PLANET SGSD-1022 - Manual (Page 160)

User’s Manual of SGSD-1022 / SGSD-1022P
SGSW-2840 / SGSW-2840P
4.7.1.2 STA Configuration
Configuring Global Settings
Global settings apply to the entire Managed Switch.
Command Usage
■ Spanning Tree Protocol
Uses RSTP for the internal state machine, but sends only 802.1D BPDUs. This creates one spanning tree instance for the entire
network. If multiple VLANs are implemented on a network, the path between specific VLAN members may be inadvertently
disabled to prevent network loops, thus isolating group members. When operating multiple VLANs, we recommend selecting the
MSTP option.
■ Rapid Spanning Tree Protocol
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.
■ Multiple Spanning Tree Protocol
MSTP generates a unique spanning tree for each instance. This provides multiple pathways across the network, thereby
balancing the traffic load, preventing wide-scale disruption when a bridge node in a single instance fails, and allowing for faster
convergence of a new topology for the failed instance.
- -To allow multiple spanning trees to operate over the network, you must configure a related set of bridges with the same
MSTP configuration, allowing them to participate in a specific set of spanning tree instances.
- -A spanning tree instance can exist only on bridges that have compatible VLAN instance assignments.
- -Be careful when switching between spanning tree modes. Changing modes stops all spanning-tree instances for the
previous mode and restarts the system in the new mode, temporarily disrupting user traffic.
Figure 4-7-2 STA Configuration page screenshot
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