GS-2750 User’s Guide
215
C
H A P T E R
25
Loop Guard
This chapter shows you how to configure the Switch to guard against loops on the edge of
your network.
25.1 Loop Guard Overview
Loop guard allows you to configure the Switch to shut down a port if it detects that packets
sent out on that port loop back to the Switch. While you can use Spanning Tree Protocol (STP)
to prevent loops in the core of your network. STP cannot prevent loops that occur on the edge
of your network.
Figure 108
Loop Guard vs STP
Loop guard is designed to handle loop problems on the edge of your network. This can occur
when a port is connected to a Switch that is in a loop state. Loop state occurs as a result of
human error. It happens when two ports on a switch are connected with the same cable. When
a switch in loop state sends out broadcast messages the messages loop back to the switch and
are re-broadcast again and again causing a broadcast storm.
If a switch (not in loop state) connects to a switch in loop state, then it will be affected by the
switch in loop state in the following way:
• It will receive broadcast messages sent out from the switch in loop state.
• It will receive its own broadcast messages that it sends out as they loop back. It will then
re-broadcast those messages again.
STP
Loop Guard
Summary of Contents for GS-2750
Page 2: ......
Page 7: ...Safety Warnings GS 2750 User s Guide 7 This product is recyclable Dispose of it properly ...
Page 8: ...Safety Warnings GS 2750 User s Guide 8 ...
Page 26: ...List of Figures GS 2750 User s Guide 26 ...
Page 32: ...32 ...
Page 40: ...Chapter 2 Hardware Installation and Connection GS 2750 User s Guide 40 ...
Page 48: ...48 ...
Page 58: ...Chapter 4 The Web Configurator GS 2750 User s Guide 58 ...
Page 64: ...Chapter 5 Initial Setup Example GS 2750 User s Guide 64 ...
Page 70: ...Chapter 6 System Status and Port Statistics GS 2750 User s Guide 70 ...
Page 82: ...Chapter 7 Basic Setting GS 2750 User s Guide 82 ...
Page 84: ...84 ...
Page 120: ...Chapter 11 Spanning Tree Protocol GS 2750 User s Guide 120 ...
Page 134: ...Chapter 15 Link Aggregation GS 2750 User s Guide 134 ...
Page 144: ...Chapter 17 Port Security GS 2750 User s Guide 144 ...
Page 155: ...Chapter 19 Policy Rule GS 2750 User s Guide 155 Figure 73 Policy Example example ...
Page 156: ...Chapter 19 Policy Rule GS 2750 User s Guide 156 ...
Page 160: ...Chapter 20 Queuing Method GS 2750 User s Guide 160 ...
Page 166: ...Chapter 21 VLAN Stacking GS 2750 User s Guide 166 ...
Page 194: ...Chapter 23 Authentication Accounting GS 2750 User s Guide 194 ...
Page 220: ...220 ...
Page 232: ...Chapter 28 Differentiated Services GS 2750 User s Guide 232 ...
Page 242: ...Chapter 29 DHCP GS 2750 User s Guide 242 ...
Page 252: ...Chapter 30 VRRP GS 2750 User s Guide 252 ...
Page 254: ...254 ...
Page 278: ...Chapter 32 Access Control GS 2750 User s Guide 278 ...
Page 280: ...Chapter 33 Diagnostic GS 2750 User s Guide 280 ...
Page 284: ...Chapter 34 Syslog GS 2750 User s Guide 284 ...
Page 298: ...Chapter 39 Routing Table GS 2750 User s Guide 298 ...
Page 301: ...301 PART VI Product Specifications Product Specifications 303 ...
Page 302: ...302 ...
Page 310: ...310 ...
Page 322: ...Appendix B Legal Information GS 2750 User s Guide 322 ...
Page 328: ...Appendix C Customer Support GS 2750 User s Guide 328 ...