Accton Technology ES4524D, ES4548D, 24/48-Port manual 22-14

22 Spanning Tree Algorithm Configuration

The following interface attributes can be configured:

•Spanning Tree – Enables/disables STA on this interface. (Default: Enabled)

•Priority – Defines the priority used for this port in the Spanning Tree Protocol. If the path cost for all ports on a switch are the same, the port with the highest priority (i.e., lowest value) will be configured as an active link in the Spanning Tree. This makes a port with higher priority less likely to be blocked if the Spanning Tree Protocol is detecting network loops. Where more than one port is assigned the highest priority, the port with lowest numeric identifier will be enabled.

•Default: 128

•Range: 0-240, in steps of 16

•Admin Path Cost – This parameter is used by the STA to determine the best path between devices. Therefore, lower values should be assigned to ports attached to faster media, and higher values assigned to ports with slower media. (Path cost takes precedence over port priority.) Note that when the Path Cost Method is set to short (page 3-63), the maximum path cost is 65,535.

By default, the system automatically detects the speed and duplex mode used on each port, and configures the path cost according to the values shown below. Path cost “0” is used to indicate auto-configuration mode.

•Range –

-Ethernet: 200,000-20,000,000

-Fast Ethernet: 20,000-2,000,000

-Gigabit Ethernet: 2,000-200,000

•Default –

-Ethernet – Half duplex: 2,000,000; full duplex: 1,000,000; trunk: 500,000

-Fast Ethernet – Half duplex: 200,000; full duplex: 100,000; trunk: 50,000

-Gigabit Ethernet – Full duplex: 10,000; trunk: 5,000

•Admin Link Type – The link type attached to this interface.

•Point-to-Point – A connection to exactly one other bridge.

•Shared – A connection to two or more bridges.

•Auto – The switch automatically determines if the interface is attached to a point-to-point link or to shared media. (This is the default setting.)

•Admin Edge Port (Fast Forwarding) – You can enable this option if an interface is attached to a LAN segment that is at the end of a bridged LAN or to an end node. Since end nodes cannot cause forwarding loops, they can pass directly through to the spanning tree forwarding state. Specifying Edge Ports provides quicker convergence for devices such as workstations or servers, retains the current forwarding database to reduce the amount of frame flooding required to rebuild address tables during reconfiguration events, does not cause the spanning tree to initiate reconfiguration when the interface changes state, and also overcomes other STA-related timeout problems. However, remember that Edge Port should only be enabled for ports connected to an end-node device. (Default: Disabled)

•Migration – If at any time the switch detects STP BPDUs, including Configuration or Topology Change Notification BPDUs, it will automatically set the selected interface to forced STP-compatible mode. However, you can also use the Protocol

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