Dividing up a small IPv4 block

Brad Fleming bdflemin at gmail.com
Tue Jun 22 02:36:11 UTC 2010

> Thinking that they will have to go back to ARIN for additional space
> relatively quickly without intervention, can anyone provide links to
> docs that will help prevent future renumbering or decent management? I
> know that I can collapse a lot of their current waste, and I know  
> where
> I can scrounge, but where in the space should the clients be assigned
> from, and where should I reserve my p2p/32 blocks from... front or  
> back?

Only speaking from my current situation, we typically assign loops and  
links from the highest numbered portions of our space; pulling a /23  
for the task many moons ago. Loops come from the highest numbered  
block and links from the block just below. Of course that's just one  
network's approach, and we could certainly be wrong! :D

As far as efficient use of the space goes... that's a tough one. We've  
pretty much decided that creating these hard blocks of IPs that MUST  
come from one place isn't going to work as we move forward. We decided  
awhile back that our IGP is probably just going to be messy going  
forward. We try to keep things summarized but when you're out of IPs  
in this block on this AGG router, you go grave robbing another, less  
popular AGG router's space. It just happens. We kind of decided that  
we buy routers with lots of memory and CPU for a reason... might as  
well use it! Of course that's going to get some people riled up on  
this list but its the reality of being a "small guy" who is running  
out of IPv4 space. And for the record, we've been a fully dual stacked  
environment since Q1 of 2004 but people want / need more IPv4 space  
all the time.

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