Interlogix IFS MC350-4T-2S, Руководство пользователя

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4. Switch Operation
4.1 Address Table
The Industrial Gigabit Ethernet 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 node in network, including MAC address, port no,
etc. This information comes from the learning process of Industrial Gigabit Ethernet Switch.
4.2 Learning
When one packet comes in from any port, the Industrial Gigabit Ethernet Switch will record the source address, port no,
and the other related information in the 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 port of the Industrial Gigabit Ethernet Switch, it will also check the destination
address besides the source address learning. The Industrial Gigabit Ethernet 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 Ethernet 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, 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 Ethernet
Switch stores the incoming frame in an internal buffer and does the complete error checking before
transmission. Therefore, no error packets will occur. It is the best choice when a network needs efficiency and stability.
The Industrial Gigabit Ethernet 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 for segment existing in hub, 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 Gigabit Ethernet Switch, the source address and corresponding port
number of each incoming and outgoing packet is 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, reducing the overall load on the network.