This is the third in a series of articles on the six sections of Cisco’s CCNA certification exam 200-301, which earns the CCNA (Cisco Certified Network Associate) certification.
In this series, we’re taking a look at all the many things you need to know for the Cisco’s 200-301 CCNA certification exam. The 200-301 Exam blueprint is divided into 6 components, each component having a different weight associated with it. Here are the categories, weights, and possibly the number of questions for each:
- 1.0 Network Fundamentals – 20% – 20 questions
- 2.0 Network Access – 20% – 20 questions
- 3.0 IP Connectivity – 25% – 25 questions
- 4.0 IP Services – 10% – 10 questions
- 5.0 Security Fundamentals – 15% – 15 questions
- 6.0 Automation and Programmability – 10% – 10 questions
The third area of focus for the new CCNA exam is IP Connectivity. Here is a breakdown from Cisco of the components of the IP Connectivity section which makes up 25% of the total exam.
3.0 IP Connectivity
3.1 Interpret the components of a routing table
- 3.1.a Routing protocol code
- 3.1.b Prefix
- 3.1.c Network Mask
- 3.1.d Next hop
- 3.1.e Administrative distance
- 3.1.f Metric
- 3.1.g Gateway of last resort
3.2 Determine how a router makes a forwarding decision by default
- 3.2.a Longest match
- 3.2.b Administrative distance
- 3.2.c Routing protocol metric
3.3 Configure and verify IPv4 and IPv6 static routing
- 3.3.a Default route
- 3.3.b Network route
- 3.3.c Host route
- 3.3.d Router ID
3.4 Configure and verify single area OSPFv2
- 3.4.a Neighbor adjacencies
- 3.4.b Point-to-Point
- 3.4.c Broadcast (DR/BDR selection)
- 3.4.d Router ID
3.5 Describe the purpose of first hop redundancy protocol
All these topics are covered in the Implementing and Administering Cisco Solutions (CCNA v1.0) training class.
Even though Cisco calls it IP Connectivity, really what this section is all about is how routers behave, both by default and when configured. Let’s take a deeper look and remember, that by default, routers must be configured for IP functionality.
Interpret the components of a Routing Table
In much the same way that we look at a spreadsheet and see values in boxes having resulted from formulas and variables run on the raw data that comprised the behind the scenes math, a routing table is really just another form of that. What we see if the real time information that the router is using to route packets from one network segment to another. What we don’t often see is all the math going on in the background – which is fine. Recall from your studies or from one of our classes taught by any number of award-winning Instructors here at Skyline ATS (ok….shameless plus … but just saying) that the command <show ip route> really gives us a real time view of how the router is making decisions.
Also anything other than C, L, S and S* noted entries are typically representative of some dynamic routing protocol, or said another way, a routing protocol language that the router is speaking to other routers. It will serve you well to remember the popular routing protocol codes, like D, O, and R, and remember that each routing protocol uses some kind of metric to figure out how to get to the destination network it is aware of. In addition, remember what I often refer to as the safety net at the bottom of the table (provided one has been learned or configured) that we call the default route (referred to in the routing table as the Gateway of Last Resort). It will also serve you well to remember that if a router does not have a route to the destination network you are trying to get packets to, it simply discards your traffic. But wait, there is more.
Determine how a router makes a forwarding decision by default
In so much as a router needs to have interfaces that are IP addressed (v4 or v6, or both) and turned on, this is the starting point. When we do these configurations in our routers, we are effectively setting up the baseline of IP operations for the routing of packets and the re-writing of Ethernet or other frame types. Remember that you cannot have hot water if you don’t have running water, so getting interfaces into an up/up state with some reference to an IP address and network segment is critical. When we do this, we in effect create some networks that this router can reach. Often when I speak of the difference between a Connected Network and a Local Host Route (Cs and Ls), I refer to this as outbound versus inbound traffic. Also recall, and I say this at the risk of repeating myself that if we present to the router multiple options for getting to remote networks, it has a pecking order that it follows to fill in the routing table. It goes like this: lowest administrative distance, lowest metric to the destination network, and longest bit pattern match on the destination.
Configure and verify IPv4 and IPv6 static routing
I have to admit that there are times when I am a huge fan of static and default routing. Like the ninja movies that I enjoy, this is how I think of static and default routing – silent, effective, reliable. You get the idea. You will be well served to know the syntax of both IPv4 and IPv6, and to remember that you can point both of them to either a next-hop IP address or you can point them to an egress interface on the routing device on which they are being configured.
Configure and verify single area OSPFv2
Now onto the routing protocols – those magical multicasting protocols that routers just tend to speak natively (in truth they are programs running in the background, but I like the idea of magic in the router). In this portion of the exam, I would expect questions on the difference between the administrative distance and the metric being used by a particular routing protocol, as well as how routers are known to other routers in the form of a router ID. I would also remember that unless you are a good neighbor, there is no adjacency, and if there is no adjacency, there is no information exchange. So, you have to be good neighbors, and there are attributes that determine that (hello/dead intervals, area ID, stub area flag and authentication agreements). There are slight differences when it comes to routers sharing a broadcast domain versus being connected in a point-to-point environment (to have or not have a Designated Router and the selection process that determines that). But hey, if you have read the book and done some lab work, you should be fine on this. And finally,
Describe the purpose of First Hop Redundancy Protocol
I got up one morning not too long ago and my only means of making coffee would not make coffee. Now if you are anything like me, I really need/want that first cup of coffee to get me started at the beginning of the day. Without it, it is like I am a wounded wild animal – just ask my wife. So, when I went to the local big box store, you guessed it, I bought two coffee makers instead of one. One is in my kitchen ready to make coffee, and the other is in my laundry room, ready to take over should the primary coffee maker fail. Truthfully, I should have known my old coffee maker was getting ready to quit working. I don’t think it’s supposed to sound like an electric ice cream maker when it makes coffee. But in any case, this is what FHRPs (First Hop Redundancy Protocols) are all about.
Now of course there are names like HSRP, VRRP, and GLBP, but the point is that they all do pretty much the same thing – sort of. HSRP and VRRP (Cisco proprietary and Open Standard respectively) allow for a dynamic shift of the default gateway for LAN connected devices. Should one fail, the other one takes over. GLBP is for load balancing traffic out of the router. So again, when I think about them, I think inbound to the router (HSRP and VRRP) and outbound from the router (GLBP).
If I have not said it yet, thank you for taking the time to read all these blog posts. My hope is that they are helpful to you. I will again repeat that I believe in you and have confidence that you will succeed. Happy examing everyone!