IP: CableLabs trying stop NAT and "unpaid" multiple IP addresses

[David Farber <dave () farber net>]

> Sender: rberger () imap ultradevices com
> Date: Tue, 27 Nov 2001 15:11:54 -0800
> From: "Robert J. Berger" <rberger () ultradevices com>
>
> The CAT and the NAT
> The woes of wireless hubs
>
> By Leslie Ellis, Technology Analyst
> http://www.cedmagazine.com/ced/2001/1101/11d.htm
>
> The good news is, the dishonest people who know how to do it are already 
> doing it, but
> they?re a slender fraction of today?s installed cable modem base.
>
> The bad news is, there?s nothing you can do about it. At least, not
> anytime soon.
>
> Such is the case with some wireless home networking hubs, which use a
> form of over-the-counter routing known as ?network address
> translation,? or NAT.
>
> Just as, to some, ?take one? always means ?take three,? and
> ?contribution appreciated?  always means ?free,? so can the bandwidth
> of a legal cable modem subscription become wirelessly shared among
> neighbors. It can be shared omnidirectionally, as it turns out, for
> about 300 feet-the range of wireless hubs based on the 802.11b home
> networking specification.
>
>                 This probably doesn?t come as a big surprise to CED?s
> readers. The NAT conundrum is reminiscent of the early days of pay
> television-when descrambler boxes presumed for use on additional TVs
> within a subscribing household mysteriously found their way into
> someone else?s house- someone who wasn?t paying for HBO or Showtime or
> a similar premium service.
>
>                 What?s different between the two types of thievery,
> technologists say, is that descrambler boxes of yore, and particularly
> those sold for additional outlets, could be (and were, once the
> debauchery was discovered) provided at an additional, and
> undiscounted, rental fee.
>
> But NAT, because it is invisible to the cable modem, can theoretically
> continue its stealth stride into cable networks, undetected. The only
> remedy-at least until CableLabs? ?CableHome?  effort releases its
> antidote, known as Cable Address Translator, or CAT-is to trust in
> humanity?s application of right and wrong: ??Tis a sin, to steal a
> pin, as we, all of us, used to be informed in the nursery,? as the
> 1875 proverb goes. Or, in this case, ?tis a sin, to steal bandwidth,
> as we, all of us, learned in the workplace.
>
>
>
>
> What?s the value of the stolen goods? Revenues associated with
> additional IP addresses, for one. Let?s say one in 10 of the 5 million
> U.S. cable modem subscribers are usurping IP addresses without paying
> the $4.95 per month fee that?s typically charged (beyond a
> pre-specified limit, which varies MSO to MSO.) Right off that bat,
> that?s just shy of $30 million lost, annually.
>
> Under NAT?s hat Network address translation started out innocently
> enough. Back in 1993, the World Wide Web consisted of just a handful
> of graphically-oriented destinations-what we now call ?Web sites?-and
> a group of data-minded, engineering members of the Internet
> Engineering Task Force got worried.
>
> There was no question that the Internet, and its TCP/IP-based
> underpinnings, would get big, the engineers mused. And when it did,
> how on earth would the distribution of zillions of Internet Protocol
> (IP) addresses be managed, let alone scaled?
>
> At its inception, NAT was viewed as a way to ward off a looming
> shortage of IP addresses.
>
> The only answer, the engineers decided, was some form of hierarchical
> distribution, handled transparently at drop-off points. Something that
> could partition IP addresses for multiple, simultaneous use by devices
> ?lower? in the hierarchy. The drop-off point, though, was imagined
> more as a standard LAN than a home network.
>
> NAT was also meant to simplify matters. Specifically, it was intended
> to simplify small business networks, so that the
> technologically-challenged small business owner could install and run
> IP address-sharing on a run-of-the-mill local area network, without
> having to go to night school to acquire a data communications
> doctorate.
>
> Who knew?  At the time, eight or so years ago, no one had fully
> imagined that regular, everyday consumers would someday own multiple
> PCs, and would want a way to hook them together.  Nor had anyone fully
> imagined that a cable or DSL modem could be hooked into a residential
> network, and its IP address resource shared. (The Internet, mostly a
> bulletin board at the time, topped out at 9600 baud back then.) And
> certainly, no one had fully imagined that the resources shared by a
> single, wirelessly-networked residence would also be shared among
> other devices, at other residences, within 300 feet.
>
> What happened is the inverse of the old Ivory soap story: Upon going
> to lunch one day, somebody forgot to turn off the mixer. An ordinary
> accident. The result was soap that floated: A good, marketable,
> accidental discovery. NAT turns out to accidentally be a bad,
> unmarketable discovery. Its intentions were good; but one portion of
> its reality is clearly not so good.
>
> Reality, right now, is walking into a computer store and buying a
