CCNA Data Center DCICN 640-911 Official Cert Guide

Part V: IPv4 Routing

Data center networks use Ethernet technology, a technology that implements Layers 1 and 2 of the OSI model. Data center designers also need to use routing technology as well, to forward IP packets from the IP subnet on each virtual local-area network (VLAN) to the IP subnets on the other VLANs. In other words, to allow communications between VLANs, data centers use routing.

Cisco Nexus data center switches implement routing concepts by acting as a multilayer switch (also called a Layer 3 switch). Basically, the switch can be configured to also perform IP routing. As for terminology, because the device is called a “switch,” the industry refers to this IP routing in a switch with other terms, for instance, “Layer 3 switching,” ...