For BCMSN exam I did not attend for any classes and did not do any labs. But strictly speaking this is not good. To me BCMSN is not that much important to me. That's why I did not put that much effort on that. And that's the main reason why I got very low marks in that exam.
The concepts in the BCMSN was important to me.
I don't have much experience in BCMSN to share with you.
Sunday, June 15, 2008
Sunday, February 3, 2008
Passing BSCI 642-901
Well this is for all those who are willing to do Cisco BSCI 642-901 module and get through the exam.
From my point of view, this is an interesting module and it's all about routing. All you need is to study the Student Guides provided by Cisco. All of the questions are based on the information in the Student Guides.
You MUST have hands on experience on labs, because it's the only way you can improve. And also it is a must to pass the exam. Most of the questions are based on troubleshooting stuff. The one I messed up was the multicasting stuff.
For those who can't afford buying cisco products to build a home lab, the best solution is to go for dynamips. I really love it. You need a cisco IOS to run it. Dynamips is actually a router emulator rather than a simulator. It actually acts like a router. You can configure more than one router and various topologies including frame-relay clouds. It's actually created for CCIE labs.
To download and learn more about dynamips click here.
You need dynagen too.
Don't worry these are all free tools.
From my point of view, this is an interesting module and it's all about routing. All you need is to study the Student Guides provided by Cisco. All of the questions are based on the information in the Student Guides.
You MUST have hands on experience on labs, because it's the only way you can improve. And also it is a must to pass the exam. Most of the questions are based on troubleshooting stuff. The one I messed up was the multicasting stuff.
For those who can't afford buying cisco products to build a home lab, the best solution is to go for dynamips. I really love it. You need a cisco IOS to run it. Dynamips is actually a router emulator rather than a simulator. It actually acts like a router. You can configure more than one router and various topologies including frame-relay clouds. It's actually created for CCIE labs.
To download and learn more about dynamips click here.
You need dynagen too.
Don't worry these are all free tools.
Tuesday, January 29, 2008
What is an E1?
In digital communication systems, many voice channels are carried in a single piece of wire (or rather using a pair of wires, one for transmitting and the other for receiving).
As we all know the humans can hear sounds from 20Hz to 20kHz. When we speak, we put out a combination of frequencies varying (roughly) from 20Hz to 20kHz. For distance communication, we need to transmit this information over wires. If we try to transmit this voice signal as it is, it will eat up the bandwidth of the physical path available for communication. To convey the information needed and to identify the speaker, frequencies up to 4kHz is enough. According to Nyquist criteria the minimum frequency we need to sample this signal is 8kHz. If we use 8bits to represent the sampled signal, the bit rate will be 8000x8 bps (bits per second). i.e. 64kbps. This is the bit rate used in basic digital communication lines (in PSTN).
This 64kbps slot is called an E0. A combination of 32 of these slots is called an E1. That is an E1 is made out of 32 time slots, each carrying 8bits and the time used to transmit the whole E1 frame is 125us.
This gives a basic idea of an E1.
As we all know the humans can hear sounds from 20Hz to 20kHz. When we speak, we put out a combination of frequencies varying (roughly) from 20Hz to 20kHz. For distance communication, we need to transmit this information over wires. If we try to transmit this voice signal as it is, it will eat up the bandwidth of the physical path available for communication. To convey the information needed and to identify the speaker, frequencies up to 4kHz is enough. According to Nyquist criteria the minimum frequency we need to sample this signal is 8kHz. If we use 8bits to represent the sampled signal, the bit rate will be 8000x8 bps (bits per second). i.e. 64kbps. This is the bit rate used in basic digital communication lines (in PSTN).
This 64kbps slot is called an E0. A combination of 32 of these slots is called an E1. That is an E1 is made out of 32 time slots, each carrying 8bits and the time used to transmit the whole E1 frame is 125us.
This gives a basic idea of an E1.
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