Example 2, VLANs Across Multiple Switches
13-26 VLAN Operation and Network Applications
13.13.1 Solving the Problem
To solve the problem in this example, the users are assigned to VLANs using Switch 4 and Switch
2 as shown in Figure13-12. Redco us ers are assigned to the Red VLAN and Blue Industries users
to the Blue VLAN. The following information shows how Switch 4 and Switch 2 are configured to
create the two VLANs to isolate the users of the two companies from one another on the network
using the existing infrastructure.
Switch 4
Switch 4 is set as follows:
1. Two VLANs are added to the list of VLANs in the Static VLAN Configuration screen. An
FDB ID is automatically assigned to each VLAN. In this example, the following VLANs are
created:
VLAN ID 2, FDB ID 2, with a VLAN Name of Red
VLAN ID 3, FDB ID 3, with a VLAN Name of Blue
Because the VLANs are assigned to two separate FDB IDs, the users on VLAN ID 2 and
VLAN ID 3 cannot communicate with each other.
2. The Egress type for both VLAN ID 2, Port 1, and VLAN ID 3, Port 3, are set to UNTAGGED
using the Static VLAN Egress Configuration screen. This means that these ports will transmit
only untagged VLAN frames.
3. Ports 1 and 3 are configured as follows using the VLAN Port Configuration screen:
Port 1 is set as follows:
PVID: 2
Acceptable Frame Types: ADMIT ALL FRAMES
Ingress Filtering: ENABLED
GVRP Status: DISABLED
Port 3 is set as follows:
PVID: 3
Acceptable Frame Types: ADMIT ALL FRAMES
Ingress Filtering: ENABLED
GVRP Status: DISABLED
This causes the switch to classify all untagged frames received as belonging to the VLAN
specified by each port PVID and to replace the previous PVID information in the port VLAN
List with the new PVID information. This makes Port 1 part of the Red VLAN, Port 3 part of
the Blue VLAN, and both are set to the VLAN frame format of untagged.