1 / 16

A Comparative Study of Extensible Routers

A Comparative Study of Extensible Routers. Yitzchak Gottlieb and Larry Peterson. Extensibility: Why?. New Services Packet taggers Filters Firewalls Overlay Networks Old Routers Fixed. Extensibility: How?. Software routers Easy to change Rewrite code Hard to extend Little guidance

dermot
Download Presentation

A Comparative Study of Extensible Routers

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. A Comparative Study of Extensible Routers Yitzchak Gottlieb and Larry Peterson

  2. Extensibility: Why? • New Services • Packet taggers • Filters • Firewalls • Overlay Networks • Old Routers • Fixed

  3. Extensibility: How? • Software routers • Easy to change • Rewrite code • Hard to extend • Little guidance • Extensible software routers • Easy to extend • Defined architecture

  4. Extensibility: Who? • Scout • Princeton University • SILK (Scout in Linux Kernel) • Click • MIT • Linux Kernel Module • Router Plugins (Crossbow) • Washington U St. L, ETH Zürich, Ascom • BSD Hack

  5. How To Choose? • Choose Scout • Bias? • Choose at random • Compare strengths and weaknesses • Does your application fit its model? • Does it provide access to what you need? • Is it hard to program?

  6. Modeling Extensible Routers • Basis for comparison • Abstracts implementation • Simple • Few components • Comprehensible • Powerful • Models all three systems

  7. C S F Model: The Players • Queues • FIFO • Classifiers • One to many • Schedulers • Many to one • Forwarders • One to one

  8. Comparing Extensible Routers • Extensibility • Classifiers • Schedulers • Forwarders • Process Scheduling • Flow Isolation

  9. Extensibility: Two approaches • Outside the architecture • Extend the fixed pieces • Why use extensible routers • Within the architecture • Insert • Replace • Program • Parameterize • Add Code

  10. Extending Components

  11. Forwarders in Click • Small (Null element: 8 lines) • Multiple

  12. F F F C S F F S F C F F Forwarders in Crossbow • Bigger (Null plugin: 98 lines) • Restricted placement

  13. S F F Forwarders in Scout C • Biggest (Null module: 200 lines) • Powerful

  14. Process scheduling • Scout • Classify to path • Schedule Path • Click • Pull from upstream queue • Push until downstream queue • Crossbow • Process at arrival

  15. Flow Isolation • Scout • Paths are isolated • Click • Queues isolate subgraphs • Crossbow • No isolation

  16. Conclusions • Powerful default classifier • Programmable substructure • Flow isolation • Schedule whole computation • Small components • Good aggregation tools

More Related