Interlogix MC352-4P-2S - Manual (Page 25)

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4. Switch Operation
4.1 Address Table
The Industrial Gigabit PoE+ Switch is implemented with an address table. This address table is
composed of many entries. Each entry is used to store the address information of some nodes in
network, including MAC address, port no, etc. This information comes from the learning process of
Industrial Gigabit PoE+ Switch.
4.2 Learning
When one packet comes from any port, the Industrial Gigabit PoE+ Switch will record the source
address, port number and the other related information in address table. This information will be used
to decide either forwarding or filtering for future packets.
4.3 Forwarding & Filtering
When one packet comes from some ports of the Industrial Gigabit PoE+ Switch, it will also check the
destination address besides the source address learning. The Industrial Gigabit PoE+ Switch will look
up 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 a different port from this packet
that comes in, the Industrial Gigabit PoE+ 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 that comes in, then this packet will be filtered;
thereby increasing the network throughput and availability.
4.4 Store-and-Forward
Store-and-Forward is one type of packet-forwarding techniques. A Store-and Forward Industrial
Gigabit PoE+ Switch stores the incoming frame in an internal buffer and does the complete error
checking before transmission. Therefore, no error packets occur. It is the best choice when a network
needs efficiency and stability.
The Industrial Gigabit PoE+ Switch scans the destination address from the packet-header, searches
the routing table provided 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. However, the switch is most commonly used to segment
existing hubs, which nearly always improves the overall performances. An Ethernet Switching can
be easily configured in any Ethernet network environment to significantly boost bandwidth using the
conventional cabling and adapters.
Due to the learning function of the Industrial Gigabit PoE+ 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 reduces
the overall load on the network.