Interlogix NS3702-24P-4S User Manual - Manual (Page 378)

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