Lately i have been making it a goal of mine to watch a TED video a day. I do this in order to expand my horizon and learn things that i normally wouldnt pay much attention to. Something as foreign to me as a music conductor explaining how to perform a piece of music, what it takes and why he does it, makes me a more informed human being.

In this post i will shed some light on some spanning-tree info that has been floating around. But also an explanation why i choose a non-obvious answer to an IPexpert question. Specifically 2 things. The first one is the selection of ports and what _exactly_ selects the root port.

I am back from our company trip to Dubai. Dubai is a fantastic place. Its my first time in the middle east and it left a great impression. The whole city struck me as a proof-of-concept kind of city. They decided they wanted to do something great and they went ahead and did it.

It seems that everywhere i look, be it on twitter, google+ or my regular reading list of blogs, Openflow comes up alot. What is Openflow? Openflow is an initiative to create a protocol and an API infrastructure to improve overall functionality of your network.

One of my friends told me about a feature called SPD and whether i knew about it. I didnt so i decided to read a bit more about it. SPD stands for Selective Packet Discard. As the name implies it has something to do with discarding packets.

Lately theres been some fuzz in the corners about the need for NAT in the new world order of IPv6. I think its a poor design choice and ill give my reason below. One of the reasons why people seem to feel like they need NAT, is accessibility to IPv4 only content.

It seems like every day, there are some vulnerability or crack announced on the geek news-outlets. For some reason, the recent publication of an exploit of a flaw in the SSL/TLS implementation in some versions, made me extra curious and it made me think a little harder about this whole security business.

Flex Links, otherwise known as the devil for your L2 network. In all fairness, lets actually figure out what this feature is used for. The most important thing you need to know is the fact that Flex links disable your spanning-tree process.

I just watched this great lecture from INE on multicast. Well worth sharing:

Lately i have been watching a Ted video each day. I find this fascinating as i learn stuff in areas i would not normally be looking. I can highly recommend this to anyone in order to stay informed on whats going on in our world.

Using L2 tunnel protocol version 3, you can accomplish what so many scientists are working on. A Wormhole! Granted, this wormhole is just through your L3 network, so it might not raise as many eyebrows, but its still a nifty tool in your toolbox.

In this small post i want to clarify the use of the “ip verify” command. There has been some confusion on the usage of this command, especially in conjunction with the access-list parameter. I would like to clarify this here.

Being a network consultant means getting access to lots of customers using a range of different equipment. One thing thats common for almost all of them, is the fact that the time is not in sync throughout their devices. As you may know, this is a real issue when you are trying to sort out a problem.

Some time has passed since i got my CCIE number. I have spent the time reflecting on the time that has passed since starting my CCIE journey. I will write down my journey in more detail later on for those who are interested.

Hi everyone, I am happy to announce that this week i passed the R&S CCIE lab exam. CCIE #29189. Its been a long journey for me. Working full time, not taking any dedicated time off work to do so, has been challenging.

In this article i will try and setup a very simple example using Cisco IOS IPS (Intrusion Prevention System). As before, a simple topology consisting of 3 routers will suffice. They are configured as follows: Topology for IPS example. R1 will act as our source host.

My take on the Microsoft purchase of Skype. Only last week i attended a mandatory briefing of Lync, Microsofts all-in-all wonder for communicating. Basically its a PBX, IM-server, Video-conferencing, Outlook-Integrator kind of a product. Basically they have taken alot of code from alot of different half-done products and thrown them into one big pile and put alot of marketing money behind it.

Warning: The following is primarily a rant! You might not find it applicable in your situation, or you might simply not care. You have been warned 🙂 Having been a consultant for a while now, i am constantly amazed at how solutions are made up and what is sold simply because it has a buzz-word in its title or description.

I am going through the detailed blueprint, one item at a time and verifying that there are no surprises. Especially IP services and security is something i havent paid enough attention to in the past. Anyways, there are lots of items on that darn list and going through them all takes alot of time.

Link optimization on frame-relay. Using frame-relay, bandwidth is especially a concern. It is possible to optimize this bandwidth in several ways. I will concentrate this post about compression and fragmentation. First off, with compression on frame-relay there several methods of accomplishing this.

