DES-3326S Layer 3 Fast Ethernet Switch User’s Guide

Layer 3 VLANs must be configured on the switch before they can be assigned IP subnets. Further, the static VLAN configuration is specified on a per port basis. On the DES- 3326S, a VLAN can consist of end-nodes – just like a traditional layer 2 switch, but a VLAN can also consist of one or more layer 2 switches – each of which is connected to multiple end-nodes or network resources.

So, a Layer 3 VLAN, consisting of 4 ports, could be connected to 4 layer 2 switches. If these layer 2 switches each have 24 ports, then the Layer 3 VLAN would contain 4 x 24 = 96 end nodes. Assigning an IP subnet to the Layer 3 VLAN would allow wire-speed IP routing from the WAN to each end node and between end nodes.

So, the IP subnets for a network must be determined first, and the VLANs configured on the switch to accommodate the IP subnets. Finally, the IP subnets can be assigned to the VLANs.

Assigning IP Network Addresses and Subnet Masks to VLANs

The DES-3326S allows the assignment of IP subnets to individual VLANs. Any VLAN configured on the switch that is not assigned an IP subnet, will behave as a layer 2 VLAN and will not be capable of IP routing – even if the switch is in IP Routing mode.

Developing an IP addressing scheme is a complex subject, but it is sufficient here to mention that the total number of anticipated end nodes – for each Layer 3 VLAN – must be accommodated with an unique IP address. It should be noted that the switch regards a VLAN with an IP network address and corresponding subnet mask assigned as an IP interface in IP Routing mode.

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Web-Based Switch Management

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D-Link DES-3326S manual Assigning IP Network Addresses and Subnet Masks to VLANs, 170