November 2011

EIGRP Notes – Overview and Neighbors

I’m back to studying for my CCNP R&S. I’m going back with a new mindset. I want to read to understand and do a lot of labs that will help make me understand the concepts.

What is the basic EIGRP configuration command?

router eigrp asn
network net-id wildcard-mask

What is the concept of the router EIGRP configuration commands?

For routers to become neighbors they must be configured with the same ASN number. Enabled interfaces are matched by the network command. Those interfaces enabled will attempt to discover neighbors on that interface by sending EIGRP multicast hello messages. Advertisements are also made to neighbors on the enabled interface about the connected subnet.

If no wildcard mask is configured with the network command then it will use the classful network number. The wildcard mask acts like an ACL by applying a logic comparing the network id with each interface’s IP address.

What are some key EIGRP verification commands?

  • show ip eigrp interfaces
  • show ip protocols
  • show ip eigrp neighbors
  • show ip eigrp topology
  • show ip route

What command is used to verify EIGRP enabled interfaces?

  • show ip eigrp interfaces
  • show ip protocols

What steps does EIGRP follow to add routes to the IP routing table?

1. Neighbor discovery via Hello messages

2. Topology exchange – Full updates then partial updates

3. Choosing routes – lowest-metric routes

How does EIGRP exchange topology information?

1. EIGRP router sends neighbor discovery Hello message

2. Router sends full routing update

3. Router’s continue to send Hello messages

4. Changes are sent using Partial Updates

[click to continue…]

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CCNP Study Plan

I’m back on the certification train. I had studied for the CCNP ROUTE a while back and attempted the written test in August 2011. Unfortunately, I failed that exam.

I have taken a break from certification study to learn about other technologies such as Exchange 2010, Microsoft Virtualization and Active Directory.

This time around I’ve written down my plan to pass ROUTE. I listened in on Ed Tittel’s webinar on creating a study plan for certifications so I wrote down my personal and career goals. Writing down both goals gave me a good overview of what I need to do to acquire more knowledge and obtain a certification while living my personal life.

I’ll go over my specific plan which I drew on my moleskin:

  1. Print out the blueprint – be sure to master each line in the blueprint
  2. Read OCG – my study plan for ROUTE is to read through the Official Certification Guide. I feel that I would learn a lot more because of the amount of information and depth.
  3. To create a timeline, I wanted to dedicate a chapter each week with 1.5 hours of uninterrupted reading time.
  4. Before getting into the book I will use the Boson practice exam to see where I’m at with my knowledge.
  5. With the practice exam results I will start focusing on my weak areas first.
  6. While reading, I will write down notes and mark the book for important topics to remember.
  7. I must remember to not rush through this process and really take in the material.
  8. An important part of my studying is doing a lot of labbing with GNS3 and physical hardware. For labs, I will be using the Cisco ROUTE Lab Manual.
  9. After each chapter I will answer the chapter quizes. If I don’t score over 90% then I must go back and review the material, retake the chapter quiz and score over 90% before moving forward.
  10. I’ll go back and look at the blueprint to make sure I master each item.
  11. As I go through each chapter I will publish my notes here on this blog.
  12. After finishing the whole book and labs I will do the Boson practice exam again to see if my score as improved. If I don’t score over 90% I will go back to my weak areas and do more studying until I score over 90%.
  13. After I am happy with my practice test results I will take the real exam ;)

CCNP ROUTE SWITCH TSHOOT study plan

There you have it! That’s my plan. I’ll probably revise it along the way to fit my needs but that’s what I’ll be working off of for the next few months.

What is your study plan?

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Keeping an Eye on IIS Web Servers

Monitoring IIS Servers

Systems Administration usually comes with a lot of monitoring. But what exactly are we monitoring and why are we monitoring? Are we just gathering raw data that sits on spindles in a PC underneath your desk?

I’m on the topic of monitoring web servers running IIS. There are a couple of questions I had to ask myself before blindly selecting counters in a whim to fulfill my need to monitor.

  • How will I know it’s time to upgrade my web server? And how do I know what kind of hardware to purchase?
  • Do I have a baseline of how the load looks like on a regular day?
  • What resources are targetted on a web server?

Those are just some of the questions. To get an idea of what I’m dealing with I’ll give a few statistics.

  • Small time, Mission Critical. Our site is relatively small but is crucial for keeping the lights on.
  • Public vs Private. We have a public facing site and a membership site.
  • 30k. There are about 30k unique visitors a month. Total we have about 60k total visits a month.
  • Windows. We’re a Windows shop so we’re using IIS and SQL.

So what am I looking to monitor on my web servers?

% Processor Time

The CPU processor counter which determines the percentage of time the processor is busy. Ideally this should be less than 75% for a web server. If the counter is greater than 70% you should plan to upgrade.

Memory available bytes

Memory counter which displays the amount of available memory. The lower the better.

% Disk Time

The hard disk counter monitors the percentage of time that the disk is busy with read/write activity. The lower the better. If you’re looking at high % disk time then you may want to monitor the disk queue to ensure that requests are not waiting to be processed.

I asked a question on Server Fault on input regarding monitoring the Logical Disk or the Physical Disks. The responses are interesting but points to what you’re trying to achieve with monitoring the disks.

Requests Succeeded

ASP.NET counter which will display the number of requests that have successfully executed. This will give a status code of 200. There are other codes you could monitor such as 404s, 500s, etc.

Application Restarts

ASP.NET counter which displays the aggregate number of restarts for all ASP.NET applications. There are many reasons why an application would restart and to figure out why you’ll have to hit up the logs.

Get Requests/sec

A request counter that displays the rate (in seconds) at which HTTP requests have been made.

So far this is my running list. Consider it a work-in-progress as I am still finding things that need to be monitored. The next step would be determining thresholds for these counters. At what value would be a warning threshold and a critical threshold. For example, is 30% available memory an OK, warning or critical status.

Once the thresholds are nailed down, what do we do if we reach a warning or critical status. Do notifications get emailed to systems administrators? Do we reboot a service?

I’ll continue this conversation on another post. What counters are you using to monitor your IIS web servers?

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