Re: filtering long prefixes
Yup, 206.12/16 is the first area that jumped out at me after noting that many /19s and longer under 206/8 can easily be aggregated under /16s or better. Is Herb Kugel still the IP registrar for Canada? One thing to note right now is that because of the 206.12/16 prefix itself, traffic to subnets of 206.12/16 that aren't heard within SprintLink will get delivered to InternetMCI, which announces the /16 to us. Unless InternetMCI changes its configurations to do similar filtering, they may end up dumping traffic for subnets of 206.12/16 onto the MAE or NAP where they receive it from AS 1239. If they change the configuration, then they will follow the longest prefixes they have, which may be the /16, and deliver the traffic appropriately. At that point, some traffic for non-CA*Net sites will hit CA*Net, and whether it gets delivered or not deepends on local connectivity within Canada. It'll work handily for sites that peer with CA*Net or BCNet (which seems to be the CA*Net member that announces 202.12/16). Such is the price of geographical allocation. Something to be considered by the folks who recommend that approach. Sample traceroutes follow. Sean. P.S.: This raises an interesting point that has been raised in private email to various folks concerned with 206/8: if local aggregation cannot be done, then I suppose it would be easy enough to have some well-connected provider somewhere generate a prefix that is 18 bits long or shorter and deliver to the subnets appropriately. Whether this would be done out of the goodness of that provider's well-connected heart, or for a fee, is an interesting question. - -- : chops.icp.net-MHRC ; traceroute 206.12.101.1 traceroute to 206.12.101.1 (206.12.101.1), 30 hops max, 40 byte packets 1 sl-hrn-1-E5.sprintlink.net (199.0.55.1) 5.006 ms 5.927 ms 4.424 ms 2 sl-fw-8-S3/0-T1.sprintlink.net (144.228.38.61) 44.53 ms 40.226 ms 40.043 ms 3 sl-fw-6-F0/0.sprintlink.net (144.228.30.6) 41.199 ms 39.808 ms 39.474 ms 4 sl-ana-1-H2/0-T3.sprintlink.net (144.228.10.30) 73.9 ms 63.938 ms 63.856 ms 5 sl-ana-2-F0/0.sprintlink.net (144.228.70.2) 67.004 ms 63.935 ms 64.846 ms 6 sl-stk-6-H2/0-T3.sprintlink.net (144.228.10.25) 75.445 ms 115.007 ms 130.088 ms 7 sl-mae-w-H1/0-T3.sprintlink.net (144.228.10.46) 120.591 ms 75.239 ms 74.903 ms 8 mae-west.SanFrancisco.mci.net (198.32.136.12) 106.208 ms 84.766 ms 84.696 ms 9 mae-west.net99.net (198.32.136.16) 91.729 ms 81.322 ms 185.042 ms 10 seattle-1-E0.net99.net (204.157.228.50) 121.525 ms 119.73 ms 118.15 ms 11 cortland/C4-0/T1.net99.net (204.157.10.50) 123.203 ms 123.439 ms 119.942 ms 12 cyber/westnet.cyberstore.ca (199.45.68.6) 136.102 ms 125.274 ms 136.192 ms 13 vanrs001.cyberstore.ca (199.45.66.251) 106.903 ms 115.651 ms 107.9 ms 14 sl-chi-4-S3/2-T1.sprintlink.net (144.228.54.37) 103.651 ms 106.569 ms 106.307 ms 15 sl-chi-6-F0/0.sprintlink.net (144.228.50.6) 153.965 ms 221.79 ms 224.213 ms 16 sl-chi-nap-H1/0-T3.sprintlink.net (144.228.56.10) 106.431 ms 105.126 ms 107.66 ms 17 aads-F.mci.net (198.32.130.227) 111.367 ms 111.693 ms 109.686 ms 18 border2-hssi1-0.Chicago.mci.net (204.70.25.5) 104.894 ms 109.886 ms 106.115 ms 19 core-fddi-1.Chicago.mci.net (204.70.3.81) 136.612 ms 159.454 ms 245.642 ms 20 core1-hssi-2.NorthRoyalton.mci.net (204.70.1.94) 104.756 ms 109.119 ms 109.809 ms [ and goes around in circles, because this prefix doesn't seem to be pointed at anything...] : chops.icp.net-MHRC ; traceroute 206.12.117.1 