Planet Technology WGS3-2620 - Manual (Page 250)

WGS3 Layer 3 Switch User’s Manual - 242 -
6.3.3 Connecting VLAN Groups
The switch supports communication within a common VLAN using store-and-forward switching. However,
if you have devices in separate VLANs that must communicate, and it is not practical to include these
devices in a common VLAN, then the VLANs can be connected via Layer 3 routing provided by this
switch.
Traditional routers use only physical port numbers in their routing tables, which provides no support for
VLANs. By contrast, this device supports Layer 3 routing by using both logical and physical port numbers
to support VLANs and Layer 3 switching simultaneously.
By using the abstraction of a logical port number to represent a collection of physical switch ports in the
same VLAN, Layer 3 switching can occur from one VLAN to another transparently without changing the
routing protocol and IP routing software, while Layer 2 switching is still used for intra-VLAN traffic.
The switch uses standard routing tables that are constructed via static configuration or dynamic routing
protocols such as RIP. Each routing entry consists of a network address (that is, an IP address with a
subnet mask), and a virtual interface number. Each virtual interface corresponds to a virtual LAN,
identified by the VLAN ID. Also note that multiple routing entries can be provided for the same virtual
interface by adding the required routing table entries for the same virtual interface. A simple VLAN
configuration that supports routing is shown below.
VLANs Connected via IP Routing