bandwidth, data rate and its upgrade

antennaboy35

Hello Forum,
I have a general question about bandwidth, data rate and its upgrade:

Let's say we have a broadband internet connection at home that allows us an average download speed, say 10 Mbps, and of course a slower upload speed.
If we decided (by paying a higher cost) to increase the download speed to 20 Mbps, we would simply call our ISP and the game would be done.
What does the ISP exactly do to allow us to have a higher download speed?
Does it tweak a switch located at the central office (CO) so more packets are allowed to reach our premises at a faster rate? No new hardware gets installed at the customer premises, our home....Where and what type of modification takes place?

Example: image the media content we want to view is sitting on some server in China. We send our request for that content via the web browser. Eventually the data packets travel very very fast from China, via fiber optics cables, back to our local ISP. The ISP switch does not transmit those packets to us at fiber optics speeds (Terabits/s) but at a much slow rate.
When our download speed gets increased do we gain some sort of priority at the switch level relative to other customers?


What happens?

vinbuck

depends on the equipment and the carrier, but it usually happens closer to the access layer in a Layer 2 device. Most switches support rate-limiting of this type...

antennaboy35

Thanks for the reply.
sure, any carrier is different, but do you know what the general procedure to increase someone's home download speed is, from the ISP point of view?
Surely they don't turn a faucet and let more bandwidth flow, right ?

thanks
antennaboy35

drkat

Typically a cable modem will be pushed a new bin file and it tells the device at what speed to operate at.

The carrier network isnt limited but the device is provisioned or the port is limited.

networker050184

Depends on the type of access you have. DSL is usually rate limited at the DSLAM as to how fast your modem can connect. Not too familiar with the technicalities behind cable or FiOS, but I'd assume there is a similar function in a CMTS or other equipment.

vinbuck

antennaboy35 wrote: »

Thanks for the reply.
sure, any carrier is different, but do you know what the general procedure to increase someone's home download speed is, from the ISP point of view?
Surely they don't turn a faucet and let more bandwidth flow, right ?

thanks
antennaboy35

They are all different...what kind of access network are you on - DSL, Cable, Fiber, WiMAX, WiFi?

Each has specific ways of doing what you're asking and even then it depends on the equipment...most carriers are not using Cisco gear at the edge, more frequently it will be Adtran, Calix or the like...

What is it that you are after? Are you trying to bump up your speed without the carrier's knowledge? Most carrier networks have rate-limiting applied throughout the network so that if someone does manage to compromise the access layer, there will still be limitations at other points in the network with resepect to a single customer.

antennaboy35

Hi, no, no free lunch

I am just trying to understand, on a more pragmatic, practical level, what happens after I call my ISP and ask to have my download speed increased (at a higher cost of course). That takes a short time to happen....
What happens, conceptually, to allow my computer to download stuff at a higher rate? Clearly packets are being delivered faster to my computer....Again, I would like to know the mechanisms of a conceptual level...

I live in an apartment complex and personally have Uverse at my house, 15,16 Mbps...I think it is coaxial cable connected to the main data room. Then fiber to the Central office....

Also, question #2, if I have a wireless network at home, with maximum download speed of, say, 20 Mbps, and two computers, A and B, and I want to have computer A to always have a higher download speed than computer B, what setting should I modify and where?
thanks,
antennaboy

vinbuck

antennaboy35 wrote: »

Hi, no, no free lunch

I am just trying to understand, on a more pragmatic, practical level, what happens after I call my ISP and ask to have my download speed increased (at a higher cost of course). That takes a short time to happen....
What happens, conceptually, to allow my computer to download stuff at a higher rate? Clearly packets are being delivered faster to my computer....Again, I would like to know the mechanisms of a conceptual level...

I live in an apartment complex and personally have Uverse at my house, 15,16 Mbps...I think it is coaxial cable connected to the main data room. Then fiber to the Central office....

Also, question #2, if I have a wireless network at home, with maximum download speed of, say, 20 Mbps, and two computers, A and B, and I want to have computer A to always have a higher download speed than computer B, what setting should I modify and where?
thanks,
antennaboy

This is an IPTV deployment...two major things come into play.

