH Telstra Internet 10 Capacity Guidelines Link Utilisation Link Utilisation Average weekly traffic level set to 40% of available bandwidth. Average weekly traffic level set to 40% of available bandwidth. Core network capacity should be in excess of access bandwidth Core network capacity should be in excess of access bandwidth

11. GH Telstra Internet 11 Link Usage Profile - optimal peak loading less than 10% time peak loading less than 10% time greater than 50% loading for 50% time greater than 50% loading for 50% time traffic bursting visible traffic bursting visible

12. GH Telstra Internet 12 Link Usage Profile - overloaded 90% peak loading for 45% time 90% peak loading for 45% time 60% peak loading for 60% time 60% peak loading for 60% time no burst profile at peak loads no burst profile at peak loads imbalanced traffic (import based) imbalanced traffic (import based)

13. GH Telstra Internet 13 Link Usage Profile - saturated visible plateau traffic load signature visible plateau traffic load signature small load increases cause widening plateau small load increases cause widening plateau

14. GH Telstra Internet 14 Overall Growth Levels More users More users More intense network use by increasingly sophisticated applications More intense network use by increasingly sophisticated applications No visible saturation of demand to date No visible saturation of demand to date