Network
Bandwidth Explained
15.November.2010 06:09 Filed in: Tech Tips
"Nope, sorry. We can't do that."
"We don't have enough bandwidth."
"We're looking at increasing our bandwidth to make that possible."
"Yep. We understand that you can do that at home. Here at school we don't have enough bandwidth."
"We do all have to share this small amount of bandwidth, unfortunately."
The quotes listed above are what staff members throughout School District 21 regularly hear said to them by members of District 21's Technology Team. As frustrating as these responses are to hear for teachers who want to try something new, they are equally frustrating for Tech Team members to have to say. Here, we want to provide a brief explanation as to what bandwidth actually is.
Simply put, bandwidth is the maximum amount of information that can be transferred in a given amount of time. Bandwidth is usually measured in bits per second. Bits are tiny little chunks of data, or information. Today's high-speed bandwidth connections allow millions of bits per second to be moved across high-speed data lines. This rate is called megabits per second (abbreviation: Mb/s). This is not to be confused with Megabytes--a measure used to define the capacity of memory. As the need for greater bandwidth increases, connections now also reach Gigabit speeds, allowing data to move even more quickly.
Do you remember when the Internet was referred to as The Information Superhighway in the mid-1990s? If so, that metaphor was true at the time and is still true today. Just like on the road, how network traffic moves is determined by how fast the road can allow traffic to move (speed limit--roads; bandwidth--network connections) and by how much traffic there actually is (roads & network connections). When there's too much traffic, it is not possible to go the speed limit (roads & network connections).
Within our internal local area networks (within a school), we have Gigabit connections in place. Our elementary schools have connections of a minimum of 5 Mb/s, and our middle schools have connections of a minimum of 10 Mb/s. Of course, as in the traffic analogy described above, there are all kinds of factors that impact real-life performance. At home, many people have much faster bandwidth connections. DSL subscribers typically have about the same performance as one of our entire schools, and cable subscribers might have up to twice as much bandwidth as one of our schools! At school, that bandwidth is likely to be share by anywhere from 90 to 150 computers. At home, it might be share by as many as 5 or 6 Internet-connected devices. This is why we have to be very careful about how we use our limited bandwidth at school. There's just not as much to go around.
The charts below show these differences.
On a Sunday night at home, when traffic is high on a shared cable connection in the neighborhood, one still can get very high bandwidth speeds as pictured below. 19.11 Mb/s--Almost twice as much as any of our middle schools can get at this time.
At that same time at school, when traffic was very low (because the buildings were empty), we can see the speeds listed below for Cooper (first) and then for Poe (second).
Cooper--A decent 8.53 Mb/s connection at that time.
Poe--A very poor 1.42 Mb/s connection at that time.
While these numbers at school are dismal compared to the numbers at home, only 16 months ago, the entire District shared a connection of only 6 Mb/s--less than Cooper had by itself on this Sunday night. So, bandwidth underwent a dramatic increase in 2009-2010--by a factor of about 12!!!
We are currently beginning the E-Rate funding process for the 2011-2012 school year, and we are seeking to dramatically increase bandwidth again. E-Rate funding provides District 21 with reimbursements of approximately 60% on our telecommunications expenses, a significant number that cannot be underestimated in allowing us, financially, to make these changes. Like other organizations, including area school districts, we also understand that regular increases in bandwidth (i.e., faster roads) will be a necessary and regular upgrade to our infrastructure.
"We don't have enough bandwidth."
"We're looking at increasing our bandwidth to make that possible."
"Yep. We understand that you can do that at home. Here at school we don't have enough bandwidth."
"We do all have to share this small amount of bandwidth, unfortunately."
The quotes listed above are what staff members throughout School District 21 regularly hear said to them by members of District 21's Technology Team. As frustrating as these responses are to hear for teachers who want to try something new, they are equally frustrating for Tech Team members to have to say. Here, we want to provide a brief explanation as to what bandwidth actually is.
