[arin-ppml] Rationale for /22

Joel Jaeggli joelja at bogus.com
Tue Jul 28 10:32:56 EDT 2009

William Herrin wrote:
> On Tue, Jul 28, 2009 at 4:43 AM, Joel Jaeggli<joelja at bogus.com> wrote:
>> Bill Darte wrote:
>>> Every effort to lower minimum allocations throughout the years has met
>>> with resistance.  Each successful policy managed a 'bit at a time' to
>>> ensure 'nothing bad happened'....
>> Realistically is it in the interest of a prospective multihomer to a
>> recieve a prefix that's likely longer than the one they already use?
> Joel,
> I don't follow your logic here. Why would a multihomer request less IP
> addresses than he already uses, regardless of the minimum prefix size?
>> How quickly does one chew up /32s /30 /28s in the process of multihoming
>> the internet facing infrastructure in a smple-multihomed network?
> When I was at the DNC, I structured the network to justify a /22. I
> really wanted a /23 but a /22 was what I could get.
> I'm faced with a similar situation today. I need a /24 but I'll
> structure the network so that it justifies a /22. Just to be clear, I
> won't tell a single lie. I'll simply structure the network so that
> everything which could consume a public IP address does.
> I doubt my experience is unique. I expect that many if not most of the
> /22 end-user requests are similarly padded, not because the registrant
> actually wants that many addresses but because that's what they can
> get.
> Given the shortage of IPv4 addresses, why structure the policies so
> that we give anyone more than they actually want?

The minimum number of addresses that can be used may not in fact reflect
the minimum that should be used.

	For the purposes of minimizing fragmention.

	Supporting basic network operation (it's nice when traceroute
	and pmtud work) because your intermediate routers are privately
	Limiting the consequences of imagination failure, which may
	sound flippant but renumbering, requesting an additional block,
	or and point one and two are good reasons to make a potential
	multi-homer justify the assignment of a block of the appropriate
	size for that activity.

> Regards,
> Bill Herrin

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