Catch up on stories from the past week (and beyond) at the Slashdot story archive

 


Forgot your password?
Close
typodupeerror
×
Intel

Multihomed WLANs from Intel 128

Posted by michael 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.
This discussion has been archived. No new comments can be posted.

Multihomed WLANs from Intel More

Multihomed WLANs from Intel

Comments Filter:

  • Multi homed? (Score:1, Funny)

    by dadaist ( 544022 )
    I have trouble leaving my own home as it is. Please.
  • ...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...

  • Frats with LANs? (Score:3, Funny)

    by Skyshadow ( 508 ) on Friday March 01, 2002 @02:49PM (#3092510) Homepage
    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.
    • There seems to be a dense white cloud running on air tubes from time to time too, but none remembers what it is.

    • Re:Frats with LANs? (Score:5, Informative)

      by garcia ( 6573 ) on Friday March 01, 2002 @02:55PM (#3092580)
      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 ;(
    • Perhaps it's because I went to an engineering school, but not only did my Fraternity have a LAN (which I installed) I also got the ISDN up and running back when the phone company sales reps didn't even know they SOLD ANYTHING CALLED ISDN. Unfortunately we have more data on tap than beer now:(
      • 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.
        • Everybody I know that was doing ISDN in those days was using a loophole in the business ISDN (at least with the Bell Atlantic tariff) that allowed "voice" calls to be placed for 10 cents a call. Then you'd get a Data-Over-Speech-Bearer capable router, like the Ascend Pipeline, and make exactly two calls per month; one per B channel.

          Presto. 112K full-time connectivity for $35 a month. Plus twenty cents, of course.

    • What you dont realize is that i have a bunch of friends in a fraterity and they are rather high tech. The one guys does the website [millersville.edu] and they run all thier partys off laptops with mp3s. No need to Worry about cds getting ripped off. Oh and BTW they were featured on collegehumor [collegehumor.com] for the largest game of beer pong 720 cups
    • Well things have changed. My fraternity house had a major remodeling and had 2-4 ethernet drops put into every room in the 3 story house. For a while we were just connected via a dialup modem, but then our school ran single mode fiber the mile or so to our house (for free! & the house is not owned by the school). All we had to do was buy the expensive transceiver for our end, and we had access to the campus lan and internet. We thought the number of drops for each room was crazy at first, but then every Freshmen after my class got a Thinkpad laptop, and the extra drops in the rooms and even basement (for DJing mp3s through our huge stereo) came in real handy.

  • New Software (Score:1, Offtopic)

    by inerte ( 452992 )
    Reminded me of the IWarez history. Getting software will be easier, and while you walk with the dog.

    Maybe a MS Office Lane, or Metallica Street?

  • What we really need (Score:5, Interesting)

    by vlag ( 552656 ) on Friday March 01, 2002 @02:54PM (#3092570) Homepage
    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?

    • who pays for firmware upgrade? (Score:3, Insightful)

      by Anonymous Coward
      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.
      • And yet, my sonicwall firewall works exactly that way. I bought it three years ago, it's out of warranty, and still it faithfully tells me each time there is new firmware available. That firmware may fix bugs, counter new attacks, or add other features.

        I believe the enabling technology is that sonicwall chose to build on a extendible, scalable platform themselves. A big benefits is that their systems do get better over time, unlike most pieces of hardware or software in which each new device/version often moves the users back down the reliability curve until the bugs get worked out.
      • 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.

    • Re:What we really need (Score:2, Informative)

      by eqteam ( 322882 )
      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
      • I understand the underlying technology and that different gear is needed to work at different frequencies, but one thing I find to be lacking is backwards compatibility. These cards are being made smaller and smaller. Right now, they are being manufactured small enough to fit 2 802.11b devices on a single compact flash card. Area wise, we should be able to fit 4 on a PCMCIA card, no sweat. Antenna size might be an issue but other wise, these wouldn't be a problem. The real problem here is the fact that most of the manufacturers are more interested in selling new product instead of bearing out their existing product lines. I love the bandwidth of 802.11a but it just rendered my 802.11b gear useless. I try to turn over my clients' networking gear every 4 years with 1 upgrade in between. I'd far rather buy a $250 PC card every 3-4 years than new access points and cards every 8 months. I've stammered and grumbled enough. It boils down to this: why not examine the next few proposed standards, and put the transmission / reception products on board now and make them active with future firmware updates. As long as the transmission hardware is present, we could off-load the "work" onto the CPU like a Winmodem (which is the bane of my existance) or AC'97-style onboard audio present on those cheap motherboards. Not the most elegant choice, but I'd buy into it for a little longer product life.
      • 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.
  • 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...
    • Obviously, you've never undocked your laptop from your desk, and walked to a conference room in another part of the building, having to connect to a walljack and renew leases (or if Windows is having its typical day, reboot). This makes that problem vanish, with proper implementation.

