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Multihomed WLANs from Intel

Posted by ryuzaki0 on from the war-walking dept.

accessdeniednsp writes: "El Reg gives us some insight on Intel Labs' new software to let your wireless LAN card hop between various networks (802.3, 802.11, and 'fixed Ethernet' they call it). Perfect for us snoopers to walk by college frat houses and hopping on the 'net with our linux ipaq's :)" First company to come out with a "universal connectivity" PCMCIA card wins all the marbles.

31 of 128 comments (clear)

  1. Just means people who are serious about... by mystery_bowler · · Score: 3

    ...network security are going to have to be even more "on their toes" about their wireless network.

    I certainly think it's a good idea, though. I can imagine this kind of universal wireless compatibility preventing a lot of headaches for busy travelers when airports and mass transit terminals start implementing WLANs.

    Now if I could only get my boss to let us put up an 802.11 network so I can code from Barnes & Noble down the street...

    --

    My sigs always suck.
  2. Frats with LANs? by Skyshadow · · Score: 3, Funny

    Maybe I've been out of college for too long, but the highest level of connectivity I've observed at most frats was the build-in beer taps.

    --
    Every year during my review, I just pray the words "slashdot.org" aren't mentioned.
    1. Re:Frats with LANs? by garcia · · Score: 5, Informative

      I am not in a frat, but I do have a wireless LAN in my apartment. Playing MP3s to the stereo from a laptop (and using it to surf from the couch) is far easier and safer (for drunken idiots) than running ethernet to the living room from the hub in my room.

      I do phone support and I hear a lot of people getting into wireless routers b/c of the ease of having it run to all the computers in the house. Why not do it for frats?

      And unfortunatly I do have a WLAN but no kegerator ;(

    2. Re:Frats with LANs? by jandrese · · Score: 2

      I remember those days. Those were the days when the phone company assumed that anybody who wanted an ISDN line was a business. I remember pricing schemes like: 56k (full duplex though): $250/month + 2 cents a megabyte + 10 cents a minute. I don't know if anybody ever actually bought that, but it seemed like a complete ripoff to me. The scary part was, they actually offered more expensive options (dual line ISDN).

      I'm pretty sure they really wanted you to buy the T1 for $4500/month. Even these days with DSL and Cablemodem everywhere they still want $1500/month for a T1 and have completly forgotten about ISDN again.

      --

      I read the internet for the articles.
  3. Re:Who does the hardware? by keep_it_simple_stupi · · Score: 2, Interesting

    "what new and funky harware are we going to need?"
    Not only this, but will the hardware be reliable? I recently set up a LinkSys Wireless router for a friend and anytime more than one PC generates traffic, the router simply locks up - it must be reset. If this is how the hardware is going to be than no thanks.
    I hope someone is using their head and actually tests this equipment before putting it out on the marketplace.

  4. What we really need by vlag · · Score: 5, Interesting

    What we all really need is a wireless nic that can be upgraded to new wireless standards à la 802.11x via firmware. The argument exists that we don't have the components to build these cards but I feel that this is where research should move. As it stands now, we are poised for a new standard roll-out every 8 months for the next few years. Anyone know about this type of tech being develloped?

    --
    Do you want to remove linux?
    1. Re:What we really need by eqteam · · Score: 2, Informative

      Companies are working on 802.11b/a and a/g solutions, but you will not see $199 cards for this until 2003 (from what I hear). The biggest issue concerning the ability to support the newer standards via a 'firmware upgrade' is the fact that the 11a/g handle the air interface differently from 11b. This requires different/upgraded transcievers in the card itself, not to mention new access points.

      To get specific, 802.11a uses a different spectrum (5.5GHz) and 802.11g uses OFDM for modulation at 2.4GHz, and both of these are vastly different (hardware level) from 802.11b. Secondarily, the other 802.11x standards mostly effect the MAC layer (QoS et al) and this is typically not handled by a general purpose processor, so just upgrading the firmware won't necessarily help here either.

      Just my 2 cents

    2. Re:What we really need by jbf · · Score: 2

      eqteam, thanks for the sanity =)

      If you think you can offload OFDM encoding and decoding to the CPU, think about the kind of bus bandwidth you'd need to do it. PCI runs 64 bits at 66 MHz, best case. That's a bandwidth of 512MBps. Suppose you could specify a single chip with one bit on the bus; then you could live with a chipping rate of 4Gcps. Given the 10.4dB processing gain, you're _bus_ bandwidth capped at 372Mbps, and that's with nothing else running.

