Intel ZT 8101 10/100 Using the Web Console, VLAN Layout, IP Addressing Scheme for VLANs

Using the Web Console

•Develop a policy scheme—Some subnets will have a greater need for multicasting bandwidth, for example. A policy is a mechanism to alter the normal packet forwarding in a network device, and can be used to intelligently allocate bandwidth to time-critical applications such as the integration of voice, video, and data on the network.

•Develop a redundancy scheme—Planning redundant links and routes to network-critical resources can save valuable time in case a link or device fails. You can use the Spanning Tree Protocol to block the redundant link until it is needed.

VLAN Layout

VLANs on the ZT 8101 switch have more functions than on a traditional Layer 2 switch and must therefore be laid-out and configured with a more care. Layer 3 VLANs could be thought of as network links rather than as a collection of associated end users. Further, Layer 3 VLANs are assigned an IP network address and subnet mask to enable IP routing between them.

Layer 3 VLANs must be configured on the switch before they can be assigned IP subnets. Also, the static VLAN configuration is specified on a per port basis. On the ZT 8101 switch, 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.

For example, a Layer 3 VLAN, consisting of four ports, could be connected to four switches. If these switches each have 24 ports, then the Layer 3 VLAN would contain 96 (4 x 24) 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.

Therefore, 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.

IP Addressing Scheme for VLANs

The ZT 8101 switch 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.

Developing an IP addressing scheme is a complex subject. As you are developing your scheme, remember that the switch requires a unique IP address for all the anticipated end nodes on each Layer 3 VLAN. The switch treats a VLAN with an IP network address and subnet mask as an IP interface in an IP routing mode.

Static Route Assessment

You need to define static routes for the following types of subnets:

•Subnets not accessible through the default route

•Subnets that the switch does not already know about internally

•Subnets not learned through the dynamic routing protocols

You determine how these packets are routed by entering static routes into the switch’s static/default routing table.

90 Intel® NetStructure™ ZT 8101 10/100 Ethernet Switch User’s Manual