      Or, how about moving from one building on campus to another with your laptop packed up in sleep-mode, breaking it out in your next class ready to go with no hassle?

      It's not necessarily for your literal WWW-on-the-go, but for the hassle of getting there and moving from net to net. Those of us who do have it (I've got my wireless NIC at work) would *love* to see that.

  • all the marbles (Score:1, Offtopic)

    by wiredog ( 43288 )
    Personally, I don't want any of the marbles. Keep stepping on the damn things late at night.
  • What happens when you walk accross the floor of your office and your DHCP server disapears?

    Or maybe a better example would be your intranet mail server disapears because now you're hooked into the Starbucks network?

    Is thought being dedicated to when the user wants to switch providers?

    _Am

  • Frats (Score:3, Funny)

    by SilentChris ( 452960 ) on Friday March 01, 2002 @03:13PM (#3092767) Homepage
    "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...

    • Let me get this right. You would rather snoop around a frat house looking to hop on the net instead of hopping in on the fun? hehehe.

      for the numbers, im in a fraternity and every room is fully hardwired. Plus we have a 802.11 hub running for public access. Works great for sharin MP3 libraries during parties! And the 802.11 draws in TONS of geeks with ipaqs for us to throw water balloons at!! woohoo!

      Roland
      ;)
    • One word: Porn.
    • well, the thing is, jus this past week, a buddy of mine and i had a laptop with the orinoco card, the home-built extended antenna and the appropriate access-point snooping software. we drove down the main street in one of the local college towns. just so happened to be driving by frat houses and local businesses when we found 30 open APs in a 2 mile stretch. we gracefully hopped onto a few and we were browsing internet sites at stop lights up and down the street ;) so yeah, frat houses have WLANs these days it seems...
  • The Nokia D211 [nokia.com] supports 802.11 and GSM/GPRS. I guess it's only lacking Bluetooth.

  • you can do much of this now (Score:5, Informative)

    by The Pim ( 140414 ) on Friday March 01, 2002 @03:37PM (#3092964)
    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 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)
      • 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.

  • Now what?

  • what do they mean with 802.3 *and* fixed ethernet? (Score:3, Insightful)

    by ruud ( 7631 ) on Friday March 01, 2002 @04:08PM (#3093312) Homepage
    802.3 is fixed ethernet, see this page [http].
  • From the article:

    Intel's demo showed Skamania (cute name) hopping between 802.11, 802.3 and fixed Ethernet, ....

    Skamania is the name of a county along Washington State's southern border with Oregon, by the Columbia River.
    Intel has a facility nearby.

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

    --Blair

  • OSX? (Score:3, Informative)

    by BWJones ( 18351 ) on Friday March 01, 2002 @05:10PM (#3093922) Homepage Journal
    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.
  • 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 [slashdot.org]

    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.
  • 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!

  • Nokia Wins (Score:3, Informative)

    by rbeattie ( 43187 ) <russ@russellbeattie.com> on Friday March 01, 2002 @07:54PM (#3095274) Homepage

    Here's a news item at InfoSync [infosync.no] about the new Nokia GSM, GPRS, HSCSD, and WiFi PCMCIA card.

    Pretty freakin' cool. I want one.

    -Russ

  • funny (Score:1, Funny)

    by Anonymous Coward
    Intel's demo showed Skamania (cute name) hopping between 802.11, 802.3 and fixed Ethernet...

    it's not really a cute name...Skamania is the name of a county near Portland (Intel HQ)
    They get all their names from locations here...Wilamette, Tualitin, etc...

    BUT IT'S NOT CUTE!

Slashdot Top Deals

He has not acquired a fortune; the fortune has acquired him. -- Bion

Close