Rapid Pvst+ Interoperation With 802.1S Mst; High Availability For Rapid Pvst; Virtualization Support For Rapid Pvst - Cisco Nexus 7000 Series Configuration Manual

Rapid PVST+ Interoperation with 802.1s MST

• Acknowledgment—When an 802.1w device receives a TCN message on a designated port from an
• Protocol migration—For backward compatibility with 802.1D devices, 802.1w selectively sends 802.1D
Rapid PVST+ Interoperation with 802.1s MST
Rapid PVST+ interoperates seamlessly with the IEEE 802.1s Multiple Spanning Tree (MST) standard. No
user configuration is needed. To disable this seamless interoperation, you can use PVST Simulation.

High Availability for Rapid PVST+

The software supports high availability for Rapid PVST+. However, the statistics and timers are not restored
when Rapid PVST+ restarts. The timers start again and the statistics begin from 0.
See the Cisco Nexus 7000 Series NX-OS High Availability and Redundancy Guide for complete information
Note
on high-availability features.

Virtualization Support for Rapid PVST+

This figure shows how the system provides support for VDCs. Using VDCs, you have a separate Layer 2
virtualization in each VDC, and each VDC runs a separate STP.
Each VDC will have its own Rapid PVST+. You cannot configure Rapid PVST+ across VDCs with Cisco
NX-OS software. However, you can run Rapid PVST+ in one VDC and run MST in each VDC.
For example, VDC1 can run MST, VDC2 can run Rapid PVST+, and VDC3 can run MST.
Cisco Nexus 7000 Series NX-OS Layer 2 Switching Configuration Guide, Release 5.x
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802.1D device, it replies with an 802.1D configuration BPDU with the TCA bit set. However, if the
TC-while timer (the same as the TC timer in 802.1D) is active on a root port connected to an 802.1D
device and a configuration BPDU with the TCA set is received, the TC-while timer is reset.
This method of operation is required only for 802.1D devices. The 802.1w BPDUs do not have the TCA
bit set.
configuration BPDUs and TCN BPDUs on a per-port basis.
When a port is initialized, the migrate-delay timer is started (specifies the minimum time during which
802.1w BPDUs are sent), and 802.1w BPDUs are sent. While this timer is active, the device processes
all BPDUs received on that port and ignores the protocol type.
If the device receives an 802.1D BPDU after the port migration-delay timer has expired, it assumes that
it is connected to an 802.1D device and starts using only 802.1D BPDUs. However, if the 802.1w device
is using 802.1D BPDUs on a port and receives an 802.1w BPDU after the timer has expired, it restarts
the timer and starts using 802.1w BPDUs on that port.
Configuring Rapid PVST+ Using Cisco NX-OS