1) The physical sync rate of your DSL modem to the MSAP (A DSLAM that carries voice/video)
2) Rate limiting on the PPPoE connection from your modem to the BRAS. This is the component that controls your "Internet" speed.

As for your other question, this is something you would do on a router inside your home and would depend on which piece of gear you are using for wireless access.

antennaboy35

Hi,
thanks for your answer. I am going to study it and get a clear idea of how MSAP and BRAS work...

Why do you say that it is a IPTV situation? IPTV is a system of delivering television content to consumers over the infrastructure of the Internet. Like google TV, right?

In my case, I just called my ISP, which is ATT, and asked for more download speed (15 Mbps) for my internet, because it was too slow (only 5 Mbps)...

thanks
antennaboy

vinbuck

antennaboy35 wrote: »

Hi,
thanks for your answer. I am going to study it and get a clear idea of how MSAP and BRAS work...

Why do you say that it is a IPTV situation? IPTV is a system of delivering television content to consumers over the infrastructure of the Internet. Like google TV, right?

In my case, I just called my ISP, which is ATT, and asked for more download speed (15 Mbps) for my internet, because it was too slow (only 5 Mbps)...

thanks
antennaboy

IPTV is any deployment where the end video is being delivered using IP. ATT Uverse is IPTV because they multicast IP video channels to the Set Top Box (STB) over a VDSL connection.

AT&T U-verse IPTV Technology - Resources

antennaboy35

So, in your opinion is it true what I was told, that Uverse is fiber optics based, from the data room in my building to the CO?

You mention VDSL: wikipedia describes it as being copper or coaxial but no fiber...

it_consultant

antennaboy35 wrote: »

Hello Forum,
I have a general question about bandwidth, data rate and its upgrade:

Let's say we have a broadband internet connection at home that allows us an average download speed, say 10 Mbps, and of course a slower upload speed.
If we decided (by paying a higher cost) to increase the download speed to 20 Mbps, we would simply call our ISP and the game would be done.
What does the ISP exactly do to allow us to have a higher download speed?
Does it tweak a switch located at the central office (CO) so more packets are allowed to reach our premises at a faster rate? No new hardware gets installed at the customer premises, our home....Where and what type of modification takes place?

Example: image the media content we want to view is sitting on some server in China. We send our request for that content via the web browser. Eventually the data packets travel very very fast from China, via fiber optics cables, back to our local ISP. The ISP switch does not transmit those packets to us at fiber optics speeds (Terabits/s) but at a much slow rate.
When our download speed gets increased do we gain some sort of priority at the switch level relative to other customers?


What happens?

Have you ever heard the expression "the last mile"? That is where the magic happens with any internet delivery. It determines your maximum speed - if I am right across the street from a POP I can get a gigabit internet connections. If you are paying for less it is normally (but not always) configured into your CPE.

vinbuck

antennaboy35 wrote: »

So, in your opinion is it true what I was told, that Uverse is fiber optics based, from the data room in my building to the CO?

You mention VDSL: wikipedia describes it as being copper or coaxial but no fiber...

It really depends on where you live...

-A single family home will most likely be VDSL
-An Apartment complex, high rise or condo structure can be either VDSL or Ethernet/Coax (MoCA) in a high density access device that is fed by fiber.
-Some areas will have Fiber to the Home (FTTH) but this is usually the exception rather than the rule.

Most carrier nodes (not customer) in an IPTV deployment are fiber backhauled - meaning the transit back to the core or distribution layer of the carrier network.

This is a decent drawing except that DSLAM is not an accurate term to aggregate data/voice/video as it really happens over an MSAP (Multi Service Access Point) in modern deployments.

antennaboy35

I am reading this book that talks about wired routers speeds. The book says that they range from 100 Mbps to 1000Mbps. but there are also high performance routers that go 10 Gbps....
what is the point of that speed? I don't know of any internet connection that fast?
Is that 10 Gbps speed useful for an internal network, between computers in that network? A modern computer can output data at Gbps speed correct?

