Gigabit Ethernet Switch Management Guide

4-1
C HAPTER 4
A DVANCED T OPICS
This TigerSwitch 1000 supports Layer 2 switching and other
advanced features, which are described in this chapter.
Layer 2 Switching
When a frame enters a port, its destination MAC address is checked in
the address database to see which port leads to this destination. If the
destination address belongs to the incoming port, the frame is
dropped or “filtered” because it addressed to the local segment. If the
destination address if found on another port, the frame is forwarded
to that port and queued for output. But, if the destination address is
not found in the address database, the frame is sent to one or more
output ports based on the rules for handling tagged or untagged
VLAN frames.
If the source MAC address of the frame was not found in the address
database, it is recorded along with the incoming port number where it
entered the switch. This information is then used to make later
decisions for frame forwarding.
Switching involves the following steps:
◆ VLAN Classification
◆ Learning
◆ Filtering
◆ Forwarding
◆ Aging