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  1. #1
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    Default Slow Radio to Radio Throughput on a Soekris net4521-30

    Has anyone noticed this bottleneck?

    I have an intel mini tower running star-os as AP. If I connect to it from my laptop I can get 4786 Kbits/s throughput, about the max one would expect.

    I have a Soekris net4521-30 with two pcmcia lucent silver cards (the miniTower has a senao 200, the laptop has a cisco 350). In the Soekris one card is a client of the minitower and the other is in AP mode. If I connect my laptop to the SoekrisAP my throughput falls to 1612 Kbits/s.

    Everything is in the same room with no extrenal antennas. Wep is not turned on. The two cards in the Soekris are at channel 1 and 11. The minitower is on channel 1.

    I have swapped cards and tried different settings and nothing changes the throughput more than a couple of percent.

    Has anyone else seen this characteristic? Is the Soekris sharing an interrupt for both pcmcia cards?

    It should really go faster than this.

    TIA

  2. #2
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    Default Re: Slow Radio to Radio Throughput on a Soekris net4521-30

    There is a good chance the Soekris cannot handle the full throughput of two cards operating simutaniously. To see if this is the case, check your system load while doing a download. You can find this at the top of the System Information window that is under Advanced->Reports.

    Thanks!

  3. #3
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    Does this mean that have to have 2 soekris boards to make a star-os powered access point that has a wireless backhaul?

    Doesn't it also mean that a single board as a repeater would be ineffective?

    Why am I suddenly experiencing a nasty sinking feeling in the pit of my stomach?

  4. #4
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    It is indeed one of those interesting things. The SC520 wasn't really designed in terms of speed, to handle more than one really busy link. It works great if you use it as two APs, as the traffic is mixed between the two, giving really good response however when each packet has to pass through two wireless interfaces on the board, that instantly doubles the system requirements. It's a real shame that 802.11b cards are all PIO based, which is really taxing on slower systems. Thankfully, this has been addressed with the introduction of 802.11a/g cards.

    Out of curiosity, what is the system load on the unit when doing a large download?

    Thanks!

  5. #5
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    So, is there an SBC that CAN handle the load?

    At any price?

    I nearly made a huge mistake, because I was under the impression this would work.

  6. #6
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    Default

    We are preparing to use some VIA mini ITX motherboards. The smallest has a fanless 533 MHz PII clone. It takes standard SDRAM, builtin Ethernet (we support it) and one PCI slot. I have also tested a unit with 800 MHz CPU (requires a fan) and other specs are the same.

    I have some 12VDC converters that give ATX power and a nice 90 degree riser to keep the case thin. I have to find a good regulated 12 VDC adapter.

    We have found some nice cases with 150W AC supplies for those spots that have a good power source. We do not have any good cases for outdoor use yet.

    The 533 MHz units draw just under 1A with a radio and 128 MB ram.

    We are looking at some units with 3 PCI slots and about the same power drain, but they will take a case that is close to a standard PC.

    Do you actually NEED the SBC? They are WAY more costly and only provide a bit smaller size but much less computing power. If size is not the object then do yourself a favour and build a PC with the juice to do what you really want.

    Don't want to build? Then consider buying and we will build it for you.
    ..a computer is a stupid machine with the ability to do incredibly smart things, while computer programmers are smart people with the ability to do incredibly stupid things. They are,in short, a perfect match..

    Try the latest 4.4.5.7-7842 release. It fixes the 11N card reset issue.
    http://www.star-os.com/ http://www.star-os.com/store

  7. #7
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    lonnie- where did you find the 12v atx power supply? I have been looking for one for quite a while.

  8. #8
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    Default CPU Load

    Test Goal: Check Soekris CPU load under heavy radio traffic.

    Ok, I am using two clients now. On one I mapped two drives, one each on two differrent servers on the wired network. From one of the clients I copied a couple of hundred megs of files from one of the mapped drive to the other. This gets you near the max upload and download limits. On the second client I ran some other speed test programs out to the internet, one far away (numioin.com) and one two hops away on my ISP's backbone (the target of my first test that started this thread).

    The Soekris System Load Average reports

    1.30 0.95 0.73

    There were no errors reported for either of the interfaces.


    The base station reports

    0.15 0.03 0.01 over the same time period.


    This smells interrupt bound to me. I noticed that both radios on the Soekris are sharing interupt 10. Is there a way to force it to use different interrupts for the two pcmcia radio cards?

    I have a couple of more tests to do before I come to any conclusions but so far this is not a good box for backhaul of anything over T-1 speeds.


    Thanks
    GT

  9. #9
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    I was given the source of the ATX dc-dc board as a favour for some work we did for an OEM customer and I was asked not to spread the source around. We are buying on the tail end of their orders. I'm happy to send you some for $25 US with ATX power cable and hard drive power cable. Get 10 and the price can be $20, since the large cost of these items is the preparation for shipping.

    You have to add a regulated 12VDC adapter. I have not found a good source yet, but I'm expecting to have to pay another $20, and right now you would have to find that part on your own.
    ..a computer is a stupid machine with the ability to do incredibly smart things, while computer programmers are smart people with the ability to do incredibly stupid things. They are,in short, a perfect match..

    Try the latest 4.4.5.7-7842 release. It fixes the 11N card reset issue.
    http://www.star-os.com/ http://www.star-os.com/store

  10. #10
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    Lonnie, will the mini ITX boards be poe compatible?

    Group: I think the mini-pci slot on the Soekirs is on a different interrupt than the pcmcia cards. I've ordered a Senao miniPCI (EL-2511MP PLUS ) from netgate. The recieve sensitivity is not what one dreams about, but if known one can design around these things. I'll re-run some tests and report back.

    gt

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