CCNP Basic OSPF Theory

Today I started my studying on OSPF in the CCNP BSCI Study Guide book. It was mainly just review of LSDB's, LSA's, and the packets that are used to get OSPF up and running. While most of it was CCNA review material the book did go in-depth regarding the packet types and their function. It also displayed interesting diagrams and analogies to help understand how OSPF builds its Link-State Database (LSDB). You can think of LSDB as a map you're looking at in the mall, and the mall it self being the OSPF network. There are multiple maps placed throughout the mall with the same information regarding where every store is located just the same as each router has the same LSDB in an OSPF network . The only difference between the maps in the mall is the "you are here" dot. The dot determines where you are in the mall and the best path to get to every store within that mall. OSPF functions very similar to this, each router uses the LSDB and it's location in the network to determine the best path to get to every other router within the OSPF network!

Tonight I will be finishing up a few more pages regarding OSPF theory and then tomorrow I hope to jump right into configurations, the fun stuff. The pic I added today shows the current topology of the entire global network, pretty wild stuff!

CCNP Chapter 3 EIGRP Lab

Today I finished up my EIGRP studies by compelting the end of chapter lab along with Q&A's. The lab wasn't to bad and I was able to get through it in a more timely matter than the last chapters lab due to not having to use 11 routers! By time I went through the lab I already knew how to set most things up due to going through all the examples so it really made the lab a breeze. Next week I begin my OSPF studies which I here is one of the most tested subjects on the exam.

EIGRP Stub Configuration

Today I finished up the rest of the CCNP theory for EIGRP. I learned more about manipulating DUAL by using specific commands of eigrp stub on remote routers to elimante the need for hub routers to query the remote routers for networks that they do not have to begin with. I also went through the various show and debug commands for EIGRP just to get a feel on what really happens when routers are talking to each other via EIGRP. Tomorrow I'll be finishing up Chapter 3 in the CCNP Study Guide book by completing the provided lab and answering a few questions. Next week I begin in depth OSPF theory, there's two whole chapters on this stuff so I'm thinking it's going to take about 3-4 weeks to get through all the OSPF topics in this book.

EIGRP Queries and SIA's

Today I learned a little more theory behind DUAL and it's process, along with a few ways to manipulate the way DUAL queries are sent. The EIGRP DUAL process is very efficiant and can be very scalable in larger networks but only with proper planning. When there are houndreds of routers in a given network, the convergence time for EIGRP can be much longer and more complex than needed. To eliminate convergence time as much as possible, it is smart to plan networks in such a way that there are no more than 7 hops between two routers on a network. One good way to cut down on convergence time is to summarize networks along with using default routes on remote routers that connect to the core. I also learned a lot how SIA (Stuck-in-Active) works and how it can increase convergence time quite a bit on redundant networks. The next few days I will be finishing up my EIGRP study and will be going through mainly labs since most of the theory is finished for this chapter.

EIGRP Bandwidth and Authentication

Today I spent most of my time learning the EIGRP Bandwidth theory along with authentication. Math isn't one of my most favorite subjects but in order to understand route manipulation you have to understand the mechanics behind it. EIGRP is setup to use only 50% of available bandwidth for it's routing by default. So as the picture shows, you will have to manipulate the EIGRP topology in believing that a link is slower than it really is in cases such as Frame Relay multi-point and point-to-point. I spent the last part of my studying time configuring MD5 authentication between two routers by enabling MD5 on the interface and configuring my key chains on both sides of the routers. I won't have time to study like I want to due too my shift beginning tomorrow but I should be wrapping up my CCNP EIGRP studies next week. It's hard to believe that I'm really working on obtaining such a prestigious certification but I'm focused so i don't ponder to much on it. So far the BSCI is doing a very good job of answering a lot of the questions I had while studying the CCNA.

EIGRP DUAL and Basic Configuration

Today I spent time learning exactly how DUAL works within EIGRP by reading through the CCNP Study Guide along with creating lab scenarios and watching EIGRP debugs. Seeing it in action through the debugs and reading the study-guide book examples gave me a way better understanding of exactly what's going on when the EIGRP AS topology changes. Using the EIGRP Packets it sends EIGRP Queries, Updates, and Replies when the topology changes. I have a fuller understanding of why this protocol is considered a hybrid protocol .Because it does distant-vector tendencies like split-horizon and hold-down timers while it does link-state tendencies such as using the metrics too determine the best path rather than hop count. I finished up tonight by going through one quick simple lab regarding manual route summarization based off the examples that were provided in the study guide. I've also been practicing setting up IP host translations for telnetting between devices. It's a little bit of a pain setting it up but once you do it's a beautiful thing being able to quickly telnet to the device you want rather than having 10 console screens open!

CCNP EIGRP Theory

Yesterday I spent most of my time in the CCNP Study Guide book learning about EIGRP in a little more detail. Such things as the metric used for calculating routes:

EIGRP associates five different metrics with each route:

K1 = Bandwidth modifier

• Minimum Bandwidth (in kilobits per second)

K2 = Load modifier

• Load (number in range 1 to 255; 255 being saturated)

K3 = Delay modifier

• Total Delay (in 10s of microseconds)

K4 = Reliability modifier

• Reliability (number in range 1 to 255; 255 being the most reliable)

K5 = MTU modifier

• Minimum path Maximum Transmission Unit (MTU) (though not actually used in the calculation)

I also spent time learning about the neighbor table, topology table, and routing tables EIGRP use to determine the best route or Successor route. I spent time going through the 5 types of packets EIGRP uses for making this routing protocol works. Hello's, Updates, Queries, Replies, and ACK (Acknowledgements) are all used in conjunction to make EIGRP work. Today I'm going to be going through many different EIGRP configuration scenarios along with learning more about the DAUL algorithm.