C
HAPTER
33
| Spanning Tree Commands
– 769 –
COMMAND USAGE
◆ An edge port should only be connected to end nodes which do not
generate BPDUs. If a BPDU is received on an edge port, this indicates
an invalid network configuration, or that the switch may be under
attack by a hacker. If an interface is shut down by BPDU Guard, it must
be manually re-enabled using the no spanning-tree spanning-disabled
command.
◆ Before enabling BPDU Guard, the interface must be configured as an
edge port with the spanning-tree edge-port command. Also note that if
the edge port attribute is disabled on an interface, BPDU Guard will also
be disabled on that interface.
EXAMPLE
Console(config)#interface ethernet ethernet 1/5
Console(config-if)#spanning-tree edge-port
Console(config-if)#spanning-tree bpdu-guard
Console(config-if)#
RELATED COMMANDS
spanning-tree edge-port (770)
spanning-tree spanning-disabled (777)
spanning-tree cost This command configures the spanning tree path cost for the specified
interface. Use the no form to restore the default auto-configuration mode.
SYNTAX
spanning-tree cost cost
no spanning-tree cost
cost - The path cost for the port. (Range: 0 for auto-configuration,
1-65535 for short path cost method
12
, 1-200,000,000 for long path
cost method)
12. Use the spanning-tree pathcost method command on page 762 to set the path cost
method.
Table 100: Recommended STA Path Cost Range
Port Type IEEE 802.1D-1998 IEEE 802.1w-2001
Fast Ethernet 10-60 20,000-2,000,000
Gigabit Ethernet 3-10 2,000-200,000
Table 101: Recommended STA Path Cost
Port Type Link Type IEEE 802.1D-1998 IEEE 802.1w-2001
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
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