How can router decide so fast?

Cisco created all sorts of different magic inside their boxes that optimize forwarding processing of packets.

CEFMain router function is fairly self-explanatory. Router performs IP forwarding more often called IP routing. IP routing is process of deciding where to send the packet after it was received.




IP Routing explained in detail

Logic behind IP forwarding is listed in steps here with the assumption it will be an IPv4 packet that was received. This is process switching explained in 11 steps:

I became CCIE# 46173

This is the story on how I became CCIE# 46173

To be honest, when I look back, I do not really know the main reason behind going through all this trouble, but I can tell you the story about how I did it. It’s mostly a thriller, and some drama towards the end. I will give you an overview of the whole process including the materials used, videos watched, books read and struggles that I went through.

I think that is the right thing to do. This article is for all of you out there who are still trying to study for this exam and need some suggestions. One of the most important things for me was to gather others candidate experience and suggestions in making a good study plan and get the info about the books and stuff. This is also a perfect occasion to brag about passing the damn thing and write a bit about myself. On technology blog, this is a rare opportunity when is alright to write a self reflection.

Cisco VIRL is finally out

Cisco virl logoCisco finally released long-awaited personal network simulator VIRL. VIRL is a simulator like Cisco CML – Cisco Modelling Lab released few moths ago which is made available for business network simulations and testing in engineering normal day job. With VIRL we got a personal version of CML with drastically lower price tag aimed to help students preparing for Cisco CCNP and more than that for those preparing CCIE lab exam. VIRL will surely help the engineers managing small business network to proof their configuration change before applying it to real network.


This solution give us a more stable and “official” GNS3 which will save all the time spent troubleshooting lab issues that were really GNS3 issues.

INE v5 Full-Scale Practice Lab1 TS GNS3 topology

Few days ago I added an article with Config GNS3 topology for newly published INE Routing and Switching Workbook v5 Full-Scale LAB1. Here’s now the topology with starting config of TS section for LAB1.

I will not insert here any of my stories today as the same article was published before but with other topology files so if you would like more info, just go to previous post INE R&Sv5 Workbook Full-Scale Practice Lab1 made in GNS3



When they throw a Cisco guy to do something with HP networking gear

…There’s a nice little pdf to get you through

HP is aware that most of networking engineers start their learning process in Cisco Networking Academy. Is is a normal course of events if you want to learn networking. Cisco has the very best study materials and best, carefully developed syllabus that is both high quality and most detailed in the world of networking. Not to mention the high reputation that engineers get with Cisco certificates standing by their names.

Cisco CLI

On the other hand, when you take an average mid-size business customer today you will probably see that he is mostly concerned about the price and not so much about the feature-set and robustness of IT equipment. And there you have your situation in which customer decides to go with HP rather than Cisco gear in their communication closet.

INE R&Sv5 Workbook Full-Scale Practice Lab1 made in GNS3

Yesterday INE finally added a Full-Scale LAB in their new CCIE Route and Switching blueprint 5 workbook.
I realized this morning that you maybe don’t want to spend half of your day (like me) configuring this topology in GNS3. Better to just take it from here and start your lab right away.

In my study process for the last year I made almost all my labs from INE on GNS3. In that way I was able to run the labs for more days in a row and not think about the money I would spent on rack rentals. Of course, you will still need some rack rentals particularly for troubleshooting sessions. For troubleshooting you need preconfigured rack because if you configure those topologies by yourself there is a big chance that you will see ticket answers and that will break the point of troubleshooting study process.

All my config sessions were done on GNS3 and this one in the next few days will be also done in GNS3. If you want to spare some time and get the topology ready, up and running in few minutes you can download it at the end of this article.


Read more and download files!

What is the difference between tunnel | transport mode in IPsec


IPsec makes VPN connection possible. I enables to simulate a leased line across public Internet and thus enable us to get secure connection across unsecured environment. It enables encryption, authentication and protection of our data when sent across insecurity of the world’s biggest internetwork – Internet.

It’s the cheap way to simulate a leased line, the way to send private data across the public network without compromising privacy. The goal of IPsec is to secure services and lower the cost of data transfer. Try to compare it to pricing of data transfers across dark cables / leased lines.

There are two parts of IPsec security suite
– ESP – Encapsulating Security Payload
– AH – Authentication Header

Based on our situation we can configure two different modes of operation and here we are to make the things clear about the differences and the technology behind those modes.

IPSec Transport Mode and Tunnel Mode