Specifications

8-38 Rapier Switch Software Reference
Software Release 2.7.3
C613-03098-00 REV A
To modify the parameters controlling these time intervals, use the command:
set stp={stp-name|all} [forwarddelay=4..30] [hellotime=1..10]
[maxage=6..40]
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 switch’s priority for becoming the
Root Bridge or a Designated Bridge in the network, with a lower number
indicating a higher 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 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 priority parameters
for at least one of the switches should be modified.
To change the STP priority value, use the command:
set stp={stp-name|all} priority=0..65535
To restore STP timer and priority defaults, use the command:
set stp={stp-name|all} default
Changing the 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[={stp-name|all}]
Each port has a port priority, with a default of 128, used to determine which
port should be the root port for the STP if two ports are connected in a loop. A
lower number indicates the higher priority.
set stp={stp-name|all} port={port-list|all}
portpriority=0..255
Each port also has a path cost, which is used if the port is the root port for the
STP on the switch. The path cost is added to the root path cost field in
configuration messages received on the port to determine the total cost of the
path to the Root Bridge. The default pathcost values and the range of
recommended pathcost values depend on the port speed and mode, see
Table 8 -9 and Tabl e 8-10 . If the path cost for a port is not explicitly set, it varies
as the speed of the port varies.
Table 8-9: Path cost values and port speed for standard mode
Port speed Default PATHCOST Recommended PATHCOST range
10Mbps 100 50-600
100Mbps 19 10-60
1Gbps 4 3-10