ZXR10 5900E Series Configuration Guide (IPv6)
DHCPv6 Principle
Each DHCPv6 client or server has a unique identifier, that is, a DHCP Unique Identifier
(
). There are several modes to generate DUIDs. The lengths of DUIDs are different.
Not each message needs to carry a DUID, so a DUID is contained in the option information.
Identity Association (
) is an abstract concept used by DHCPv6 servers and clients to
identify, group and management multiple addresses. A network interface needs at lest
one IA to manage the IPv6 address information obtained on this interface. An IA must
be associated with a unique network interface. Different IAs are identified by IAIDs. The
IPv6 address information allocated by DHCPv6 is contained in IAs. An IA can carry the
information of several addresses.
DHCPv6 uses UDP to transport the protocol packets. The detection port on clients is
Port 546, and the detection port on servers and relays is Port 547. Clients always use
multicast packets to start interactions. DHCPv6 defines two multicast addresses. One is
the multicast address (FF05::1:3) of all local DHCP servers, and the other is the multicast
address (FF02::1:2) of all servers and relay agents.
There are the following types of standard DHCPv6 messages.
l
Solicit message (1): A client uses Solicit messages to locate the position of a server.
l
Advertise message (2): A server sends an Advertise message to reply a Solicit. An
Advertise message contains the allocated address and option information.
l
Request message (3): A client sends a Request message to a specified server to
request an address and configuration information.
l
Confirm message (4): A client sends Confirm messages to any reachable server to
check whether the current IPv6 address it obtained is suitable for the connected links.
l
Renew message (5): A client uses Renew messages to extend the address lease
term and update other configuration information.
l
Rebind message (6): If the renew message is not replied, a client will use a Rebind
message to extend the address lease term and update other configuration information.
l
Reply message (7): A server uses Reply message to respond Request, Renew,
Rebind, Release, Decline and Information-request messages. A Reply message can
carry an address and configuration information. In an exception, a Reply message
also can carry the status code information of an error.
l
Release message (8): When a client sends a Release message to a server that
allocates an address for this client, the client does not use the address (or addresses)
any longer.
l
Decline message (9): When a client sends a Decline message to a server, the address
(or addresses) has (have) been used on a link (or links).
l
Reconfigure message (10): A server can send a Reconfigure message to a client to
hint the configuration information that the client can update.
l
Information-request message (11): A client sends an Information-request message to
a sever to request configuration information without requesting an IP address.
l
Relay-forward message (12): A relay agent sends a Relay-forward message to a
server to replay information.
20-2
SJ-20150114102049-011|2015-01-15 (R1.0)
ZTE Proprietary and Confidential