Users Guide

Troubleshoot a Stack..................................................................................................................................................... 874
Recover from Stack Link Flaps.............................................................................................................................. 875
Recover from a Card Problem State on a Stack..................................................................................................875
50 Storm Control.......................................................................................................................................... 877
Congure Storm Control............................................................................................................................................... 877
Conguring Storm Control from INTERFACE Mode........................................................................................... 877
Conguring Storm Control from CONFIGURATION Mode................................................................................ 878
51 Spanning Tree Protocol (STP).................................................................................................................. 879
Protocol Overview......................................................................................................................................................... 879
Congure Spanning Tree.............................................................................................................................................. 880
Related Conguration Tasks...................................................................................................................................880
Important Points to Remember................................................................................................................................... 880
Conguring Interfaces for Layer 2 Mode.................................................................................................................... 881
Enabling Spanning Tree Protocol Globally...................................................................................................................882
Adding an Interface to the Spanning Tree Group...................................................................................................... 884
Modifying Global Parameters....................................................................................................................................... 884
Modifying Interface STP Parameters..........................................................................................................................885
Enabling PortFast.......................................................................................................................................................... 885
Prevent Network Disruptions with BPDU Guard.................................................................................................886
Selecting STP Root....................................................................................................................................................... 888
STP Root Guard.............................................................................................................................................................888
Root Guard Scenario............................................................................................................................................... 888
Conguring Root Guard..........................................................................................................................................889
Enabling SNMP Traps for Root Elections and Topology Changes.......................................................................... 890
Conguring Spanning Trees as Hitless........................................................................................................................890
STP Loop Guard............................................................................................................................................................ 890
Conguring Loop Guard..........................................................................................................................................892
Displaying STP Guard Conguration........................................................................................................................... 892
52 SupportAssist.......................................................................................................................................... 894
Conguring SupportAssist Using a Conguration Wizard........................................................................................895
Conguring SupportAssist Manually...........................................................................................................................895
Conguring SupportAssist Activity..............................................................................................................................897
Conguring SupportAssist Company..........................................................................................................................898
Conguring SupportAssist Person.............................................................................................................................. 899
Conguring SupportAssist Server...............................................................................................................................899
Viewing SupportAssist Conguration......................................................................................................................... 900
53 System Time and Date.............................................................................................................................902
Network Time Protocol.................................................................................................................................................902
Protocol Overview...................................................................................................................................................903
Congure the Network Time Protocol..................................................................................................................903
Enabling NTP........................................................................................................................................................... 904
Conguring NTP Broadcasts................................................................................................................................. 904
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Contents