[arin-ppml] Draft Policy 2010-2: /24 End User Minimum Assignment Unit - Correct Title

Owen DeLong owen at delong.com
Tue Jan 26 00:03:01 EST 2010

On Jan 25, 2010, at 12:32 PM, Jim McBurnett wrote:

>> From Ted:
>>>>  Secondly, if you can only justify a /23 then your actually better
>>>> off "getting another ISP to advertise a competing ISP's space" than
>>>> in attempting to get your own /23 or /24, even if this policy is
>>>> approved.  The reason why is that while your /23 or /24 would be
>>>> a part of the DFZ, it would be so small in comparison to most of
>>>> the blocks advertised on the Internet that there's a lot of networks
>>>> (particularly running on routers with low ram in them) that will
>>>> filter your /23 or /24 out entirely, and just default-route to
>>>> one of their upstreams to cover the advertisements smaller than their
>>>> filter break.  It is a mistake to assume a /24 is globally visible
>>>> in all routers on the Internet, if you spend some time working with
>>>> different Looking Glasses (you can find a list on traceroute.org) you
>>>> will quickly see that the smaller the advertisement the fewer routers
>>>> it appears in.   You may get suboptimal routing if you use a
>>>> smaller block that is not part of a supernet, then if you use a
>>>> small block that IS part of a supernet.
>>>>  Also, your going to quickly find that it's just as difficult to
>>>> get a small portable block advertised from those "competing ISP's"
>>>> as a small block that's assigned from an ISP.
> Please forgive the intrusion... I post rarely---
> As a consultant, I have several customers that are multi-homed. Many have the issue of getting
> IP Space from an ISP.  Some ISP's have to be read ARIN policy on the multi-home requirement
> To allow for a /24.. Granted some of these customers cannot truly justify a /24 for that site.
> HOWEVER-- there are concerns for them to do some other redundancy options..
> Correct me if I am wrong-- But over on Cisco-NSP on Jared Mauch's site, I remember a conversation 
> A few months ago covering the /24 filtering.. many thought it was only being done on old routers..
> And someone went so far to say that it was only done when it was a lower tier edge from a small ISP.
> I think there was a branch on that thread that mentioned a default injection too.. But lots of water has 
> Flowed under the bridge since then....
> As it is written today, I believe it sounds reasonable... and actually have a few end users that would benefit.
> I am specifically addressing the small user, not the IBM as mentioned in the thread by Bill Herrin.
> He has a very valid point, IMHO...
> I know there are lots of folks here that members of the other RIR's lists.. so:
> My parting shots are this:  
> What are the other RIR's doing?
RIPE and APNIC will issue /24 and in some cases even smaller.
I do not know for sure about AfriNIC (I think they go down to /24) or LACNIC.
> IF they are already doing this, why is ARIN not?
I think that's an excellent question.

> IF they are not, what makes ARIN different?
> This is not to say, ARIN should emulate the other RIR's but their logic may discount or account for issue or non-issues we may see here...
Thanks for your comments.

I hope you will post more often and make your voice known at the public
policy meeting, either in person, or, through remote participation.


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