H3C Technologies H3C S12500 Series Switches - Manual (Page 147)

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398B
PD
The DHCPv6 server creates a prefix delegation (PD) for each assigned prefix to record the IPv6 prefix,
client DUID, IAID, valid lifetime, preferred lifetime, lease expiration time, and IPv6 address of the
requesting client.
286B
DHCPv6 address pool
The DHCP server selects IPv6 addresses, IPv6 prefixes, and other parameters from an address pool, and
assigns them to the DHCP clients.
399B
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.
400B
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.
401B
Address pool selection
The DHCPv6 server observes the following principles to select 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 and assigns the statically bound IPv6 address
or prefix and other configuration parameters to the client.
2. If the receiving interface has an address pool, the DHCP server selects an IPv6 address or prefix
and other configuration parameters from this address pool.
3. If there is no static address pool and the receiving interface has no address pool, the DHCPv6
server selects an address pool in the following way:
{
If the client and the server reside on the same subnet, the DHCP server matches the IPv6
address of the receiving interface against the subnets of all address pools, and selects the
address pool with the longest-matching subnet.
{
If the client and the server reside on different subnets (a DHCPv6 relay agent is in-between), the
DHCPv6 server matches the IPv6 address of the DHCPv6 relay agent interface closest to the