Enterasys Networks 6H3xx Betriebsanweisung
VLAN Configuration
VLAN Operation and Network Applications
13-11
13.7.2.2 Known Unicasts
When a VLAN switch receives a frame with a known MAC address as its destination address, the
action taken by the switch to determine how the frame is transmitted depends on the VLAN, the
VLAN associated FDB ID, and if the port identified to send the frame is enabled to do so.
action taken by the switch to determine how the frame is transmitted depends on the VLAN, the
VLAN associated FDB ID, and if the port identified to send the frame is enabled to do so.
When a frame is received it is classified into a VLAN. The destination address is looked up in the
FDB ID associated with the VLAN. If a match is found, it is forwarded out the port identified in
the lookup if, and only if, that port is allowed to transmit frames for that VLAN. If a match is not
found, then the frame is flooded out all ports that are allowed to transmit frames belonging to that
VLAN.
FDB ID associated with the VLAN. If a match is found, it is forwarded out the port identified in
the lookup if, and only if, that port is allowed to transmit frames for that VLAN. If a match is not
found, then the frame is flooded out all ports that are allowed to transmit frames belonging to that
VLAN.
For example, assume that a frame is received by the switch depicted in
unicast untagged frame received on Port 3. The frame is then classified for VLAN C. The switch
then makes its forwarding decision by comparing the destination MAC address to its filtering
database. In this case, the MAC address is looked up in the filtering database FDB ID 3, which is
associated with VLAN C and VLAN D. The switch recognizes the destination MAC address of the
frame as being located out Port 4.
then makes its forwarding decision by comparing the destination MAC address to its filtering
database. In this case, the MAC address is looked up in the filtering database FDB ID 3, which is
associated with VLAN C and VLAN D. The switch recognizes the destination MAC address of the
frame as being located out Port 4.
Having made the forwarding decision, the switch now examines the Port VLAN List of Port 4 to
determine if it may transmit a frame belonging to VLAN C. If so, the frame is transmitted out Port
4. If Port 4 has not been configured to transmit frames belonging to VLAN C, the frame is
discarded.
determine if it may transmit a frame belonging to VLAN C. If so, the frame is transmitted out Port
4. If Port 4 has not been configured to transmit frames belonging to VLAN C, the frame is
discarded.
13.8 VLAN CONFIGURATION
This chapter describes how to set up the switch for local or remote management, and the VLAN
Local Management screens used to create and configure VLANs in the switch.
Local Management screens used to create and configure VLANs in the switch.
13.8.1
Managing the Switch
The switch may be managed locally via a terminal connected to the COM port, or remotely
(SNMP or Telnet sessions) from a management station connected to a switch port that is a member
of the same VLAN as the switch’s Host Data Port. (By default, this is the default VLAN.) When
the switch is configured with VLANs, special precautions must be taken to use remote
management.
(SNMP or Telnet sessions) from a management station connected to a switch port that is a member
of the same VLAN as the switch’s Host Data Port. (By default, this is the default VLAN.) When
the switch is configured with VLANs, special precautions must be taken to use remote
management.
13.8.2
Switch Without VLANs
When the switch is powered up, the switch uses its default settings to switch frames like an 802.1Q
switch. In this default configuration, all ports are a member of the default VLAN (VLAN 1)
including the virtual Host Data Port of the switch, so any port can be used to manage the device as
shown in
switch. In this default configuration, all ports are a member of the default VLAN (VLAN 1)
including the virtual Host Data Port of the switch, so any port can be used to manage the device as
shown in