Table 11-2 Recommended Sta Path Costs - Edge-Core ES3528-WDM Management Manual

11
Spanning Tree Algorithm
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.)
(Range: 0 for auto-configuration, 1-65535 for the short path cost method
1-200,000,000 for the long path cost method)
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. When the short path cost
method is selected and the default path cost recommended by the IEEE 8021w
standard exceeds 65,535, the default is set to 65,535.
Table 11-1 Recommended STA Path Cost Range
Port Type
Fast Ethernet
Gigabit Ethernet
Port Type
Fast Ethernet
Gigabit Ethernet
Port Type
Fast Ethernet
Gigabit Ethernet
20. Refer to "Configuring Global Settings" on page 6 for information on setting the path cost
method.
11-14
IEEE 802.1D-1998
10-60
3-10

Table 11-2 Recommended STA Path Costs

Link Type IEEE 802.1D-1998
Half Duplex 19
Full Duplex 18
Trunk 15
Full Duplex 4
Trunk 3
Table 11-3 Default STA Path Costs
Link Type
Half Duplex
Full Duplex
Trunk
Full Duplex
Trunk
IEEE 802.1w-2001
20,000-2,000,000
2,000-200,000
IEEE 802.1w-2001
200,000
100,000
50,000
10,000
5,000
IEEE 802.1w-2001
200,000
100,000
50,000
10,000
5,000
20
,