R0106-HP MSR Router Series Layer 2 - LAN Switching Configuration Guide(V7)

MSTI calculation

Within an MST region, MSTP generates different MSTIs for different VLANs based on the

VLAN-to-instance mappings. For each spanning tree, MSTP performs a separate calculation process

similar to spanning tree calculation in STP. For more information, see "Calculation process of the STP

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In MSTP, a VLAN packet is forwarded along the following paths:

• Within an MST region, the packet is forwarded along the corresponding MSTI.

• Between two MST regions, the packet is forwarded along the CST.

MSTP implementation on devices

MSTP is compatible with STP and RSTP. Devices that are running MSTP and that are used for spanning

tree calculation can identify STP and RSTP protocol packets.

In addition to basic MSTP functions, the following functions are provided for ease of management:

• Root bridge hold

• Root bridge backup

• Root guard

• BPDU guard

• Loop guard

• TC-BPDU guard

• Port role restriction

• TC-BPDU transmission restriction

• Support for hot swapping of interface cards and active/standby changeover.

Protocols and standards

MSTP is documented in the following protocols and standards:

• IEEE 802.1d, Media Access Control (MAC) Bridges

• IEEE 802.1w, Part 3: Media Access Control (MAC) Bridges—Amendment 2: Rapid Reconfiguration

• IEEE 802.1s, Virtual Bridged Local Area Networks—Amendment 3: Multiple Spanning Trees

• IEEE 802.1Q-REV/D1.3, Media Access Control (MAC) Bridges and Virtual Bridged Local Area

Networks —Clause 13: Spanning tree Protocols

Feature and hardware compatibility

This feature is supported on the following hardware:

MSR routers installed with Layer 2 switching modules.

Spanning tree configuration task lists

Before configuring a spanning tree, complete the following tasks:

• Determine the spanning tree protocol to be used (STP, RSTP, PVST, or MSTP).