Ipv6 Address/Prefix Allocation Sequence - HP FlexNetwork MSR2003 Configuration Manual

Address allocation mechanisms
DHCPv6 supports the following address allocation mechanisms:
•
Static address allocation—To implement static address allocation for a client, create a
DHCPv6 address pool, and manually bind the DUID and IAID of the client to an IPv6 address in
the DHCPv6 address pool. When the client requests an IPv6 address, the DHCPv6 server
assigns the IPv6 address in the static binding to the client.
•
Dynamic address allocation—To implement dynamic address allocation for clients, create a
DHCPv6 address pool, specify a subnet for the pool, and divide the subnet into temporary and
non-temporary IPv6 address ranges. Upon receiving a DHCP request, the DHCPv6 server
selects an IPv6 address from the temporary or non-temporary IPv6 address range based on the
address type in the client request.
Prefix allocation mechanisms
DHCPv6 supports the following prefix allocation mechanisms:
•
Static prefix allocation—To implement static prefix allocation for a client, create a DHCPv6
address pool, and manually bind the DUID and IAID of the client to an IPv6 prefix in the
DHCPv6 address pool. When the client requests an IPv6 prefix, the DHCPv6 server assigns the
IPv6 prefix in the static binding to the client.
•
Dynamic prefix allocation—To implement dynamic prefix allocation for clients, create a
DHCPv6 address pool and a prefix pool, specify a subnet for the address pool, and apply the
prefix pool to the address pool. Upon receiving a DHCP request, the DHCPv6 server
dynamically selects an IPv6 prefix from the prefix pool in the address pool.
Address pool selection
The DHCPv6 server observes the following principles when selecting an IPv6 address or prefix for a
client:
1. If there is an address pool where an IPv6 address is statically bound to the DUID or IAID of the
client, the DHCPv6 server selects this address pool. It assigns the statically bound IPv6
address or prefix and other configuration parameters to the client.
2. If the receiving interface has an address pool applied, the DHCP server selects an IPv6 address
or prefix and other configuration parameters from this address pool.
3. If no static address pool is configured and no address pool is applied to the receiving interface,
the DHCPv6 server selects an address pool depending on the client location.
Client on the same subnet as the server—The DHCPv6 server compares the IPv6
address of the receiving interface with the subnets of all address pools. It selects the
address pool with the longest-matching subnet.
Client on a different subnet than the server—The DHCPv6 server compares the IPv6
address of the DHCPv6 relay agent interface closest to the client with the subnets of all
address pools. It also selects the address pool with the longest-matching subnet.
To make sure IPv6 address allocation functions correctly, keep the subnet used for dynamic
assignment consistent with the subnet where the interface of the DHCPv6 server or DHCPv6
relay agent resides.

IPv6 address/prefix allocation sequence

The DHCPv6 server selects an IPv6 address/prefix for a client in the following sequence:
1. IPv6 address/prefix statically bound to the client's DUID and IAID and expected by the client.
2. IPv6 address/prefix statically bound to the client's DUID and IAID.
3. IPv6 address/prefix statically bound to the client's DUID and expected by the client.
4. IPv6 address/prefix statically bound to the client's DUID.
5. IPv6 address/prefix that was ever assigned to the client.
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