Bug 733 - OLSR MPR Computation give incorrect result
OLSR MPR Computation give incorrect result
Status: RESOLVED FIXED
Product: ns-3
Classification: Unclassified
Component: routing
ns-3.5
PC Linux
: P5 normal
Assigned To: ns-bugs
:
Depends on:
Blocks:
  Show dependency treegraph
 
Reported: 2009-10-31 13:15 EDT by Omair
Modified: 2009-11-01 17:49 EST (History)
1 user (show)

See Also:


Attachments
The script used to get the mentioned results of OLSR (5.29 KB, text/x-c++src)
2009-10-31 13:15 EDT, Omair
Details
Trace file on running the above script (61.89 KB, application/x-bzip)
2009-10-31 13:19 EDT, Omair
Details

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Description Omair 2009-10-31 13:15:11 EDT
Created attachment 640 [details]
The script used to get the mentioned results of OLSR

In the OLSR Routing Protocol, the MPR set of a node is having more nodes than necessary.

/* Topology (Constant Position)
 * A---D
 * | / |
 * C---E
 * |
 * F
 *
 * F - Node 0 - IP 10.1.1.1
 * C - Node 1 - IP 10.1.1.2
 * E - Node 2 - IP 10.1.1.3
 * A - Node 3 - IP 10.1.1.4
 * D - Node 4 - IP 10.1.1.5
 *
 * Trace File Line 47625 says MPR nodes of A are C & D. But it should be only C.
 * Similarly  Line 47521 says MPR nodes of E are C & D. But it should be only C.
 */

This doesn't follow the algorithm given in the comments of the src/routing/olsr/olsr-routing-protocol.cc or the RFC. 
I mailed the developer Gustavo Carneiro
and quoting the mail:

 1. C is the only node that can reach the two-hop neighbor F, so it
should be among the first to be selected as MPR;

  2. Once C is selected as MPR, C can reach all the other nodes, so no
more MPR should be selected.

So I agree with you, the MPR set of A should be only C, not C+D.  If
this does not happen, sounds like a bug.
Comment 1 Omair 2009-10-31 13:19:11 EDT
Created attachment 641 [details]
Trace file on running the above script
Comment 2 Gustavo J. A. M. Carneiro 2009-11-01 17:49:11 EST
Please try ns-3-dev.  It should be fixed now.  And thanks for the good work providing a test case.

changeset:   5471:61831e265e20
tag:         tip
user:        Gustavo J. A. M. Carneiro  <gjc@inescporto.pt>
date:        Sun Nov 01 22:47:04 2009 +0000
summary:     Bug 733: OLSR MPR Computation give incorrect result