      Let's get a little more realistic: currently PCI runs at 32 bits 33MHz in your desktop machine. That means that if your computer is ONLY sending chips over the bus, you can't even do turbo mode (dual channel) 802.11a. (93Mbps 108Mbps).

      Now let's make things worse. To make it completely frequency independant, we assume you only need to code the ISM bands: 26MHz wide at 915MHz, 83.5MHz wide at 2.4GHz, and 125MHz wide at 5.8GHz. That's a total of 234.5 MHz of bandwidth. Now you've got to cover about 4-8 times as much ground as the simple 802.11a situation, and you're still dependant on the ASIC translating your chips into OFDM modulated stuff.

      I'm not enough the physical layer guy to tell you how much data you need to pass across the bus to get OFDM to work without the hardware knowing anything about it...

      Lots of the 802.11i stuff is aimed at being back-compatible to existing WEP hardware. It's hard to make things like QoS do that though.

      Winmodems can work because the bandwidth of a phone line is so small. With the size of frequency bands in the ISM band, you can't do that anymore.

  5. Re:catching up with the mac by keep_it_simple_stupi · · Score: 4, Informative
    You just can't beat the Mac's ability to switch networks on the fly. Since windows can't switch network settings without a reboot, this is more of an OS issue.

    You need to get your information straight. This article is talking about completely different architectures being supported with no additional hardware.

    Besides, any NT based (at least from 4.0 up to 2000 and XP) can change settings on the fly. As a matter of fact, XP can even retain settings for more than one network and automatically switch between the two, one w/ DHCP and another with static settings. Or you could use NetSwitcher to do it...
  6. Walking around campus by essiescreet · · Score: 2, Funny

    How the hell do you walk and surf the web at the same time? Those laptops must be pretty tough, b/c you'd all the time be running into things...

  7. Re:You are so funny by garcia · · Score: 2

    umm, there stereotypes are true in this case, and *most* frats should be proud of it.

    that's my opinion though.

    as far as the "white smoke running through air tubes..." I KNOW WHAT IT IS ;-)

  8. Frats by SilentChris · · Score: 3, Funny
    "Perfect for us snoopers to walk by college frat houses and hopping on the 'net with our linux ipaq's :)"

    Call me crazy, but I don't remember most of the frats in my college being crazy about wireless ethernet. They were too busy drinking/partying/etc. I guess maybe if you're at MIT...

  9. Re:Who does the hardware? by tdrury · · Score: 2

    The Linksys WAP is horrible. I had mine lock up at least once a day and needed a hard reset. I upgraded the firmware to the latest on the website (1.39.2?) and the lockups went away. But the wireless functionality stopped working. Check out DSL Reports and go into the network hardware forum for Linksys. You'll see a huge number of complaints. In fact, they had a higher rev of the firmware (1.40.x) on the site, but had to pull it because it was even buggier.

    So I bought the SMC router/wap, and guess what - it's just as buggy. It locks up every 2 or 3 days.

    -tim

  10. Re:catching up with the mac by CodeMonky · · Score: 2

    Not on the three copies of Win2k SP2 I just tried.

    --
    --"Karma is justice without the satisfaction"
  11. who pays for firmware upgrade? by Anonymous Coward · · Score: 3, Insightful

    The current model is that new features = new hardware.

    Changing that model to new features = software download is substantially different, and a little scary for business.

    If they offer a download, they would need to charge for it: software doesnt write itself.

    With all the headaches associated with verifying
    software releases across multiple hardware versions, I think it's cheaper and easier for everyone involved to just buy a new $100 hardware
    when it comes out, rather than deal with the buggy firmware upgrades.

    1. Re:who pays for firmware upgrade? by afidel · · Score: 2

      Well for the most part you have described how Cisco's IOS development works, they add new features and charge for them accordingly. They also price differentiate their line based of features, eg a basic IP 3620 costs a lot less than a enterprise 3620 with EIGRP, BGP, IPSec etc. Now the biggest problem right now as far as firmware upgradable standards goes is that the PHY's lock you into one frequency range. There is some early work going into firmware defined PHY's but with current tech they are limit to the upper bound of the frequency range they can operate at. If the frequency for the new standard is higher than what the new protocol uses then you are back into the harware upgrade cycle and your origional part was more expensive. It's almost like regular ethernet but with quicker upgrade cycles. If you have been using cat5 then you only needed to upgrade the cards and switches, not the wiring, but if you went with cat3 because it was good enough then you have to upgrade all 3 components.

