Users Guide

ethernet1/1/6:3 Root 128.282 128 2000 FWD 0 AUTO No
ethernet1/1/6:4 Altr 128.283 128 2000 BLK 0 AUTO No
EdgePort forward trac
EdgePort allows the interface to forward trac approximately 30 seconds sooner as it skips the Blocking and Learning states. The
spanning-tree bpduguard enable command causes the interface hardware to shut down when it receives a BPDU.
CAUTION: Congure EdgePort only on links connecting to an end station. EdgePort can cause loops if you enable it on an
interface connected to a network.
• Enable EdgePort on an interface in INTERFACE mode.
spanning-tree port type edge
Congure EdgePort and view interface status
OS10(conf-if-eth1/1/5)# spanning-tree port type edge
View interface status
OS10# show spanning-tree interface ethernet 1/1/5
ethernet1/1/5 of RSTP 1 is designated Forwarding
Edge port:yes port guard :none (default)
Link type is point-to-point (auto)
Boundary: YES bpdu filter :disable bpdu guard :disable bpduguard shutdown-on-
violation :disable RootGuard: disable LoopGuard disable
Bpdus (MRecords) sent 610, received 5
Interface Designated
Name PortID Prio Cost Sts Cost Bridge ID PortID
-----------------------------------------------------------------------
ethernet1/1/5 128.272 128 500 FWD 0 32768 90b1.1cf4.a911 128.272
=======================================================================
Spanning-tree extensions
STP extensions ensure ecient network convergence by securely enforcing the active network topology. OS10 supports BPDU ltering,
BPDU guard, loop guard, and root guard STP extensions.
BPDU
ltering Protects the network from unexpected ooding of BPDUs from an erroneous device. Enabling BPDU Filtering
instructs the hardware to drop BPDUs and prevents ooding from reaching the CPU. BPDU ltering is enabled by
default on Edge ports. All BPDUs received on the Edge port are dropped. If you explicitly congure BPDU ltering
on a port, that port drops all BPDUs that it receives.
BPDU guard Blocks the L2 bridged ports and LAG ports connected to end hosts and servers from receiving any BPDUs. When
you enable BPDU guard, it places a port (bridge or LAG) in an Error_Disable or Blocking state if the port receives
any BPDU frames. In a LAG, all member ports (including new members) are placed in an Blocking state. The
network trac drops but the port continues to forward BPDUs to the CPU that are later dropped. To prevent
further reception of BPDUs, congure a port to shut down using the
shutdown command. The port can only
resume operation from the Shutdown state after manual intervention.
Root guard Avoids bridging loops and preserves the root bridge position during network transitions. STP selects the root bridge
with the lowest priority value. During network transitions, another bridge with a lower priority may attempt to
become the root bridge and cause unpredictable network behavior. Congure the spanning-tree guard
root command to avoid such an attempt and preserves the position of the root bridge. Root guard is enabled on
ports that are designated ports. The root guard conguration applies to all VLANs congured on the port.
Loop guard Prevents L2 forwarding loops caused by a hardware failure (cable failure or an interface fault). When a hardware
failure occurs, a participating spanning tree link becomes unidirectional and a port stops receiving BPDUs. When a
blocked port stops receiving BPDUs, it transitions to a Forwarding state causing spanning tree loops in the
network. You can enable loop guard on a port that transitions to the Loop-Inconsistent state until it receives
170 Layer 2