TP-Link T1600G-18TS Configuration Manual page 226

Configuring Spanning Tree
Learning and Forwarding status correspond exactly to the Learning and Forwarding status
specified in STP.
In TP-Link switches, the port status includes: Blocking, Learning, Forwarding and
Disconnected.
 Blocking
In this status, the port receives and sends BPDUs. The other packets are dropped.
 Learning
In this status, the port receives and sends BPDUs. It also receives the other user packets to
update its MAC address table, but doesn't forward them.
 Forwarding
In this status, the port receives and sends BPDUs. It also receives the other user packets to
update its MAC address table, and forwards them.
 Disconnected
In this status, the port is enabled with spanning tree function but not connected to any
device.
Path Cost
The path cost reflects the link speed of the port. The smaller the value, the higher link
speed the port has.
The path cost can be manually configured on each port. If not, the path cost values are
automatically calculated according to the link speed as shown below:
Table 1-1 The Default Path Cost Value
Link Speed
10Mb/s
100Mb/s
1Gb/s
10Gb/s
Root Path Cost
The root path cost is the accumulated path costs from the root bridge to the other
switches. When root bridge sends its BPDU, the root path cost value is 0. When a
connected switch receives this BPDU, it increments the path cost of its local incoming port.
Then it forwards this BPDU to the downstream switch, with the updated root path cost. The
value of the accumulated root path cost increases as the BPDU propagates further.
Path Cost Value
2,000,000
200,000
20,000
2,000
Spanning Tree
Configuration Guide 203