Wonders of Telecom: April 2010

Wednesday, April 21, 2010

Starting new preparation. Day One. Reading...

Ok, since my last (not the first) attempt wasn't so good , I am planing to read a few book from CISCO recommendation list and post the summary here.

I will start with: Advanced MPLS Design and Implementation:

Chapter 1:
MPLS is an improved method for forwarding packets through a network using information contained in labels attached to IP packets. The labels are inserted between the Layer 3 header and the Layer 2 header in the case of frame-based Layer 2 technologies, and they are contained in the virtual path identifier (VPI) and virtual channel identifier (VCI) fields in the case of cell-based technologies such as ATM.

Benefits of MPLS - VPN's (solves the issues with IPsec (have a very high overhead and are slow and not scalable)), Traffic Engineering, QoS, Integration IP and ATM, simplify the deployment of IPv6,

Thursday, April 15, 2010

Not this time....

Unfortantly this time wasnt so good, but i was very close.
Next time i sure i will meet the goal !!!

:(

Wednesday, April 7, 2010

Understand Reverse-Path Forwarding (RPF)

Reverse-Path Forwarding (RPF) is an algorithm used for forwarding multicast datagram's.
It functions as follows:

• If a router receives a datagram on an interface that it uses to send unicast packets to the source, the packet has arrived on the RPF interface.

(then)

• If the packet arrives on the RPF interface, a router forwards the packet out the interfaces that are present in the outgoing interface list of a multicast routing table entry.

(else)

• If the packet does not arrive on the RPF interface, the packet is silently discarded to prevent loops.

PIM uses both source trees and RP-rooted shared trees to forward datagram's; the RPF check is performed differently for each.

• If a PIM router has source-tree state (that is, an (S,G) entry is present in the multicast routing table), the router performs the RPF check against the IP address of the source of the multicast packet.

• If a PIM router has shared tree state (and no explicit source-tree state), it performs the RPF check on the RP's address (which is known when members join the group).

Sparse-mode PIM uses the RPF lookup function to determine where it needs to send Joins and Prunes. (S,G) Joins (which are source-tree states) are sent toward the source.
(*,G) Joins (which are shared-tree states) are sent toward the RP.

DVMRP and dense-mode PIM use only source trees and use RPF as described above.

Core Knowledge Question (OEQ) material to read for CCIE SP

Tuesday, April 6, 2010

Brussels, Belgium here i come .....

Ok, final 3 days before my exam. Is not my first attempt and i hope it is a last one!!!
Today arrived to Brussels for my attempt in CCIE SP, went to Cisco offices to talk and meet the proctor but on reception very nice lady told me "it is impossible - he is in middle of the test , what did you think to your self?". Strange, in US (RTP) it was very different, proctor is nice and he come to you outside to give you a little briefing about the exam, but no, here is different.
Anyway, i turn around and come back to hotel to read more before this f$%&@# OEQ question.
New stuff added from my previous trying, it is evil OEQ (Core Knowledge Questions - cisco way to call it - common...).

"

04 Jan 2010

Core Knowledge Questions on Remaining CCIE Lab Exams

Effective January 4, 2010, CCIE Service Provider, Storage and Wireless lab exams will begin with a brief Core Knowledge section consisting of four, computer-delivered short-answer questions. The Core Knowledge section was added to CCIE Routing and Switching, Security and Voice earlier in the year. Candidates will type in their answers, which typically require five words or less. Questions will cover topics included on the current lab exam blueprint. Candidates are allowed a maximum of 30 minutes to complete the questions and may not use the Cisco documentation which is available for the remainder of the lab. Well-prepared candidates should be able to answer the questions in 15 minutes or less and move immediately to the next section. No extra time is being added to the eight-hour exam. All candidates must pass the Core Knowledge section in order to achieve CCIE certification.

"
Except OEQ for the lab itself i think i am ready but you never can know what to expect.
This is the beauty of this CCIE.
I study almost 1.5 years to feel that way, it is not coming easy i can tell you.
So to the practical stuff:
LAB: did all the possible labs that available on the market today: Internetwork Expert, IPExpert, CCbootcamp and a lot of mini labs from Antonio Soares ( I think personally this guy did amazing job, including configurations and different videos on his site - please visit to learn - http://ccie18473.net/ ).
After my first attempt i understood that this labs are far far away from the reality, but it is a good way to start and touch every thing that you need ( basically everything that you see on the blueprint :) ).
Now to the OEQ, Now i have a three days before my exam and i am going to read all my notes writen during this year.
It is not simple as that but i am going to focus on this now.
Going to read....

Saturday, April 3, 2010

Change the Width of Your Blog - Make the Blog Wider

This can be quite important feature, if you care about it....Changing the width of your Blogger Blog will gain you some extra space (to place more gadgets, pics, ads...), or it will make your Post section wider (meaning: larger pictures, wider paragraphs), you can also add a third column, if you want.....

