IPv4 IPv6
Identification of DHCP clients/
server
Client ID:
MAC address
 
DUID + IAID(s) = exactly one interface of the host
DUID = DHCP unique identifier
Identifies server and clients uniquely and should not change, 
not even when replacing network components!
IAID = Identity Association Identifier
At least one per interface is generated by the client and re‐
mains unchanged when the DHCP client restarts
Three methods of obtaining the DUID
● DUID-LLT
● DUID-EN
● DUID-LL
DHCP via UDP with broadcast via UDP with unicast 
RFC 3315, RFC 3363
Stateful DHCPv6 
Status-dependent configuration in which the IPv6 address and 
the configuration settings are transferred. 
Four DHVPv6 messages are exchanged between client and 
server:
1. SOLICIT: 
Sent by the DHCPv6 client to localize DHCPv6 servers.
2. ADVERTISE
The available DHCPv6 servers reply to this. 
3. REQUEST
The DHCPv6 client requests an IPv6 address and the 
configuration settings from the DHCPv6 server. 
4. REPLY
The DHCPv6 server sends the IPv6 address and the 
configuration settings.
If the client and server support the function "Rapid commit" the 
procedure is shortened to two DHCPv6 messages SOLICIT 
and REPLY .
Stateless DHCPv6
In stateless DHCPv6, only the configuration settings are trans‐
ferred.
Prefix delegation
The DHCPv6 server delegates the distribution of IPv6 prefixes 
to the DHCPv6 client. The DHCPv6 client is also known as PD 
router. 
Resolution of IP addresses in 
hardware addresses
ARP (Address Resolution 
Protocol)
NDP (Neighbor Discovery Protocol)
Description
2.6 Interface identifiers and addresses
SCALANCE W770/W730 acc. to IEEE 802.11n Command Line Interface
Configuration Manual, 09/2017, C79000-G8976-C324-08 33