Re: [6tsch] simulation for random schedule allocation

Xavi,

I'm not sure I understand the simulation completely. I just have a question
about the topology of network, which is established by choosing neighbors
randomly and independently. My feeling is it may result in a network with
cross edges, in another word, a network which cannot be placed on a 2D
plate.  Correct?  If my understanding is correct, I would like to suggest
using conventional method to establish the network, i.e. set N nodes into a
2D array, with uniform distribution. N will reflect the network density,
i.e. the average number of neighbors.

Then, based on the network, we can play cell reservation.

Thought?

Qin

On Thu, Jun 27, 2013 at 12:33 AM, Xavier Vilajosana Guillen <
xvilajosana@eecs.berkeley.edu> wrote:

> Hi Yoshihiro,
>
> you are right, the formulation of the sentence is not correct. Should be:
>
> “Topology: Random, where each node requests a random number of neighbours
> between 2 and 10.”
>
> this means that each node when created requests a number of neighbors
> between 2 and 10, meaning that other nodes when are created also request
> that number of neighbours and therefore a node can have more than 10
> neighbours, because other nodes selected it as a neighbour. From the
> simulation results I see that nodes have between 5 and 11 neighbours
> usually.
>
> However, from the numbers you point, 28 represents the number of allocated
> links (number of allocated cells in the schedule) to its neighbours, there
> might be more than one link to a neighbour in that case.
> regards,
> Xavi
>
> Xavi
>
>
> On Wed, Jun 26, 2013 at 7:28 AM, <yoshihiro.ohba@toshiba.co.jp> wrote:
>
>>  Hi Xavi,****
>>
>> ** **
>>
>> Thank you very much for the simulation.****
>>
>> ** **
>>
>> I am trying to understand the simulation model from your description and
>> the result.****
>>
>> ** **
>>
>> “Topology: Random, where each node has a random number of neighbors
>> between 2 and 10.”****
>>
>> ** **
>>
>> “****
>>
>> ************************ requesting 1 links****
>>
>> Node,Allocated Links,Collisions,Percentage****
>>
>> 0,28,0,0.0****
>>
>> “****
>>
>> ** **
>>
>> In the above result, does Node 0 actually have 28 neighbors?****
>>
>> ** **
>>
>> Regards,****
>>
>> Yoshihiro Ohba****
>>
>> ** **
>>
>> *From:* 6tsch-bounces@ietf.org [mailto:6tsch-bounces@ietf.org] *On
>> Behalf Of *Xavier Vilajosana Guillen
>> *Sent:* Wednesday, June 26, 2013 3:46 AM
>> *To:* 6tsch@ietf.org
>>
>> *Subject:* [6tsch] simulation for random schedule allocation****
>>
>> ** **
>>
>>
>> ****
>>
>> Hi all,
>>
>> I prepared a little simulation to see how random schedule allocation
>> behaves. (I have the code in Java in case someone is interested)
>>
>> here there are some details (everything can be tuned in case someone
>> wants to point me to a special case)
>>
>> Network: 50 nodes
>>
>> Topology: Random, where each node has a random number of neighbors
>> between 2 and 10.
>>
>> Each node requests a link to each of its neighbors. This is done from 1
>> to 10 times (i.e 10 tests, the first requesting 1 link to each neighbour,
>> the second 2, etc.. up to 10 links to each of the neighbors, can be
>> configured)
>>
>> The slotframe is 101 slots and 16 channels.
>>
>> The simulation prints statistics for the test (and the collisions if we
>> are interested.)****
>>
>> I used pseudo random generator from the java language assuming it
>> provides uniform or almost uniform distribution.****
>>
>> The allocation counter counts both the number of links allocated as tx
>> and the number of links allocated as rx due to a neighbour allocating a
>> link to the actual node. The percentage is the % of collisions w.r.t the
>> allocated links. ****
>>
>> Worst case is around 11% when allocating 10 links to each neighbour in
>> that 50 node network.****
>>
>> I can play more on it but I wanted to share that initial results.****
>>
>> please see attached file for the results.****
>>
>> regards,****
>>
>> Xavi****
>>
>
>
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