Multiple radios to improve throughput

-----Original Message-----
From: [email protected] [mailto:b.a.t.m.a.n-bounces@open- mesh.net] On Behalf Of Shane Chao
Sent: Tuesday, June 03, 2008 1:34 AM
To: [email protected]
Subject: [B.A.T.M.A.N.] Multiple radios to improve throughput

Elektra,

Thank you for pointing out in May 08 that most embedded boards do not have enough CPU power to saturate the capacity of single radio link. I was experimenting Batman in a straight line, three node configuration with the middle node having two radios so it doesn't have to switch between node 1 and node 3. My configuration is as follows:

node 1          node 2          node 3
------          ------          ------
  ath0 <--ch 1--> ath0
                  ath1 <--ch 11-> ath0

When I ran iperf between node 1 and 3, I did not see any throughput improvements with either one or two radios in node 2. I even stopped Batman and manually setup the routes and the performance remains the same. However, when I upgrade node 2 from a 200MHz CPU board to a 500MHz CPU board, the bandwidth went up 50%. So thanks again for pointing out my bottleneck:)

Lastly, can someone suggest some embedded boards fast enough to push wifi radios to its limits?

Thanks,
Shane
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-----Original Message-----
From: [email protected] [mailto:b.a.t.m.a.n-bounces@open- mesh.net] On Behalf Of Shane Chao
Sent: Tuesday, June 03, 2008 1:34 AM
To: [email protected]
Subject: [B.A.T.M.A.N.] Multiple radios to improve throughput

Elektra,

Thank you for pointing out in May 08 that most embedded boards do not have enough CPU power to saturate the capacity of single radio link. I was experimenting Batman in a straight line, three node configuration with the middle node having two radios so it doesn't have to switch between node 1 and node 3. My configuration is as follows:

node 1          node 2          node 3
------          ------          ------
  ath0 <--ch 1--> ath0
                  ath1 <--ch 11-> ath0

When I ran iperf between node 1 and 3, I did not see any throughput improvements with either one or two radios in node 2. I even stopped Batman and manually setup the routes and the performance remains the same. However, when I upgrade node 2 from a 200MHz CPU board to a 500MHz CPU board, the bandwidth went up 50%. So thanks again for pointing out my bottleneck:)

Lastly, can someone suggest some embedded boards fast enough to push wifi radios to its limits?

Thanks,
Shane
_______________________________________________
B.A.T.M.A.N mailing list
[email protected]
https://list.open-mesh.net/mm/listinfo/b.a.t.m.a.n

Elektra,

Thank you for pointing out in May 08 that most embedded boards do not have enough CPU power to saturate the capacity of single radio link. I was experimenting Batman in a straight line, three node configuration with the middle node having two radios so it doesn't have to switch between node 1 and node 3. My configuration is as follows:

node 1          node 2          node 3
------          ------          ------
 ath0 <--ch 1--> ath0
                 ath1 <--ch 11-> ath0

When I ran iperf between node 1 and 3, I did not see any throughput improvements with either one or two radios in node 2. I even stopped Batman and manually setup the routes and the performance remains the same. However, when I upgrade node 2 from a 200MHz CPU board to a 500MHz CPU board, the bandwidth went up 50%. So thanks again for pointing out my bottleneck:)

Lastly, can someone suggest some embedded boards fast enough to push wifi radios to its limits?

Shane Chao <[email protected]> [080603]:

Quoted 20 lines

Elektra,

Thank you for pointing out in May 08 that most embedded boards do not have enough CPU power to saturate the capacity of single radio link. I was experimenting Batman in a straight line, three node configuration with the middle node having two radios so it doesn't have to switch between node 1 and node 3. My configuration is as follows:

node 1          node 2          node 3
------          ------          ------
 ath0 <--ch 1--> ath0
                 ath1 <--ch 11-> ath0

When I ran iperf between node 1 and 3, I did not see any throughput improvements with either one or two radios in node 2. I even stopped Batman and manually setup the routes and the performance remains the same. However, when I upgrade node 2 from a 200MHz CPU board to a 500MHz CPU board, the bandwidth went up 50%. So thanks again for pointing out my bottleneck:)

Quoted 2 lines

Lastly, can someone suggest some embedded boards fast enough to push wifi radios to its limits?

