IPv4 address conservation method for hosting providers

You can configure a static route on an IRB interface with or without pinning to a specific underlying interface, thereby conserving the usage of IP address space. When a customer needs servers to be assigned within a block of IP addresses, several IP addresses are consumed. These include the network and broadcast IP addresses, the addresses for the router gateway that the servers are connected to, and the addresses of the individual servers. When this effect is multiplied across thousands of hosting providers, IP address space is far from being used efficiently. This issue can be resolved by configuring the interface on the router with an address from the reserved IPv4 prefix for shared address space (RFC 6598) and by using static routes pointed at the interface. IANA has recorded the allocation of an IPv4 /10 for use as shared address space. The shared address space address range is 100.64.0.0/10. This way, the interface in the router is allocated an IP address from the shared address space, so it is not consuming publicly routable address space, and connectivity is handled with static routes on an interface. The interface in the server is configured with a publicly routable address, but the router interfaces are not. Network and broadcast addresses are consumed out of the shared address space rather than the publicly routable address space.