Geek Certs Blog

Broadband technology is everywhere (for example DSL). The difference between broadband and baseband is that the former splits a set of copper wires into a number of channels and allows a conversation, simultaneously, on each channel. Think of channels logically – not physically – to figure it out. Take your four copper phone wires and then, in your mind, expand those into 10,000 copper wires. This, of course, is not an exact number, but you get the idea. So, you and a number of other people can share one set of copper wires and use the Internet at the same time.

Baseband works differently. It uses the same set of copper wires but doesn’t split signals into channels. As before, let’s think logically, not about physical copper wires. Let’s say that your wire is 100 feet long. Broadband technology splits the signal into segments of that wire (pick an arbitrary number of feet, say one inch long). Each signal gets one of those segments at a time.

Every network NIC (network interface card) has its own unique alphanumeric code assigned to it. The code is in hexadecimal, which uses numbers (0-9) and characters (A-F) together to make up numbers. This code is known as a MAC (machine address code) address. You can see your MAC address by opening a DOS prompt and typing in the command ipconfig /all.

Open a DOS prompt by clicking Start / Run. In the Open text box, type command and press Enter.

In the output now on your screen, look for the line that reads Physical Address. The characters that follow are your NIC’s MAC address. They should be 12 characters long (6 sets of 2 characters, each set of 2 characters separated by a dash). The MAC address is important and you will use it in your Cisco studies (especially in Cisco 3).

While you’re there, also find your IP (Internet Protocol) address. You will use this command often – in school and in the real world. Notice too that this command shows you the door your PC uses to get out of your building to the Internet. This door is called the Default Gateway and is the IP address of the router at the end of your network and at the beginning of your ISP’s (Internet Service Provider’s) network.

By the way, this router is also probably the device that provides your NIC with its IP address (that’s right, your NIC, not your PC!). When your router provides you an IP address, it is using a special protocol to do so. The protocol name is DHCP (Dynamic Host Configuration Protocol). When your PC boots up, it sends a request to the network on a special IP address that only DHCP devices (also known as servers) listen on. This IP address is 255.255.255.255 and is known as a broadcast address. You’ll set up routers to do this in Cisco 4, if you are a Cisco Academy student.

A T1 is a group of 24 physical copper phone lines that have been programmed to work together as one logical unit. Together, they provide a bandwidth of 1.544 Mbps (megabits per second). Consider how much faster this is than dial-up, with a 56 Kbps (kilobits per second) connection! Mega means millions, while kilo means thousands in this example. So, 1 Mbps = 1,000,000 bits per second. Network speed is always measured in bits.

Disk storage is generally measured in bytes. The word “bit” always has a small “b” whereas the word “byte” always has a capital “B” when used. Therefore, 100 Mb is quite smaller than 100 MB. Again, remember that when these are used, one generally measures speed (bits) and the other generally measures storage (Bytes).

A T3 is 672 phone lines logically grouped together (you can also express this as being equivalent to 28 T1 lines). Large companies that require a large Internet bandwidth use T3s whereas many small businesses use T1s – or a number of T1s. As you probably imagined, these are very expensive!

Broadband technology is everywhere (for example DSL). The difference between broadband and baseband is that the former splits a set of copper wires into a number of channels and allows a conversation, simultaneously, on each channel. Think of channels logically – not physically – to figure it out. Take your four copper phone wires and then, in your mind, expand those into 10,000 copper wires. This, of course, is not an exact number, but you get the idea. So, you and a number of other people can share one set of copper wires and use the Internet at the same time.

Baseband works differently. It uses the same set of copper wires but doesn’t split signals into channels. As before, let’s think logically, not about physical copper wires. Let’s say that your wire is 100 feet long. Broadband technology splits the signal into segments of that wire (pick an arbitrary number of feet, say one inch long). Each signal gets one of those segments at a time.

Every network NIC (network interface card) has its own unique alphanumeric code assigned to it. The code is in hexadecimal, which uses numbers (0-9) and characters (A-F) together to make up numbers. This code is known as a MAC (machine address code) address. You can see your MAC address by opening a DOS prompt and typing in the command “ipconfig /all” (without the quote marks).

Open a DOS prompt by clicking Start / Run. In the Open text box, type “command” (without the quotes) and press Enter.

In the output now on your screen, look for the line that reads Physical Address. The characters that follow are your NIC’s MAC address. They should be 12 characters long (6 sets of 2 characters, each set of 2 characters separated by a dash). The MAC address is important and you will use it in your Cisco studies (especially in Cisco 3).

While you’re there, also find your IP (Internet Protocol) address. You will use this command often – in school and in the real world. Notice too that this command shows you the door your PC uses to get out of your building to the Internet. This door is called the Default Gateway and is the IP address of the router at the end of your network and at the beginning of your ISP’s (Internet Service Provider) network.

By the way, this router is also probably the device that provides your NIC with its IP address (that’s right, your NIC, not your PC!). When your router provides you an IP address, it is using a special protocol to do so. The protocol name is DHCP (Dynamic Host Configuration Protocol). When your PC boots up, it sends a request to the network on a special IP address that only DHCP devices (also known as servers) listen on. This IP address is 255.255.255.255 and is known as a broadcast address. You’ll set up routers to do this in Cisco 4, if you are a Cisco Academy student.

A T1 is a group of 24 physical copper phone lines that have been programmed to work together as one logical unit. Together, they provide a bandwidth of 1.544 Mbps (megabits per second). Consider how much faster this is than a 56 Kbps (kilobits per second) connection! Mega means millions, while kilo means thousands in this example. So, 1 Mbps = 1,000,000 bits per second. Network speed is always measured in bits.

Disk storage is generally measured in bytes. The word “bit” always has a small “b” whereas the word “byte” always has a capital “B” when it is used. Therefore, 100 Mb is quite smaller than 100 MB. Again, remember that when these are used, one measures speed and the other measures storage.

A T3 is 672 phone lines logically grouped together (you can also express this as being equivalent to 28 T1 lines). Large companies that require a large Internet bandwidth use T3s whereas many small businesses use T1s – or a number of T1s. These are expensive!