At this stage, I will assume that you have completed your CCNA exam and you are ready to move to the next level in your cisco career. As discussed in my previous article, the next stage of your Routing and Switching career is the CCNP track. CCNP Route is one of the required exams needed to attain CCNP status. To sum it up, there are three (3) exams. In this article, we’ll be discussing the things you should know and what to expect in the exam.
Simply put, if you don’t really know what you’re doing, you won’t pass this test. The exam basically consists of 50-60 questions, complete with Multiple Choice, Multiple Answer, Drag and drop, Testlet, Simlet and Router Simulation, with a time of 120 minutes. It costs $200 to take the exam once. In this world, you’ll experience powerful, multi-path simulation engines. You’ve got to pull your requirements out of a (fairly complex) scenario and put your configuration skills to the test.
There are seven high level categories that the ROUTE exam is split into:
- Enhanced Interior Gateway Routing Protocol(EIGRP)
- Open Shortest Path First(OSPF)
- External Border Gateway Protocol(eBGP)
- Internet Protocol version 6(IPv6)
- IPv6/IPv4 redistribution
- Layer 3 Path Control
- Implement basic teleworker and branch services
We’ll be doing a breakdown of all the topics one by one. If you’re ready, let’s go!!!
ENHANCED INTERIOR GATEWAY ROUTING PROTOCOL (EIGRP) – When preparing for the ROUTE exam, an understanding of EIGRP theory is essential. This is by far, my most interesting and fun topic in the whole exam. It is one of the easiest protocols to implement. Just a few commands and you are good to go. The exam, however, goes into the core of the protocol. One of the concepts that is, at times, confusing is the difference between feasible distance and advertised distance.
Simply put, the feasible distance is the best route(s) to the destination and the advertised is the reported distance. The feasible distance is the EIGRP metric from a specific device; the advertised distance is the EIGRP metric from the neighboring device (the one with the best path) to the same destination. The feasibility condition states that for a specific route to make it into the routing table it must meet the specifications of the feasibility condition. The advertised distance for a specific route to a destination must be less than (<) the feasible distance for that same network. When there is only one path to a destination, the advertised distance will always be less than the feasible distance, but when there are multiple paths this condition must be considered to avoid loops. Confusing!!!
OPEN SHORTEST PATH FIRST (OSPF):- In CCNA, OSPF looked really easy and uncomplicated. Just create area zero (0), issue your network command and you are good to go, right? Well it’s not that simple and straight forward in the CCNP. Here we talk about multiple areas, LSA’s and STUB areas. I will explain a couple of the more difficult and confusing concepts.
This is a tricky concept. This topic is not only very helpful when it comes to the ROUTE exam but is vital when trying to understand the concepts of stub areas. There are a number of different Link State Advertisement types that exist within OSPF; for the purposes of this article, we’ll take a look at LSA type 1, 2, 3, 4 and 5, 6 and 7
LSA Type 1
The LSA Type 1 or Router LSA is sent by every router within an area to describe the state of each interface connected to the area.
LSA Type 2
The LSA Type 2 or Network LSA is sent by the Designated Router (DR) for a specific multi-access network and describes the set of routers attached to the network.
LSA Type 3 & 4
Both LSA Type 3 and 4 are considered Summary LSAs which are sent by the Area Border Router (ABR). An LSA Type 3 is used to describe the routes to the area’s networks and an LSA Type 4 is used to describe the routes to Autonomous System Boundary Routers (ASBR). An LSA Type 3 is used when summarizing routes from one OSPF area to another.
LSA Type 5
The LSA Type 5 or Autonomous System External LSA is used by the ASBR to advertise routes that are external to the OSPF network. Unlike the other LSA’s, this type is sent everywhere within the OSPF network regardless of area with the exception of stub networks.
LSA Type 6
Group Membership LSA (Only supported on a few routers) was defined for Multicast extensions to OSPF a multicast OSPF routing protocol which was not in general use. MOSPF has been deprecated since OSPFv3 and is not currently used. It may be reassigned in the future.
LSA Type 7
Routers in a Not-so-stubby-area (NSSA) do not receive external LSAs from Area Border Routers, but are allowed to send external routing information for redistribution. They use type 7 LSAs to tell the ABRs about these external routes, which the Area Border Router then translates to type 5 external LSAs and floods as normal to the rest of the OSPF network.
OSPF STUB AREAS
OSPF stub areas limit the parts of the network where specific LSAs are allowed. The idea being that if an OSPF router receives an LSA it must process it, which takes a certain amount of processor and memory resources. By limiting the types of LSAs that can reach specific networks, the devices within these stub areas do not have to be as powerful but still retain reachability to the rest of the OSPF network.
There are three main types of OSPF stub areas:
- Stub Areas
- Totally Stubby Areas
- Not So Stubby Areas
Use the area xx stub command in every router in the area to define an area as a stub area. In the topology shown below, routers in area 7 do not need to know about all the external destinations. The routers in area 7 must send a packet to the ABR to reach the ASBR, no matter what the external destination. Area 7 can be defined as a stub area by configuring the area 7 stub command in all routers in that area.
Totally Stub Area
Use the OSPF router configuration area xx stub no-summary command to define a totally stub area. In the previous network diagram, routers in area 7 do not need to know about all external destinations or any summary LSA from the backbone for other areas. The routers in area 7 must send packets to the ABR to reach any destination outside the area 7. Area 7 can be defined as a totally stub area by configuring the area 7 stub no summary command on the ABR.
