Brocade TurboIron 24X Series Configuration Guide - Manual (Page 617)

Brocade TurboIron 24X Series Configuration Guide 583
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802.1s Multiple Spanning Tree Protocol
Configuring bridge priority for an MSTP instance
Priority can be configured for a specified instance. To configure priority for an MSTP instance, use a
command such as the following at the Global Configuration level.
TurboIron(config)#mstp instance 1 priority 8192
Syntax: [no] mstp instance priority
The variable is the number for the instance of MSTP that you are configuring.
You can set a priority to the instance that gives it forwarding preference over lower priority
instances within a VLAN or on the switch. A higher number for the priority variable means a lower
forwarding priority. Acceptable values are 0 - 61440 in increments of 4096. The default value is
32768.
Setting the MSTP global parameters
MSTP has many of the options available in RSTP as well as some unique options. To configure
MSTP Global parameters for all instances on a switch.
TurboIron(config)#mstp force-version 0 forward-delay 10 hello-time 4 max-age 12
max-hops 9
Syntax: [no] mstp force-version forward-delay hello-time
max-age max-hops
The force-version parameter forces the bridge to send BPDUs in a specific format. You can specify
one of the following values:
• 0 – The STP compatibility mode. Only STP BPDUs will be sent. This is equivalent to single STP.
• 2 – The RSTP compatibility mode. Only RSTP BPDUS will be sent. This is equivalent to single
STP.
• 3 – MSTP mode. In this default mode, only MSTP BPDUS will be sent.
The forward-delay specifies how long a port waits before it forwards an RST BPDU after a
topology change. This can be a value from 4 – 30 seconds. The default is 15 seconds.
The hello-time parameter specifies the interval between two hello packets. The parameter
can have a value from 1 – 10 seconds. The default is 2 seconds.
The max-age parameter specifies the amount of time the device waits to receive a hello
packet before it initiates a topology change. You can specify a value from 6 – 40 seconds, where
the value adheres to the following formula.
max age >= 2 *(hello-time + 1)
AND
max age >= 2 *(forward-delay – 1)
The default max-age is 20 seconds.
The max-hops parameter specifies the maximum hop count. You can specify a value from
1 – 40 hops. The default value is 20 hops.