Filter
Top Products
CHAPTER
12-1
Catalyst 2950 Desktop Switch Software Configuration Guide
78-14982-01
12
Configuring RSTP and MSTP
This chapter describes how to configure the Cisco implementation of the IEEE 802.1W Rapid Spanning
Tree Protocol (RSTP) and the IEEE 802.1S Multiple STP (MSTP) on your switch. To use the features
described in this chapter, you must have the enhanced software image (EI) installed on your switch.
RSTP provides rapid convergence of the spanning tree. MSTP, which uses RSTP to provide rapid
convergence, enables VLANs to be grouped into a spanning-tree instance, 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 and RSTP 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.
Both RSTP and MSTP improve the operation of the spanning tree while maintaining backward
compatibility with equipment that is based on the (original) 802.1D spanning tree, with existing Cisco
per-VLAN spanning tree (PVST+), and with the existing Cisco-proprietary Multiple Instance STP
(MISTP). For information about STP, see Chapter 11, “Configuring STP.” For information about
optional spanning-tree features, see Chapter 13, “Configuring Optional Spanning-Tree Features.”
Note For complete syntax and usage information for the commands used in this chapter, refer to the
command reference for this release.
This chapter consists of these sections:
• Understanding RSTP, page 12-2
• Understanding MSTP, page 12-7
• Interoperability with 802.1D STP, page 12-11
• Configuring RSTP and MSTP Features, page 12-11
• Displaying the MST Configuration and Status, page 12-23