Posts

Even though my next post was going to be about some enhancements to STP, I found this little nugget about OSPF behavior, that I thought I would share with everyone.

As we know OSPF, when crossing an area boundary, the ABR (Area Border Router), will gather type 1 (router and its links) and type 2 (network information provided by the DR on a transit network) and form a type 3 LSA, which is basically a boiled down version of the two other types of LSA’s. It will send this LSA into the area (assuming its not a totally stubby/nssa area).

This is the 2nd post about 802.1D, also known as spanning-tree. In the previous post, I explained alot of functionality behind the selection of ports on both root bridges as well as non-root bridges. (Remember a switch is a bridge).

Ive spent the last couple of days playing around with the traditional Spanning-tree protocol (802.1D), which has been used for many years, but is pretty slow to converge.

As most of you know, Spanning-tree protocol (STP), is used to build a loop-free L2 topology. This is done to avoid bridging loops, where your frames gets sent around and around endlessly.

I failed my first attempt at the CCIE written exam this thursday… It really sucks.

I was very close to passing it, but unfortunally it didnt happen. I need alot more practice questions to get a “feel” of whats being asked. Also, protocol mechanics need to be practiced some more.

So I have started my review process. I have some things on my list that I need an in-depth look into.

Among these are:

• IPv6 tunneling types.
• Web Cache Communication Protocol (WCCP).
• Some Frame-Relay workings, like FRF.12 and FRF.9.
• Switching section in BCMSN, particularly MST.
• Frame-relay traffic shaping.

These are the big ones I need to tackle. On top of this I need to review the entire exam certification guide. If I have time, I will also try to define all the terms, which is one of the tasks they (exam cert. guide) suggests that you do.

I am just watching the video of the google wave application. It is really impressive what you can do with the modern web technologies. One thing that really shines through is the real-time updating.

This is a really cool technology that I can envision a bright future. If developers embrace this, and extends it, it can really be a very powerfull tool that will rival microsoft’s version, namely sharepoint, and its integration with different microsoft products. This works much more seemless. I hope that while google still have all their own tools such as calendar and email, that they will provide some integration into other applications, like sharing directly from microsoft word, and openoffice. This would make it really pain-less to work on something and share it with a bunch of other people.

Been spending the last few days doing some leg-work on understanding different ACL’s to match different networks most effeciently.

Alot of posting on Online-Study List on how to do this, all very valuable. Tyson Scott from IPexpert created a PDF file that was posted, and will also be made available from IPexpert.com in the member section. It gives some good examples of the binary math behind it all.

Great news for all you europeans!

It would seem that IPexpert is looking into creating classes on european soil. This would be really great to cut down on costs and travel time to attend IPexpert led instructor training. I hope we can get together about 10-ish people that wish to attend these classes. I for one would be one of them.

So this is the 2nd part on how PIM-SM operates. Last time I showed how the initial RPT (shared tree) was constructed, and how data would flow from the source to the receiver.

This time, I want to show you how the optimization technique in SM actually works.

I knew it would be tricky before I even started with the multicast section, but not this hard 🙂

So I wrote about PIM-DM and its flooding behavior, and how it would make sure data was flowing from the source to the receivers. I will try to give some information about PIM-SM and also some further information on IGMP.

So Brandon Carroll’s quest to do the Routing and Switching certification is scheduled to take 90’s days. I think he is very gifted and got the right stuff to do it (he’s a security CCIE). What came to mind, was this hypothesis:

I am really wondering whats up with google’s services lately. I have been having huge issues getting my mail. It times out several times, and then all of a sudden it appears, and other times it logs me out. Sometimes I have to periodically refresh.

Ive started on the Developing IP Multicast Networks book from Beau Williamson. This book is apparently “the” book on multicasting, so I hope it will help me out with this weak area of mine. So far ive read about DVMRP which is not on the blueprint, but it sounded like it would be a good help to understanding PIM modes, which are on the blueprint, so I decided to go through it anyways. So far its a good read, however you can tell that its dated a bit. The overview of the applications running on the MBone is from Windows 95 🙂 quite a few years ago.

I am almost done with the Internet Routing Architectures book, and its a great book!! You really get to understand why BGP is the way it is.

Where IGP’s as we know them concentrate on fast convergence, BGP is all about 2 things: stability and policies.

