Users Guide

852 Spanning Tree Protocol
MSTP and VLAN IDs
MSTP allows VLAN 4094 to be configured in the MD5 digest of an MSTI
region for compatibility purposes. However, the switch reserves VLAN 4094
internally for use in stacking and will drop received packets tagged with VLAN
4094.
What are the Optional STP Features?
The Dell EMC Networking N-Series switches support the following optional
STP features:
• BPDU flooding
• PortFast
• BPDU filtering
• Root guard
• Loop guard
• BPDU protection
BPDU Flooding
The BPDU flooding feature determines the behavior of the switch when it
receives a BPDU on a port that is disabled for spanning tree. If BPDU
flooding is configured, the switch will flood the received BPDU to all the
ports on the switch which are similarly disabled for spanning tree.
Port Fast
The PortFast feature reduces the STP convergence time by allowing edge
ports that are connected to end devices (such as a desktop computer, printer,
or file server) to transition to the forwarding state without going through the
listening and learning states.
BPDU Filtering
Ports that have the PortFast feature enabled continue to transmit BPDUs.
The BPDU filtering feature prevents PortFast-enabled ports from sending
BPDUs.