SMC Networks SMC8150L2 manual 121

Spanning Tree Algorithm Configuration 3

-Discarding – Port receives STA configuration messages, but does not forward packets.

-Learning – Port has transmitted configuration messages for an interval set by the Forward Delay parameter without receiving contradictory information. Port address table is cleared, and the port begins learning addresses.

-Forwarding – Port forwards packets, and continues learning addresses.

•Trunk – Indicates if a port is a member of a trunk. (STA Port Configuration only)

The following interface attributes can be configured:

•MST Instance ID – Instance identifier to configure. (Default: 0)

•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)

•MST Path Cost – This parameter is used by the MSTP 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.

-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

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