DES-3326S Layer 3 Fast Ethernet Switch User’s Guide
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Web-Based Switch Management
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.
