Planet GSD-805 [15/20] Switchoperation

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 ltering 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 ltered. Thereby increasing the network

throughput and availability.