362
Configuring Optional Spanning-Tree Features
How to Configure the Optional Spanning-Tree Features
Default Optional Spanning-Tree Settings
How to Configure the Optional Spanning-Tree Features
Enabling Optional SPT Features
Before You Begin
Make sure that there are no loops in the network between the trunk port and the workstation or server before you
enable PortFast on a trunk port.
Use PortFast
only
when connecting a single end station to an access or trunk port. Enabling this feature on an
interface connected to a switch or hub could prevent spanning tree from detecting and disabling loops in your
network, which could cause broadcast storms and address-learning problems.
An interface with the PortFast feature enabled is moved directly to the spanning-tree forwarding state without
waiting for the standard forward-time delay.
You cannot enable both loop guard and root guard at the same time.
When you enable UplinkFast, it affects all VLANs on the switch. You cannot configure UplinkFast on an individual
VLAN.
If you enable the voice VLAN feature, the PortFast feature is automatically enabled. When you disable voice VLAN,
the PortFast feature is not automatically disabled.
Table 45
Default Optional Spanning-Tree Settings
Feature
Default Setting
PortFast, BPDU filtering, BPDU guard
Globally disabled (unless they are individually configured per
interface).
UplinkFast
Globally disabled.
BackboneFast
Globally disabled.
EtherChannel guard
Globally enabled.
Root guard
Disabled on all interfaces.
Loop guard
Disabled on all interfaces.
Command
Purpose
1.
show spanning-tree active
or
show spanning-tree mst
Verifies which interfaces are alternate or root ports.
2.
configure terminal
Enters global configuration mode.
3.
spanning-tree loopguard default
Enables loop guard.
By default, loop guard is disabled.
4.
spanning-tree portfast bpduguard default
Enables BPDU guard.
By default, BPDU guard is disabled.
Содержание IE 4000
Страница 12: ...8 Configuration Overview Default Settings After Initial Switch Configuration ...
Страница 52: ...48 Configuring Interfaces Monitoring and Maintaining the Interfaces ...
Страница 108: ...104 Configuring Switch Clusters Additional References ...
Страница 128: ...124 Performing Switch Administration Additional References ...
Страница 130: ...126 Configuring PTP ...
Страница 140: ...136 Configuring CIP Additional References ...
Страница 146: ...142 Configuring SDM Templates Configuration Examples for Configuring SDM Templates ...
Страница 192: ...188 Configuring Switch Based Authentication Additional References ...
Страница 244: ...240 Configuring IEEE 802 1x Port Based Authentication Additional References ...
Страница 274: ...270 Configuring SGT Exchange Protocol over TCP SXP and Layer 3 Transport Configuring Cisco TrustSec Caching ...
Страница 298: ...294 Configuring VLANs Additional References ...
Страница 336: ...332 Configuring STP Additional References ...
Страница 408: ...404 Configuring DHCP Additional References ...
Страница 450: ...446 Configuring IGMP Snooping and MVR Additional References ...
Страница 490: ...486 Configuring SPAN and RSPAN Additional References ...
Страница 502: ...498 Configuring Layer 2 NAT ...
Страница 559: ...555 Configuring Network Security with ACLs How to Configure Network Security with ACLs Creating a Numbered Extended ACL ...
Страница 770: ...766 Configuring IPv6 MLD Snooping Related Documents ...
Страница 930: ...926 Configuring IP Unicast Routing Related Documents ...
Страница 956: ...952 Configuring IPv6 Unicast Routing Configuring IPv6 network 2010 AB8 2 48 network 2010 AB8 3 48 exit address family ...
Страница 976: ...972 Configuring Cisco IOS IP SLAs Operations Additional References ...
Страница 978: ...974 Dying Gasp ...
Страница 990: ...986 Configuring Enhanced Object Tracking Monitoring Enhanced Object Tracking ...
Страница 994: ...990 Configuring MODBUS TCP Displaying MODBUS TCP Information ...
Страница 996: ...992 Ethernet CFM ...
Страница 1030: ...1026 Working with the Cisco IOS File System Configuration Files and Software Images Working with Software Images ...
Страница 1066: ...1062 Using an SD Card SD Card Alarms ...