Allied Telesis AlliedWare Plus Operating System Version 5.4.4C (x310-26FT,x310-26FP,x310-50FT,x310-50FP) - Manual (Page 674)

IPv6 Introduction
Software Reference for x310 Series Switches
26.8 AlliedWare Plus TM Operating System - Version 5.4.4C C613-50046-01 REV A
The following table explains packet types and services.
Stateless address autoconfiguration
Stateless address autoconfiguration allows an IPv6-aware device to be plugged into a
network without manual configuration with an IP address. This plug and play functionality
results in networks that are easier to set up and modify, and simplifies the process of
shifting to use a new Internet Service Provider (ISP).
Stateless address autoconfiguration is achieved in a series of steps. Routers and hosts
perform the first three steps, which autoconfigure a link-local address. A global address is
autoconfigured in the last three steps, which only hosts perform.
On the router or
host
1. During system start-up, the node begins autoconfiguration by generating a link-local
address for the interface. A link-local address is formed by adding the interface ID to
the link-local prefix fe80::/10 (reference RFC 3513).
Packet Type Description
address resolution A method for carrying out address autoconfiguration, and
is achieved using the Neighbor Solicitation Message and
the Neighbor Advertisement Message.
router and prefix
discovery On connection to a link, a node needs to know the address
of a router that the node can use to reach the rest of the
world. The node also needs to know the prefix (or prefixes)
that define the range of IP addresses on its link that it can
reach without going through a router.
Routers use ICMP to convey this information to hosts, by
means of router advertisements. The message may have an
option attached (the source link address option), which
enables the receiving node to respond directly to the
router, without performing a neighbor solicitation.
immediate information The configuration of a router includes a defined frequency
at which unsolicited advertisements are sent. If a node
wants to obtain information about the nearest router
immediately, rather than waiting for the next unsolicited
advertisement, the node can send a router solicitation
message.
Each router that receives the solicitation message sends a
router advertisement specifically to the node that sent the
solicitation.
redirection If a node is aware of more than one router that it can use to
connect to wider networks, the router to which it sends
packets by default does not always represent the most
desirable route. ICMPv6 uses the redirect packet to
communicate a more effective path to the node.
Neighbor Unreachability
Detection (NUD) A node may issue solicitation requests to determine
whether a path is still viable, or may listen in on
acknowledgement packets of higher layer protocols, such
as TCP. If the node determines that a path is no longer
viable, it attempts to establish a new link to the neighbor,
or to re-establish the previous link. NUD can be used
between any two devices in the network, independent of
whether the devices are acting as hosts or routers.
Note Different interfaces on a device may have the same link-local address. The
switch will automatically generate a link-local address for all interfaces that are
using IPv6. Commands entered to configure link-local addresses that match
any automatically generated link-local addresses by the switch will not be
executed. Enter the show ipv6 interface command to display automatically
generated link-local addresses not shown in the running-config. Automatically
generated link-local addresses contain the last six hexadecimal numbers of the
MAC address for a given interface.