[RPRWG] Response to comments, Weighted Fairness, July meeting
This e-mail is a follow up to one of AuroraNetics' presentations from
the July meeting (title: "Providing Enhanced Fairness", July 2001)
In it, we replicated a traffic scenario from a previous Lantern
presentation: (title: "Performance Issues and Requirements",
May 2001 meeting, slide #10 of 16).
Links to the two papers are:
http://www.ieee802.org/17/documents/presentations/jul2001/nu_efa_01.pdf
http://www.ieee802.org/17/documents/presentations/may2001/ahm_pir_02.pdf
The Lantern scenario points out a performance issue with standard SRP.
AuroraNetics' presentation compares the standard SRP results with our
new "Weighted-Fairness" congestion control mechanism with favorable
results.
In the question and answer session following our presentation, there
were some comments from the audience that we would like to address:
1. Sanjay Agrawal thought that the scenario that we simulated was not
the same as Lantern's scenario
2. Raj Sharma recommended that we rerun adding some mesh traffic to
our hub-only scenario
For #1, the scenario we ran was this:
- OC-12 ring, outer ring only
- Single Hub scenario
- 8 nodes
- Each non-hub node sources 300Mbps destined to the Hub node
- Hub sources 700 Mbps, 100 Mbps destined to each non-hub node
We ran this scenario with standard SRP, and got the same results as
Lantern. Each node was limited to ~622/7, including the Hub node. We
also ran with AuroraNetics' Weighted-Fairness algorithm, which enabled
us to fully utilize the bandwidth on all links. (The hub node was no
longer limited.)
We believe that this traffic scenario is exactly the same as the one
presented in Lantern's paper. If it's not, please let us know how it
differs and we will re-run.
For #2, we reran the same scenario adding both high priority and low
priority mesh traffic in varying ammounts, and the results were still
favorable. Without Weighted-Fairness, the hub node was throttled as
expected, and only the last link was fully utilized. With Weighted-
Fairness, however, every link reaches 100%.
Thanks,
Carey Kloss
AuroraNetics