So even though im looking over my journal, and i am doing about 1,5 – 2 hours studying each day, I feel like im lacking the discipline to really make a dent in the thing called CCIE Written. I have not been using google calendar like i should, and it is really bumming me out. I would like to have two 50 mins reading sessions a day, and time to write down my notes at the end of the day.

So after learning that im not employed after september, I am on the market for a new laptop.

This new laptop will be my primary machine, as I very rarely boot up my stationary computer. It should be able to handle quite alot. Right now I have two candidates which are very appealing in their own way:

The new blueprint is out for all to see. Its version 4, and includes some interesting things. Alot of people have already analysed it in quite some detail.

The two things thats most obvious to me, is the emphasis on MPLS as more and more dominant technology. VRF’s are explored in more detail.

As the topic implies, I will be writing about a few things regarding shaping and policing. Now these are two really hard-to-understand topics for me, but they are also very usefull. To understand what they do, and the difference between them, lets define them as such:

Im at the policing and shaping section of the exam certification guide, and its very hardcore stuff in my opinion. Just finished the section on 3550 and 3560 ingress/egress queuing and scheduling methods. Wow, thats really something i gotta get my head around.

Im somewhat in the middle of the CCIE exam certification guide, and still learning alot. I am putting down the framework for more detailed examination of technologies. I have a couple of books on my reading list after this to solidify the knowledge with more in-depth details.

I am doing alot of technology focused labs, and I always learn something new, which is really good. For example, I was studying the effects of autosummarization with RIP and EIGRP. A few things cropped up.

RIP will autosummarize routes it receives from other neighbors, where as EIGRP will only summarize those, if it has a locally connected network of the same major net, and it is included in a network statement.

Im done with my first reading of Routing TCP/IP volume 1. All in all a great book, with lots of information about the various IGP’s. I skipped the IS-IS part simply because its not part of the R&S written blueprint. I made quite a few notes about each chapter along the way, which I am sure will come in handy when reviewing/troubleshooting material.

So I broke down and bought the IPexpert Blended Learning Solution the day before yesterday. I got great advice very fast from the people there, and they were very nice. Been looking over the workbooks, they seem really good and challenging 🙂 As I have written before, I will take my time and learn as much as I possibly can, so I wont even start those labs until I have a better understanding of the entire scope of this whole CCIE buisness, which in other words means alot more reading and understanding of things and passing the written exam.

Im watching some free vLectures from IPexpert here, the one im watching is the one about Spanning-Tree. Its pretty good so far. I do hope however, that their video-on-demand products are alot better quality. Im still waiting to take the plunge and buy their BLS (Blended Learning Solution) until I know where I stand both financially and knowledge wise (written).

So im finishing up some troubleshooting exercises in Routing TCP/IP. They are mainly about the metrics used by EIGPR. Here’s a review of the functionality of EIGRP and how it chooses the best path to a destination.

First of, EIGRP is an Enhancement of the proprietary IGRP protocol, which is almost but phased out by now. EIGRP is still a distance vector protocol, since it routes by rumor. Each router does not have a full view of the entire network topology and can therefor not base any decision on

At the bottom of this post is a link to a small article by Jared over at IPexpert about the books he recommends for the CCIE written exam. Anyone who looked at the recommended book list from Cisco is blown away. I believe theres 21 books on that list, most of which, I suspect is no less than 600 pages. Jareds list is only one third of that. This is a guy with 3x CCIE’s under his belt, so I take his words as the definite truth :

So im reading about EIGRP’s DUAL algorithm, and how it works, and MAN, its confusing. After the example in Routing TCP/IP, even they mention it might require several readings. Basically it boils down to the fact if a router being notified of a bad link has a feasible successor or not. If it doesnt, it goes into an active state and sends out queries to all of its neighbors. It will stay in active until it has received a reply from all of its neighbors it has queried. However, if it does have a feassible successor, it will switch to that one, and notify its neighbors of its change.

I wanted to post a link to a great site which I have started using called flashcarddb.com, what it does is pretty simple, but it does its job in a slick fashion.

There is a system called the leitner system, which in all its simplicity is making you remember things by repeating them in periods with different intervals. If you miss a question, it is scheduled to be repeated more often, until you get it right every time. This I think will come in handy with some things I simply cant remember. I will be using this along with normal note taking procedures. I want to enter in as many as required. Right now reading through Routing TCP/IP Vol. 1, I am entering in some must-remember facts, which I can then later on practice. So its not a replacement for notes, but a supplement to make sure you get facts straight.

