Reference Guide

Table Of Contents
Removing Front End Port Stacking.................................................................................................................786
Troubleshoot an S-Series Stack...........................................................................................................................786
Recover from Stack Link Flaps.......................................................................................................................786
Recover from a Card Problem State on an S-Series Stack............................................................................787
Recover from a Card Mismatch State on an S-Series Stack.........................................................................787
49 Storm Control......................................................................................................................... 791
Configure Storm Control....................................................................................................................................... 791
Configuring Storm Control from INTERFACE Mode........................................................................................791
Configuring Storm Control from CONFIGURATION Mode..............................................................................791
50 Spanning Tree Protocol (STP).............................................................................................793
Protocol Overview................................................................................................................................................ 793
Configure Spanning Tree......................................................................................................................................793
Related Configuration Tasks.......................................................................................................................... 793
Important Points to Remember.............................................................................................................................794
Configuring Interfaces for Layer 2 Mode..............................................................................................................794
Enabling Spanning Tree Protocol Globally........................................................................................................... 795
Adding an Interface to the Spanning Tree Group.................................................................................................797
Modifying Global Parameters...............................................................................................................................798
Modifying Interface STP Parameters...................................................................................................................799
Enabling PortFast..................................................................................................................................................799
Prevent Network Disruptions with BPDU Guard............................................................................................800
Selecting STP Root............................................................................................................................................... 802
STP Root Guard.....................................................................................................................................................802
Root Guard Scenario......................................................................................................................................802
Configuring Root Guard..................................................................................................................................803
Enabling SNMP Traps for Root Elections and Topology Changes....................................................................... 804
Configuring Spanning Trees as Hitless.................................................................................................................804
STP Loop Guard.................................................................................................................................................... 805
Configuring Loop Guard................................................................................................................................. 806
Displaying STP Guard Configuration.................................................................................................................... 807
51 System Time and Date..........................................................................................................809
Network Time Protocol.........................................................................................................................................809
Protocol Overview..........................................................................................................................................810
Configure the Network Time Protocol............................................................................................................810
Enabling NTP..................................................................................................................................................811
Setting the Hardware Clock with the Time Derived from NTP.......................................................................811
Configuring NTP Broadcasts..........................................................................................................................811
Disabling NTP on an Interface....................................................................................................................... 812
Configuring a Source IP Address for NTP Packets........................................................................................812