DHCPv6 Configuration
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request configurations from the DHCP server.
1. In the time of located server, the DHCP client tries to find a DHCPv6 server by
broadcasting a SOLICIT packet to all the DHCP delay delegation and server with
broadcast address as FF02::1:2.
2. Any DHCP server which receives the request, will reply the client with an
ADVERTISE message, which includes the identity of the server
–DUID, and its
priority.
3. It is possible that the client receives multiple ADVERTISE messages. The client
should select one and reply it with a REQUEST message to request the address
which is advertised in the ADVERTISE message.
4. The selected DHCPv6 server then confirms the client about the IPv6 address
and any other configuration with the REPLY message.
The above four steps finish a Dynamic host configuration assignment process.
However, if the DHCPv6 server and the DHCPv6 client are not in the same network, the
server will not receive the DHCPv6 broadcast packets sent by the client, therefore no
DHCPv6 packets will be sent to the client by the server. In this case, a DHCPv6 relay is
required to forward such DHCPv6 packets so that the DHCPv6 packets exchange can be
completed between the DHCPv6 client and server.
At the time this manual is written, DHCPv6 server, relay and prefix delegation client
have been implemented on the switch. When the DHCPv6 relay receives any messages
from the DHCPv6 client, it will encapsulate the request in a Relay-forward packet and
deliver it to the next DHCPv6 relay or the DHCPv6 server. The DHCPv6 messages
coming from the server will be encapsulated as relay reply packets to the DHCPv6 relay.
The relay then removes the encapsulation and delivers it the DHCPv6 client or the next
DHCPv6 relay in the network.
For DHCPv6 prefix delegation where DHCPv6 server is configured on the PE router
and DHCPv6 client it configured on the CPE router, the CPE router is able to send
address prefix allocation request to the PE router and get a pre-configured address prefix,
but not set the address prefix manually. The protocol negotiation between the client and
the prefix delegation client is quite similar to that when getting a DHCPv6 address. Then
the CPE router divides the allocated prefix
– whose length should be less than 64
characters, into 64 subnets. The divided address prefix will be advertised through routing
advertisement messages (RA) to the host directly connected to the client.
32.2
DHCPv6 Server Configuration
DHCPv6 server configuration task list as below:
1. To enable/disable DHCPv6 service