> $100-ish wireless home networking hub, with built-in NAT. These days,
> NAT is a feature differentiator for home networking hub
> vendors. Suppliers describe the benefits of NAT in terms of modifying
> IP and transport headers to provide transparent routing to end hosts,
> which are trying to communicate from disparate address realms.
>
> That means the NAT-based home networking hubs can create secret
> domains, behind and invisible to the cable or DSL modem. The IP
> address intended for the cable modem is partitioned into re-usable
> addresses, transparently, through software routing mechanisms.  The
> result is a sort of private, sub-network running datagrams to and from
> invisible end devices (the PCs in neighboring homes).
>
> How it works A home-networking hub is a fairly unglamorous,
> rectangular box with lights on the front that correspond to what?s
> connected. On the back there are eight or so receptacles for telephone
> wires, or thicker ?category-5? wires, for the items being
> linked-laptops, PCs, printers, the cable or DSL modem. Ditto for
> wireless hubs, except they use an antenna to send and receive
> datagrams from other antennas; those antennas are attached to the
> things to be connected.
>
> Put simply, NAT works by securing an IP address via the cable modem
> and the IP-address server (the ?DHCP,? or Dynamic Host Control
> Protocol server). NAT software resident inside the wireless hub
> handles the parsing of the IP address, as well as back-and-forth
> conversations with all connected devices. Notably, not all home
> networking hubs include NAT; in general, less-expensive $50-ish hubs
> don?t have it.
>
> Tactically, it works like this: Anyone with a networkable computer, an
> 802.11b antenna and receiver, and approval from the master PC
> connected to a wireless hub, can sit, invisibly, ?behind? the NAT, and
> share the throughput of the cable modem attached ?ahead of? the NAT.
>
> For example: Neighbor Bob buys cable modem service and a wireless home
> network. Neighbors Carol, Ted and Alice don?t buy cable modem service,
> but they go out and buy antennas compatible with Neighbor Bob?s
> wireless network. Everybody agrees to share Neighbor Bob?s
> connection. So what if it?s not quite as zippy? It?s free. Neighbor
> Bob?s cable modem, and Neighbor Bob?s broadband service provider,
> never know its throughput is being shared. They, sadly, can?t see a
> thing past the NAT.
>
> NAT also raises issues for forthcoming cable-delivered home-networking
> services. A crucial part of the success or failure of broadband home
> networks will be the set-up and ongoing care processes used to link
> PCs and consumer-electronics gear.
>
> With NAT-based hubs, cable providers won?t be able to see into all
> connected devices-making remote troubleshooting difficult-because,
> again, the NAT is speaking for all connected devices. It?s the data
> communications equivalent of, ?You wanna talk to her, you go through
> me?-except you don?t even know she?s there to talk.
>
> Cable?s CAT in the Hat MSO technologists involved with home networking
> are already sorely aware of NAT?s blemishes. In addition to what?s
> already been noted, technologists grumble that NAT hubs vary in
> operation from one supplier to the next, making uniform maintenance a
> nightmare.
>
> Gladly, there?s a remedy in the works. It?s coming from CableHome, the
> CableLabs project specifically focused on specifications for cable
> home networks.
>
> Mercifully, MSO and CableLabs technologists involved in the project
> are hard at work on a cable-friendly form of IP-address distribution
> to connected devices. They?re unofficially calling it ?CAT,? for
> ?Cable Address Translator.? In future CableHome-based networks, CAT
> software could go one step further, essentially saying, ?Pardon, NAT,
> but what?s that behind you?? Or, CAT could replace NAT altogether, at
> least in equipment hand-picked by MSOs for home-network service
> packages.
>
> At the very least, cable MSOs involved in CableHome want a counting
> mechanism, with parameters set by them, that specifies a maximum
> number of connected devices. Until then, all indicators point to
> DOCSIS 1.1, which includes methods to monitor bandwidth consumption
> (how much is used per customer) and speed (who?s bursting at what
> rates).
>
> Unquestionably, the ability to ?see? connected devices makes
> troubleshooting and customer care somewhat easier. It will also put
> some enforceability into what, today, is an unintentional honor
> system, in terms of IP address and resultant bandwidth sharing.
>
> Perhaps Theodore Geisel, Dr. Seuss? inventor, had the best advice,
> albeit not from The Cat in the Hat: ?You have brains in your head. You
> have feet in your shoes. You can steer yourself any direction you
> choose.?
>
> E-mail: Ellis299 () aol com
> --
> Robert J. Berger - UltraDevices, Inc.
> 257 Castro Street, Suite 223 Mt. View CA. 94041
> Voice: 650-237-0334 VoiceMail: 408-882-4755 Fax: 408-490-2868
> Email: rberger () ultradevices com  http://www.ultradevices.com


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