CTC Union GSW-3208M, Руководство пользователя

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Chapter 6. Manage / Configure the Switch
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3. Spanning Tree Protocol / Rapid Spanning Tree Protocol
Spanning tree is a protocol to prevent network loop in network topology. If network loop happens, it will cause
switches in the network unstable because more and more traffic will loop in the network. If network loop happens,
spanning tree protocol will block one connection in the loop automatically. But it will also cause a period of delay
(30 seconds for STP and shorter time for RSTP) if any network connection is changed because of the network
topology detection operation of the protocol.
Because there could be more than one switch in the network, users can configure this function for their network
spanning tree application.
4. Port Mirror
This switch operates in store-and-forward algorithm so it is not possible to monitor network traffic from another
connection port. But the port mirror function can copy packets from some monitored port to another port for network
monitor.
5. QoS
For Quality of Service request in a network, packets could be classified to different forwarding priorities. For real-
time network traffic (like video, audio), it needs higher priority than normal network traffic. With the definition of
packet priority, it could have 8 priority levels (from 0 to 7). This switch supports four priority level queues on each
port. It could be configured for port-based, 802.1P tagged based, or DiffServ of IP packets priority. User can define
the mapping of priority values to the priority queues.
6. Static Mac ID in ARL table
The switch can learn the Mac address from user’s packets and keep these Mac address in the ARL table for store-and-
forward table lookup operation. But these Mac addresses will be deleted from ARL table after some time when users
do not send any packets to the switch. This operation is called aging and the time is called aging time. It is about 5
minutes normally (it could be changed by users.) If users want to keep a Mac address always in ARL table on some
port, they can assign the Mac address to ARL table. These Mac ID are called Static Mac address. This switch
supports static Mac address assignment. The static Mac address assignment will also limit the Mac address could be
used on the assigned port only with the port security configuration function. For example, assigning “00-00-e2-11-
22-33” to Port 5 will always keep this Mac ID alive on Port 5 but also limit this Mac address could work on Port 5
only.