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Chapter 24 dhcpv6 configuration, 1 introduction to dhcpv6, Ntroduction to – QTECH QSW-8300 Инструкция по настройке User Manual

Page 169: Dhcp

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Chapter 24 DHCPv6 Configuration

24.1 Introduction to DHCPv6

DHCPv6 [RFC3315] is the IPv6 version for Dynamic Host Configuration Protocol (DHCP). It is

a protocol that assigns IPv6 address as well as other network configuration parameters such

as DNS address, and domain name to DHCPv6 client, DHCPv6 is a conditional auto address

configuration protocol relative to IPv6. In the conditional address configuration process,

DHCPv6 server assigns a complete IPv6 address to client, and provides DNS address,

domain name and other configuration information, maybe the DHCPv6 packet can transmit

through relay delegation, at last the binding of IPv6 address and client can be recorded by

DHCPv6 server, all that can enhance the management of network; DHCPv6 server can also

provide non state DHCPv6 service, that is only assigns DNS address and domain name and

other configuration information but not assigns IPv6 address, it can solve the bug of IPv6 auto

address configuration in non state; DHCPv6 can provide extend function of DHCPv6 prefix

delegation, upstream route can assign address prefix to downstream route automatically, that

achieve the IPv6 address auto assignment in levels of network environment, and resolved the

problem of ISP and IPv6 network dispose.

There are three entities in the DHCPv6 protocol

– the client, the relay and the server. The

DHCPv6 protocol is based on the UDP protocol. The DHCPv6 client sends request messages

to the DHCP server or DHCP relay with the destination port as 547, and the DHCPv6 server

and relay send replying messages with the destination port as 546. The DHCPv6 client sends

solicit or request messages with the multicast address

– ff02::1:2 for DHCP relay and server.

DHCPv6 negotiation

When a DHCPv6 client tries to request an IPv6 address and other configurations from the

DHCPv6 server, the client has to find the location of the DHCP server, and then request

configurations from the DHCP server.

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.

Any DHCP server which receives the request, will reply the client with an ADVERTISE

DHCPv6

CLIENT

DHCPv6

SERVER

Solicit (Muticast)

Advertise

(Unicast)

Request

(Muticast)

Reply

(Unicast)