CANOGA PERKINS 9175 Configuration Guide - Manual (Page 41)

CanogaOS Configuration Guide
8-1
8 Configuring MSTP
8.1 Overview
The MSTP (Multiple Spanning Tree Algorithm and Protocol (IEEE 802.1Q-2005))
enables multiple VLANs to be mapped to the same spanning-tree instance, thereby
reducing the number of spanning-tree instances needed to support a large number of
VLANs. The MSTP provides for multiple forwarding paths for data traffic and enables
load balancing. It improves the fault tolerance of the network because a failure in one
instance (forwarding path) does not affect other instances (forwarding paths). The most
common initial deployment of MSTP is in the backbone and distribution layers of a Layer
2 switched network; this deployment provides the highly-available network required in a
service-provider environment.
When the switch is in the multiple spanning-tree (MST) modes, the Rapid Spanning Tree
Protocol (RSTP), which is based on IEEE 802.1w, is automatically enabled. The RSTP
provides rapid convergence of the spanning tree through explicit handshaking that
eliminates the IEEE 802.1D forwarding delay and quickly transitions root ports and
designated ports to the forwarding state.
8.2 References
IEEE 802.1Q (2005)
8.3 Topology
Figure 8-1: MSTP Topology
8.4 Configurations
Note: This configuration sample assumes that you are running the Layer-2 module. If
you are using the Layer-2 module, run the switchport command on each port to set the
switching characteristics of Layer-2 protocols.
Bridge1 – Bridge4