CURRENT SITUATION (What's out there?)
There's a thousands of templates out there...you have Blogger default templates + Dozens of other sites that provide a free Blogger Templates...
All right, you knew that....but here's another thing you should consider:
There are 2 kinds of templates (layouts) you can use:

► FLUID width or STRETCH templates - template that resizes to fit any computer monitor. It stretches corresponding to the monitor resolution.
Advantage is obvious, and a big disadvantage is DESIGN. It's quite restraining when it comes to this. Of course, it depends what you like. For a professional looking template, it's great....But for a personal one, it can be a bit dull.....

► FIXED WIDTH templates - they have a fixed width, regardless of monitor resolution....They are ideal for designing and customizing, but, the width part can sometimes be a real pain in the....:]
...Why? Because:
- people have different Monitor (screen) sizes,
- and they use different resolutions on them...
...the final result is: Blog appears different in each combination!

Read more about Monitor sizes and resolution, and how to change the resolution...

◄Imagine lying down in the grass with your nose pressed deep into the thatch. Your field of vision would not be very large, and all you would see are a few big blades of grass, some grains of dirt, and maybe an ant or two. This is a 14-inch 640 x 480 monitor. Now, get up on your hands and knees, and your field of vision will improve considerably: you'll see a lot more grass. This is a 15-inch 800 x 640 monitor. For a 1280 x 1024 perspective (on a 19-inch monitor), stand up and look at the ground. Some monitors can handle higher resolutions such as 1600 x 1200 or even 1920 x 1440—somewhat akin to a view from up in a tree...►

SHOULD I CHANGE THE WIDTH OF MY BLOG?
Well, it depends. If you already have a wide template, or you're using Stretch (fluid) layout, there's no need of doing this...

Resolution friendly means that your Blog doesn't exceed the width of 750px. Why 750? Because statistics tells us that lots of people are still using a 800x600 px resolution. And if you make your Blog wider than 750, these group of people will have to scroll left-right on your page....which is quite irritating. And you can lose those visitors....

But, there's also a saying, and it goes like this:
Lie ► A Bigger Lie ► Statistics.

If you surf a bit, and pay attention to web pages width, you'll notice that lots of web sites (even popular ones), are way over the 750 px!
So, it's really up to you....

LET'S CHANGE THAT WIDTH ALREADY.....
The only problem here will be the identification of the CSS style in your template (Layout). This is the part in the code section that defines styling, including width of elements.
There's so many different templates around, and it's a different story for each one...

But don't worry....there's a pattern. A backbone. A Layout constitution. A certain way of organizing (naming) elements. It's basically the same thing, under the different name.....
For this example, we'll take a default Blogger template ► Minima. Let's do it.

1. First thing is identification. Go to: LAYOUT ► EDIT HTML, and find the parts that defines the width of the Main section, Post sections, Sidebar, Header Section and Footer.
For Minima, we have this situation:

#header-wrapper {
width:660px;
margin:0 auto 10px;
border:1px solid $bordercolor;
}
..................................

#outer-wrapper {
width: 660px;
margin:0 auto;
padding:10px;
text-align:$startSide;
font: $bodyfont;
}
..................................

#main-wrapper {
width: 410px;
float: $startSide;
..................................

#sidebar-wrapper {
width: 220px; float: $endSide;
..................................

#footer {
width:660px;
clear:both;

...in Minima (and lots of other templates) elements are categorized by these names:
► header-wrapper is Header
► outer-wrapper is our Main section, other elements are wrapped inside of it..
► main-wrapper represents Post Section
► sidebar-wrapper stands for Sidebar
► footer is Footer :]

...this means that our header-wrapper is 660px wide, outer-wrapper width (Post section + Sidebar+ margins) is also 660px, and footer 660 px.

2. Let's change the width:

#header-wrapper {
width:750px;
margin:0 auto 10px;
border:1px solid $bordercolor;
}
......................................................................
#outer-wrapper {
width: 750px;
margin:0 auto;
padding:10px;
text-align:$startSide;
font: $bodyfont;
}
.......................................................................

#main-wrapper {
width: 500px;
float: $startSide;
........................................................................

#sidebar-wrapper {
width: 220px;
float: $endSide;
........................................................................

#footer {
width:750px;
clear:both;

...I've decided to make my Post section (main-wrapper) wider. In order to do this, I have to increase my outer-wrapper. Now, here's the RULE:
◄ If you want to increase the width of your Posts section or Sidebar, you HAVE to increase your Main section width (outer-wrapper) for the same value! ►
◄ 500px + 220px + margins = 750px ►

In this example, I've increased my Post section (main-wrapper) for 90px, so I've changed 410px into 500px. I did the same for the Main section (outer-wrapper), changed 660px into 750px....I've left the Sidebar the same width, 220px.
I've also changed the width for my header-wrapper and footer....into 750px. Note that this is not necessary, but better do it...for the sake of symmetry in your Layout...

That's about it. Remember, when you're changing the width of your (custom) Blogger template, certain elements will be (can be) under different name....Do not let it confuse you! You know how the elements are organized inside of it....and in the end, its a 5 minutes job...some simple mathematics + patience.....

http://www.blogbulk.com/2009/01/change-width-of-your-blog-make-blog.html