Netgear XCM8806 Chassis User Manual - Page 642

NETGEAR 8800 User Manual duplicate, it will also be labeled as such, and must be reconfigured. On an active interface, the DAD process should occur so quickly that you would not see the address labeled as tentative. However, if you are configuring an interface before enabling it, and you display the configuration, you will see that the address is currently tentative. As soon as you enable the interface, the address should be ready to use, or labeled as duplicate and must be reconfigured. See RFC 2462, IPv6 Stateless Address Autoconfiguration, for more details. Scoped Addresses IPv6 uses a category of addresses called link-local addresses that are used solely on a local subnet. Every IPv6 VLAN must have at least one link-local address. If a global IP address is configured on a VLAN that has no link-local address, one is assigned automatically by the switch. The link-local addresses start with the prefix fe80::/64. As a result, a switch can have the same link local address assigned to different VLANs, or different neighbors on different links may be using the same link local address. Because of this, there are cases where you need to specify an address and a VLAN/tunnel to indicate which interface to use. For those cases, you can indicate the interface by using a scoped address. To scope the address, append the VLAN/tunnel name to the end of the address, separated by a percent sign (%). For example, to indicate the link local address fe80::2 on VLAN finance, use the following form: fe80::2%finance Scoped addresses also appear in the outputs of display commands. IPv6 Addresses Used in Examples For the purposes of documentation, we follow RFC 3849, which indicates that the prefix 2001:db8::/32 can be used as a global unicast address prefix and will not be assigned to any end party. Neighbor Discovery Protocol The Neighbor Discovery Protocol, as defined in RFC 2461, defines mechanisms for the following functions: • Resolving link-layer addresses of the IPv6 nodes residing on the link. • Locating routers residing on the attached link. • Locating the address prefixes that are located on the attached link. • Learning link parameters such as the link MTU, or Internet parameters such as the hop limit value that has to be used in the outgoing packets. • Automatic configuration of the IPv6 address for an interface. • Detecting whether the address that a node wants to use is already in use by another node, also known as Duplicate Address Detection (DAD). • Redirecting the traffic to reach a particular destination through a better first-hop. 642 | Chapter 21. IPv6 Unicast Routing