LevelOne FGL-2870 - Manual (Page 257)

Spanning Tree Algorithm Configuration
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3
• 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.)
• Root Guard – STA allows a bridge with a lower bridge identifier (or same identifier
and lower MAC address) to take over as the root bridge at any time. Root Guard
can be used to ensure that the root bridge is not formed at a suboptimal location.
Root Guard should be enabled on any designated port connected to low-speed
bridges which could potentially overload a slower link by taking over as the root port
and forming a new spanning tree topology. It could also be used to form a border
around part of the network where the root bridge is allowed. (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
Migration button to manually re-check the appropriate BPDU format (RSTP or
STP-compatible) to send on the selected interfaces. (Default: Disabled)
Fast Ethernet Half Duplex
Full Duplex
Trunk
19
18
15
200,000
100,000
50,000
Gigabit Ethernet Full Duplex
Trunk
4
3
10,000
5,000
Table 3-14 Default STA Path Costs
Port Type Link Type IEEE 802.1w-2001
Ethernet Half Duplex
Full Duplex
Trunk
2,000,000
1,000,000
500,000
Fast Ethernet Half Duplex
Full Duplex
Trunk
200,000
100,000
50,000
Gigabit Ethernet Full Duplex
Trunk
10,000
5,000
Table 3-13 Recommended STA Path Costs
Port Type Link Type IEEE 802.1D-1998 IEEE 802.1w-2001