      --
      There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
  12. All your marble are belong to Nokia by Wesley+Felter · · Score: 2

    The Nokia D211 supports 802.11 and GSM/GPRS. I guess it's only lacking Bluetooth.

    1. Re:All your marble are belong to Nokia by Wesley+Felter · · Score: 2

      That's what you get for buying a machine without Ethernet on the motherboard...

  13. you can do much of this now by The+Pim · · Score: 5, Informative
    I do part of this (hopping between wired and wireless) now with ordinary hardware and software, although a few bits are missing. The key piece is proxy ARP, a nifty trick I had never heard of until I tried to solve this problem.

    The basic idea is to set up a gateway on both the wired and wireless networks, and proxies ARPs on both networks, so that hosts on the different network see each other as if they were on the same LAN. This is a little like bridging--except that only a tiny bit of traffic (the ARP's) needs to "bridge" the two networks. The rest is taken care of by normal routing.

    The trick is switching a host from wired to wireless without changing its IP addresses (so it doesn't drop any connections). Note this implies that the gateway's routing table has a host route (specifying the interface) to every address that is allowed to switch networks: you can't tell from the address which side its on, so the usual subnet mask routing won't work.

    Pulling off the switch requires that the gateway be able to detect the switch, and then do two things: One, change its routing table, so that traffic for the address goes out on the right interface. Two, send "gratuitous ARPs" to other hosts, forcing them to update their ARP tables (since, if the host moved to the other network, traffic to it now needs to be routed through the gateway).

    I think the most straightforward way to detect the switch is to have the gateway run a DHCP server, and have the mobile hosts renegotiate a lease when they switch networks. Then, add a hook to the DHCP server to do the magic whenever it notices a host renegotiate on a different network. For the mobile hosts to be identifyable across networks, they need to send the same client-identifier on both networks. Since the default client-identifier is usually the MAC address, this requires configuration on the clients (I edit /etc/dhclient.conf and pick one MAC address to use as the client-identifier). Of course, the DHCP server needs to be configured to give out the same address range on both interfaces.

    Unfortunately, on the network I care about, my gateway is not the DHCP server. Instead, I run a DHCP relay. This mostly works--except the ISC DHCP relay doesn't have any hooks, and I haven't hacked it to add them. But it should be easy.

    Another way to solve this might be for the gateway simply to monitor ARPs and do something when it notices a host switch networks. I haven't found a clean way to do this, and I think it might be less than perfect, because the host wouldn't get switched until it initiated an ARP transaction.

    The last problem is that different systems seem to respond differently to gratuitous ARPs. For example, Linux systems don't seem to require them at all, because they (apparently) issue a new ARP pretty quickly after the old MAC address stops answering. But I can't get Solaris systems to listen to gratuitious ARPs at all, and they don't time out for minutes.

    Also, gratuitiously ARPing the whole network is ugly. Ideally, we would would only send an ARP when we notice another host using a MAC that we know has moved to the other network. I have no idea how to do this.

    Despite all the glitches, it's quite fun to switch to the wireless for mobility and back to the ethernet for speed, without losing my ssh connections. Improvements on this setup would be welcome!

    --

    The evaluation of an action as 'practical' . . . depends on what it is that one wishes to practice.
    1. Re:you can do much of this now by multipartmixed · · Score: 2

      The ARP thing can be done by monitoring the dhcp CLIENT end of things. If the IP number changes, broadcast ping the subnet you're on now, and the one you just left. That's enough for more hardware out there to get it's head out of its ass and recognize your host, and it's reasonably efficient, too. (Two small ICMP packets per network change)

      --

      Do daemons dream of electric sleep()?
    2. Re:you can do much of this now by The+Pim · · Score: 2
      If the IP number changes

      It doesn't. Read again. But, yeah, you could trigger this off of whatever you use to switch interfaces (ie, PCMCIA scripts).

      broadcast ping the subnet you're on now, and the one you just left. That's enough for more hardware out there to get it's head out of its ass and recognize your host

      My experience is that hardware can be pretty stubborn, but I'll try it. Thanks for the idea.

