D-Link DES-3552 [77/260] Static vlan entry

DES-3550 Fast Ethernet Layer 2 Switch

Port-based VLANs

Port-based VLANs limit traffic that flows into and out of switch ports. Thus, all devices connected to a port are members of

the VLAN(s) the port belongs to, whether there is a single computer directly connected to a switch, or an entire department.

On port-based VLANs, NICs do not need to be able to identify 802.1Q tags in packet headers. NICs send and receive normal

Ethernet packets. If the packet's destination lies on the same segment, communications take place using normal Ethernet

protocols. Even though this is always the case, when the destination for a packet lies on another switch port, VLAN

considerations come into play to decide if the packet gets dropped by the Switch or delivered.

VLAN Segmentation

Take for example a packet that is transmitted by a machine on Port 1 that is a member of VLAN 2. If the destination lies on

another port (found through a normal forwarding table lookup), the Switch then looks to see if the other port (Port 10) is a

member of VLAN 2 (and can therefore receive VLAN 2 packets). If Port 10 is not a member of VLAN 2, then the packet will

be dropped by the Switch and will not reach its destination. If Port 10 is a member of VLAN 2, the packet will go through.

This selective forwarding feature based on VLAN criteria is how VLANs segment networks. The key point being that Port 1

will only transmit on VLAN 2.

Network resources such as printers and servers however, can be shared across VLANs. This is achieved by setting up

overlapping VLANs. That is ports can belong to more than one VLAN group. For example, setting VLAN 1 members to

ports 1, 2, 3, and 4 and VLAN 2 members to ports 1, 5, 6, and 7. Port 1 belongs to two VLAN groups. Ports 8, 9, and 10 are

not configured to any VLAN group. This means ports 8, 9, and 10 are in the same VLAN group.

VLAN and Trunk Groups

The members of a trunk group have the same VLAN setting. Any VLAN setting on the members of a trunk group will apply

to the other member ports.

NOTE: In order to use VLAN segmentation in conjunction with port trunk groups, you can

first set the port trunk group(s), and then you may configure VLAN settings. If you wish to

change the port trunk grouping with VLANs already in place, you will not need to

reconfigure the VLAN settings after changing the port trunk group settings. VLAN settings

will automatically change in conjunction with the change of the port trunk group settings.

Static VLAN Entry

In the Configuration folder, open the VLAN folder and click the Static VLAN Entry link to open the following window:

Figure 6- 36. 802.1Q Static VLANs Entries window

The 802.1Q Static VLANs windows lists all previously configured VLANs by VLAN ID and VLAN Name. To delete an

existing 802.1Q VLAN, click the corresponding

button under the Delete heading.

To create a new 802.1Q VLAN, click the Add button in the 802.1Q Static VLANs window. A new window will appear, as

shown below, to configure the port settings and to assign a unique name and number to the new VLAN. See the table below

for a description of the parameters in the new window.