ZyXEL Communications GS2210-24, Руководство пользователя

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GS2210 Series User’s Guide
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H A P T E R
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Loop Guard
27.1 Loop Guard Overview
This chapt er show s you how t o configur e t he Sw it ch t o guar d against loops on t he edge of your
net wor k.
Loop guar d allow s you t o configur e t he Sw it ch t o shut dow n a por t if it det ect s t hat packet s sent out
on t hat por t loop back t o t he Sw it ch. While you can use Spanning Tr ee Pr ot ocol ( STP) t o pr event
loops in t he cor e of your net w or k. STP cannot pr event loops t hat occur on t he edge of your
net wor k.
Figure 178 Loop Guar d vs. STP
Refer t o Sect ion 27.1.2 on page 257 for m or e infor m at ion.
27.1.1 What You Can Do
Use t he Loop Gu a r d scr een ( Sect ion 27.2 on page 259 ) t o enable loop guar d on t he Swit ch and in
specific por t s.
27.1.2 What You Need to Know
Loop guar d is designed t o handle loop pr oblem s on t he edge of your net work . This can occur w hen
a por t is connect ed t o a Swit ch t hat is in a loop st at e. Loop st at e occur s as a r esult of hum an er r or.
I t happens w hen t w o por t s on a sw it ch ar e connect ed w it h t he sam e cable. When a sw it ch in loop
st at e sends out br oadcast m essages t he m essages loop back t o t he sw it ch and ar e r e- br oadcast
again and again causing a br oadcast st or m .
I f a sw it ch ( not in loop st at e) connect s t o a sw it ch in loop st at e, t hen it w ill be affect ed by t he
sw it ch in loop st at e in t he follow ing way:
STP
Loop Guard