Chapter 13 Spanning Tree Protocol

13.1.4 Multiple RSTP

MRSTP (Multiple RSTP) is ZyXEL’s proprietary feature that is compatible with RSTP and STP. With MRSTP, you can have more than one spanning tree on your Switch and assign port(s) to each tree. Each spanning tree operates independently with its own bridge information.

In the following example, there are two RSTP instances (MRSTP 1 and MRSTP2) on switch A.

Figure 57 MRSTP Network Example

To set up MRSTP, activate MRSTP on the Switch and specify which port(s) belong to which spanning tree.

Note: Each port can belong to one STP tree only.

13.1.5 Multiple STP

Multiple Spanning Tree Protocol (IEEE 802.1s) is backwards 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.

•Load-balancing is possible as traffic from different VLANs can use distinct paths in a region.

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ES3500 Series User’s Guide