ACI works extremely well by itself; however, as the great John Donne once said, "no man is an island." Here, we will look at how to extend ACI through routing. Before we delve into the world of routing, we will look at helping our nodes get IP addresses by creating a DHCP relay and help them resolve names through DNS. Once we have covered this, we will look at configuring Border Gateway Protocol (BGP), Open Shortest Path First (OSPF), and Enhanced Interior Gateway Routing Protocol (EIGRP). We will then look at how easy IPv6 and multicast support is within ACI, before finishing the chapter looking at transit routing.