TELECOM Digest Sat, 10 Oct 92 13:58:00 CDT Volume 12 : Issue 771 Index To This Issue: Moderator: Patrick A. Townson Re: Comments on the Multimedia Article (James Hanlon) Re: More LATA Nuttiness (David Esan) Re: LD Transmission Quality Comparison (Andy Sherman) ---------------------------------------------------------------------- From: tcubed@ddsw1.mcs.com (James Hanlon) Subject: Re: Comments on the Multimedia Article Date: Sat, 10 Oct 1992 16:51:45 GMT Organization: ddsw1.MCS.COM Contributor, Chicago, IL FZC@CU.NIH.GOV (Paul Robinson) writes: > The problem we have is that we have copper wire (or that cheap > substitute I can't remember the name for, DXC, DGC or something) which > can't handle large bandwidth. When people switched from outhouses to All the above is true enough, but I can get a 500Mhz bandwidth pipe to my house tomorrow for ten dollars (sometimes less during promotions). It's coax, but it's 50,000X the bandwidth of tip-ring, and 300X that of T1. The issue is not "copper is slow, fiber is fast", it's that telco thinking invariably excludes options that don't involve sending billions of dollars to them to Rewire America. > servicing this demand, the only answer we have is to tear out the > wires and put fiber in. We will buy the capacity as we want it. Just > have the capacity there and have it low enough cost to allow anyone > who can afford a phone now to get in on this stuff. How much is an RF modem, bandwidth of 1MHz or so? 50 bucks? How complex are RF multiplexors? Can you go RF to T-1 or T-3? (MCI seems to). > Note to anyone working for a telephone company: Do us all a favor and > oversupply capacity! You should build for a factor of one hundred There is so much excess capacity today that moneymaking organizations routinely send crude text messages (required bandwidth: roughly 300 baud) down 6MHz-wide channels 24 hours a day. They know they have bandwidth to burn. >> Many feel that for the market to take off, the country must have >> a new communications network capable of opening a video circuit >> between any given point and another -- just as today's telephone >> network does for calls. > "Video Dial Tone". You can get it now, it's just too expensive. What Or, by changing our perspective, we can merely alter an existing video communications network from unidirectional to bidirectional capability. > terms of what people use the space for and instead simply allocate > them a block of frequency. If they buy 6MHZ space, they can do FCFMV > or they can transmit 500 simultaneous telephone calls. What is > expensive is the switching equipment. But it can be done. Just how expensive are video matrix switches? Who makes them? > FCFMV telephone calls at $1 a minute. Charge someone $300 to install > his line on a finance basis, say over a ten month period. Charge $100 > a month for the service. It is currently about $10/$25 for coax-to-the-home; 300/100 is a tough sell. >> Highly complex software also will be needed to control and >> manage new networks capable of carrying large amounts of digital >> data. > I believe this to be true; it therefore behooves all of us that the > systems be done small and simple; it makes failures less dangerous. The software to allocate, track usage of, and bill for, 50,000X chunks of bandwidth-time, is not 50,000X more complex than that for X chunks. Any software developer that quoted me 2X, in fact, would be in for a cross-examination of his motives. > To reuse an overworked quote from a movie I've never seen, "If you > build it, they will come." If the capacity is there, people will find > ways to use it that the inventors would never even dream of. When the A duchess once said: "You can never have too much bandwidth." > We need new ideas and we need to think of new ways to use the > technology and the capacity we have. Some ideas: RBOCs forbidden by law to subsidize the rebuilding of the Venezuelan phone system, or to