RSTP Parameters and Defaults

The following table lists the default RSTP states for RUCKUS devices.

Default RSTP States

Device Type Default RSTP Type Default RSTP State Default RSTP State of New VLANs
Router image default IEEE 802.1W Enabled Disabled

The following table lists the default RSTP bridge parameters. The bridge parameters affect the entire spanning tree. If you are using Multiple Spanning Tree Protocol (MSTP), the parameters affect the VLAN.

Default RSTP Bridge Parameters

Parameter Description Default and Valid Values
Forward Delay

The period of time spent by a port in the listening and learning state before moving on to the learning or forwarding state, respectively.

The forward delay value is also used for the age time of dynamic entries in the filtering database, when a topology change occurs.

5 seconds

Possible values: 4 through 30 seconds

Maximum Age

The interval a bridge will wait for a configuration BPDU from the root bridge before initiating a topology change.

20 seconds

Possible values: 6 through 40 seconds

Hello Time

The interval of time between each configuration BPDU sent by the root bridge.

2 seconds

Possible values: 1 through 10 seconds

Priority

A parameter used to identify the root bridge in a spanning tree (instance of RSTP). The bridge with the lowest value has the highest priority and is the root.

A higher numerical value means a lower priority; thus, the highest priority is 0.

32768

Possible values: 0 through 61440 (in increments of 4096)

Note: If a switch is to become a root bridge, before upgrading to FastIron release 10.0.20a, the switch priority must be configured to be less than 4096 and the priority of the other switches must be configured to be greater than 4096.
Note: If the priority of a switch is less than 4096, the priority will be updated to 0 after the upgrade to FastIron release 10.0.20a. If the switch priority is greater than 4096 and not a multiple of 4096, the priority will be updated to the lower multiple of 4096 after upgrade to FastIron release 10.0.20a.
Note: If you plan to change RSTP bridge timers, RUCKUS recommends that you stay within the following ranges (as defined in section 8.10.2 of the IEEE 802.1D STP specification): 2 * (forward_delay – 1 second) >= max_agemax_age >= 2 * (hello_time + 1 second).

The following table lists the default RSTP port parameters. The port parameters affect individual ports and are separately configurable on each port.

Default RSTP Port Parameters

Parameter Description Default and Valid Values
Priority

The preference that RSTP gives this port relative to other ports for forwarding traffic out of the spanning tree.

A higher numerical value means a lower priority.

128

Possible values: 0 through 240 (configurable in increments of 16)

Path Cost The cost of using the port to reach the root bridge. When selecting among multiple links to the root bridge, RSTP chooses the link with the lowest path cost and blocks the other paths. Each port type has its own default RSTP path cost.

10 Mbps: 2,000,000

100 Mbps: 200,000

1 Gbps: 20,000

10 Gbps: 2,000

possible values: 1 through 200000000