Simply put, bandwidth is the maximum amount of information that can be transferred in a given amount of time. Bandwidth is usually measured in bits per second. Bits are tiny little chunks of data, or information. Today's high-speed bandwidth connections allow millions of bits per second to be moved across high-speed data lines. This rate is called megabits per second (abbreviation: Mb/s). This is not to be confused with Megabytes--a measure used to define the capacity of memory. As the need for greater bandwidth increases, connections now also reach Gigabit speeds, allowing data to move even more quickly.
Do you remember when the Internet was referred to as The Information Superhighway in the mid-1990s? If so, that metaphor was true at the time and is still true today. Just like on the road, how network traffic moves is determined by how fast the road can allow traffic to move (speed limit--roads; bandwidth--network connections) and by how much traffic there actually is (roads & network connections). When there's too much traffic, it is not possible to go the speed limit (roads & network connections).
Within our internal local area networks (within a school), we have Gigabit connections in place. Our elementary schools have connections of a minimum of 5 Mb/s, and our middle schools have connections of a minimum of 10 Mb/s. Of course, as in the traffic analogy described above, there are all kinds of factors that impact real-life performance. At home, many people have much faster bandwidth connections. DSL subscribers typically have about the same performance as one of our entire schools, and cable subscribers might have up to twice as much bandwidth as one of our schools! At school, that bandwidth is likely to be share by anywhere from 90 to 150 computers. At home, it might be share by as many as 5 or 6 Internet-connected devices. This is why we have to be very careful about how we use our limited bandwidth at school. There's just not as much to go around.
The charts below show these differences.
On a Sunday night at home, when traffic is high on a shared cable connection in the neighborhood, one still can get very high bandwidth speeds as pictured below. 19.11 Mb/s--Almost twice as much as any of our middle schools can get at this time.
At that same time at school, when traffic was very low (because the buildings were empty), we can see the speeds listed below for Cooper (first) and then for Poe (second).
Cooper--A decent 8.53 Mb/s connection at that time.
Poe--A very poor 1.42 Mb/s connection at that time.
While these numbers at school are dismal compared to the numbers at home, only 16 months ago, the entire District shared a connection of only 6 Mb/s--less than Cooper had by itself on this Sunday night. So, bandwidth underwent a dramatic increase in 2009-2010--by a factor of about 12!!!
We are currently beginning the E-Rate funding process for the 2011-2012 school year, and we are seeking to dramatically increase bandwidth again. E-Rate funding provides District 21 with reimbursements of approximately 60% on our telecommunications expenses, a significant number that cannot be underestimated in allowing us, financially, to make these changes. Like other organizations, including area school districts, we also understand that regular increases in bandwidth (i.e., faster roads) will be a necessary and regular upgrade to our infrastructure.
Transitioning to the New Wireless Network
19.May.2010 09:53 Filed in: Tech Tips
On Thursday, May 20, 2010, the new CCSD21 wireless
network will be up and running. Over the following
week and a half, there will still be additional
testing, surveying, and troubleshooting.
For those computers that are Staff MacBooks, the computers will just automatically see and connect to the CCSD21 network (as pictured in the image below).
For existing laptops, such as student laptops and administrator laptops, the Tech Office will need to connect your laptop to this new network. We will be doing that over the coming weeks to all student and administrator laptops. In the meantime, to use a wireless connection, student laptops and administrator laptops need to connect to CCSD21_Temp (pictured below). This network does not require a password. In June, this network will be eliminated.
For those computers that are Staff MacBooks, the computers will just automatically see and connect to the CCSD21 network (as pictured in the image below).
For existing laptops, such as student laptops and administrator laptops, the Tech Office will need to connect your laptop to this new network. We will be doing that over the coming weeks to all student and administrator laptops. In the meantime, to use a wireless connection, student laptops and administrator laptops need to connect to CCSD21_Temp (pictured below). This network does not require a password. In June, this network will be eliminated.
