Implementing OSPF for CCNP Routing and Switching 300-101 ROUTE

Implementing OSPF for CCNP Routing and Switching 300-101 ROUTE
Welcome to Pluralsight, I'm Ben Piper and this is Implementing OSPF for CCNP Routing and Switching 300-101 ROUTE. In this course, we're going to cover everything you need to know about configuring OSPF, the Open Shortest Path First dynamic routing protocol for the CCNP ROUTE exam. Now this course is the second in a five course series covering all of the required topics for the CCNP ROUTE exam. We're going to start by introducing core OSPF concepts, then we'll jump into configuring OSPF for IPv4 including various features such as route summarization and authentication. Next we'll configure OSPFv3 for IPv6 and finally route redistribution between OSPF and other interior gateway routing protocols. Now before we get into the course content, let me give you a layout of the course as a whole, so you can follow along and go into this with the right expectations. First, prerequisites. I'm assuming that you've already watched the first course and are comfortable with the material. You don't need to have memorized it, but you need to at least understand it before beginning this course. If you're planning on following along with the labs, please make sure that you've already completed all the labs from the last course. Now to make things easier, the course exercise files contain all the router base configurations that you're going to need to get started. OSPF is a significant part of the CCNP routing and switching certification track. This course corresponds to sections 3. 24 through 3. 29 of the ROUTE exam topics. Now this may not sound like very much but trust me, you must be able to configure and troubleshoot OSPF. I promise you the time you spend studying OSPF will be time very well spent.

Configuring OSPF for IPv4
In this module, we're going to delve into configuring OSPF for IP version 4. First we're going to cover just enough of the operational theory behind OSPF to get started, and then we're going to hit the command line where we'll be spending most of our time. This module is going to be a big one and we're going to just from feature to feature configuring one after another in an almost rapid fire fashion. Remember, in the exam you're going to have to do exactly that, configure or answer questions about various OSPF features and configurations in quick succession. So get your fingers ready if you're following along and let's get started. Now we know how the OSPF protocol works but we need to talk about the Cisco specific implementation of it. On Cisco routers and layer 3 switches an OSPF instance runs in what's called a process. A single router can have multiple OSPF processes, each with its own link state database and routing topology. There're two things to keep in mind when it comes to this. First, an OSPF process is given a number and that number is locally significant to the router. This means that one router can use OSPF process number 1, and another can use number 12, and it doesn't matter, they can still establish an OSPF adjacency. The second thing is that OSPF processes are completely separate from one another. If a router is running two OSPF processes, those link state databases are not combined or shared in any way unless you explicitly configure route redistribution between them.

Route Redistribution
Route redistribution is one of my favorite networking topics. Route redistribution allows you to bring networks together in a sense by joining and sharing information between different routing protocols, for instance, between OSPF and RIP. The simplest definition of route redistribution is using a routing protocol to advertise routes that were not learned by that protocol. Now that's a pretty broad definition that covers a lot of potential routing sources, and for good reason, as we'll see in this module. But redistribution is about more than just injecting routes into routing protocols. It also allows you to selectively filter routes, manipulate cost metrics and metric types, and a whole lot more. In this module, we're going to cover redistributing connected networks, which is an alternative way of getting routes into OSPF without using the network command, then we'll redistribute RIP routes into OSPF, which is going to get you warmed up to the idea of redistributing between OSPF and more advanced routing protocols like EIGRP later on. Next we'll use IP prefix lists and route maps to control what prefixes we allow into OSPF and how those prefixes are treated. Then we'll finish out the module by summarizing some of our external routes, and finally injecting a default route into OSPF.

Configuring OSPFv3 for IPv6
In this module, we're going to have some fun configuring OSPF version three for IPv6. OSPFv3, like its predecessor OSPFv2, is a link-state routing protocol. RFC 5340 also refers to OSPFv3 as OSPF4 IPv6 because it was designed specifically for IPv6. OSPFv2, which is the version of OSPF we've been learning about, runs over IPv4 and advertises IPv4 prefixes. OSPFv3, on the other hand, runs over IPv6 and advertises IPv6 prefixes. Now although the OSPFv2 and v3 protocols are completely separate and independent, they do have more similarities with each other than they do differences. One similarity is that both use the same dotted quad IPv4 format for the RID. In fact, if you run OSPFv3 on a router with no IPv4 addresses, you have to manually configure a RID. Another similarity is that virtual links across transit areas are created using the RID and the similarities continue when it comes to timers, network types, and neighbor states. So thus far, much of what you already know about OSPFv2 applies to OSPF version three as well. Another very important similarity is that unicast routing must be enabled for OSPFv2 or v3 to work. In OSPFv3, IPv6 routing must be enabled with the ipv6 unicast-routing command. Now if you forget to do this on a router and you try to run OSPFv3, the OSPF process will complain that the router is not an IPv6 router.