Chapter 13 Spanning Tree Protocol
XGS1930 Series User’s Guide
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13.8 Technical Reference
This section provides technical background information on the topics discussed in this chapter.
13.8.1 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 104
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.
Designated Bridge
ID
This field displays the identifier of the designated bridge to which this port belongs when the
port is a designated port. Otherwise, it displays the identifier of the designated bridge for the
LAN segment to which this port is connected.
Designated Port ID
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.
Designated Cost
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,
Table 64 Advanced Application > Spanning Tree Protocol > Status: MSTP (continued)
LABEL
DESCRIPTION