The Neighbor Discovery Protocol (NDP) is a protocol that

• operates at the link layer and manages the discovery of other nodes on the network link

• determination of their link-layer addresses, identification of available routers, and

• the maintenance of reachability information for neighboring nodes.

A Router Advertisement (RA) is an IPv6 Neighbor Discovery Protocol (NDP) message

• sent by routers to communicate network parameters such as available routers

• network prefixes for IPv6 address configuration, and

• link MTU information to hosts on the link.

RAs play a vital role in this process by allowing hosts to detect routers, generate IPv6 addresses, and configure other connection parameters.

Routers send RAs either on a regular basis or in response to Router Solicitation messages from hosts.

IPv6 wireless client mobility manages the IPv6 RA packet. The device forwards the link-local all-nodes multicast RA packets to both local and roaming wireless nodes mapped on the same VLAN where the RA was received.

Figure 1 illustrates how a roaming client “MN” receives RA from VLAN 200 in a foreign controller and how it acquires an new IP address and breaks into L3 mobility's point of presence.

A router advertisement throttle is a network control mechanism that

• enforces limits on the frequency of router advertisement (RA) packets sent toward the wireless network

• ensures routers that send multiple RA packets are restricted to a minimum frequency required for IPv6 client connectivity, and

• maintains uninterrupted IPv6 connectivity for new or roaming clients by allowing RA packets in response to Router Solicitation (RS) packets.

If a client sends an RS packet, the router sends an RA back to the client. The controller allows this RA to pass and delivers it as a unicast message to the client. This process ensures that new or roaming clients are not affected by RA throttling.

IPv6 address learning is the process

• by which IPv6 clients acquire IP addresses, and

• network devices such as switches or controllers, observe and record these assignments.

There are three ways for an IPv6 client to acquire IPv6 addresses:

• Stateless Address Auto-Configuration (SLAAC)

• Stateful DHCPv6

• Static configuration

For these methods, the IPv6 client always sends NS DAD (duplicate address detection) to ensure that there is no duplicated IP address on the network. The device snoops the client's NDP and DHCPv6 packets to learn about the client's IP addresses. It then updates the controller's database. The database then informs the controller about the client's new IP address.

An IP address is a network identifier that

• uniquely distinguishes a device on a network

• supports both IPv4 and IPv6 formats, and

• can be dynamically assigned, updated, or displayed for client devices.

If a new IP address is received after the RUN state, whether it is an addition or removal, the controller updates its local database with the new IP addresses for display purposes. IPv6 uses the same PEM state machine code flow as IPv4. When external entities, such as Prime Infrastructure, request IP addresses, the controller includes all available IPv4 and IPv6 addresses in the API or SPI interface response.

An IPv6 client can acquire multiple IP addresses from the stack for different purposes. For example, a client may have a link-local address for local traffic and a routable unique local or global address.

When the client is in the DHCP request state and the controller receives the first IP address notification from the database, for either an IPv4 or IPv6 address, the PEM moves the client into the RUN state.

If a new IP address is received after the RUN state, whether it is an addition or removal, the controller updates its local database with the new IP addresses for display purposes.

When external entities, such as Prime Infrastructure, request IP addresses, the controller provides all available IPv4 and IPv6 addresses.

A IPv6 configuration is a network setup that

• enables seamless support for IPv6 clients alongside IPv4 clients

• requires manual VLAN configuration by the administrator to activate IPv6 features, and

• implements snooping and throttling functionality to manage NDP packets between the switch controller device and its clients.