Siemens S223 - Manual (Page 208)

UMN:CLI User Manual
SURPASS hiD 6615 S223/S323 R1.5
208 A50010-Y3-C150-2-7619
SWITCH A negotiates with root through BPDU. To make link between SWITCH A and root,
port state of non-edge designated port of SWITCH is changed to blocking. Although
SWITCH A is connected to root, loop will not be created because SWITCH A is blocked to
SWITCH Band C. In this state, BPDU form root is transmitted to SWITCH B and C
through SWITCH A. To configure forwarding state of SWITCH A, SWITCH A negotiates
with SWITCH B and SWITCH C.
Switch B Switch C
ROOT
Switch D
3. Forwarding
3. Negotiate between
Switch A and Switch C
(Traffic Blocking)
Switch A
3. Negotiate between
Switch A and Switch B
(Traffic Blocking)
Fig. 8.18 Network Convergence of 802.1w (2)
SWITCH B has only edge-designated port. Edge designated does not cause loop, so it is
defined in 802.1w to be changed to forwarding state. Therefore, SWITCH B does not
need to block specific port to forwarding state of SWITCH A. However since SWITCH C
has a port connected to SWITCH D, you should make blocking state of the port.
Switch B Switch C
ROOT
Switch D
Switch A
4. Forwarding state 4. Forwarding state
4. Block to make Forwarding
state of Switch A
Fig. 8.19 Network Convergece of 802.1w (3)