Technical Reference; Mstp Network Example - ZyXEL Communications XS3800-28 User Manual

Table 64 Advanced Application > Spanning Tree Protocol > Status: MSTP (continued)
LABEL
Designated Port ID
Designated Cost
Root Guard State

13.10 Technical Reference

13.10.1 MSTP Network Example

The following figure shows a network example where two VLANs are configured on the two switches. If
the switches are using STP or RSTP, the link for VLAN 2 will be blocked as STP and RSTP allow only one link
in the network and block the redundant link.
Figure 134 STP/RSTP Network Example
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.
Chapter 13 Spanning Tree Protocol
DESCRIPTION
This field displays the priority and number of the bridge port (on the designated bridge),
through which the designated bridge transmits the stored configuration messages.
This field displays the path cost to the LAN segment to which the port is connected when the
port is a designated port. Otherwise, it displays the path cost to the root bridge from the
designated port for the LAN segment to which this port is connected.
This field displays the state of the port on which root guard is enabled.
• Root - inconsistent - the Switch receives superior BPDUs on the port and blocks the port.
• Forwarding - the Switch unblocks and allows the port to forward frames again.
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