Make a test with 2 atheros minipci cards on a Alix 3C3 (500mhz) and try to find out if the CPU is saturated.

--
Benjamin Henrion <[email protected]>
FFII Brussels - +32-484-566109 - +32-2-4148403
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Now, is this CPU bottleneck because of batman and routing or something else? (cannot forward packets fast enough?)
11mbits isn't really that much and I still have to see my setup hit that figure between only two nodes, let alone multi-hop.

Now that we've played around a bit can someone please provide some benchmarks of a 5-node network (with some multi-hop paths) with batman and with just the whole network bridged and on the same subnet.

What sort of performance should you expect in either scenario?

As I said before, I used to get 1MB/s with non-routed bridged network of two atheros devices but ever since I started using batman, 300KB/s is the most I was ever able to achieve between the same two nodes. 2 hops and it goes down to 40KB/s.

Quoted 30 lines

-----Original Message-----
From: [email protected] [mailto:b.a.t.m.a.n-bounces@open- mesh.net] On Behalf Of Shane Chao
Sent: Tuesday, June 03, 2008 1:34 AM
To: [email protected]
Subject: [B.A.T.M.A.N.] Multiple radios to improve throughput

Elektra,

Thank you for pointing out in May 08 that most embedded boards do not have enough CPU power to saturate the capacity of single radio link. I was experimenting Batman in a straight line, three node configuration with the middle node having two radios so it doesn't have to switch between node 1 and node 3. My configuration is as follows:

node 1          node 2          node 3
------          ------          ------
  ath0 <--ch 1--> ath0
                  ath1 <--ch 11-> ath0

When I ran iperf between node 1 and 3, I did not see any throughput improvements with either one or two radios in node 2. I even stopped Batman and manually setup the routes and the performance remains the same. However, when I upgrade node 2 from a 200MHz CPU board to a 500MHz CPU board, the bandwidth went up 50%. So thanks again for pointing out my bottleneck:)

Lastly, can someone suggest some embedded boards fast enough to push wifi radios to its limits?

Quoted 6 lines

Thanks,
Shane
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I too would like to see this benchmark setup. I have a private mesh that I've been using batman and olsr on that consists of about 8 nodes that end up spread out of about a 2000m x 2000m area and right now I'm only using one radio for the mesh. I'm pushing video from about 4 of these nodes and if I try to do more than 2 hops with the video I see drastic drops in the video performance.

I use Avila Gateworks boards that have 533 MHz Intel Xscale processors and I've never seen the cpu even close to taxed by batman, olsr, or the radios, as a point of reference for the original poster. They also have a newer board with a 633 Mhz cpu.

I have bought 12 foneras to make a test with 6 nodes (2 foneras per node), to see if OLSR chooses the fastest route in terms of throughput, and it does not. I have to try to play with LinkQualityMult on the ethernet link.

Hi all,

I ran another iperf test with the following scenario below:

node 1          node 2          node 3
------          ------          ------
 ath0 <--ch 1--> ath0
                 ath1 <--ch 11-> ath0

Both nodes 1 and 3 are still using WRAP board w/ 266MHz cpu with single radio inside but this time I replaced node 2 with a desktop PC w/ 1GHz cpu and 2 radios. The PC is running Ubuntu Linux and Madwifi drivers. The result of iperf from node 1 to 3 isn't any better than when node 2 was using WRAP w/ 2 radios. I was expecting higher throughput from node 1 to 3 due to a faster cpu on node 2 to forward packets between the 2 radios inside but I am now confused.

I am currently not running Batman and instead manually creating the route table in trying to isolate the throughput problem.

Maybe there is some configuration parameters that need to be set on node 2? Any advice would be appreciated.