Routing at a Glance

At the core of Networking is routing. Routing is what makes the Internet work. There are three basic types of routes: Static, Dynamic and Connected. This article and accompanying video describe the basic differences between the three and how they work.

The three categories of networking can be expanded to include different routing methods. There are Policy Based Routes and specific Network Address Translation (NAT) rules that dictate where to send packets. There are different versions of dynamic routing protocols such as EIGRP and OSPF. MPLS is sometimes referred to as a “layer 2.5 routing protocol” because of the way that it uses tags to route packets on a network. Without the BGP routing protocol we wouldn’t have the Internet. These and many other routing technologies exist and are currently being developed. This article does not cover them but instead focuses on the three core types of routes.

Dynamic

Out of the three, dynamic routes are at the bottom of the order of precedence by default. This means that without any additional configuration dynamic routes such as OSPF and EIGRP will always be trumped by static and connected routes. When having to configure a medium to large network environment it is always best to use dynamic routes over static routes. Dynamic routes provide fault tolerance and save time when it comes to configuration multiple devices.

Static

Static routes are #2 out of 3 in the order of precedence. They are statically configured on each routing device. Static routes should be avoided in favor of dynamic routes when possible. By themselves they provide no fault tolerance and take more time to configure when having to do so on multiple devices.

Connected

It can be argued that connected routes are not really routes at all. They are connected because the interface IP address of a layer three device is included in the subnet of the hosts it provides routing functionality to. This typically means that the layer three device is the “Default Gateway” for hosts within a subnet.

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