SMC Networks 1000BASE-X 用户手册
4-1
C
HAPTER
4
A
DVANCED
T
OPICS
This TigerStack 100 supports Layer 2 switching and other advanced
features, which are described in this chapter.
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.
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.
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
◆ Learning
◆ Filtering
◆ Forwarding
◆ Aging