Chapter 13 Spanning Tree Protocol
GS2210 Series User’s Guide
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STP Port States
STP assigns five por t st at es t o elim inat e packet looping. A br idge por t is not allow ed t o go dir ect ly
fr om blocking st at e t o for war ding st at e so as t o elim inat e t ransient loops.
Multiple RSTP
MRSTP ( Mult iple RSTP) is Zy XEL’s pr opr iet ar y feat ur e t hat is com pat ible w it h RSTP and STP. Wit h
MRSTP, you can have m or e t han one spanning t r ee on your Swit ch and assign por t ( s) t o each t r ee.
Each spanning t ree operat es independent ly w it h it s ow n br idge inform at ion.
I n t he following exam ple, t her e ar e t w o RSTP inst ances ( M RSTP 1 and M RSTP2 ) on sw it ch A.
To set up MRSTP, act ivat e MRSTP on t he Sw it ch and specify w hich por t ( s) belong t o w hich spanning
t ree.
Not e: Each por t can belong t o one STP t r ee only.
Figure 92
MRSTP Net w ork Exam ple
Multiple STP
Mult iple Spanning Tr ee Pr ot ocol ( I EEE 802.1s) is backwar d com pat ible w it h STP/ RSTP and
addr esses t he lim it at ions of exist ing spanning t r ee pr ot ocols ( STP and RSTP) in net w or ks t o include
t he follow ing feat ur es:
Table 47
STP Por t St at es
PORT STATE
DESCRIPTION
Disabled
STP is disabled ( default ) .
Block ing
Only configurat ion and m anagem ent BPDUs are r eceived and pr ocessed.
List ening
All BPDUs ar e r eceived and pr ocessed.
Note: The listening state does not exist in RSTP.
Lear ning
All BPDUs ar e r eceived and pr ocessed. I nfor m at ion fram es ar e subm it t ed t o t he learning
pr ocess but not for war ded.
For war ding
All BPDUs ar e r eceived and pr ocessed. All infor m at ion fram es ar e received and forwar ded.
