Extreme Networks ExtremeWare XOS 10.1, Manual

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142 ExtremeWare XOS 10.1 Concepts Guide
Spanning Tree Protocol (STP)
Rapid Root Failover
ExtremeWare XOS supports rapid root failover for faster STP failover recovery times in STP 802.1d
mode. If the active root port link goes down ExtremeWare XOS recalculates STP and elects a new root
port. Rapid root failover allows the new root port to immediately begin forwarding, skipping the
standard listening and learning phases. Rapid root failover occurs only when the link goes down, and
not when there is any other root port failure, such as missing BPDUs.
The default setting is disabled. To enable rapid root failover, use the following command:
enable stpd <stpd_name> rapid-root-failover
To display the configuration, use the following command:
show stpd {<stpd_name> | detail}
STP Configurations
When you assign VLANs to an STPD, pay careful attention to the STP configuration and its effect on
the forwarding of VLAN traffic.
This section describes three types of STP configurations:
• Basic STP
• Multiple STPDs on a single port (EMISTP)
• A VLAN that spans multiple STPDs
Basic STP Configuration
This section describes a basic, 802.1D STP configuration. Figure 9 illustrates a network that uses VLAN
tagging for trunk connections. The following four VLANs have been defined:
• Sales is defined on switch A, switch B, and switch M.
• Personnel is defined on switch A, switch B, and switch M.
• Manufacturing is defined on switch Y, switch Z, and switch M
• Engineering is defined on switch Y, switch Z, and switch M.
•
Marketing is defined on all switches (switch A, switch B, switch Y, switch Z, and switch M).
Two STPDs are defined:
• STPD1 contains VLANs Sales and Personnel.
• STPD2 contains VLANs Manufacturing and Engineering.
The carrier and protected VLANs are also defined:
• Sales is the carrier VLAN on STPD1.
• Personnel is a protected VLAN on STPD1.
• Manufacturing is a protected VLAN on STPD2.