Re: [Roll] Fwd: New Version Notification for draft-tripathi-roll-rpl-simulation-04

[Philip Levis <[e-mail]>]

On Jun 14, 2010, at 1:53 PM, Joydeep Tripathi wrote:

> Hi,
> 
> We have published the fourth revision of the simulation document. This
> time, we have simulated a large scale network (2442 nodes), whose data
> have been gathered from a chunk of a huge smart meter network. To show
> the scalability of RPL, it includes the relevant metrics such as path
> stretch, delay and control overhead. Please let us know your feedback.

Joydeep,

1) My concerns with the methodology remain; assuming independent packet losses over 10-minute intervals can have significant effects on how a protocol reacts (e.g., NUD). It makes me unable to make strong conclusions from any of the rest of the results.

2) "To simulate a more realistic scenario, 20% of the generated packets by each node are destined to the root, and the remaining 80% of the packets are uniformly assigned as destined to nodes other than the root." Can you provide some insight into why this is more "realistic?" Networks rarely follow uniform distributions, and using one can make you reach the wrong conclusion (e.g., algorithm X scales when it doesn't in real patterns).

Note that these are basic concerns with the methodology to obtain the results.

Phil