TP-Link TL-SG2424 User Manual page 32

function of IPv4). DAD is accomplished through NS and NA messages. The DAD procedure is
as follows:
Node A sends an NS message whose source address is the unassigned address :: and

destination address is the corresponding solicited-node multicast address of the IPv6
address to be detected. The NS message contains the IPv6 address.
If node B uses this IPv6 address, node B returns an NA message. The NA message

contains the IPv6 address of node B.
Node A learns that the IPv6 address is being used by node B after receiving the NA

message from node B. Otherwise, node B is not using the IPv6 address and node A can
use it.
2. IPv6 Router Advertisement Message
Router advertisement (RA) messages, which have a value of 134 in the Type field of the ICMP
packet header, are periodically sent out each configured interface of an IPv6 router.
RA messages typically include the following information:
One or more onlink IPv6 prefixes that nodes on the local link can use to automatically

configure their IPv6 addresses.
Lifetime information for each prefix included in the advertisement.

Sets of flags that indicate the type of autoconfiguration (stateless or stateful) that can be

completed.
Default router information (whether the device sending the advertisement should be used

as a default router and, if so, the amount of time, in seconds, the device should be used as
a default router).
Additional information for hosts, such as the hop limit and maximum transmission unit (MTU)

a host should use in packets that it originates.
RAs are also sent in response to device solicitation messages. Device solicitation messages,
which have a value of 133 in the Type field of the ICMP packet header, are sent by hosts at
system startup or anytime needed so that the host can immediately autoconfigure without
needing to wait for the next scheduled RA message.
Hosts discover and select default devices by listening to Router Advertisements (RAs).
Stateless address autoconfiguration means that the node automatically configures an IPv6
address and other information for its interface according to the address prefix and other
configuration parameters in the received RA messages.
3. IPv6 Neighbor Redirect Message
A value of 137 in the type field of the ICMP packet header identifies an IPv6 neighbor redirect
message. Devices send neighbor redirect messages to inform hosts of better first-hop nodes
on the path to a destination.
24