IPv6 Management Features

Viewing and Clearing the IPv6 Neighbors Cache

Viewing the Neighbor Cache

Neighbor discovery occurs when there is communication between IPv6 devices on a VLAN. The Neighbor Cache retains data for a given neighbor until the entry times out. For more on this topic, refer to “Neighbor Discovery (ND)” on page 4-17.

Syntax: show ipv6 neighbors [vlan < vid >]

Displays IPv6 neighbor information currently held in the neighbor cache. After a period without communication with a given neighbor, the switch drops that neighbor’s data from the cache. The command lists neighbors for all VLAN interfaces on the switch or for only the specified VLAN. The following fields are included for each entry in the cache:

IPv6 Address: Lists the 128-bit addresses for the local host and any neighbors (on the same VLAN) with whom there has been recent communication.

MAC Address: The MAC Address corresponding to each of the listed IPv6 addresses.

VLAN < vid >: Optional. Causes the switch to list only the IPv6 neighbors on a specific VLAN configured on the switch.

Type: Appears only when VLAN is not specified, and indicates whether the corresponding address is local (configured on the switch) or dynamic (configured on a neighbor device).

Age: Appears only when VLAN is specified, and indicates the length of time the entry has remained unused.

Port: Identifies the switch port on which the entry was learned. If this field is empty for a given address, then the address is configured on the switch itself.

State: A neighbor destination is reachable from a given source address if confirmation has been received at the source veri­ fying that traffic has been received at the destination. This field shows the reachability status of each listed address:

•INCOM (Incomplete): Neighbor address resolution is in progress, but has not yet been determined.

•REACH (Reachable): The neighbor is known to have been reachable recently.

—Continued on the next page. —

5-3