Im having some “fun” with static routes. Its an okay topology, 4 routers connected. The task asked for having some floating static routes, along with some load-balancing routes. Since they are CEF based, it will be load-shared by default to destination load sharing. Note to self: if incomming interface is CEF, what is the output switching method going to be? — Thats right, CEF.

So like many others finishing their CCNP’s, ive been looking at the CCIE R&S track. There are two obstacles to become one of the prestigious ones with CCIE digits. One is the written exam, and the second is the lab exam. Of these two, the lab exam seems to be the big one of the two. I would like to add a third however. That one is the study path to passing the other two.

So yesterday I setup a BGP scenario which you can see below:

I am doing mutual redistribution on both R1 and R3, between BGP and EIGRP.

I am advertising a couple of routes from R4 (AS 65001) to R1 (AS 65000).

This week I will be spending alot of time at various of doctors unfortunally. I still suffer from fearing everything is physically wrong with me. Im having it all checked out. I would really like a blank sheet to start a new life from. However, a blank sheet requires a total checkup. I hope everything works out! I am also going to a hypnotist, to see if she can somehow tweak my mind into something else than thinking about my physical state constantly. This dominates my life, and it shouldnt be.

Thought I would share some lab pictures:

I just emptied my shopping basket on amazon again. This means I ordered what was in it 🙂

I got some CCIE books, but this doesnt mean anything except I am interested in whats in them. Also got a few other non-technical books. Among other things I ordered Brian Tracy’s book: Goals! which I saw mentioned on Chris Bryants site. Maybe I can pick up a few tips and tricks. Also got a book on anxiety and how to combat it without the use of drugs. I am interested in learning how other people cope with this, and for me, that means reading about it.

I am finally done. ONT was passed today, and with a pretty good score as well. I am very happy. Now it is time for some relaxing, and get on with my training schedule. I really wish we had a testing center somewhere closer that was actually worth going to. It is a 2 hour drive for me to goto each exam, which I think is a long time.

I am in the process of reviewing and labbing from the lab portfolio. I need to have the verification commands down, so I can troubleshoot different QoS scenarios. I find it very hard to do much configuration though.

Also, the wireless section is kind of hard to get good hands-on experience with since I dont have access to any WCS (Wireless Control System). At work, we only have WLC (Wireless Lan Controllers) that I can get some practical hands-on experience with. How does everyone else go about getting enough “dirt-under-the-nails” with these technologies? Buying them is obviously out of the question, since I dont have that kind of budget to do these things on. I have already used all of the strings I have to borrow equipment, so I doubt my hands-on experience will get much better than it is.

I just purchased a Linksys USB ethernet adapter to try out with Gnu/Linux. I have tried it with both 32 and 64bit, and it works like a charm. It was just an experiment to see how I could create a box with a large density of LAN ports. Since im on a budget and only have dual NIC’s available, I was looking at different motherboards with lots of LAN ports. Only two I could find were Asus P5Q Premium and Gigabyte DQ6, which both had 4 onboard LAN ports. Both of them only offered 2 PCI slots. That would give me a total of 8 ports – 1 for management. That means only 7 ports. With this option, and a standard of like 6 USB ports (I havent tested an USB hub yet), I get at least 13 ethernet ports.

So I am almost done with the wireless section, but alot of things still needs to click in, especially regarding the security aspect of it all. Some more reading on that is needed next. QoS in wireless is done by basically lowering the back-off time in CSMA/CA for higher priority traffic. The Wifi Alliance released an interim solution based on 4 categories. Platinum, Gold, Silver and Bronze. Platinum is used for voice, Gold for video, Silver is best effort, and Bronze is “background” stuff, I guess thats your typical P2P applications along with random non-categorized stuff.

I am finishing up on chapters regarding WRED and LFI.

WRED is a congestion avoidance mechanism. What that means, is that when congestion occurs, you try and avoid filling up the buffers completely by dropping some packets. Normally the standard queueing for fast interfaces (>E1) is FIFO, with the congestion avoidance of tail dropping. That means whenever the buffers are full, any new packets to the queue, gets dropped. This has a nasty habbit of producing TCP synchronization.

So im studying about congestion management, namely the use of queuing and the different discplines of queuing.

FIFO = First In First Out. This is a straight forward queue which doesnt take any priority, delay or bandwidth into account. This is the default on Cisco equipment for interfaces > 2.048 Mbps (E1 lines or slower).