[ros-users] Wireless router/card recommendations

[Eric Perko]

Anton,

I was able to do some tests with the N router I have at home (WRT300n
running DD-WRT) and WPA2 Personal encryption, and it sadly didn't look
so good. Using iperf, measured speeds from a Thinkpad client with the
Intel 4965agn to one of those Asus cards in my desktop, iperf only
reported speeds around 1.5 Mbits/s (yup... those are the right units).
I was able to get full 95ish Mbit/s out of a 100Mbit Ethernet link, so
iperf should be functioning fine. I did notice that iwconfig only
reported a bitrate of 54Mbits/s for the 4965, and I was able to bump
it to some sort of auto mode and get speeds of around 50Mbit/s to a
wired iperf server where I had previously gotten 3-5 Mbit/s. All of
the systems involved are running Ubuntu 9.10 x64. My current
hypothesis for the less than spectacular speeds reported by iperf is a
combination of a few things:

* Poor autoconfiguration of the wireless N cards by Linux
* Running my home router in a mixed mode because we have a few G-only
clients, so maybe we cannot do full N speeds anyways
* Tons of wireless interference in my apartment building... there
really aren't any wide open channels between 1-11, so interference may
be an important factor

I plan on trying to test the latter two once the lab N router
reappears (it seems to have been loaned out and hasn't come back yet).
I would also like to try it on an unencrypted network and see if that
increases the speeds. The first is trickier and will require finding
the right iwconfig commands... the ones I tried quickly with the Intel
card didn't seem to put it into an N mode.

Though I did successfully change my rate on the Intel card to some
sort of auto rate, I was unable to set it to a wireless N speed. Does
anyone else have a wireless N setup (preferably N-only) that they
could report the output of `iwconfig` for the bitrate value?

I guess the moral of the story from these tests is that just because
there is some N equipment doesn't mean we are getting anything close
to N speeds...

- Eric

On Wed, Jun 9, 2010 at 11:48 PM, Antons Rebguns <arebgun at gmail.com> wrote:
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> Eric,
>
>> We've been using one of these
>> http://www.newegg.com/product/product.aspx?Item=N82E16833320048 in our
>> system and it has been working quite well with Ubuntu 9.10. I can't
>> really comment on it's full speed potential doing 802.11n, as we only
>> have a WRT54G router, but it hasn't dropped out or had any problems
>> being recognized by Ubuntu like some of the other cards/USB adapters
>> we tried. Also, it goes on sale at MWave every so often for about $12,
>> which is helpful if you don't have a huge budget for Wifi cards.
>
> Actually we do have a pretty good wireless G setup, I was thinking about something faster like wireless N. We do have an
> Intel 4965agn card that should support N speeds, but I was unable to get it to run any faster than G speeds (steady 60
> mbit/s though).
>
>>
>> I could run some bandwidth tests or something with our WRT54G if you
>> give me some commands to run on each computer. I might also be able to
>> try it on a WRT610n, if I can find it in the lab.
>>
>
> That would be great if you could test wireless N setup if you have one available. We have been using iperf to do
> bandwidth tests. It's in Ubuntu repos, just do "sudo apt-get install iperf". Then on one computer run "iperf -s" and on
> another run "iperf -c IP_ADDRESS_OF_ANOTHER_COMPUTER".
>
> Thanks!
> Anton
>
>> - Eric
>>
>> On Wed, Jun 9, 2010 at 8:36 PM, Antons Rebguns <anton at email.arizona.edu> wrote:
>>> Hello ROS users,
>>> We are updating our networking setup and I was wondering what other
>>> people/labs use on their robots? Something that is well supported in Linux
>>> and is fast, since network traffic is pretty significant with all the
>>> sensors/cameras running on the robot.
>>> Thanks,
>>> Anton
>>> _______________________________________________
>>> ros-users mailing list
>>> ros-users at code.ros.org
>>> https://code.ros.org/mailman/listinfo/ros-users
>>>
>>>
>> _______________________________________________
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>
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