Fig. 8.13 Port Priority; Fig. 8.14 Port State - SMC Networks 7824M/VSW - annexe 1 Manual

Management Guide
TigerAccess™ EE
SMC7824M/VSW
Root
( 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 )
Fig. 8.13 Port Priority
Port States
Each port on a switch can be in one of five states.
BPDUs or timeout indicate
Potential to become active
Blocking
BPDUs indicate port
should not be active
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.
- Path-cost 100
- Port priority 7
- Port 1
Path 1
Path 2
- Path-cost 100
- Port priority 8
- Port 2
Listening
BPDUs indicate port
should not be active
BPDUs indicate port
should not be active
Forwarding
Disabled
Forwarding timer
expired
Learning
Forwarding timer
expired
CLI
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