Handbook

N8406-023 1Gb Intelligent L3 Switch Application Guide 90
Basic IP routing
This chapter provides configuration background and examples for using the 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
IP routing benefits
The 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. The 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
In this example, a corporate campus has migrated from a router-centric topology to a faster, more powerful, switch-
based topology. As is often the case, the legacy of network growth and redesign has left the system with a mix of
illogically distributed subnets.
Switch
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