IPv6 Addressing
Address Types and Scope
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Address Types
IPv6 uses these IP address types:
■Unicast: Identifies a specific IPv6 interface. Traffic having a unicast destination address is intended for a single interface. Like IPv4 addresses, unicast addresses can be assigned to a specific VLAN on the switch and to other IPv6 devices connected to the switch. At a minimum, a given interface must have at least a
■Multicast: Provides a single destination address for traffic intended for all members of a group, and provides a means for reducing unnecessary traffic to interfaces that do not belong to a given multicast group. Member ship in a group can be determined by request or by a characteristic, such as all nodes, all routers, or all routers of a given type. Multicast traffic can be generated by a single source or multiple sources, but in either case is intended for multiple destinations.Common types of multicast traffic include streaming video and audio to multiple receivers who have joined a specific group from diverse locations.
Unlike IPv4, broadcast addresses are not used in IPv6. Multicast addresses are used instead. For more on this topic, refer to “Multicast Application to IPv6 Addressing” on page
■Anycast: A single address of this type can be assigned to multiple interfaces, possibly on separate devices within a defined address scope, where any of the interfaces having the anycast address can provide the desired service or response. A packet sent to a given anycast address is delivered only to the nearest interface having an instance of the address. This option is useful where multiple servers provide the same service, and it does not matter to the client which source it uses to acquire the service. Anycast usage can be of value, for example, in a network supporting multiple DNS servers. Refer to “Anycast Addresses” on page
A given interface can have only one