dream up new, expensive ways of delivering video to my home when I already have an old, cheap way. Jim Hanlon tcubed@ddsw1.mcs.com ------------------------------ From: de@moscom.com (David Esan) Subject: Re: More LATA Nuttiness Date: 8 Oct 92 19:29:44 GMT Organization: Moscom Corp., Pittsford NY In article johnl@iecc.cambridge.ma.us (John R. Levine) writes: > While we're looking at pointless LATA statistics, the Atlantic City > LATA appears to be the smallest one in the country based on the number > of prefixes, of which it only has 64, and probably number of > subscribers. Are there any other smaller ones? It may also be the > smallest in land area, since it takes only an hour on the Parkway to > drive from Barnegat at the north end to Cape May at the south end. Pointless V&H statistics are my business. :-). Attached are a list of LATAs and the number of exchanges in each. It is possible that there are minor errors here, since this information is transcribed from a tape to my database, and in doing 50,000+ of these some errors will creep in. But, it should be close. The smallest LATAs have just one entry: 999 is in NPA 504 and is labelled as "OFF SHORE". I assume that it is the offshore drilling platforms. 930 is EPPES FORK, VA. Anyone know anything about it? 921 is FISHERS ISLAND, NY. One exchange on one island. 981 is in Utah. It includes three exchanges, for HALCHITA, MONUMENT VALLEY, and MONTEZUMA CREEK-ANETH. My guess is a small independant company. The largest is 730, the monster that takes in a large part of southern California and a piece of Arizona. A complete list of NPA/LATA combinations is below the count list. LATA NXX LATA NXX LATA NXX LATA NXX LATA NXX LATA NXX LATA NXX 730 2405 234 435 538 275 252 196 546 147 374 100 376 65 830 1980 632 431 834 272 230 192 478 147 953 94 977 64 460 1889 628 417 134 266 634 191 133 146 828 92 960 61 132 1856 324 414 848 262 344 189 668 144 624 92 973 57 854 1696 832 412 350 257 728 183 426 144 436 90 850 57 358 1277 952 409 326 257 352 182 626 142 370 90 736 57 722 1198 348 401 232 257 638 181 440 141 526 89 550 57 858 1154 732 388 676 250 124 181 130 139 432 87 826 54 238 1053 532 388 354 249 738 179 368 137 362 86 364 54 552 987 528 382 140 248 846 178 544 135 956 85 521 52 438 924 636 378 652 242 670 177 474 135 740 85 428 51 458 894 356 369 122 241 254 175 488 133 240 85 938 48 236 822 482 364 450 237 464 174 256 132 366 82 824 48 128 791 844 353 490 236 630 173 126 132 322 82 570 45 560 777 640 352 454 236 568 172 564 127 446 81 484 45 224 777 939 351 468 233 244 171 338 126 548 79 456 45 228 765 660 350 226 231 648 170 724 122 961 78 937 40 340 686 120 347 852 230 558 166 342 120 562 78 856 39 520 672 452 340 466 228 658 165 242 120 530 78 932 36 566 607 644 335 448 228 654 165 444 119 734 77 980 24 674 586 726 323 222 223 650 165 334 117 330 77 928 24 842 569 534 320 462 221 430 165 556 115 246 76 963 22 524 563 664 319 646 215 325 162 346 114 420 75 862 19 840 550 470 309 248 210 332 161 492 110 360 72 927 16 656 547 320 305 958 207 721 158 442 110 976 70 822 11 920 496 974 302 424 206 138 152 949 109 250 70 929 10 536 492 422 296 522 205 923 150 542 109 220 69 981 3 666 456 476 293 328 205 434 149 480 108 978 67 999 1 860 450 136 293 486 204 951 147 477 107 924 66 930 1 672 442 922 283 635 203 720 147 472 107 540 66 921 1 336 437 620 278 820 200 554 147 This is a list of LATAs and the NPAs that they include. NPAs may contain more than one LATA, and LATAs may contain more than one NPA. LATA NPA LATA NPA LATA NPA LATA NPA LATA NPA LATA NPA LATA NPA 120 207 250 919 376 217 474 606 538 918 636 605 670 503 122 603 252 804 420 704 474 615 540 505 636 701 670 916 124 802 252 919 422 704 474 704 540 915 638 406 672 206 126 413 254 304 422 803 476 205 542 915 638 605 672 503 128 508 254 703 422 919 477 205 544 806 638 701 672 509 128 617 256 304 424 919 477 601 546 405 640 307 674 206 130 401 256 412 426 919 478 205 546 