Allied Telesis AT-8800 Series Switch - Manual (Page 76)

76 AT-8800 Series Switch User Guide
Software Release 2.6.1
C613-02039-00 REV A
Figure 14: VLANs with tagged ports.
VLAN Membership of Untagged Packets
A VLAN that does not send any VLAN-tagged frames is a logical grouping of
ports. All untagged traffic arriving at those ports belongs to that VLAN.
VLANs based on untagged ports are limited, because each port can only
belong to one VLAN as an untagged port. Limitations include:
■ It is difficult to share network resources, such as servers and printers,
across several VLANs. The routing functions in the switch must be
configured to interconnect using untagged ports only.
■ A VLAN that spans several switches requires a port on each switch for the
interconnection of the various parts of the VLAN. If there are several
VLANs in the switch that span more than one switch, then many ports are
occupied with connecting the VLANs, and so are unavailable for other
devices.
Table 12: VLAN membership of example of a network using tagged ports.
VLAN Member ports
Training 3, 26 on Switch A
21, 22, 25 on Switch B
Marketing 2, 4, 26 on Switch A
23, 25 on Switch B
Admin 1, 2 on Switch A
Port 3
Training VLAN VID=3
411
SWITCH3
Marketing VLAN VID=4 Admin VLAN VID=2
Switch A
Switch B
VLAN-aware
server
Port 4 Port 1
Port 2
Port 26
Port 25
Port 22
Port 21
Port 23