Siemens S223 User Manual

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

A50010-Y3-C150-2-7619                                                                         209 

It is same with 802.1d to block the connection of SWITCH D and SWITCH C. However, 
802.1w does not need any configured time to negotiate between switches to make for-
warding state of specific port. So it is very fast progressed. During progress to forwarding 
state of port, listening and learning are not needed. These negotiations use BPDU. 
 

RSTP internally includes STP, so it has compatibility with 802.1d. Therefore, RSTP can 
recognize BPDU of STP. But, STP cannot recognize BPDU of RSTP. For example, as-
sume that SWITCH A and SWITCH B are operated as RSTP and SWITCH A is connected 
to SWITCH C as designated switch. Since SWITCH C, which is 802.1d ignores RSTP 
BPDU, it is interpreted that switch C is not connected to any switch or segment. 

Switch A
(802.1w)

Switch B
(802.1w)

Switch C

(802.1d)

 

Compatibility with 802.1d (1) 

 

However, SWITCH A converts a port received BPDU into RSTP of 802.1d because it can 
read BPDU of SWITCH C. Then SWITCH C can read BPDU of SWITCH A and accepts 
SWITCH A as designated switch. 

Switch A
(802.1w)

Switch B
(802.1w)

Switch C

(802.1d)

 

Compatibility with 802.1d (2) 

 

 

To operate the network more effectively, the hiD 6615 S223/S323 uses MSTP (Multiple 
Spanning-Tree Protocol). It constitutes the network with VLAN subdividing existing LAN 
domain logically and configure the route by VLAN or VLAN group instead of existing rout-
ing protocol.