ZyXEL Communications XGS4700 Series, Manual

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Chapter 13 Spanning Tree Protocol
XGS4700-48F User’s Guide
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13.1.3 STP Port States
STP assigns five port states to eliminate packet looping. A bridge port is not
allowed to go directly from blocking state to forwarding state so as to eliminate
transient loops.
13.1.4 Multiple RSTP
MRSTP (Multiple RSTP) is ZyXEL’s proprietary feature that is compatible with RSTP
and STP. With MRSTP, you can have more than one spanning tree on your Switch
and assign port(s) to each tree. Each spanning tree operates independently with
its own bridge information.
In the following example, there are two RSTP instances (MRSTP 1 and MRSTP2)
on switch A.
Figure 61 MRSTP Network Example
To set up MRSTP, activate MRSTP on the Switch and specify which port(s) belong
to which spanning tree.
Table 27 STP Port States
PORT
STATE
DESCRIPTION
Disabled STP is disabled (default).
Blocking Only configuration and management BPDUs are received and processed.
Listening All BPDUs are received and processed.
Note: The listening state does not exist in RSTP.
Learning All BPDUs are received and processed. Information frames are submitted
to the learning process but not forwarded.
Forwarding All BPDUs are received and processed. All information frames are received
and forwarded.