Concept Guide

Recover from Stack Link Flaps..............................................................................................................................890
Recover from a Card Problem State on a Stack................................................................................................. 890
50 Storm Control..........................................................................................................................................892
Congure Storm Control...............................................................................................................................................892
Conguring Storm Control from INTERFACE Mode...........................................................................................892
Conguring Storm Control from CONFIGURATION Mode................................................................................893
51 Spanning Tree Protocol (STP)..................................................................................................................894
Protocol Overview.........................................................................................................................................................894
Congure Spanning Tree.............................................................................................................................................. 895
Related Conguration Tasks...................................................................................................................................895
Important Points to Remember................................................................................................................................... 895
Conguring Interfaces for Layer 2 Mode....................................................................................................................896
Enabling Spanning Tree Protocol Globally...................................................................................................................897
Adding an Interface to the Spanning Tree Group...................................................................................................... 899
Modifying Global Parameters.......................................................................................................................................899
Modifying Interface STP Parameters..........................................................................................................................900
Enabling PortFast.......................................................................................................................................................... 900
Prevent Network Disruptions with BPDU Guard................................................................................................. 901
Selecting STP Root....................................................................................................................................................... 903
STP Root Guard.............................................................................................................................................................903
Root Guard Scenario...............................................................................................................................................903
Conguring Root Guard..........................................................................................................................................904
Enabling SNMP Traps for Root Elections and Topology Changes.......................................................................... 905
Conguring Spanning Trees as Hitless........................................................................................................................905
STP Loop Guard............................................................................................................................................................ 905
Conguring Loop Guard..........................................................................................................................................907
Displaying STP Guard Conguration........................................................................................................................... 907
52 SupportAssist..........................................................................................................................................909
Conguring SupportAssist Using a Conguration Wizard.........................................................................................910
Conguring SupportAssist Manually............................................................................................................................910
Conguring SupportAssist Activity.............................................................................................................................. 912
Conguring SupportAssist Company...........................................................................................................................913
Conguring SupportAssist Person............................................................................................................................... 914
Conguring SupportAssist Server................................................................................................................................914
Viewing SupportAssist Conguration.......................................................................................................................... 915
53 System Time and Date..............................................................................................................................917
Network Time Protocol..................................................................................................................................................917
Protocol Overview....................................................................................................................................................918
Congure the Network Time Protocol...................................................................................................................918
Enabling NTP............................................................................................................................................................ 919
Conguring NTP Broadcasts.................................................................................................................................. 919
Disabling NTP on an Interface................................................................................................................................920
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