SonicWall Switch Getting Started Guide
Configuring from the Firewall
53
Setting Spanning Tree Protocol
Loops occur when alternate routes exist between hosts. Loops in an extended network can cause the Switch to
forward traffic indefinitely, resulting in increased traffic and reducing network efficiency. Once the STP is
enabled and configured, primary links are established and duplicated links are blocked automatically. The
reactivation of the blocked links is also accomplished automatically. STP provides a tree topology and other
Spanning tree versions supported include STP, Multiple Spanning Tree Protocol (MSTP), and Rapid Spanning
Tree Protocol (RSTP). Please note that only one spanning tree can be active on the Switch at a time. The default
setting is: MSTP.
Multiple Spanning Tree Protocol (MSTP) defined in IEEE 802.1s, enables multiple VLANs to be mapped to reduce
the number of spanning-tree instances needed to support a large number of VLANs. If there is only one VLAN in
the network, a single STP works appropriately.
If the network contains more than one VLAN however, the logical network configured by a single STP would
work, but it becomes more efficent to use the alternate paths available by using an alternate spanning tree for
different VLANs or groups of VLANs. MSTP (which is based on RSTP for fast convergence) is designed to support
independent spanning trees based on VLAN groups. MSTP provides multiple forwarding paths for data traffic
and enables load balancing.
STP and RSTP prevent loops from forming by ensuring that only one path exists between the end nodes in your
network. RSTP is designed as a general replacement for the slower, legacy STP. RSTP is also incorporated into
MSTP. With STP, convergence can take up to a minute to complete in a larger network. This can result in the
loss of communication between various parts of the network during the convergence process so STP can
subsequently can lose data packets during transmission.
To set Spanning Tree Protocol Configuration:
1 Navigate to
MANAGE | Switch Controller > Overview
and then click on the 3 dot menu to at the right
end of the Switch graphic. When the menu appears, click on
Edit
. Then click on
Advanced
. The dialog box
will appear:
2 For the two STP entries:
• STP Mode
— Sets the protocol version to Multiple (MSTP) or Rapid (RSTP).
• STP State
— Enables or Disables spanning tree operation on the Switch.
3 Click on
OK
.
