What's the Frequency, Flik?

The internet is pretty slick. Every attached computer has a unique address sort of like a phone number. (Sometimes, entire sub-networks lurk behind a single address through the miracles of IP and routing and such, just as entire switchboards of phones may lie behind the phone number of a main switchboard, but that's another story.) Continue reading….


Last 5 posts by David Byron


  1. says

    Science: "Here's a phial of info about how packing works. Go to the monocot. Go to the conch.
    John David Galt: "So?"

    Science: "Behold these navigational facilities, and those birdbrains."
    John David Galt: "So?"

    Science: "Attend! An automaton!"
    John David Galt: "So?"

    Science: "Here. Throw this chicken."
    John David Galt: "I would prefer not to."

  2. AlphaCentauri says

    Everyone else calls "Baba O'Reilly" "Teenage Wasteland," but my kids call it "Out here in the Fields," because they were so impressed by it in A Bugs Life.

  3. Joe Pullen says

    I would like to find a way to blame TCP flow control for the speed at which money leaves our bank account – it would save a lot of arguments with the wife.

  4. En Passant says

    Science: "Here. Throw this chicken."
    John David Galt: "I would prefer not to."

    Reflect on the tragedy of the unfortunate Adams and the still more unfortunate Colt in the solitary office of the latter. Perhaps recall the divine injunction: "A new commandment give I unto you, that ye love one another."

    No man that ever I heard of, ever committed a diabolical murder for sweet charity's sake. Mere self-interest, then, if no better motive can be enlisted, should, especially with high-tempered men, prompt all beings to charity and philanthropy.

  5. Grifter says


    That bit reads almost familiar, is it paraphrased from something?

    You made me SWLOL (snort with laughter, out loud).

  6. James Pollock says

    While you were praising the "efficiency" of TCP's "sliding window feature", you missed the significance of it. There are two (main) transport protocols used on the Internet, TCP and UDP. Both break transmissions into packets, which are sent one after the other as quickly as the network will allow (it is a different feature that actually slows things down if the router is congested).
    TCP is more inefficient that UDP, because it has a feature that UDP lacks, which is the "ACK' message. UDP works like normal mail… you put your packet in the mail, and the system does its best to route that packet to its destination, and it almost always works. TCP is more like registered mail… the receiver acknowledges receipt of each packet. This allows the sender to be certain that each packet has been received (and, act accordingly, typically by re-sending the lost packet).
    What the "sliding window" feature does is assess the reliability of network delivery, and allows the system to send acknowledgements less frequently than every packet. (If you send an ACK for every packet, then 50% of all the packets carried on your network are ACK messages, for an efficiency of 50%. The sliding window tells the sender to send 2, 4, 8 or even 16 packets before pausing to make sure an ACK has been received, thus reducing the number of ACK messages that need to be sent (but possibly increasing the number of packets that need to be resent if one goes missing.) This increases the efficiency of transmission relative to 1:1 ACK messages, but is not as efficient as UDP, which sends no ACK messages at all.
    TCP/IP is a bit of a misnomer, as not all IP messages are TCP (not by a long shot… depending on the type of information transmitted, the percentage of TCP traffic may be under 1%.
    Note that TCP/IP is hardware independent, and there is, in fact, an official TCP/IP standard that details how TCP/IP would work with carrier pigeons as network media.

  7. says

    @James Pollock

    While you were praising the "efficiency" of TCP's "sliding window feature", you missed the significance of it….
    …TCP is more inefficient that UDP….
    …not as efficient as UDP, which sends no ACK messages at all.

    While you were explaining differences between TCP and UDP, you seem to have missed the significance of my praise, which had nothing to do with how TCP stands relative to UDP.

    My interest was in protocols that guarantee delivery and respond appropriately to meta-info concerning success in that undertaking. Specifically, I drew attention to two of these: TCP and HAFB (harvester ant foraging behavior).

    UDP, in contrast, guarantees nothing. (Hence all the mildly amusing jokes like the one I retweeted last week.) That puts UDP outside the scope of what I was describing.

    Thanks for your comments about ack rates. They illustrate TCP's lovely efficiency.

  8. Karasu says

    Well, the obvious insect-computer I can think of is Hex in the discworld, which actually uses ants.

    (And Cheese)

    (For the mouse, of course)

  9. James Pollock says

    Well, TCP is nowhere near the pinnacle of efficiency amongst guaranteed-delivery protocols, either. There was considerable progress (and much flame-warring) over the topic of the best protocol back in the 90's. TCP most resembles XMODEM in it's design… none of the partisans (ZMODEM vs. Kermit vs. Punter as examples of the loudest partisans, if I recall).
    Apparently, ant technology hasn't spread worldwide; the nests near my house have not yet discovered the timeout, as no matter how many of the little invaders I kill, they keep coming in the house. In fact, household odiferous ants have exactly the opposite reaction, as a crushed ant releases a scent that triggers a flood.

