Default Settings For Stp Extensions - Cisco Nexus 9000 Series Configuration Manual

Configuring STP Extensions Using Cisco NX-OS
• We recommend that you enable BPDU Guard on all edge ports.
• Enabling Loop Guard globally works only on point-to-point links.
• Enabling Loop Guard per interface works on both shared and point-to-point links.
• Root Guard forces a port to always be a designated port; it does not allow a port to become a root port.
• Loop Guard has no effect on a disabled spanning tree instance or a VLAN.
• Spanning tree always chooses the first operational port in the channel to send the BPDUs. If that link
• If you group together a set of ports that are already blocked by Loop Guard to form a channel, spanning
• If a channel is blocked by Loop Guard and the channel members go back to an individual link status,
• You should enable Loop Guard globally on a switch network with physical loops.
• You should enable Root Guard on ports that connect to network devices that are not under direct

Default Settings for STP Extensions

This table lists the default settings for STP extensions.
Table 14: Default STP Extension Parameters
Parameters
Port type
Bridge Assurance
Global BPDU Guard
BPDU Guard per interface
Global BPDU Filtering
Loop Guard is effective only if the port is a root port or an alternate port. You cannot enable Loop Guard
and Root Guard on a port at the same time.
becomes unidirectional, Loop Guard blocks the channel, even if other links in the channel are functioning
properly.
tree loses all the state information for those ports and the new channel port may obtain the forwarding
state with a designated role.
spanning tree loses all the state information. The individual physical ports may obtain the forwarding
state with the designated role, even if one or more of the links that formed the channel are unidirectional.
You can enable UniDirectional Link Detection (UDLD) aggressive mode to isolate the
Note
link failure. A loop may occur until UDLD detects the failure, but Loop Guard will not
be able to detect it. See the Cisco NX-OSSeries NX-OS Interfaces Configuration Guide,
for information on UDLD.
administrative control.
Cisco Nexus 9000 Series NX-OS Layer 2 Switching Configuration Guide, Release 7.x
Default Settings for STP Extensions
Default
Normal
Enabled (on STP network ports only)
Disabled
Disabled
Disabled
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