802.1w Rapid Spanning Tree Protocol (RSTP) 802.1d Spanning Tree Protocol (STP)

How Spanning Tree Operates

C a u t i o n

In addition to faster network reconfiguration, RSTP also implements greater ranges for port path costs to accommodate the higher and higher connection speeds that are being implemented.

RSTP is designed to be compatible with IEEE 802.1d STP, and HP recommends that you employ it in your network. For more information, refer to “Transi­ tioning from STP to RSTP” on page 13-8.

STP (802.1d)

The IEEE 802.1d version of spanning tree has been in wide use and can coexist in a network in which RSTP (802.1w) has been introduced. if your network currently uses 802.1d STP and you are not yet ready to implement RSTP, you can apply STP to the Series 5300XL switches until such time as you are ready to move ahead with RSTP. STP on the Series 5300XL switches offers the full range of STP features found in earlier product releases, including:

STP Fast Mode for Overcoming Server Access Failures: If an end node is configured to automatically access a server, the duration of the STP startup sequence can result in a “server access failure”. On ports where this is a problem, configuring STP Fast Mode can eliminate the failure. For more information, see “STP Fast Mode” on page 13-26.The next sections describe how to configure STP on the switch. For more information on STP operation, see “How Spanning Tree Operates” on page 13-4.

Fast-Uplink STP for Improving the Recovery (Convergence) Time

in Wiring Closet Switches with Redundant Uplinks: This means that a Series 5300XL switch having redundant links toward the root device can decrease the convergence time to a new uplink port to as little as ten seconds. For more information, refer to “Fast-Uplink Spanning Tree Protocol (STP)” on page 13-27.

Because the switch automatically gives faster links a higher priority, the default STP parameter settings are usually adequate for spanning tree operation. Also because incorrect STP settings can adversely affect network performance, you should not make changes unless you have a strong understanding of how STP operates. For more on STP, see the IEEE 802.1D standard.

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