HP J3188A Installation And Reference Manual page 35

BAckup
To configure one of the hub's ports for dedicated use in a backup
(redundant) link to another hub.
An HP Hub-16M allows you to use any two of its network ports for a redundant
link to another hub in your network. The backup link normally carries no
traffic, but it is automatically activated if the primary link fails. Note that any
of the ports can be the backup port to any other port.
When you enter the Backup command, you are prompted for these values:
Backup Port
Primary Port
Remote MAC
address
Seconds Between
Test Packets
Consecutive
Failures
The hub monitors the primary link by sending IEEE 802.2 Test packets at the
specified frequency to the specified remote hub. If "n" consecutive Response
packets are not returned from the remote hub, the primary port is disabled
and the backup port is enabled.
When the primary link is repaired, you must re-enable the primary port by
using the Port command. It is not automatically re-enabled. When the primary
port is re-enabled, the backup port is disabled automatically and returned to
backup mode. See the appendix on Backup Links. This appendix also covers
more information on backup links, including requirements, limitations, and
sample topologies.
Default Description
Disabled The port used for the backup link. Enter the port ID.
Or, enter DI (for disable) if you wish to remove an
existing backup link configuration.
None The port used for the primary link. Enter the port ID.
000000-000000 The 12-digit hexadecimal MAC address of the hub at
the remote end of the critical link.
1 second How often you want the hub to send an IEEE 802.2
Test packet to the remote hub over the primary link.
2 failures The number of consecutive Test packet response
failures that will trigger activation of the backup link.
For example, enter 5 to activate the backup link on
the fifth failure.
Managing the Hub
Console Command Reference
3-5