traceroute to 206.12.117.1 (206.12.117.1), 30 hops max, 40 byte packets 1 sl-hrn-1-E5.sprintlink.net (199.0.55.1) 4.724 ms 2.708 ms 3.42 ms 2 sl-fw-8-S3/0-T1.sprintlink.net (144.228.38.61) 43.637 ms 39.825 ms 39.304 ms 3 sl-fw-6-F0/0.sprintlink.net (144.228.30.6) 52.659 ms 42.551 ms 41.278 ms 4 sl-ana-1-H2/0-T3.sprintlink.net (144.228.10.30) 71.023 ms 64.961 ms 63.816 ms 5 sl-ana-2-F0/0.sprintlink.net (144.228.70.2) 67.1 ms 63.442 ms 64.288 ms 6 sl-stk-6-H2/0-T3.sprintlink.net (144.228.10.25) 76.548 ms 72.84 ms 73.785 ms 7 sl-mae-w-H1/0-T3.sprintlink.net (144.228.10.46) 79.905 ms 75.496 ms 74.788 ms 8 mae-west.SanFrancisco.mci.net (198.32.136.12) 89.111 ms 87.641 ms 217.096 ms 9 t3-0.enss144.t3.nsf.net (192.203.230.253) 107.938 ms 95.99 ms 96.662 ms 10 t3-3.cnss8.San-Francisco.t3.ans.net (140.222.8.4) 99.96 ms 95.953 ms 109.311 ms 11 t3-1.cnss88.Seattle.t3.ans.net (140.222.88.2) 112.245 ms 113.35 ms 111.012 ms 12 cnss93.Seattle.t3.ans.net (140.222.88.197) 127.135 ms 114.558 ms 114.102 ms 13 192.103.70.62 (192.103.70.62) 118.403 ms 122.704 ms 122.746 ms 14 192.197.172.25 (192.197.172.25) 141.079 ms 135.193 ms 130.761 ms 15 206.12.117.98 (206.12.117.98) 227.997 ms 144.418 ms 133.641 ms 16 206.12.117.98 (206.12.117.98) 129.806 ms !H !H [ok] : chops.icp.net-MHRC ; traceroute 206.12.154.1 traceroute to 206.12.154.1 (206.12.154.1), 30 hops max, 40 byte packets 1 sl-hrn-1-E5.sprintlink.net (199.0.55.1) 4.548 ms 3.199 ms 4.35 ms 2 sl-fw-8-S3/0-T1.sprintlink.net (144.228.38.61) 41.879 ms 40.927 ms 41.546 ms 3 sl-fw-6-F0/0.sprintlink.net (144.228.30.6) 46.436 ms 41.338 ms 40.558 ms 4 sl-ana-1-H2/0-T3.sprintlink.net (144.228.10.30) 66.792 ms 64.395 ms 63.976 ms 5 sl-ana-2-F0/0.sprintlink.net (144.228.70.2) 66.02 ms 63.443 ms 64.024 ms 6 sl-stk-6-H2/0-T3.sprintlink.net (144.228.10.25) 75.06 ms 74.22 ms 71.917 ms 7 sl-mae-w-H1/0-T3.sprintlink.net (144.228.10.46) 77.256 ms 76.258 ms 74.408 ms 8 mae-west.SanFrancisco.mci.net (198.32.136.12) 88.265 ms 86.16 ms 85.054 ms 9 border2-hssi2-0.SanFrancisco.mci.net (204.70.33.13) 86.393 ms 87.029 ms 84.88 ms 10 borderx2-fddi0-0.SanFrancisco.mci.net (204.70.3.164) 87.03 ms 84.509 ms 87.846 ms 11 core2-fddi-1.SanFrancisco.mci.net (204.70.158.65) 86.86 ms 87.3 ms 85.111 ms 12 core1-hssi-2.Sacramento.mci.net (204.70.1.146) 89.264 ms 86.404 ms 87.708 ms 13 core-hssi-3.Seattle.mci.net (204.70.1.150) 98.816 ms 90.917 ms 92.826 ms 14 border2-fddi-0.Seattle.mci.net (204.70.3.146) 92.045 ms * * 15 fonorola-internet.Seattle.mci.net (204.70.53.22) 103.243 ms 96.078 ms 104.548 ms 16 IceOnline-GW.vancouver.fONOROLA.net (198.53.80.250) 102.898 ms 103.595 ms 109.361 ms 17 router.iceonline.com (204.191.208.2) 104.766 ms 114.713 ms 107.489 ms 18 cisco.iceonline.com (204.191.208.1) 101.188 ms 102.015 ms 104.648 ms 19 router.iceonline.com (204.191.208.2) 120.781 ms 106.341 ms 102.491 ms 20 cisco.iceonline.com (204.191.208.1) 114.748 ms * 104.974 ms 21 router.iceonline.com (204.191.208.2) 112.519 ms 107.59 ms 110.332 ms [again, not really aimed at anything] SL-CHI-6>trace 206.12.229.1 Type escape sequence to abort. Tracing the route to 206.12.229.1 1 sl-chi-nap-H1/0-T3.sprintlink.net (144.228.56.10) 4 msec 0 msec 0 msec 2 aads-F.mci.net (198.32.130.227) [AS 3561] 28 msec 28 msec 28 msec 3 border2-hssi1-0.Chicago.mci.net (204.70.25.5) [AS 3561] 28 msec 76 msec 212 msec 4 core-fddi-1.Chicago.mci.net (204.70.3.81) [AS 3561] 28 msec 28 msec 24 msec 5 core1-hssi-2.NorthRoyalton.mci.net (204.70.1.94) [AS 3561] 28 