505 640 308 674 509 132 203 320 216 428 803 478 912 546 719 640 402 676 208 132 212 322 216 428 919 480 205 546 806 640 406 676 503 132 516 322 412 430 704 480 601 548 817 640 507 676 509 132 718 324 614 430 803 480 904 550 915 640 605 720 503 132 914 325 216 432 803 482 205 552 214 640 701 720 702 132 917 326 313 434 803 482 318 552 817 640 712 720 916 133 717 326 317 436 803 482 504 552 903 644 308 721 702 133 914 326 419 438 205 482 601 554 501 644 402 722 408 134 413 328 513 438 404 482 901 554 903 644 605 722 415 134 518 330 812 438 706 484 504 556 817 644 712 722 510 136 315 332 219 438 912 484 601 558 512 644 816 722 707 136 607 334 219 440 803 486 318 560 409 646 303 724 916 138 607 334 419 440 912 486 501 560 713 646 307 726 916 138 717 336 217 442 404 486 903 562 409 646 308 728 209 140 716 336 219 442 706 488 318 564 210 646 605 730 213 140 814 336 317 442 803 490 504 564 512 646 913 730 310 220 609 338 812 442 912 490 601 566 210 648 208 730 602 222 609 340 313 444 912 492 504 566 512 648 406 730 619 224 201 340 517 446 912 520 314 568 210 650 307 730 714 224 609 342 715 448 205 520 618 568 512 650 406 730 805 224 908 342 906 448 904 521 314 570 409 650 701 730 818 226 215 344 517 450 904 522 316 620 319 652 208 730 909 226 717 346 517 450 912 522 417 620 507 652 307 732 619 226 814 348 517 452 904 522 501 620 515 652 503 734 805 228 215 348 616 454 904 522 918 620 605 652 702 736 408 228 302 350 414 456 904 524 712 620 712 652 801 738 209 230 814 350 715 458 407 524 816 624 218 654 208 740 805 232 215 352 612 458 904 524 913 624 715 654 303 820 809 232 717 352 715 460 305 526 417 626 218 654 307 822 809 232 814 354 608 460 407 526 501 626 605 654 308 824 809 232 908 354 815 462 502 526 918 626 612 654 406 826 809 234 412 356 414 462 606 528 314 628 612 654 605 828 809 236 202 356 815 462 812 528 501 630 402 654 801 830 809 236 301 358 219 464 502 528 901 630 507 656 303 832 907 236 410 358 312 464 615 528 918 630 605 656 308 834 808 236 703 358 414 464 901 530 318 630 712 656 719 840 403 238 301 358 708 466 606 530 501 632 319 656 801 842 604 238 410 358 815 466 615 532 316 632 507 658 719 844 204 240 301 360 608 468 502 532 405 632 515 660 303 846 506 240 304 360 815 468 601 532 417 632 712 660 602 848 709 240 717 362 618 468 901 532 719 632 816 660 702 850 403 240 814 364 815 470 205 532 918 634 309 660 801 850 819 242 301 366 217 470 502 534 308 634 319 664 505 852 902 242 410 366 309 470 615 534 402 634 608 664 915 854 416 244 615 366 815 472 205 534 719 634 815 666 602 854 519 244 703 368 309 472 404 534 913 634 816 666 619 854 613 246 703 368 815 472 615 536 405 635 319 666 801 854 705 248 804 370 217 472 704 536 806 635 507 668 505 854 807 250 804 374 217 472 706 538 316 636 218 668 602 856 902 858 416 920 203 923 614 937 317 952 813 960 208 976 217 858 418 921 516 924 814 937 513 953 904 960 406 977 217 858 514 922 513 927 703 938 217 956 615 960 509 977 309 858 519 922 606 928 804 938 812 956 703 961 915 978 618 858 613 922 812 929 703 939 813 958 402 963 406 980 602 858 819 923 216 930 804 949 919 958 712 973 619 981 801 860 306 923 419 932 304 951 919 958 913 974 716 999 504 862 403 923 513 932 703 David Esan de@moscom.com ------------------------------ Date: Fri, 9 Oct 92 09:32:01 EDT From: andys@internet.sbi.com (Andy Sherman) Subject: Re: LD Transmission Quality Comparison On 6 Oct 92 06:06:36 GMT, gerg@netcom.com (Greg Andrews) said: > john@zygot.ati.com recently wrote: >> Every so often, I find that a better rate can be had from MCI or from >> Sprint by using some plan or another. Each time I have started routing >> calls over anyone other than AT&T, all hell breaks loose. I find >> failed conversations aplenty. UUCP sends me messages right and left >> peppered with 'LOGIN FAILED' or 'CONVERSATION FAILED' or 'LOST LINE'. >> Frequently, throughput falls from 1400 CPS to something like 300-400 >> CPS. And invariably, my overall bill goes WAY