LevelOne GSW-2692 - Manual (Page 133)

Spanning Tree Algorithm Configuration
3-97
3
Configuring Global Settings
Global settings apply to the entire switch.
Command Usage
• Spanning Tree Protocol*
Uses RSTP for the internal state machine, but sends only 802.1D BPDUs.
• Rapid Spanning Tree Protocol* 8
RSTP supports connections to either STP or RSTP nodes by monitoring the
incoming protocol messages and dynamically adjusting the type of protocol
messages the RSTP node transmits, as described below:
- STP Mode – If the switch receives an 802.1D BPDU (i.e., STP BPDU) after a
port’s migration delay timer expires, the switch assumes it is connected to an
802.1D bridge and starts using only 802.1D BPDUs.
- RSTP Mode – If RSTP is using 802.1D BPDUs on a port and receives an RSTP
BPDU after the migration delay expires, RSTP restarts the migration delay timer
and begins using RSTP BPDUs on that port.
Command Attributes
Basic Configuration of Global Settings
• Spanning Tree State – Enables/disables STA on this switch. (Default: Enabled)
• Spanning Tree Type – Specifies the type of spanning tree used on this switch:
- STP: Spanning Tree Protocol (IEEE 802.1D); i.e., when this option is selected,
the switch will use RSTP set to STP forced compatibility mode).
- RSTP: Rapid Spanning Tree (IEEE 802.1w); RSTP is the default.
• Priority – Bridge priority is used in selecting the root device, root port, and
designated port. The device with the highest priority becomes the STA root device.
However, if all devices have the same priority, the device with the lowest MAC
address will then become the root device. (Note that lower numeric values indicate
higher priority.)
- Default: 32768
- Range: 0-61440, in steps of 4096
- Options: 0, 4096, 8192, 12288, 16384, 20480, 24576, 28672, 32768, 36864,
40960, 45056, 49152, 53248, 57344, 61440
Root Device Configuration
• Hello Time – Interval (in seconds) at which the root device transmits a
configuration message.
- Default: 2
- Minimum: 1
- Maximum: The lower of 10 or [(Max. Message Age / 2) -1]
8. STP and RSTP BPDUs are transmitted as untagged frames, and will cross any VLAN
boundaries.