Hi Mikael, (Sorry if you are getting a duplicate copy of this.) In our network we had a couple of problems with RFC3069. Not all the hardware we currently use supports the RFC so we tried to come up with a solution that worked and didn't have us opening a lot of ERs (I know I reference 1 ER in the presentation but that's just 1 rather than a lot). We have more than just routers to consider (i.e. load balancers, firewalls, etc..) and don't want to lock ourselves in to any particular vendor. We also wanted a solution that we could easily migrate our customers into rather than completely taking them off line while we "retrofit" them into a new config (as probably would've been the case if we tried implementing RFC3069). Additionally, for a number of our customers we needed a solution that worked with a FHRP. I don't currently see a way to do that with RFC3069 but if I've missed something please let me know. Thanks, ChrisP. SoftLayer Technologies chrisp@softlayer.com -----Original Message----- From: Mikael Abrahamsson [mailto:swmike@swm.pp.se] Sent: Tuesday, June 04, 2013 5:34 PM To: nanog@nanog.org Subject: IP4 address conservation method I read: http://www.nanog.org/sites/default/files/tues.general.Papandreou.conservatio... I would like to point out RFC 3069. On most cisco equipment this is done using static routes and "ip unnumbered". So my question is basically: What am I missing? Why can't data center guys not build their network the same way regular ETTH is done? Either one vlan per customer and sharing the IPv4 subnet between several vlans, or having several customers in the same vlan but use antispoofing etc (IETF SAVI-wg functionality) to handle the security stuff? One vlan per customer also works very well with IPv6. -- Mikael Abrahamsson email: swmike@swm.pp.se