-----Original Message----- From: William Herrin [mailto:herrin-nanog@dirtside.com] Sent: Monday, October 05, 2009 12:58 PM To: Brian Johnson Cc: nanog@nanog.org Subject: Re: ISP customer assignments
/60 - the smallest amount you should allocate to a downstream customer with more than one computer. Anything smaller will cost you extra management overhead from not matching the nibble boundary for RDNS delegation,
I have a lack of imagination, I guess. I can't imagine anyone larger than a small residential user being assigned a /60 or less. Therefore, nybble boundary for rDNS delegation only matters if you delegate rDNS for that block.
handling multiple routes when the customer grows, not
Any customer getting a /60 or less will be dynamically numbered (RA, DHCPv6, whatever), and if more space is needed, should be easily renumbered into a larger prefix.
matching the standard /64 subnet size and a myriad other obscure issues.
I don't know about "myriad" but I agree that /64 is the standard subnet size. I am *not* advocating assignments of /60 or less, just pointing out that if you do it, it doesn't have to break. Lee