Interlogix NS3500-28T-4S User Manual - Manual (Page 357)

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5. SWITCH OPERATION
5.1 Address Table
The 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 Ethernet Switch.
5.2 Learning
When one packet comes in from any port, the 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 Ethernet Switching, it will also check the destination address besides
the source address learning. The Ethernet Switching 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 Ethernet Switching 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 Ethernet Switching 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 Ethernet 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 signifi-cantly boost bandwidth using
conventional cabling and adapters.
Due to the learning function of the Ethernet switching, the source address and corresponding port number of each