      --

      The evaluation of an action as 'practical' . . . depends on what it is that one wishes to practice.
  14. what do they mean with 802.3 *and* fixed ethernet? by ruud · · Score: 3, Insightful

    802.3 is fixed ethernet, see this page.

    --
    bgphints - internet routing news, hints and ti
  15. Re:Who does the hardware? by afidel · · Score: 2

    I would suggest looking for a Cisco home base station. Although they were EOL'd a few months ago they are based on a similar platform to their enterprise AP's. They cost more than the Linksys or SMC units but you get what you pay for. I have never had mine lock up =)

    --
    There are 4 boxes to use in the defense of liberty: soap, ballot, jury, ammo. Use in that order. Starting now.
  16. Too little too late? by blair1q · · Score: 2

    Why do I get the feeling that just as we get this problem solved, 100mbit wireless LAN will become available at reasonable prices?

    --Blair

  17. I figured they were just Skam Records fans. by dave-fu · · Score: 2

    You know. Autechre and Boards of Canada and all them lovely folks.

    --
    Easy does it!
    This comment has been submitted already, 276865 hours , 59 minutes ago. No need to try again.
  18. OSX? by BWJones · · Score: 3, Informative

    Shoot, why not just get a Mac running OSX? I have been doing just this sort of thing for almost a year now with a Powerbook and now an iBook running OSX. The iBooks are really impressive small laptops that can be had for as little as $1100 and they give you a hell of a nice GUI and the option to X-windows or CLI in UNIX to your hearts content.

    --
    Visit Jonesblog and say hello.
  19. Power Consumption Reference Also Interesting by meehawl · · Score: 2, Insightful

    Sehert said the CPU only accounted for seven per cent of the typical power consumption of a mobile device (although the chipset accounted for another 13 per cent). With the LCD sucking up a third of the power consumed

    It seems to me that controlling power consumption requires a user eye-tracking mode. As I look at my dual screen setup, at every moment my focus rests only on a small couple of square cm of the screen. Surely with eye tracking it should be possible to dim/fade the rest of the screen, cutting down power consumption.

    This might also have advantages for graphics cards/CPU, because you could concentrate on doing most your rendering and aliasing in only the portion of the screen within eye focus. For that to work you'd need some sort of tile-based rendering system though.

    --

    Da Blog
  20. Re:what do they mean with 802.3 *and* fixed ethern by Guy+Harris · · Score: 2
    802.3 is fixed ethernet, see this page ...

    Try this link instead, as it actually works. (The "Preview" button, and the left mouse button, are your friends.)

    (BTW, the top-level 802.x page has links to a lot of information about 802.x standards, including a page of links to pages for the working groups for each 802.x standard (I'm amused to find that the 802 standards committee appears to be supersititious - they say 802.13 wasn't used), as well as a link to the Get IEEE 802(TM) page from which you can download, for free, PDFs for 802.x standards that were published 6 or more months ago.

  21. Wireless Frat Houses? by Wintermancer · · Score: 2

    Dear God.

    I can only imagine what would happen for people using netstumbler:
    "The airwaves! They're saturated! I've never seen so much pr0n!"

    In all honesty, I've mentioned a number of times the advantage of wiring up the ol' fraternity house.
    Since most of them are not geeks, their eyes get more glazed over than after a 6 kegger party. Simply stated, most fraternity members are not interested in being able to run SSH over an 802.11b WLAN.

    Being able to score with the hotties in the sorrority next door, that's another thing entirely.

    Go Deke!

  22. Nokia Wins by rbeattie · · Score: 3, Informative


    Here's a news item at InfoSync about the new Nokia GSM, GPRS, HSCSD, and WiFi PCMCIA card.

    Pretty freakin' cool. I want one.

    -Russ

    --
    Me
  23. Re:Who does the hardware? by stripes · · Score: 2
    I would suggest looking for a Cisco home base station. Although they were EOL'd a few months ago they are based on a similar platform to their enterprise AP's. They cost more than the Linksys or SMC units but you get what you pay for. I have never had mine lock up =)

    Mine never locked up either, not even after it broke. It just started dropping about 30% of the traffic. Cisco wanted $750 to fix it (which is more then I payed for it). Apparently that's more then they sell for right no too.

    I bought a new Apple base station, which seems to have less range then the Cisco, but it is prettier.