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User’s Manual
387
5. SWITCH OPERATION
5.1 Address Table
The
Industrial Managed Switch
is implemented with an address table. This address table composed of many entries. Each
entry is used to store the address information of some node in network, including MAC address, port no, etc. This in-formation
comes from the learning process of
Industrial Managed Switch
.
5.2 Learning
When one packet comes in from any port, the
Industrial Managed Switch
will record the source address, port no. And the
other related information in address table. This information will be used to decide either forwarding or filtering for future packets.
5.3 Forwarding & Filtering
When one packet comes from some port of the
Industrial Managed Switch
, it will also check the destination address besides
the source address learning. The
Industrial Managed Switch
will lookup the address-table for the destination address. If not
found, this packet will be forwarded to all the other ports except the port, which this packet comes in. And these ports will
transmit this packet to the network it connected. If found, and the destination address is located at different port from this packet
comes in, the
Industrial Managed Switch
will forward this packet to the port where this destination address is located
according to the information from address table. But, if the destination address is located at the same port with this packet
comes in, then this packet will be filtered. Thereby increasing the network throughput and availability.
5.4 Store-and-Forward
Store-and-Forward is one type of packet-forwarding techniques. A Store-and-Forward
Industrial Managed Switch
stores the
incoming frame in an internal buffer, do the complete error checking before transmission. Therefore, no error packets
occurrence, it is the best choice when a network needs efficiency and stability.
The
Industrial Managed Switch
scans the destination address from the packet-header, searches the routing table pro-vided
for the incoming port and forwards the packet, only if required. The fast forwarding makes the switch attractive for connecting
servers directly to the network, thereby increasing throughput and availability. How-ever, the switch is most commonly used to
segment existence hubs, which nearly always improves overall performance. An Ethernet Switching can be easily configured in
any Ethernet network environment to significantly boost bandwidth using conventional cabling and adapters.
Due to the learning function of the
Industrial Managed Switch
, the source address and corresponding port number of each
incoming and outgoing packet are stored in a routing table. This information is subsequently used to filter packets whose
destination address is on the same segment as the source address. This confines network traffic to its respective domain and
reduce the overall load on the network.
The
Industrial Managed Switch
performs
"Store and Forward"
therefore, no error packets occur. More reliably, it reduces
the re-transmission rate. No packet loss will occur.