KB.15.15

at the source verifying that traffic has been received at the destination. The neighbor cache retains

data for a given neighbor until the entry times out. You can view and clear the contents of the

neighbor cache using the commands described in this section. For more on this topic, see “Neighbor

discovery” (page 30).

Clear the neighbor cache

When there is an event such as a topology change or an address change, the neighbor cache

may have too many entries to allow efficient use. Also, if an unauthorized client is answering DAD

or normal neighbor solicitations with invalid replies, the neighbor cache may contain a large

number of invalid entries and communication with some valid hosts may fail, the show ipv6

neighbors command output may become too cluttered to efficiently read, or both. In such cases,

the fastest way to restore optimum traffic movement on a VLAN may be to statically clear the

neighbor table instead of waiting for the unwanted entries to time-out.

SNTP and Timep

About configuring (enabling or disabling) the SNTP mode

The switch supports both Timepv6 and SNTPv6 time services. Software release K.13.01 and greater

enables configuration of a global unicast address for IPv6 SNTP time server.

This section lists the SNTP and related commands, including an example of using an IPv6 address.

For the details of configuring SNTP on the switch, see the "Time Protocols" chapter in the

Management and Configuration Guide for your switch.

The following commands are available at the global config level for SNTP operation:

FunctionCommands affecting SNTP

Display the current SNTP configuration.show sntp

Enable either SNTP or Timep as the time synchronization method on the

switch without affecting the configuration of either.

timesync [ sntp | timep ]

Enable time synchronization. (Requires a timesync method to also be

enabled.) The no version disable time synchronization without affecting

the configuration of the current time synchronization method.)

[no] timesync

Enables SNTP with the current SNTP configuration. The no version disables

SNTP without changing the current SNTP configuration.

[no] sntp

Configures the SNTP mode. Default: Broadcastsntp [ unicast | broadcast ]

Changes the interval between time requests. Default: 720 secondssntp 30 - 720

About configuring an IPv6 address for an SNTP server

To use a global unicast IPv6 address to configure an IPv6 SNTP time server on the switch, the

switch must be receiving advertisements from an IPv6 router on a VLAN configured on the switch.

To use a link-local IPv6 address to configure an IPv6 SNTP time server on the switch, it is necessary

to append %vlan followed immediately (without spaces) by the VLAN ID of the VLAN on which

the server address is available. (The VLAN must be configured on the switch.)

For example:

fe80::11:215%vlan10

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