msec 28 msec 28 msec 6 core1-hssi-3.WestOrange.mci.net (204.70.1.102) [AS 3561] 28 msec 28 msec 28 msec 7 204.70.1.97 [AS 3561] 28 msec 28 msec 28 msec 8 border2-fddi-0.NewYork.mci.net (204.70.3.18) [AS 3561] 24 msec 28 msec 28 msec 9 sprint-nap.NewYork.mci.net (204.70.45.6) [AS 3561] 64 msec 28 msec 28 msec 10 fd-0.enss218.t3.ans.net (192.157.69.4) 28 msec 24 msec 28 msec 11 t3-3.cnss32.New-York.t3.ans.net (140.222.32.4) [AS 690] 32 msec 32 msec 32 msec 12 t3-0.cnss48.Hartford.t3.ans.net (140.222.48.1) [AS 690] 40 msec 36 msec 40 msec 13 t3-2.cnss43.Cleveland.t3.ans.net (140.222.43.3) [AS 690] 52 msec 52 msec 48 msec 14 t3-1.cnss27.Chicago.t3.ans.net (140.222.27.3) [AS 690] 60 msec 56 msec 56 msec 15 t3-1.cnss96.Denver.t3.ans.net (140.222.96.2) [AS 690] 84 msec 84 msec 84 msec 16 t3-0.cnss88.Seattle.t3.ans.net (140.222.88.1) [AS 690] 100 msec 100 msec 100 msec 17 cnss93.Seattle.t3.ans.net (140.222.88.197) [AS 690] 100 msec 100 msec 96 msec 18 192.103.70.62 [AS 1331] 148 msec 308 msec 152 msec 19 192.197.172.2 [AS 1691] 176 msec 152 msec 128 msec 20 192.197.174.34 [AS 577] 128 msec 120 msec 164 msec 21 pme0.awinc.com (199.175.168.240) [AS 1691] 128 msec 196 msec 184 msec 22 pmeMsync.awinc.com (199.175.169.150) [AS 1691] 240 msec 264 msec 256 msec 23 * * * 24 * * * [thud]
On Thu, 21 Sep 1995, Sean Doran wrote:
P.S.: This raises an interesting point that has been raised in private email to various folks concerned with 206/8: if local aggregation cannot be done, then I suppose it would be easy enough to have some well-connected provider somewhere generate a prefix that is 18 bits long or shorter and deliver to the subnets appropriately. Whether this would be done out of the goodness of that provider's well-connected heart, or for a fee, is an interesting question.
Are you suggesting some sort of exchange point or NAP specifically to break out longer prefixes from shorter prefixes that cannot be topologically aggregated? Would something like this enable people to maintain provider independent addressing (i.e. no renumbering) by merely paying a fee to an exchange point that is well connected and settling for less optimal routing? If this will work in practice, it seems like the perfect tradeoff. On the one hand you must renumber when changing providers but you get optimal routing. On the other hand, you avoid renumbering but you pay a few bucks and have less than optimal routing. Am I missing anything here? Michael Dillon Voice: +1-604-546-8022 Memra Software Inc. Fax: +1-604-542-4130 http://www.memra.com E-mail: michael@memra.com
Are you suggesting some sort of exchange point or NAP specifically to break out longer prefixes from shorter prefixes that cannot be topologically aggregated? Would something like this enable people to maintain provider independent addressing (i.e. no renumbering) by merely paying a fee to an exchange point that is well connected and settling for less optimal routing?
If this will work in practice, it seems like the perfect tradeoff. On the one hand you must renumber when changing providers but you get optimal routing. On the other hand, you avoid renumbering but you pay a few bucks and have less than optimal routing.
Am I missing anything here?
Perhaps a couple of things: - Common transit agreements for all particpants - Single point of attachment, ie you must renumber if you home to another provider or exchange. -- --bill
participants (3)
-
bmanning＠ISI.EDU -
Michael Dillon -
Sean Doran