  10. says

    @James Pollock

    Thanks for your input. Indeed, TCP isn't tops. However, it is the protocol to which the researchers discovered a natural fourmilicious analog. The ants, man! Think of the ants! That's the link under discussion; nothing else.

    The deeper issue is knowing one's audience and its interests. Epitomizing protocol specifications and segment definitions? Wide of the mark. Linking a high level cartoon of the transport layer to the unexpected behavior of foraging insects? A bit closer to home. Ken mocking feckless would-be gainsayers with snort-related threats and pudendal buffoonery? Right On Target!

    I recall using ZModem back in the day when its error correction seemed to put it light years ahead of Kermit. We used modems back then, and most of the web was summarized in Scott Yanoff's circular. ;)

    Speaking of snorting, I hear yellowjackets also seek vengeance on their odiferous, squashed brethren. These stinky kinsman redeemers are indeed odious and feral.

  11. Gavin says

    I'd note that the packets are also numbered so that if disruption occurs they don't have to send all packets over again, just the ones that didn't get there. Learning about frames and packets is certainly interesting.

    I like how science is looking at the animal kingdom and learning where it can, like that mold that shows the most efficient ways to design transit systems by the way the mold grows from one food source to another and then links it back to other parts.

  12. Josh C says

    That's really neat, and a nice analogy. It does look like it reduces to "Harvester ants use closed-loop positive feedback in their foraging behavior." That's interesting, but doesn't seem revolutionary. Am I missing something?

  13. Alex Ponebshek says

    Good analogy, but a technical correction: TCP does *not* regulate speed based on response times, only packets dropped entirely. Even if packets are taking longer and longer to round-trip, TCP keeps speeding up until packets are actually being lost.

  14. wgering says

    "Popehat: come for the discussion of ant-based connection protocols, stay for the pudendal buffoonery."

    Yep, sounds accurate.

  15. George Martin says

    James Pollock said:
    Note that TCP/IP is hardware independent, and there is, in fact, an official TCP/IP standard that details how TCP/IP would work with carrier pigeons as network media.

    That was an April 1st RFC (Request For Comment). The IETF (Internet Engineering Task Force) has a tradition of publishing humorous gag RFCs on April 1st. That particular one was: D. Waitzman (1 April 1999). IP over Avian Carriers with Quality of Service. RFC 2549. Updates RFC 1149, listed above. (see IP over Avian Carriers) That was one of the ones for 1999. If you use Google to search for RFC 2549, you will find it. Other April 1st RFcs for that year were:

    S. Glassman, M. Manasse, J. Mogul (1 April 1999). Y10K and Beyond. RFC 2550.


    S. Bradner (1 April 1999). The Roman Standards Process — Revision III. RFC 2551.


  16. George Martin says

    Oops, RFC 1149 in 1990 was the original one. You can get a list of all of the April 1st RFCs here: http://en.wikipedia.org/wiki/April_1st_RFC



    RFC 1149 starts with:

    A Standard for the Transmission of IP Datagrams on Avian Carriers

    Status of this Memo

    This memo describes an experimental method for the encapsulation of
    IP datagrams in avian carriers. This specification is primarily
    useful in Metropolitan Area Networks. This is an experimental, not
    recommended standard. Distribution of this memo is unlimited.

    Overview and Rational

    Avian carriers can provide high delay, low throughput, and low
    altitude service. The connection topology is limited to a single
    point-to-point path for each carrier, used with standard carriers,
    but many carriers can be used without significant interference with
    each other, outside of early spring. This is because of the 3D ether
    space available to the carriers, in contrast to the 1D ether used by
    IEEE802.3. The carriers have an intrinsic collision avoidance
    system, which increases availability. Unlike some network
    technologies, such as packet radio, communication is not limited to
    line-of-sight distance. Connection oriented service is available in
    some cities, usually based upon a central hub topology.

  17. Joe says

    The bumblebee (genus Bombus) with a brain the size of a pinhead, may be smarter than humans and computers in some respects. In the game of chess, humans and computers will often come to a draw. There is one mathematical puzzle, however, where apparently neither would stand a chance against this fuzzy hymenopteran.

    The travelling salesman problem.

    If you are a salesperson and you must visit a number of cities and businesses to sell your solution, the problem before you is how to hit every city and location at least once and to travel the shortest possible distance in the process. A concept that to this day that continues to elude my travel booking tool and my assistant.

    Computers solve this problem the hard way by calculating all the possible routes and distances before arriving at a solution, a process that could take hours depending on the complexity of the problem.

    However, apparently researchers have discovered that bumblebees solve this problem all the time. Given a selection of pollen-rich flowers, the bees don't hit the flowers in order of discovery, but rather take a broader approach and automatically find the shortest path to land on all the flowers at least once.

    Of course part of the problem may be because we have physicaconstraints in our model that the bumblebee doesn’t such as roads, available airline flights, airport locations, etc. so unlike the bumblebee we humans can’t plot a straight line from one appointment to the next for maximum efficiency.