I have read recently read about millimeter waves and laser links (all this is wireless) being able to offer 2 or 3 Gbps speeds. That is low compared to the speed of those routers...What type of signal allows 10Gbps speed on those routers? An electrical signal, since it is a wired connection...but is that possible?

thanks
antennaboy

networker050184

A single computer isn't going to put out 10G, but what if you have 10,000 computers putting out 512k? Thats some serious bandwidth coming back to the service provider and they need a router to handle it. And its definitely not uncommon these days for a company to do more than a gig of traffic. I think you just need to step back and take a higher level view on the network as a whole.

vinbuck

antennaboy35 wrote: »

I am reading this book that talks about wired routers speeds. The book says that they range from 100 Mbps to 1000Mbps. but there are also high performance routers that go 10 Gbps....
what is the point of that speed? I don't know of any internet connection that fast?
Is that 10 Gbps speed useful for an internal network, between computers in that network? A modern computer can output data at Gbps speed correct?

I have read recently read about millimeter waves and laser links (all this is wireless) being able to offer 2 or 3 Gbps speeds. That is low compared to the speed of those routers...What type of signal allows 10Gbps speed on those routers? An electrical signal, since it is a wired connection...but is that possible?

thanks
antennaboy

It all depends on how much traffic you need to process and where it needs to go. I work on carrier networks and we have routers that handle 720 Gbps per slot and some of them have as many as 9 slots so you're looking at Terabit speeds. We usually don't use all that capacity, but within carrier networks, there are plenty of traffic types that don't ever leave that carrier's network, so it's not having to traverse a more limited peering point. Video is one traffic type that will usually be received via satellite and then placed into the carrier network close to where the last mile delivery access rings are.

Router performance is all about backplane speed (commonly measured in Packets Per Second) and what can be handled by hardware acceleration vs. punted to the CPU. Like networker said, you may want to do some foundational reading so you can put these numbers into context.

goalied00d

There's has been a huge technology advancement in the digital signal processing industry that allows for bandwidth at those rates to be realized over both copper and optical interfaces. A single processor these days can effectively handle 500+ gbps of traffic across multiple interfaces. A chassis can often support several of these line cards to provide a large back plane bandwidth for routing and switching.

There's even faster connections than 10gbit like 40gbit, 80gbit and even 100gbit for a single port(and I'm sure there is some even faster stuff out there). These interfaces are very useful in LAN/WAN SANs, virtualized computing, and carrier applications (those are just a few) where many devices need a fast network backbone and aggregating multiple slower connections won't cut it since it takes up more ports and rack space.

antennaboy35

Hello everyone and thank you. I am studying all these replies. First a comment for networker050184.
So if 10 computers have each a data output with speed 10 Mbps, the router will need to have a speed of 10*10=100 Mbps for every computer to not have delays?
Are those 10 different 10Mbps streams of data multiplexed together into one faster 100 Mbps data stream? How? Using time division multiplexing?

2) I have heard of GigaEthernet with speeds of Gbps: I guess that is only for a short physical distance. A single fiber optics cable, with a single lambda, can carry a maximum of 10 Gbps. Only if multiple lambdas (WDM or DWDM) we can achieve data rate in the hundreds of Gbps, correct? Each of those lambdas carry a multiplexed traffic containing data from multiple users (i.e. aggregating slow data rate traffic), correct?

networker050184

No offense, but you need to start at the beginning rather than jumping somewhere in the middle and expecting to understand it all. If you don't even know how a router forwards packets then its going to be nearly impossible to understand higher level concepts.

antennaboy35

True, I will do some homework and catch up. I guess the books I read are too elementary and don't get into those details. They give too much a general overview...
Thanks!

goalied00d

It's not elementary, it's just probably not in the scope of most networking books (especially when it comes to certifications) to explain everything from an electrical engineering standpoint on how data gets sent over a patch cable in great detail.

If that's what you're interested in, then go study EE with an focus on signal processing.

networker050184

goalied00d wrote: »

It's not elementary, it's just probably not in the scope of most networking books (especially when it comes to certifications) to explain everything from an electrical engineering standpoint on how data gets sent over a patch cable in great detail.

If that's what you're interested in, then go study EE with an focus on signal processing.

