Allied Telesis 2.6.1 manual Vlan Membership of Untagged Packets, Member ports

76 AT-8800 Series Switch User Guide

Figure 14: VLANs with tagged ports.

	Training VLAN VID=3
Port 3	Port 22	Port 21
Switch A	Port 26	Switch B
	Port 25
Port 1	Port 4
Port 2	Port 23
Admin VLAN VID=2	Marketing VLAN VID=4
	411
VLAN-aware
server
		SWITCH3

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

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.

Software Release 2.6.1 C613-02039-00 REV A