Siemens S223, S323 user manual STP Operation, Root Switch, A50010-Y3-C150-2-7619 201

User Manual	UMN:CLI
SURPASS hiD 6615 S223/S323 R1.5

Meanwhile, RSTP (Rapid Spanning-Tree Protocol) defined in IEEE 802.1w innovate re- duces the time of network convergence on STP (Spanning-Tree Protocol). It is easy and fast to configure new protocol.

Also, 802.1w includes 802.1d inside, so it can provide compatibility with 802.1d. For more detail description of STP and RSTP, refer to the following.

•STP Operation

•RSTP Operation

•MSTP Operation

•Configuring STP/RSTP/MSTP/PVSTP/PVRSTP Mode (Required)

•Configuring STP/RSTP/MSTP

•Configuring PVSTP/PVRSTP

•Root Guard

•Restarting Protocol Migration

•Bridge Protocol Data Unit Configuration

•Sample Configuration

8.3.1STP Operation

The 802.1d STP defines port state as blocking, listening, learning, and forwarding. When STP is configured in LAN with double-path, switches exchange their information including bridge ID. It is named as BPDU (Bridge Protocol Data Unit). Switches decide port state based on the exchanged BPDU and automatically decide optimized path to communicate with the root switch.

Root Switch

The most important information to decide the root switch is bridge ID. Bridge ID is com- posed of 2 bytes-priority and 6 bytes-MAC address. The root switch is decided with the lowest bridge ID.

Switch A

Priority : 8

DP DP

RP

Switch B

Priority : 9

DP

RP

Switch D

Fig. 8.10 Root Switch

ROOT

RP

Switch C

Priority : 10

DP

RP = Root Port

DP = Designated Port

A50010-Y3-C150-2-7619 201