Stp Operation; Fig. 8.10 Root Switch - Siemens S223 User Manual

User Manual
SURPASS hiD 6615 S223/S323 R1.5
8.3.1
A50010-Y3-C150-2-7619
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
•
STP 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
RP
Switch B
Priority : 9
DP
Switch D
Root Switch
Fig. 8.10
ROOT
DP
RP
Switch C
Priority : 10
DP
RP
RP = Root Port
DP = Designated Port
UMN:CLI
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