ZyXEL Communications NetAtlas, Руководство пользователя

Страница: 71 / 340

Chapter 5 View
NetAtlas EPON Manager User’s Guide
71
On each bridge, the root port is the port through which this bridge communicates
with the root. It is the port on this switch with the lowest path cost to the root (the
root path cost). If there is no root port, then this switch has been accepted as the
root bridge of the spanning tree network.
For each LAN segment, a designated bridge is selected. This bridge has the lowest
cost to the root among the bridges connected to the LAN.
5.4.2 STP Port States
STP assigns five port states (see next table) 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.
5.4.3 STP/RSTP Status
View current STP information in the Spanning Tree Protocol Status screen.
Click View > Spanning Tree Protocol Status and select a device from the
device list located on the left-hand side of the screen. The fields on the right will
display the device’s STP information. The screen varies depending on which STP
mode (STP, MRSTP or MSTP) you configure on the selected device.
Table 28 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.
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.