TP-Link T2600G-18TSTL-SG3216 T2600G-18TSUN V1 Configuration Guide - Page 322

Configuring Spanning Tree 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 Path Cost Value 2,000,000 100Mb/s 1Gb/s 200,000 20,000 10Gb/s 2,000 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. Configuration Guide 292