The outside pools in deterministic NAT can contain an arbitrary number of address ranges, where each address range can contain an arbitrary number of IP addresses (up to the ISA maximum).
The maximum number of NAT subscribers that can be mapped to a single outside IP address is configurable using a subscriber-limit command under the pool hierarchy. For Deterministic NAT, this number is restricted to the power of 2 (2^n). The consequence of this is that the number of NAT subscribers must be configuration-wise organized in ranges with the boundary that must be power of 2.
For example, in LSN44 where the NAT subscriber is an IP address, the deterministic subscribers would be configured with prefixes (for example, 10.10.10.0/24 – 256 subscribers) instead of an IP address range that would contain an arbitrary number of addresses (for example, 10.10.10.10 – 10.10.10.50).
On the other hand, in DS-Lite the deterministic subscribers are for the most part already determined by the prefix with the subscriber-prefix-length command under the DS-Lite configuration node.
The number of subscribers per outside IP (the subscriber-limit command [2^n]) multiplied by the number of IP addresses over all address-range in an outside pool determines the maximum number of subscribers that a deterministic pool can support.