BNG IPoE on ASR9000: address exhaustion problem

[Normando Marcolongo]

Hi! I followed the walkthrough and the guide to set up an IPoE BNG router with ASR9001 from xthuijs. Everything has worked flawlessly for the last 4 years or so.

My concern is relative to the requirement of the unnumbered (from a loopback interface) configuration on the dynamic template used for many aspects: the default gateway for the client and as a giaddr for DHCP.

Say you end up without any more IPs in that subnet. You can't just add a subnet/pool to the DHCP server expecting things to work. That is because on the router we have only one address on the loopback interface used for the unnumbered config...

How do we deal with that situation?

Thanks,
Norm

[Fredrik Lonnman]

You can add multiple secondary subnets on the loopback used as unnumbered source. Be sure to add them to the router configuration before adding them to the dhcp server so that the default gw and routing will work for the subscribers in the new subnets when the dhcp server starts handing them out.