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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

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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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Thought’s on Cisco ACE Deployment

I’m in the planning phases of deploying a load balancer for our public website. We’ve made the decision to move forward with the Cisco Application Control Engine, otherwise known as ACE.

The current environment is fairly simple. We have a firewall, switch and servers connected to the switch. All the servers are on the same vlan.

Where I am now left off at is figuring out how I want to insert the Cisco ACE into our current environment without having to create more work or modifications to the current network.

One of the options was to deploy the ACE in inline mode.

Cisco ACE Diagram

The downside is that I have to change the default gateway on the servers to point to the Cisco ACE. I don’t plan load balancing all the servers on that particular vlan so I decided not to go this route.

One-arm mode.

Using the One-arm mode deployment method is a less intrusive way to load balance only certain servers.

Cisco Ace deployment diagramEssentially, the ACE sits outside an interface, or four, from the switch. All traffic destined to the web servers hit a virtual ip address on the ACE, which the ACE then load balances to the real servers.

The advantages to one-arm mode:

  • Easy to configure
  • Less intrusive on current network design
  • ACE uses a virtual IP address (VIP) for traffic destined for web servers
The only disadvantage I can see:
  • NAT is performed on the ACE
Once client/outside traffic reaches the VIP, the ACE will NAT that connection from it’s pool and then send the traffic to one of the real servers. The reason why Cisco ACE uses NAT is so that the real servers have a path back to the ACE which then gets translated back in the ACE to the client.
That’s where we stand on the design and now I’m moving towards finishing up the configuration.

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