Re: [Ospf-manet] MPR-OSPF GTNetS simulations report

[Richard Ogier <[e-mail]>]

Emmanuel and all,

I ran some simulations to compare INRIA's solution
with MPR LSA reduction and adjacency reduction
to MDR with min-cost LSAs and 1-connected adjacencies.

I noticed that you used my database exchange optimization
(by defining OSPF6_MANET_MDR_FLOOD_DD in Makefile).
http://www.ietf.org/internet-drafts/draft-ietf-ospf-dbex-opt-00.txt

I guess you forgot to mention this.  This reduces DD overhead
by about 50%, and therefore reduces the difference between
INRIA and MDR overhead, but it does not change the fact that
DD overhead increases much faster with MPR adjacency reduction
than with MDR, as the number of nodes increases.
So the difference in overhead is still quite dramatic in larger
networks, as the results below show.

I used your GTNetS code with MPR LSA reduction and MPR adjacency
reduction.  I used the following parameters for both INRIA and MDR,
to agree with your report:

Max velocity: 16 m/s
Pause time: 1s
HelloInterval: 2 s
DeadInterval: 6 s
RxmtInterval: 7 s
MinLSInterval: 5 s
MinLSArrival: 1 s
AckInterval: 500 ms

(Your report does not mention PushbackInterval, but it was
set to 3500 msec in your perl file, so I used that value.)
The database exchange summary list optimization was used
with both INRIA and MDR.

I ran simulations with 40, 60, 80, and 100 nodes, with range = 250 m.
The results for 40 nodes agree with your graphs (for overhead and
delivery ratio).  The results are summarized below.

MDR                       40 nodes  60 nodes  80 nodes  100 nodes
---                       --------  --------  --------  --------
Total Overhead (kbps)      72.50    138.84    252.79    370.76
LSU overhead (kbps)        17.57     29.02     49.82     65.88
LS Ack overhead (kbps)     17.31     36.66     73.46    118.57
DD overhead (kbps)         10.50     21.52     38.97     54.60
Adjacencies/node            2.66      3.02      2.83      2.41
Adj changes/node/sec        0.05      0.04      0.05      0.04
Avg LSAs out of sync        0.48      0.35      0.30      0.24
Delivery ratio              0.939     0.941     0.935     0.938

INRIA                     40 nodes  60 nodes  80 nodes  100 nodes
-----                     --------  --------  --------  --------
Total Overhead (kbps)     160.80    369.07    670.03   1174.08 (3 x MDR)
LSU overhead (kbps)        27.97     58.66    100.02    177.27
LS Ack overhead (kbps)     49.15    109.55    183.28    294.12
DD overhead (kbps)         51.21    138.09    277.72    537.95 (10 x MDR)
Adjacencies/node           16.37     21.08     26.49     31.78
Adj changes/node/sec        0.25      0.29      0.34      0.42 (10 x MDR)
Avg LSAs out of sync        1.79      1.78      1.61      1.66
Delivery ratio              0.849     0.845     0.867     0.844

For 100 nodes, INRIA's DD overhead is about 10 times that
of MDR, resulting in 3 times as much total overhead.
But there seems to a problem (perhaps a bug) with INRIA's
code, since INRIA has a much lower delivery ratio,
and a much larger number of LSAs out of sync than MDR.

Richard


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