As promised, here is a couple of photos of the final layout.

 

 

 

Thats all there is to it 🙂

 

So I modified the previous layout a bit. The concern i voiced about the 3640 was enough to make me figure out a way to have that one as the bottom piece of equipment. This is what i ended up with:

I need to start cabling all of this gear into place. I have made a layout which i think i will try out. The only thing that concerns me is the weight of the 3640 router. Its a heavy baby.

I have received the rest of my routers (1841s), I have also received the memory and flash upgrades for them all (256meg memory and 64mb flash). The guy who sold them to me was very helpful and it turned out he had the cables that i needed as well (some Smart-serial to Smart-serial, as well as some DB60 ones).

So i have decided to extend my rack functionality. I have the nessecary switching capacity, but what i need are the “correct” routers. Because of that, i have so far purchased 4x 1841 + a 2811. I still need 3 more before its in order.

NTP is one of those things that really keeps messing with my head. To break it down, what does it do for us? Simple. It provides the correct time of the day. How does it accomplish this? Now this is where it gets interesting.

I want to point everyones attention at this blog post made by Marko over at IPX. Its a good read and i think you will all enjoy it!

 

http://blog.ipexpert.com/2011/01/19/old-ccie-myths-vlan-1/

Welcome to 2011. I hope that you have had time to enjoy the holidays and all the festivities that come with it. Personally i have been doing alot of work stuff. Moving data centers is no small task when the customers want constant uptime.

The month of December has been crazy for me. A ton of work related stuff has been going on. Our HQ move has taken its toll on everybody. Ive been working through every weekend, putting in some 20 odd hours on some days.

My understanding of IRB: I did another Volume 1 lab yesterday. Again i hit my head against the infamous IRB feature. IRB stands for Integrated Routing and Bridging. Below is my understanding of the technology. I could be very wrong about this, so please correct me if i state something completely incorrect.

Its been just over two weeks since my lab attempt. I have basically done no studying at all during that time. Time has come to get back in the game. I do have alot of work to do in the near future, but i will still try and do all the studying i can squeeze in.

I had a bit of spare time yesterday, and i stumbled across a great video walkthrough of the Cisco documenation by Internetwork Expert (INE), and i thought i would share it with you in case you hadnt already discovered it:

First shot = Failure. So i had my first lab attempt on tuesday the 2nd of November. Boy was it hard 🙂 Unfortunally i didnt pass this time around. I did very well in the troubleshooting part, but the configuration part, got the best of me.

At the bootcamp last week, i was almost out of reach from my lab. Even though i just got the remote power controller, the network at both the conference place as well as the hotel (especially the hotel!) was pretty bad.

This was all written yesterday 🙂 Airport fun! So right now (im sitting in London Stansted Airport after having attended the last of Narbiks bootcamp. Its going to be good to get home to the girlfriend and my puppy. He had a guest with him this time around.

As you may have noticed from my inexcusable lack of posts, ive been very busy. I have been finishing up IPexperts volume 1 workbooks and now going through volume 2. Still lots of interesting details to learn about. I have also managed to get most of my video-on-demand material onto my iPad so i have easier access to it.

I wanted to point your attention to gns3vault.com. Alot of students use GNS3 (front end for dynamips) to do alot of their lab work. Rene Molenaar created this site, which is basically a site with free labs that you can download and practice on.

Im back from vacation. I can now with convinction state that hotels in Spain are not up to par with other places. I have been to Spain twice now, and they NEVER have an internet connection in the rooms. You had Wifi in the lobby, 2€ for an hour, and it barely worked.

Awesome. Got alot of EEM ground covered today. Seems like a very powerful scripting engine that stands out, by having the ability to be triggered under certain circumstances. Lets check out an example using the topology below: EEM Topology R1 is connected to an ethernet segment.

I have started doing IPexpert Vol 1. technology labs. They are pretty challeging. They make you think out of the box. Almost none of it is vanilla configuration. I dont know how closely these labs reflect the real one. Ofcourse these are Vol.