nanog mailing list archives

Re: Will a single /27 get fully routed these days?


From: "John R. Levine" <johnl () iecc com>
Date: 26 Jan 2014 21:02:28 -0500

and we'll see endless arguments between buyers of IPv4 space and ARIN, when ARIN refuses the updates to the address registry.

This would be "bad". I can think of few more effective ways of destroying the RIR system than by refusing to update the address registry.

I completely agree, but there are other places to argue about that particular question.

I don't see any reason for the people who run defaultless routers all over the world to change the /24 rule.

So IIUC, the theory goes that ISPs will be encouraged by their customers (upon pain of those customers becoming former customers) to announce their long prefixes, even though the ISPs will say "but nobody will listen". ...

Well, maybe. My vision is that the ISP calls up their upstreams and/or peers, some say OK, many say, sorry, unless you're offering to fund some very expen$ive router upgrade$, we can't do it. Even the ones who say OK will have little incentive to push their peers, so there will be flaky islands of routing.

The customer will continue to whine, of course, at which point the ISP has the bright idea to do some traceroutes and figure out which ISP announces the enclosing block. They call up that ISP and ask, what would you charge to tunnel that traffic back to us? The other ISP, who's been throwing away the /27's traffic anyway, quotes a reasonable price, and now we have universal reachability, accompanied by endless route flaps and very inconsistent performance.

The customer continues to whine about performance. Our ISP says, ah, you need our Preferred Thoughput Upgrade Innovation (PTUI), available at modest extra cost. The extra cost, of course, it what it costs to buy a /24 and get the customer into the real routing table.

Regards,
John Levine, johnl () iecc com, Primary Perpetrator of "The Internet for Dummies",
Please consider the environment before reading this e-mail. http://jl.ly

PS: In the sequel, some ill-advised LIR starts handing out /27s with no enclosing block, so a bunch of little ISPs get into a flapping contest to see who's going to announce the /24 and get everyone else to pay them to tunnel the traffic back.


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