# Configuring the neighbor cache

Neighbor cache in IPv6 is similar to the IPv4 Address Resolution Protocol (ARP) table. The neighbor cache is a set of entries for individual neighbors to which traffic was sent recently. You make entries on the neighbor on-link unicast IP address, including information such as the link-layer address. A neighbor cache entry contains information used by the Neighbor Unreachability Detection algorithm, including the reachability state, the number of unanswered probes, and the time the next Neighbor Unreachability Detection event is scheduled.

## Procedure steps

1. From the navigation tree, double-click IPv6.

2. Double-click IPv6.

3. Click the Neighbors tab.

4. Click Insert.

5. In the IfIndex box, click Port in VLAN, and select a VLAN.

6. Edit the remaining fields.

7. Click Insert.

8. Click Apply.

## Variable definitions

The following table describes the fields of the Neighbors tab.

Variable | Value
--- | ---
IfIndex | A unique value to identify a logical interface (VLAN). For the VLAN, the value is the ifindex of the vlan.
NetAddress | The IP address corresponding to the media-dependent physical address.
PhyAddress | The media-dependent physical address. The range is 0–65535. For Ethernet, this is a MAC address.
Interface | Either a physical port ID or the MLT port ID. This entry is associated either with a port or with the MLT in a VLAN.
LastUpdated | The value of sysUpTime at the time this entry was last updated. If this entry was updated prior to the last reinitialization of the local network management subsystem, this object contains a zero value.
Type | The mapping type is as follows: Dynamic type: indicates that the IP address to the physical address mapping was dynamically resolved using, for example, IPv4 ARP or the IPv6 Neighbor Discovery Protocol. Static type: indicates that the mapping was statically configured. Local type: indicates that the mapping is provided for the interface address. The default is static.
State | The Neighbor Unreachability Detection state for the interface when the address mapping in this entry is used. If Neighbor Unreachability Detection is not in use (for example, for IPv4), this object is always unknown. Options include the following: reachable: confirmed reachability stale: unconfirmed reachability delay: waiting for reachability confirmation before entering the probe state probe: actively probing invalid: an invalidated mapping unknown: state cannot be determined incomplete: address resolution is being performed