Blade ICE G8000 - Manual (Page 137)

RackSwitch G8000 Application Guide
Chapter 10: High Availability „ 137 BMD00041, November 2008
Failure Detection Pair
To use UFD, you must configure a Failure Detection Pair and then turn UFD on. A Failure
Detection Pair consists of the following groups of ports:
„ Link to Monitor (LtM)
The Link to Monitor group consists of one port or one trunk group. The switch monitors
the LtM for link failure.
„ Link to Disable (LtD)
The Link to Disable group consists of one or more ports and trunk groups. When the
switch detects a link failure on the LtM, it automatically disables all ports in the LtD.
When the LtM returns to service, the switch automatically enables all ports in the LtD.
Spanning Tree Protocol with UFD
If Spanning Tree Protocol (STP) is enabled on ports in the LtM, then the switch monitors the
STP state and the link status on ports in the LtM. The switch automatically disables the ports in
the LtD when it detects a link failure or STP BLOCKING state.
When the switch determines that ports in the LtM are in the FORWARDING State, then it
automatically enables the ports in the LtD, to fall back to normal operation.
Configuration guidelines
This section provides important information about configuring UFD.
„
Only one Failure Detection pair (one group of Links to Monitor and one group of Links to
Disable) is supported on the switch (all VLANs and Spanning Tree Groups).
„ A LtM may contain either one port or one Multi-Link trunk group.
„ Ports that are already members of a trunk group are not allowed to be assigned to a LtM.
„
A port cannot be added to a trunk group if it already belongs to a LtM.
„ A LtD can contain one or more ports, and/or one or more trunks.
Use the following command to find out how many times link failure was detected on the LtM,
how many times Spanning Tree blocking state was detected on the LtM, and how many times
UFD disabled ports in the LtD:
RS G8000 (config)# show ufd counters