IBM Flex System and PureFlex System Network Implementation with Juniper Networks

Layer 3 Overview

This chapter provides an overview of Layer 3.

4.1 Layer 3

Without Layer 3 IP routing at the switch level, all cross-subnet traffic is relayed to the default gateway. That gateway provides the necessary IP address information and sends the data back down to the Layer 2 switch. Placing Layer 3 IP routing on the switch allows for cross-subnet traffic within the switch, which frees up the upstream router to handle only in-bound and out-bound traffic. Because IBM System networking switches use application-specific integrated circuits ...