Specifications

Management Guide CLI
TigerAccess™ EE
SMC7824M/VSW 261
- Path-cost 100
- Port priority 7
- Port 1
Root
Path 2
Path 1
( path-cost of PATH 1 = path-cost of PATH 2 = 100 ∴ unable to compare
PATH 1 port priority = 7, PATH 2 port priority = 8, PATH 1＜ PATH 2, ∴ PATH 1 is chosen )
- Path-cost 100
- Port priority 8
- Port 2
Fig. 8.13 Port Priority
Port States
Each port on a switch can be in one of five states.
Blocking
Listening
Learning
Forwarding
BPDUs or timeout indicate
Potential to become active
BPDUs indicate port
should not be active
Forwarding timer
expired
BPDUs indicate port
should not be active
BPDUs indicate port
should not be active
Forwarding timer
expired
Disabled
Fig. 8.14 Port State
• Blocking
a port that is enabled, but that is neither a Designated port nor a Root port, will be in
the blocking state. A blocking port will not receive or forward data frames, nor will it
transmit BPDUs, but instead it will listen for other’s BPDUs to determine if and when
the port should consider becoming active in the spanning tree.
• Listening
the port is still not forwarding data traffic, but is listening to BPDUs in order to
compute the spanning tree. The port is comparing its own information (path cost,
Bridge Identifier, Port Identifier) with information received from other candidates and
deciding which is best suited for inclusion in the spanning tree.