Use the OSPF router configuration area xx nssa command to define an NSSA. For example, in the topology below, we configured Area 2 as an NSSA by entering the area 2 nssa command on all routers in the area. This protects Area 2’s internal routers from all the AS-external LSAs imported by the OSPF ASBR, but still allows for the attachment of the non-OSPF router. External routing information is imported into an NSSA in Type-7 LSAs. Type-7 LSAs are similar to Type-5 AS-external LSAs, except that they can only be flooded into the NSSA. In order to further propagate the NSSA external information, the Type-7 LSA must be translated to a Type-5 AS-external-LSA by the NSSA ABR. NSSA is supported in Cisco IOS 11.2 and later.
NSSA Totally Stub Area
Use the OSPF router configuration command area xx nssa no-summary command to define an NSSA totally stub area. In the previous network diagram, we configured area 2 as NSSA totally stub by entering the area 2 nssa no-summary command on the NSSA ABR. This keeps any Type 5 AS-external or Type 3 summary routes from leaking in area 2.
EXTERNAL BORDER GATEWAY PROTOCOL (eBGP)
This is by far the most difficult concept to understand. Many people spend years trying to understand it, and they still don’t. It can get really complex and complicated. BGP can simply be defined as the routing protocol for the internet, as it is mostly used by ISPs. BGP is a path vector protocol or a variant of a Distance-vector routing protocol. BGP does not involve traditional Interior Gateway Protocol (IGP) metrics, but routing decisions are made based on path, network policies and/or rule-sets.
Basic BGP Configuration Commands
|router bgp AS-number||Starts the BGP routing process on the router.|
|neighbor ip-address remote-as AS-number||Sets up peering between BGP routers. IP address must match the source of routing updates.|
|neighbor peer – group-namepeer-group||Creates a peer group to which you can then assign neighbors.|
|neighbor ip-address peer-group peer-group-name||Assigns a neighbor to a peer group.|
|neighbor ip-address next-hop-self||Configures a router to advertise its connected interface as the next hop for all routes to this neighbor.|
|neighbor ip-address update-source interface-type number||Configures a router to use the IP address of a specific interface as the source for its advertisements to this neighbor.|
|no synchronization||Turns off BGP synchronization.|
|network prefix [ masksubnet-mask ]||Initiates the advertisement of a network in BGP.|
BGP Peering States
The command show ip bgp neighbors shows a list of peers and the status of their peering session. This status can include the following states:
- Idle: No peering; router is looking for neighbor. Idle (admin) means that the neighbor relationship has been administratively shut down.
- Connect: TCP handshake completed.
- OpenSent or Active: An open message was sent to try to establish the peering.
- OpenConfirm: Router has received a reply to the open message.
- Established: Routers have a BGP peering session. This is the desired state.
You can troubleshoot session establishment with debug commands. Use “debug ip bgp events” or” debug ip bgp ipv4 unicast” (in IOS versions 12.4 and up) to see where the process fails. Some common failure causes include AS number misconfiguration, neighbor IP address misconfiguration, a neighbor with no neighbor statement for your router, and a neighbor with no route to the source address of your router’s BGP messages.
INTERNET PROTOCOL VERSION 6 (IPV6):- This basically talks about the IPv6 protocol and the configuration. It is required that a student know how to configure IPv6 for routing. Not too many questions on it from my experience.
IPV6/IPV4 REDISTRIBUTION: – Redistribution is very essential, not only in the exam, but in real life. At its simplest, the idea of redistribution is easy. Simply take networks that exist within one routing protocol and place them in another. For example, it is common to see OSPF networks redistributed into EIGRP or vice versa. It is also possible to redistribute networks from one like network to another; for example, from one OSPF network to another separate OSPF network.
There are two issues that can make redistribution a pain. The first being what happens when using two-way redistribution and the other is related to metrics. When performing redistribution, it is easy to simply configure both networks to redistribute routes to the other; however a problem that can occur is when one network advertises routes that it just learned back into the initial network with a different metric. For example, if an OSPF and RIP network are being redistributed into each other using multiple routers; it is possible for a RIP route to be redistributed into OSPF and then have that same route be redistributed back into RIP with a different metric on the other redistributing router, now the redistribution configuration has created a loop. It is advisable that you know it very well before deploying it in a real life network.
IMPLEMENT LAYER 3 PATH CONTROL SOLUTION – This deals with how to create a Layer 3 path control implementation plan based upon the results of the redistribution analysis, create a Layer 3 path control verification plan, configure Layer 3 path control, verify that a Layer 3 path control was implemented and document results of a Layer 3 path control implementation and verification plan.
IMPLEMENT BASIC TELEWORKER AND BRANCH SERVICES: – this covers a student’s skill on how to describe broadband technologies, configure basic broadband connections, describe basic VPN technologies, configure GRE, and describe branch access technologies.
ADVICE FOR TEST TAKERS
All this topics are covered in the exam. Take each category and focus on it by itself until the material is very familiar. Don’t worry about being familiar with absolutely everything; this is how many candidates get in trouble. You want to know enough to be comfortable with the material so that each concept makes sense; you don’t have to know everything that’s written in your CCNP ROUTE book like the back of your hand.
Create lab scenarios either with GNS 3 or with real routers. Practice exams in particular are a great resource because they help you not only validate your knowledge before attempting the exam, but also practice taking the exam and getting used to the types of questions that are being asked.
What is my recipe for passing the exam? Simple, just relax, practice and don’t try to overthink the exam.