GE Tag Vlan vs. Port Vlan, Multilink ML1200 supports up to 32 VLANs per switch

CHAPTER 10: VLAN VLAN

If VLANs are entirely separate segments or traffic domains - how can the VLANs route traffic (or “talk”) to each other? This can be done using routing technologies (e.g., a router or a L3-switch). The routing function can be done internally to a L3-switch. One advantage of an L3 switch is that the switch can also support multiple VLANs. The L3 switch can thus route traffic across multiple VLANs easily and provides a cost effective solution if there are many VLANs defined.

As shown below, routing between different VLANs is performed using a router or a Layer 3 switch (L3-switch)

SEGMENT 1

SEGMENT 2

ROUTER

ROUTER or L3 SWITCH

CONSOLE

POWER

VLAN 1 VLAN 2

FIGURE 10–3: VLAN routing

The Multilink ML1200 supports up to 32 VLANs per switch

10.1.2 Tag VLAN vs. Port VLAN

What is the difference between tag and port VLAN? In a nutshell - port VLAN sets a specific port or group of ports to belong to a VLAN. Port VLANs do not look for VLAN identifier (VID) information nor does it manipulate the VID information. It thus works “transparently” and propagates the VLAN information along.

In the tag VLAN, an identifier called the VLAN identifier (VID) is either inserted or manipulated. This manipulated VLAN tag allows VLAN information to be propagated across devices or switches, allowing VLAN information to span multiple switches.

As described earlier, VLAN is an administratively configured LAN or broadcast domain. Instead of going to the wiring closet to move a cable to a different LAN segment, the same task can be accomplished remotely by configuring a port on an 802.1Q-compliant switch to belong to a different VLAN. The ability to move end stations to different broadcast domains by setting membership profiles for each port on centrally managed switches is one of the main advantages of 802.1Q VLANs.

MULTILINK ML1200 MANAGED FIELD SWITCH – INSTRUCTION MANUAL 10–3