up. Why? First there is >> the lower throughput. Then there are the billing errors. > I can't speak to the billing errors, but the modem symptoms you > describe seem to this Telebit technician like a well-known interaction > between Telebit's PEP modulation and the echo cancellers used my MCI, > Sprint, and others. > Rather than poor quality, the problem was being caused by the echo > cancellers interfering with the modem transmissions. When the modems > stopped sending data to train themselves to the line conditions, the > echo cancellers would turn themselves off. The difference in the > modem 'conversation' between data transfer mode and training mode was > enough for the echo cancellers to change their behavior. The modems > saw an undisturbed line when they trained, so they couldn't adapt. > Why didn't AT&T lines do this? They used different brands of echo > cancellers. (Perhaps because their network hadn't used fiber optics > until very recently?) First off, AT&T has had *some* optical fiber in the network for some time. But the particular medium of digital transmission should matter not one whit for how to do echo cancellation. The propagation delays are the same for all terrestrial links. Yes AT&T uses an echo cancellation scheme that is different from that used by the other carriers. Wanna take a guess as to which brand? Most of the AT&T long distance network is switched by #4 ESS(R) switches, which have integral echo cancellation on all trunks that are greater than some given distance. (Some one of my former colleagues can tell us if that number is proprietary). These echo cancellers automatically drop out as soon as a modem guard tone is detected. That's why none of the modems had a problem on AT&T. (It was once alleged in this forum, by some dweeb or another, that AT&T never had a modem problem because AT&T didn't do echo cancellation, but that was B.S.) > Telebit worked with the engineers from a couple of the echo canceller > manufacturers for several months. Eventually a solution was found > where the modems would be able to keep the echo cancellers disabled. > The modem firmware was updated to add the 'echo canceller mods' > starting with version 7.00 (BC7.00, GE7.00, and GF7.00, though the > T1000 uses FA2.10). Had the echo cancellers done the right thing to begin with, Telebit would never have had the problem. > The point I've been trying to make is that your connection troubles > might have been caused by this interaction and not by the quality of > the LD carrier. It would be unfair to criticize the LD carrier > because the original PEP modems couldn't keep their echo cancellers > off the line. Really? I consider the inability of echo cancellers to detect a modem to be a quality issue. It is not a quality, customer driven solution to force customers to modify their CPE because the network infrastructure is of inferior quality. Remember that there was one carrier whose infrastructure never had the problem and whose network could and can deal with the unmodified Telebit modems. The problem was not that the PEP modems couldn't turn off the echo cancellers, the problem was that the echo cancellers couldn't (and can't) detect the PEP modem without forcing the modem manufacturer to add non-standard stuff. You don't consider that a quality metric? I do. Besides all that, every now and then somebody posts a throughput test for the big three carriers, and AT&T almost always wins. That also is John Higdon's experience, but I don't know if he's ever posted the numbers or any $$/KB_transferred figures derived from them. Needless to say, I speak for neither my former nor current employers. Andy Sherman Salomon Inc - Unix Systems Support - Rutherford, NJ (201) 896-7018 - andys@sbi.com or asherman@sbi.com "These opinions are mine, all *MINE*. My employer can't have them." ------------------------------ End of TELECOM Digest V12 #771 ******************************