Using VLANs, Spanning Tree, and Hunt Groups (Layer 2 and Layer 3)

Note: The switch supports a feature called Automatic VLAN Creation for tagged frames. When this feature is enabled, the switch creates new VLANs when it receives packets from previously unknown VLANs.

Forwarding Rules

These rules determine the set of ports on the switch through which members of the VLAN can be reached. This is called binding a port to a VLAN. A port may be bound to a VLAN using four methods:

❒Setting the Port VLAN attribute in the Switch Port Configuration dialog box of the port form. This identifies the VLAN to which all untagged frames received on the port are forwarded.

Note: A port has one Port VLAN. Changing this to a new VLAN removes the port from the old VLAN.

❒Setting the VLAN Binding attribute in the Switch Port Configuration dialog box to Bind to All. This causes the port to be bound to all VLANs known to the switch (for example, all current VLANs and all VLANs added in the future).

❒Setting the VLAN Binding attribute in the Switch Port Configuration dialog box to Bind to Received. This causes the port to be bound to all VLANs (as identified by the VLAN tag in tagged frames) received on this port. Consequently, ports are bound to those VLANs that actually have members that are reachable through the port.

❒Manually creating a VLAN Switch Port in the VLAN Switch Ports dialog box.

Egress Rules

For a given port/VLAN combination, egress rules determine whether frames transmitted from the port on the VLAN are tagged or untagged. This is accomplished by setting the Trunking Mode attribute in the Switch Port Configuration dialog box.

For example, choosing the IEEE 802.1Q trunk mode causes all frames transmitted out of the port to be tagged using the IEEE 802.1Q tag header format. Individual port/VLAN combinations may be changed to cause frames transmitted from the port to be untagged for particular VLANs.

Port-Based VLANs

VLAN assignment of a packet is based on global VLAN ID. Regardless of any name you assign to a VLAN, the switch looks only at the VLAN ID number to determine a packet’s VLAN destination.

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Cajun P550/P220 Switch Operation Guide