Test 6 is enabled

I have just enabled Test 6 for a week. Some of you have a lot to catch up.

Test 5 is now enabled

Tests 5 is now enabled for everyone until 18:22 03/03/2009. Some of you are doing very well, but keep in mind that the assesments are due on 10th and 12th of March. Please, if there is any problem, make a comment here.

Software is what matters

This post has nothing to do with the curriculum but after browsing on Lifehacer I found it interesting. As usual, Software is what it matters and Linux is the King. However Cisco is still more robust and trustworthy. The guys from Lifehacer show how to turn your $60 router into a highly configurable $600 router in two different ways, using different distributions based on linux kernels.



Extracted from: Lifehacker

Clock Rate on Cisco Serial Interfaces

The clock rate command is used only on a serial interface that has a DCE cable plugged into it. There must be a clock rate set on every serial link between routers. It does not matter which router has the DCE cable plugged into it or which interface the cable is plugged into. Serial 0 on one router can be plugged into Serial 1 on another router.

The clock rate command is set in bits per second. Besides looking at the cable end to check for a label of DCE or DTE, you can see if a router’s serial interface has a DCE cable connected with the show controllers int command. The new ISR routers automatically detect DCE connections and set the clock rate to 2000000. However, you still need to understand the clock rate command, even though the new routers set it for you automatically!

CLock Rate

Clock rate is all to do with Timing. A serial interface will send data along the line in the form of ones & zeroes 00110001111000010.
There are start bits and stop bits along with parity which all get put together to form a frame of information when that data gets sent across the connection, it has to get reassembled and look like the original data that was sent. If one device is sending a simple code of 8 bits ( we won't go into start, stop & parity) in this format 00110011 and it sends them 1 second at a time per digit ie 8 seconds to transmit the 8 binaries but the opposite end is actually receiving the data at 0.5seconds per binary then the receiving device will look at the same bit twice and place it in memory twice for every bit that is sent. Unfortunately this doesn't mean that, should we send the word cat across the network we will end up with ccaatt. In the example above 00110011 means that we get 0000111100001111. If you have ever seen what happens when a serial communications device is set at differing speeds at both ends you will have seen what happens .. gibberssh! Until the send / receive speeds match and synchronize

So what is clock rate .. it's the speed that we set the transfer rate across a communications medium. It allows the data to be clocked through the interface and put into memory at the same speed that it was sent.

In any transmission medium there are two types of devices .. DTE and DCE. Most routers are considered to be DTE. When two routers are place at opposite ends of a serial line one has to be DTE and the other DCE. DTE is Data Terminal Equipment. A device that is placed at the end of the line. It Terminates the line. DCE is Data Communications Equipment. It Controls the transfer. It has the pleasure of giving the Clock signal. DCE - Controls & Clocks .. that's how I remember where to place the Clock Rate command.

Extracted from the forum: Andy_Capp

Packet Tracer Tutorial 320 x 240

VTP modes

Test 4 is now enabled

Test 1 , 2 , 3 and 4 are enabled until 26/02/2009 19:13 .

Test for Chapter 1 , 2 and 3 activated

Test 3 is enabled. Test 1 and 2 re-enabled (do not get used to it).
Please read chapter 4 (VTP). Chapters 2,3 and 4 are related. Don't read chapter 4 without reading 2 and 3.

If you have time, lab 4.1 from the cisco.netacad.net. Do not download the pdf. Instead open the *.pkt file offered in the link. That will open your Packet Tracer 5.1 (that should have been installed).

Any problem, reply to this post.

Be aware

Chapters 3, 4 , 5 and 6 (VLAN's, VTP, STP and Inter-VLAN concepts) are the most important chapters this semester ( and TOP priority for Final CCNA Examination). Please start studying in advance.

Test Activation

Everyone should be enrolled in the class, by now. If not, please send me your details via e-mail archipestre@gmail.com and I will do so.

Useful Posters

Please, download this: Posters

New Packet Tracer 5.1

Remember to download the new version of packet tracer in your PC at home:

Go to http://www.cisco.com/web/learning/netacad/course_catalog/PacketTracer.html and login with your academy username.

Test for Chapter 1 & 2

Test for Chapter 1 & 2 of CCNA 3 "LAN Switching and Wireless" have been enabled. They expired on 18/02/2009 at 14:33. Please, read chapter 2 before Thursday.

Tests CCNA3

Dear students, I will enable the class and the tests tomorrow morning. In the meantime you can still use "course materials" to have have a look at Chapter 2. Please, do read the chapter before the Presentation on Thursday.

Welcome

First Blog Entry for the Cisco group study starting on September 2008. My e-mail address is archipestre@gmail.com.

Victor Castano