[Olsr-users] Regarding 3+ radio mesh routing nodes

Benjamin Watson (spam-protected)
Thu Jun 7 05:32:18 CEST 2007

Greetings list,

I've been using OLSR in conjunction with Pyramid Linux on some Metrix
Mark II mesh routing nodes quite well for some time.

These particular nodes have an Ethernet port as well as two radios for

For my current implementation, I've earmarked the Ethernet port on all
boxes for traditional wired Internet/LAN access when available.

I only run OLSR on what I'd consider my "mesh backhaul" interface.  In
each mesh router, I have an 802.11a radio to serve as this backhaul.
The boxes discover one another and route traffic to/from one another,
providing Internet/Network access to those nodes that aren't directly

The other radio is aimed at being used as a traditional Access Point
serving end users (e.g. laptops).  And again, OLSR maintains the
routing tables wonderfully, allowing these users to communicate via
the Mesh network to the Internet, etc.

Enough beating around the bush, onto the question.

You may or may not be aware of a website: www.meshdynamics.com.  The
site owner has detailed analysis showing how multi-hop wireless
communication using a single "backhaul" radio breaks down rapidly has
the hop count grows.  This is due to the inherent half-duplex nature
of wireless communication.

The solution is to add another radio.  By using one radio to send, and
the other to receive, full-duplex communication can be achieved.

Is there any way that OLSR could support this?

I know that OLSR can operate on more than one interface at a given
time.  I'm curious as to what modifications, if any, would be needed
for this 3 radio scenario.  Perhaps OLSR could run on both interfaces
simultaneously, only each radio is tuned to a different channel and
has the same IP address?

Any thoughts?


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