Planet Technology GSW-1601 - Manual (Page 12)

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3. Switch Operation
3.1 Address Table
The Gigabit Ethernet 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
information comes from the learning process of Gigabit Ethernet Switch.
3.2 Learning
When one packet comes in from any port. The Gigabit Ethernet 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.
3.3 Forwarding & Filtering
When one packet comes from some port of the Gigabit Ethernet Switch, it will also
check the destination address besides the source address learning. The Gigabit
Ethernet 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 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 comes in, then this packet will be filtered. Thereby increasing the network
throughput and availability.
3.4 Store-and-Forward
Store-and-Forward is one type of packet-forwarding techniques. A Store-and
Forward Gigabit Ethernet 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 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 to segment existing hubs, which
nearly always improves overall performance. An Ethernet Switching can be easily