Install guide

42 Release Note
Rapier Switch Software Release 2.1.0
C613-10200-01 Rev A
there can be delays in adapting to a change in the topology, for instance when a
fault occurs.
The FORWARDDELAY parameter is used to prevent temporary loops in the
network occurring in the briefly unstable topology while a topology change is
propagated through the network. When a port that has been in the Blocking
state in a particular STP topology is to move into the Forwarding state after a
topology change, it must first pass through the Listening and Learning states,
during which it cannot receive or transmit packets. The FORWARDDELAY
parameter determines how long the ports remains in each of the Listening and
Learning states before moving on to the Forwarding state in the active
topology, that is half the time between when it is decided that the port will
become part of the spanning tree, and when it is allowed to forward traffic. The
FORWARDDELAY parameter should be at least half the time it takes for a
topology change message to reach the whole network. A value that is too short
risks the temporary creation of loops, which can seriously degrade switch
performance. A longer value can result in delays in the network after topology
changes. The default FORWARDDELAY value is 15 seconds.
To modify the parameters controlling these time intervals, use the command:
SET STP={stpname|ALL} [FORWARDDELAY=4..30] [HELLOTIME=1..10]
[MAXAGE=6..40] [other-parameters...]
The value of the PRIORITY parameter is used to set the writable portion of the
bridge ID, i.e. the first two octets of the (8-octet long) Bridge Identifier. The
remaining 6 octets of the bridge ID are given by the MAC address of the
switches. The Bridge Identifier parameter is used in all configuration Spanning
Tree Protocol packets transmitted by the switch. The first two octets, specified
by the PRIORITY parameter, determine the switches priority for becoming the
root bridge or a designated bridge in the network, with the lowest number
indicating the highest priority. In fairly simple networks, for instance those
with a small number of switches in a meshed topology, it may make little
difference which switch is selected to be the root bridge, and no modifications
may be needed to the default PRIORITY parameter, which has a default value
of 32768. In more complex networks, one or more switches are likely to be more
suitable candidates for the root bridge role, for instance by virtue of being more
central in the physical topology of the network. In these cases the STP
PRIORITY parameters for at least one of the switches should be modified.
To change the STP priority value, use the command:
SET STP={stpname|ALL} PRIORITY=0..65535 [other-parameters...]
The PRIORITY parameter sets the priority of the switch to become the Root
Bridge. The lower the value of the Bridge Identifier, the higher the priority. If
the PRIORITY parameter is set, either by specifying the PRIORTY or DEFAULT
parameters, the specified STP is initialised. Counters for the STP are not
affected. The default value for PRIORITY is 32768.
To restore STP timer and priority defaults, use the command:
SET STP={stpname|ALL} [DEFAULTS]
Changing the STP PRIORITY using either of the previous commands initialises
the STP, so that elections for the root bridge and designated bridges begin
again, without resetting STP counters. To display general information about
STPs on the switch, use the command:
SHOW STP[={stpname|ALL}]