ZyXEL Communications MGS-3712F User Manual page 129

blocked as STP and RSTP allow only one link in the network and block the
redundant link.
Figure 67 STP/RSTP Network Example
VLAN 1
With MSTP, VLANs 1 and 2 are mapped to different spanning trees in the network.
Thus traffic from the two VLANs travel on different paths. The following figure
shows the network example using MSTP.
Figure 68 MSTP Network Example
VLAN 1
13.1.5.2 MST Region
An MST region is a logical grouping of multiple network devices that appears as a
single device to the rest of the network. Each MSTP-enabled device can only
belong to one MST region. When BPDUs enter an MST region, external path cost
(of paths outside this region) is increased by one. Internal path cost (of paths
within this region) is increased by one when BPDUs traverse the region.
MGS-3712/MGS-3712F User's Guide
A
VLAN 2
B
A
VLAN 2
B
Chapter 13 Spanning Tree Protocol
129