Will a single /27 get fully routed these days?

John R. Levine johnl at iecc.com
Mon Jan 27 02:02:28 UTC 2014

>> 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.

John Levine, johnl at 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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