Tuning Route Redistribution using AD

Today I went through a quick study session and lab that shows how administrative distance can cause suboptimal routing when using route redistribution. I tested this with a lab that was redistributing RIP and OSPF both ways. Since OSPF has the default AD of 110 and RIP has an AD of 120, the ASBR routers redistributing chose the OSPF routes even when the RIP routes were closer. To modify this I had to create an access-list with all the possible RIP routes and assign it the AD of 125 on the two ASBR routers and inject the access-list into the OSPF routes. Now when the ASBR's received a RIP route from OSPF (due to redistribution) it automatically had an AD value of 125 which was larger than the default RIP AD 120. The RIP routes were installed into the ASBR's routing table due to having a lower AD value of 120!

Route Maps and Distribution Lists

I spent most of my afternoon covering the topics for Route Maps and Distribution Lists. I've actually been waiting to get to this topic for quite awhile because I see these commands in my work environment all the time. Both of these tools are similar to access-lists but their purpose is to tune or route specific IP packets. Distribution lists filter routing updates which is something you can't do with a regular access-list. Route maps gives the engineer a lot of flexibility on what specific ip packets should be tuned and what should be tuned such as the router metric. Tomorrow I will learn more about tuning administrative distance (AD) to control the flow of routing packets.

Controlling Routing Updates

This morning I spent most of my time learning about passive-interfaces and the many ways we can control and tune routing updates. This chapter actually puts together a lot of pieces to the puzzle because it explains how routing protocols work together and how you can limit what each protocol knows about the other specifically. I also learned a little bit about distribution lists and will be creating a few labs for this tomorrow.

In other news I'm creating a lab ebook for all of you CCNA test takers out there so be on the look out for that. I will most likely make it a series along with splitting the ebooks up into ICND1 and ICND2. I want to make sure that the series is not only helpful but also very affordable because we all know that the study material, equipment, and exam isn't cheap by any means. I'm actually looking to hand out a few beta copies of my book for free to review and provide constructive criticism. Email me at shawnmoore_1@hotmail.com if you're interested and I'll add you to my current list of reviewers, spots are already filling up so be hasty!

Redistributing between Routing protocols

Today I spent most of my time going through the various redistributing differences between routing protocols. The hardest redistributing to remember was the metric for the protocols that used distance-vector technology which is RIP, EIGRP, and IGRP. The metric for these protocols have a default value of infinity which means that any other routing protocol wouldn't be redistributed unless you defined the metric that is to be used. Also OSPF doesn't redistribute classless IP routes by default, you have to specify that subnets will be used for whatever reason. IS-IS was surprisingly the easiest but maybe that's because I just finished that chapter last week? I have a ways to go to finish this chapter won't be until sometime next week most likely. I will run through some labs in my portable command-guide the next few nights to get some more practice with the theory I've learned so far.

Chpt. 7 Redistribution Overview

Today I went over the beginning pages of Chapter 7 regarding manipulating routing updates. This chapter started off with route redistribution which I have a little experience with all ready from previous labs and on the job experience. The pages I read went to the reasons why you would want to redistribute and situations that you want to look out for when injecting different AS protocols into another AS protocols. There really wasn't much to lab but I did create a lab based on an example provided in the study-guide book. Tomorrow should be a lot of configuration using the various routing protocols that has been learned through out the book so far.

Chapter IS-IS End of Chapter Lab

Today I finished up the short Chapter 6 lab on IS-IS and actually managed to get everything up and working this time. I'm still not sure why my other IS-IS lab wouldn't inject the routes correctly as I should so I'll probably run over that labs configuration again at some point. I also ended the chapter by finishing the multiple choice questions presented. As current CCNP's and above mentioned, the questions presented in the back of the book are CCNA level type of questions which really doesn't help enforce your command of the topics given.

I'm actually only 4 chapters away before finishing the entire book so I'm making really good progress thanks to the holidays I was able to get some extra study time in at work. Once i finish the study guide and go through the portable command-guide book I'm going to purchase the exam and lab guide and double up my studies. Once that's complete I'm going to hopefully fill in any gaps by going through any labs and CBT's from Cisco.com I can get my hands on along with going through white papers and RFC's. Repetition Repetition Repetition is the key to mastering and becoming successful with anything I believe, hopefully it pays off for the exam!

IS-IS Configuration

Well i finally came across a lab for IS-IS, this is going to be a topic I'm going to have to come back and review a little harder for sure. The most confusing part about configuring IS-IS is remembering that a IS can only be in one area unlike OSPF but the interfaces on the IS can be set to send specific IIH PDU's (L1, L2, or both). There isn't an ABR like OSPF that sits in between two areas, also IS-IS doesn't use an area 0 bypassing hierarchy which allows for better scalability with IS-IS. I had some problems getting my loopback interfaces to connect via IS-IS even after redistributing my connected links into IS-IS I had problems. Tomorrow there's the end of chapter lab so hope fully i can better get my head wrapped around it! I also tested some SSH connections by setting up static host mappings using the ip host hostname ipaddress subnetmask command. I created loop back interfaces for my host ip address which as we know never shuts down compared to using a real serial or Ethernet interface. I want to start some security but I know my time will better spent focusing on the core CCNP topics. I'm going to have focus on all the topics presented thoroughly in order to pass the BSCI.