Chapter 13 Spanning Tree Protocol
Note: Each port can belong to one STP tree only.
Figure 66 MRSTP Network Example
13.1.5 Multiple STP
Multiple Spanning Tree Protocol (IEEE 802.1s) is backward compatible with STP/ RSTP and addresses the limitations of existing spanning tree protocols (STP and RSTP) in networks to include the following features:
•One Common and Internal Spanning Tree (CIST) that represents the entire network’s connectivity.
•Grouping of multiple bridges (or switching devices) into regions that appear as one single bridge on the network.
•A VLAN can be mapped to a specific Multiple Spanning Tree Instance (MSTI). MSTI allows multiple VLANs to use the same spanning tree.
•
13.1.5.1MSTP 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
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