How big a network is routed these days?

Owen DeLong owen at
Wed Jan 17 23:36:26 UTC 2007

>>>> Single Connection
>>>> The minimum block of IP address space assigned by ARIN to end- 
>>>> users is a /20. [...]
>>>> Multihomed Connection
>>>> For end-users who demonstrate an intent to announce the  
>>>> requested space in a multihomed fashion, the minimum block of IP  
>>>> address space assigned is a /22. [...]
>>>> 4.4 Micro-allocation
>>>> ARIN will make micro-allocations to critical infrastructure  
>>>> providers of the Internet, including public exchange points,  
>>>> core DNS service providers (e.g. ICANN-sanctioned root, gTLD and  
>>>> ccTLD operators) as well as the RIRs and IANA. These allocations  
>>>> will be no longer than a /24 using IPv4 or a /48 using IPv6. [...]
>> As far as I know, all of the PI /24's are thus "legacy" in nature.
> As the above snippet from the policy manual suggests (and as my  
> experience confirms) there are recent assignments made to end users  
> by ARIN under the micro-allocation policy which were made with the  
> expectation that individual /24s would be advertised globally.  
> Clearly these are not the most usual case, as the description of  
> those who qualify for such assignments above indicates, but it  
> would be a mistake to assume that *all* /24 assignments are legacy.
Actually, generally, the expectation under 4.4 is that the addresses  
will not be advertised at all for the most
part, since, generally, there's no need to advertise the route to the  
exchange point, itself, into the global
routing table.  4.4 is intended to support internet exchanges, ala  
MAEs, etc.

In terms of and, I believe ARIN has worked very hard  
to express no expectation or
intent about how assignments relate to route advertisements and  
routing policy.


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