ProLiant BL p-Class GbE2 Interconnect Switch Application Guide

Basic IP routing 90
Basic IP routing
This chapter provides configuration background and examples for using the GbE2 Interconnect Switch to perform
IP routing functions. The following topics are addressed in this chapter:
• IP Routing Benefits
• Routing Between IP Subnets
• Example of Subnet Routing
• Defining IP Address Ranges for the Local Route Cache
• Dynamic Host Configuration Protocol
IP routing benefits
The GbE2 Interconnect Switch uses a combination of configurable IP switch interfaces and IP routing options. The
switch IP routing capabilities provide the following benefits:
• Connects the server IP subnets to the rest of the backbone network.
• Provides another means to invisibly introduce Jumbo frame technology into the server-switched network by
automatically fragmenting UDP Jumbo frames when routing to non-Jumbo frame VLANs or subnets.
• Provides the ability to route IP traffic between multiple Virtual Local Area Networks (VLANs) configured on
the switch.
Routing between IP subnets
The physical layout of most corporate networks has evolved over time. Classic hub/router topologies have given
way to faster switched topologies, particularly now that switches are increasingly intelligent. GbE2 Interconnect
Switches are intelligent and fast enough to perform routing functions on a par with wire speed Layer 2 switching.
The combination of faster routing and switching in a single device provides another service — it allows you to
build versatile topologies that account for legacy configurations.
For example, consider the following topology migration:
Figure 14 Router legacy network