This means that the DHCP-PD server has 2^16 prefixes (i.e., 80 - 64) that are 80 bits long that it can delegate to requesting DHCP-PD clients.
Here's is a simpler example using "pd_pool_1 2200:1::/60 64".
ipv6 dhcp pool dhcp_pd_pool_1 prefix-delegation pool pd_pool_1 ! interface GigabitEthernet0/1 duplex auto speed auto media-type rj45 no negotiation auto ipv6 address 2200:1::1/64 ipv6 enable ipv6 dhcp server dhcp_pd_pool_1 ! ipv6 local pool pd_pool_1 2200:1::/60 64
In this case the 7200 as a DHCP-PD server will have a pool 4 bits "wide" (i.e., 64 - 60) from which to pull prefixes that it can delegate to requesting DHCP-PD clients.
|0 16|17 32|33 48|49 60|61 64| +------|------|------|------|------| | 2200 : 0001 : 0000 : 000 0:: | ^ | +----4 bits for a pool of 16 prefixes
The prefixes would be:
The requesting DHCP-PD clients will then have the remaining 64 bits of host addresses to assign to its hosts.