How big a network is routed these days?

Marshall Eubanks tme at
Wed Jan 17 17:43:28 UTC 2007

On Jan 17, 2007, at 12:19 PM, David Freedman wrote:

> I'm interested as to why RIRs dont set the minimum PI allocatable
> to /24 in order to fit with the current trend.

In the 2002-3 micro-assignment policy, the RIR's assign a minimum of  
a /22. As far as I know, all of the PI
/24's are thus "legacy" in nature. From my experience, /24's and longer
assigned by RIRs likely to be routed, as well as ones
from the old class C space, and people have mostly had problems with / 
24 PA space in the old Class A and B space.

Your milage, of course, definitely may vary here.


> I mean, I can see the reason for smaller allocations where an LIR  
> routes and aggregates both but these are rare and probably legacy  
> examples.
> Changing the allocation policy such that a /24 minimum exists for  
> PI would be a good thing IMHO, forcing people to either apply for  
> portions of PA space from LIRs (and having LIRs do what they should  
> be doing)
>  or lie through their teeth to get a /24 (but then not try and  
> wonder why anything smaller is not routed correctly)
> Of course I'm probably opening the proverbial can of worms about  
> who should or shouldn't apply and how they do, but I do find the  
> possibility of obtaining a sub /24 PI allocation a little odd in  
> this day and age.
> Dave.
> Justin M. Streiner wrote:
>> On Wed, 17 Jan 2007, John Smith wrote:
>>> my organization is considering PI addresses as a way to multihost.
>>> Having read the archives regarding disadvantages and alternatives,
>>> my question is how big a network must one have to be reasonably
>>> sure the BGP routers will accept the route?
>> A /24 is the smallest block of IPv4 addresses that you can  
>> reasonably expect to be globally reachable.  Depending on where  
>> you're located, the different address registries (ARIN, RIPE,  
>> APNIC, etc...) have different policies regarding the smallest PI  
>> block they'll allocate to end users.
>> jms

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