You don't have to study EE to know how a router forwards packets and in what order onto a physical medium. Its pretty straight forward and covered in Cisco certifications.

goalied00d

I was talking about his couple of replies. He seems to have gone from general networking related topics to questions about how it's possible hardware can transfer data at these high speeds.

antennaboy35

I found this: Exploration Routing Chapter 1

I am going to understand it fully.

antennaboy35

hello everyone,
sorry for the low level of my questions. I am just trying to learn some fundamental concepts. I am not interested in physical layer details (voltages, pins, etc...) That is EE stuff. I have read a good bit, but I am not able to come up the answers I want....

Routers connect different subnets together. They are smart devices that use routing tables to figure out the best way for the packets to go to destination. Routing tables can be either static or dynamic.
A router is a layer 2 device: it is networkable, i.e. it knows how to read network adresses and how to select the destination or target network. It can route individual packets over multiple paths.
A router has two types of ports:input ports and output ports.
The router processes packets in the order in which they were received. That means FIFO method?
There is an input queue: it is an holding area. If it is full some packets get lost.

Ok, I did some homework. Now, in a home network with 3 computer (3 users) and a total download speed of 12 Mbps coming in, we can connect the 3 computers with wires to a router/switch. If the connection is wired, it "should" mean that each computer gets 4 Mbps of download speed, correct?
Each computer enjoys the same, equally divide bandwidth.
In a wireless network the switch/router does not work that way: the 3 wireless computer in the home network my each experience asymmetric speeds. Why? What distinguishes the wireless router from the other router with wire connected computers?
Each computer sends (and receive) packets to the router in the temporal order they were received...But why do some packets arrive before others?

thanks,
Antennaboy

it_consultant

It takes a lot of effort to get equally divided bandwidth. The tap is on-demand if you will, if one computer demands 10 Mbps then your other computers will have only 2 to use. It isn't like telephony where you channelize the pipe and each phone call takes exactly one channel.

antennaboy35

Is that true for both a wired and a wireless connection between computers and the router/switch?

I have read that

If you examine a single computer on the network and how many requests it makes, this is how it usually breaks down:

• Web browser
• Instant messaging

Some it is all about the number of requests a single computer makes. The router must work in a round robin fashion, like a crazy waiter serving a table...

networker050184

The router just processes packets as they arrive. Its not a round robin fashion its first come first serve.

vinbuck

it_consultant wrote: »

It takes a lot of effort to get equally divided bandwidth. The tap is on-demand if you will, if one computer demands 10 Mbps then your other computers will have only 2 to use. It isn't like telephony where you channelize the pipe and each phone call takes exactly one channel.

There are actually some advanced bandwidth controls you can put in and rate-limit just about wherever you want to in order to meet certain requirements. Rate limiting can be done at the port or on certain types of traffic - combine that with QoS and you can pretty much dictate what each end "packet generator" will and won't do. The only major limitations are hardware capability and administrative overhead. However, most Layer2/3 switches deployed these days support a wide variety of rate-limiting options.

It seems to be more common in the Enterprise to let the end user/device have the full bandwidth of the access port because it is easier but in the carrier world, rate-limiting is what we specialize in and there are some neat tricks you can do with rate-limiting to smooth out the network.

antennaboy35

Hi Networker0501084,

thank you (thanks everyone). I ask for patience, soon my questions will be more mature and advanced. Sometimes the basics are insidious....

So packets arrive at the router from multiple computers. No round-robin but FIFO method. Packets are put in a queue and processed, one at a time...

How do I interpret what is going on when there are 2 computers, computer A and computer B, wirelessly connected to a router in a HAN and computer A has engaged into heavier downloading, like videoconferencing or else, and it is sucking all the bandwidth?

How does A manage to get control of all the bandwidth? Is it throwing packets at the router faster than B? Both A and B are sending packets to the router, but why does the one involved in heavy downloading manage to keep the control of most of the bandwidth?

What if B (slow activity, few requests) started its browsing activity before computer A started its heavy downloading? Would the bandwidth still go to computer A?

thanks,
antennaboy

networker050184

Its just what ever gets there first. The router has no control of what it receives. As vinbuck pointed out there are technologies available to prevent this "first come first serve" behaviour though. The router can limit the amount of bandwidth a single device, interface, protocol etc can use by selectively dropping or queuing traffic.

Again I think you are getting ahead of yourself which is why its hard to understand at this point.