MPLS Intro Series – Destination Routing
Yes, we are going to talk about destination routing. I know it sounds boring and archaic, and it is. But it is also necessary to contrast against another topic that I intend to introduce. As I scour PacketU, I see a substantial number of page views on articles about segmentation and VRFs. One thing I often tell my customers is that once a VRF-lite implementation reaches a certain scale, the configuration can become unwieldy.
This article is a first in a series where we will discuss MPLS. This technology enables VPNv4 and is a common method of networking. MPLS can connect VRFs without compromising their segmentation characteristics. In this first article, we are going to examine traditional destination-based routing. This is meant to nail down some of the typical behavior of an IPv4 routed network. These characteristics will not go away entirely, but it is important to understand how routing changes as we introduce label switching concepts.
Throughout this series, we will use a common topology. In later articles, we will expand as necessary to introduce the relevant topics.
To illustrate a point, I have pre-configured OSPF on all links and loopback 0 of all routers. In a minute, I will bring Continue reading