Compaq SW3324, SW3323, SW3322 manual Vlan Application Example, 4Virtual Lans VLANs

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C-4Virtual Lans (VLANs)

In example 3 in Figure C-3B, an untagged frame arrives at the left side port (1). The frame is tagged with a VLAN X tag (2), and comes out Port Y with a VLAN X tag (3). The ultimate destination of the frame may be on the outgoing port’s segment or on another segment.

Example 4 in Figure C-3B, is similar to Example 3 except that both ports (incoming and outgoing) are on VLAN X. The untagged frame arrives at incoming port X (1), gets tagged with a VLAN X tag (2), and comes outs VLAN X (3) with the tag stripped off. The packet thus comes in and out of the switch port untagged, the same as the access port type case in Figure C-2.

Figure C-3BVLAN Hybrid Ports (Examples 3 and 4)

VLAN Application Example

As the network administrator can use VLANs to define user groups regardless of the physical LAN segment to which they are connected, both hybrid and access links can further refine traffic flow in a multi-switch environment. Figure C-4 shows the combination of both hybrid and access links for a network with three different VLANs. Note that VLAN Y packets are tagged on the internal (corporate) network, but VLAN Z packets are not. No packets are tagged on the access links.