1 / 10

A FreeBSD-based prototype of a Time-Driven Priority router

Politecnico di Torino Istituto Superiore Mario Boella. A FreeBSD-based prototype of a Time-Driven Priority router. Mario Baldi Guido Marchetto. Goals. First implementation of TDP Until now analytical studies and software simulations only Identification of possible criticalities

calvin
Download Presentation

A FreeBSD-based prototype of a Time-Driven Priority router

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. Politecnico di Torino Istituto Superiore Mario Boella A FreeBSD-based prototype of a Time-Driven Priority router Mario Baldi Guido Marchetto

  2. Goals • First implementation of TDP • Until now analytical studies and software simulations only • Identification of possible criticalities • Visually show TDP benefits through multimedia demonstration • Video quality with TDP vs asynchronous packet switching

  3. Network prototype topology TDP network router host

  4. Router architecture • PC based • FreeBSD operating system • Four components: • TDP input classifier • TDP output buffers (ALTQ extension) • TDP scheduler • Asynchronous input shaper(Dummynet extension)

  5. Common Time Reference (CTR) • Adopted card: Symmetricom • Periodic interrupt over the PCI bus • Programmable interrupt frequency • Each interrupt represents the beginning • of a new TF

  6. Implementation issues • Interfaces are not served at the same time • Interrupts are served with latency • Both servicing times are variable

  7. Consequences • Transmissions do not start as soon asthe TF begins • Violation of nominal time frame boundaries • Transmissions start with a variable delay • Potential bandwidth waste

  8. Facts • Latency equivalent to longer links • Interrupt and interface service latencyis low • Latency variation is absorbed by “delaying” forwarding time-frame • Interrupt and interface service latency has low variability • “EXTRA” CROSSING DELAY IN THE NODE • “EXTRA” BUFFERING IN ORDER TO HANDLE THIS DELAY

  9. Conclusions • Contribution • Proof of concept: • Algorithm and system semplicity(~1000 LOC) • PC architecture can support TDP • Future work • Performance evaluation • Realization of the network testbed and demonstration

  10. Thank you. Questions?

More Related