1. ESLEA Closing Conference, Edinburgh, March 2007, R. Hughes-Jones Manchester 1 The Uptake of High Speed Protocols or Are these protocols making their way into everyday use ? Panel Discussion Richard Hughes-Jones The University of Manchester www.hep.man.ac.uk/~rich/ then “Talks” www.hep.man.ac.uk/~rich/

2. ESLEA Closing Conference, Edinburgh, March 2007, R. Hughes-Jones Manchester 2 Which Protocol for my Network

3. ESLEA Closing Conference, Edinburgh, March 2007, R. Hughes-Jones Manchester 3 Transports for LightPaths uHost to host Lightpath One Application No congestion Lightweight framing uLab to Lab Lightpath Many application share Classic congestion points TCP stream sharing and recovery NEEDED Advanced TCP stacks

4. ESLEA Closing Conference, Edinburgh, March 2007, R. Hughes-Jones Manchester 4 Transports for Academic Networks uMany different technologies – often low Bandwidths uCautious/conservative Transport Protocols Standard TCP Linux & BIC Microsoft & C-TCP uHigh Bandwidth Backbones But care needed with Access links – Countries and Campus Many Application flows uNote the Digital Divide uRoles for Advanced TCP stack and other transports. Transports for Global Internet

5. ESLEA Closing Conference, Edinburgh, March 2007, R. Hughes-Jones Manchester 5 Transport Protocols u TCP Reno; HS-TCP; Scalable; H-TCP; C-TCP; BIC; CUBIC; LCTP u XCP u UDP Some applications NEED this form of delivery u RTP / RTSP Lots of streaming applications available now u DCCP Interest from e-VLBI u multicast

6. ESLEA Closing Conference, Edinburgh, March 2007, R. Hughes-Jones Manchester 6 Potential Problems u Advanced TCP stacks cant be used at my site because: Security concerns My Grid software MUST HAVE version 2.4.-200 ! u Disk performance limits throughput Depends how the storage is arranged Hight performance SANs – Commercial Data Centres RAID systems Distributed disks - dcache u Network congestion Campus MAN Backbone Long distances eg Australia

7. ESLEA Closing Conference, Edinburgh, March 2007, R. Hughes-Jones Manchester 7 Gridmon from last week SJ5 Transition 10% packet loss to RAL

8. ESLEA Closing Conference, Edinburgh, March 2007, R. Hughes-Jones Manchester 8 Some Areas for Discussion u What is the interaction between Application and Transport Protocol? u What is the relative importance of fairness vs throughput? rtt fairness (OK what is fairness?) mtu fairness TCP friendliness u How to AIMD rate fluctuations relate to stability & sharing? Stability of Achievable Throughput u Does provable stability of protocols matter? u Is the computational complexity of a protocol important? u What is the relative importance of convergence time? Link utilisation (by this flow or all flows) u Should there be a bias towards "mice“? – Applications u Is conceptual simplicity of the protocol important?