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LAwLz

The Networking board's Frequently Asked Questions, Pre-answered!

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Perhaps it would be worth talking about the difference between bandwidth and the actual speed or delay of a connection. It's very common now for most people to refer to bandwidth as speed. Bandwidth is a measure of the amount of data that can be sent over a link while speed/delay is a measure of the time it takes that data to reach the other side (and get a response in some cases). I know I used to be confused about this when I first got into things.

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The difference between bandwidth and throughput is an interesting one and can be complicated by things like TCP windows sizes etc. There is a simple and easy formula to calculate theoretical throughput.

 

Throughput (bps) = TCP Window Size (bits) / Round Trip Time (seconds)

 

E.g.

Bandwidth: 100Mbps

Window Size: 64KB

RTT: 30ms

 

512000 / 0.03 = 17066666 bps

Throughput = 17Mbps

 

UDP data transfers do not require acknowledgement of sent data so 'should' always be able to achieve maximum throughput equal to bandwidth.

 

More information see link below

http://cisconet.com/traffic-analysis/throughput/104-tcp-throughput-calculation-formula.html

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Nice thread, 10.0.0.1 is also used sometimes as standard gateway on some routers (at least some Zyxel routers).

 

You could also add some information about static leases :)

10.0.0.1 Error connection refused


OFF TOPIC: I suggest every poll from now on to have "**CK EA" option instead of "Other"

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I'd also add a quick section on IPv4 subnets, and what the difference is between a Class A, Class B, and Class C subnet.

 

Class A example: 10.0.0.0/12 - Supports up to 16,777,616 IP addresses - 2^24 - Subnet Mask: 255.0.0.0

Class B example: 172.10.0.1/16 - Supports up to 65,534 IP addresses - 2^16 - Subnet Mask: 255.255.0.0

Class C example: 192.168.0.1/24 - Supports up to 254 IP addresses - 2^8 - Subnet Mask: 255.255.255.0

 

To calculate the amount of IP's in a  subnet, use the power of 2^bits in an octet. There are 8 bits in an octet (X.X.X.X).

 

.0 is your netmask, .1 is usually your gateway, and .255 is usually your broadcast.

OH SHIT

THIS HELPED ME SO MUCH

MY IPHONE IS A CLASS B SUBNET

MY SCHOOL WIFI IS A CLASS A SUBNET

MY HOME WIFI IS A CLASS C SUBNET!!!11!1

IM SO SMART!!!!


OFF TOPIC: I suggest every poll from now on to have "**CK EA" option instead of "Other"

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Thank you for posting up this thread, helped me tweak my router/modem. Could I ask your help with something @LAwLz ?

 

When I do my "speedtest" via speedtest.net or other sites, I receive a line speed down of 5.00mb-6.40mb and a line speed up of 0.70kb-0.77kb. The question I have though is this, when I look at my ADSL2+ system log on my router (Asus DSL-N55U) it shows I have a vastly different down and up rate. Heres the details.

 

Modulation : ADSL2+
Annex Mode : Annex A/L
Line State : up
Lan Tx : 272118
Lan Rx : 259256
ADSL Tx : 157941
ADSL Rx : 158150
CRC Down : 0
CRC Up : 1428
FEC Down : 0
FEC Up : 51296
HEC Down : 3534
HEC Up : 0
SNR Up : 6.4
SNR Down : 1.1
Line Attenuation Up : 35.5
Line Attenuation Down : 56.2
Data Rate Up : 916          <<<<<<<<<<<
Data Rate Down : 7475   <<<<<<<<<<<

 

So I guess what I'm wondering is, is it possible to achieve those rate speeds with a speedtest? or is the system log a more pure test of my internets connection?

 

Thank you in advance for any assistance.

Cartdog,

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Posted · Original PosterOP

So I guess what I'm wondering is, is it possible to achieve those rate speeds with a speedtest? or is the system log a more pure test of my internets connection?

That's really hard to say because I don't know how the router measures the connection, or even what it is measuring (I assume it is Kbps?). I tried looking around in my Asus router's setting and could not find anything similar to what you are posting. Sorry.

 

For now my only explanation is that your router probably measures the data rate on its own port, while the speed test measures the speed of the entire path from and back to you again. The speedtest therefore has a lot more overhead and possible bottlenecks than what you see in the system log. That's just an "educated guess" though so take it with a grain of salt. The speedtest will be a pretty good indication of what you will be able to get in real world scenarios.

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That's really hard to say because I don't know how the router measures the connection, or even what it is measuring (I assume it is Kbps?). I tried looking around in my Asus router's setting and could not find anything similar to what you are posting. Sorry.

 

For now my only explanation is that your router probably measures the data rate on its own port, while the speed test measures the speed of the entire path from and back to you again. The speedtest therefore has a lot more overhead and possible bottlenecks than what you see in the system log. That's just an "educated guess" though so take it with a grain of salt. The speedtest will be a pretty good indication of what you will be able to get in real world scenarios.

Okay, well thank you for taking the time to give your opinion. Regarding where I found that data, I opened my router/modem config and went down to Advanced Settings > System  Log > DSL Log. Though it may be under the Administration tab depending on your make and or model. Thanks again.

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"modem takes the signal you get through your telephone and/or TV line and splits it into two streams. One for Internet traffic and one for regular phone/TV signals."

 

​You may wish to clarify your definition of a modem. There is no "splitting" taking place. The modem just tunes to the frequency in the spectrum the signal is carried. This is true for both DSL and cable ISPs. 

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There's also 802.11ad now.  It's not used widely yet but scheduled for release in 2014.  AKA WiGig uses 2.4GHz, 5GHz, and 60GHz with maximum throughput of 7Gb/s.  The 60GHz band cannot penetrate walls however so roaming devices are put down to 2.4GHz/5GHz.

 

Quote

A router is something that routes packets from one network to another. If you want to send a packet from network A to network B, then you have to have a router between them. You can’t link two routers together without special configurations (more on that can be found in “how to improve my wireless speed”).

 

A switch is a device that can send packets from one device to another device if they are on the same network. You can link several switches together without having to think about anything special. They are just “plug and play”.

 

A modem takes the signal you get through your telephone and/or TV line and converts it into a standard Ethernet signal.

 

Consumer routers are actually routers and switches, all in one. Some of them also include a modem built in. When people say routers, they usually talk about the router/switch combo.

I suggest adding Access Points.  Standalone access points also exist as they can plug in via Ethernet and provide wireless connectivity but they can also exist in a consumer router.  Routers can exist that are not wireless.  So a consumer "router" is actually a router, switch, and access point all in one USUALLY.  You can buy non access point routers but who really does these days?  

 

On 28/09/2014 at 4:22 AM, Helios79 said:

I'd also add a quick section on IPv4 subnets, and what the difference is between a Class A, Class B, and Class C subnet.

 

Class A example: 10.0.0.0/12 - Supports up to 16,777,616 IP addresses - 2^24 - Subnet Mask: 255.0.0.0

Class B example: 172.10.0.1/16 - Supports up to 65,534 IP addresses - 2^16 - Subnet Mask: 255.255.0.0

Class C example: 192.168.0.1/24 - Supports up to 254 IP addresses - 2^8 - Subnet Mask: 255.255.255.0

 

To calculate the amount of IP's in a  subnet, use the power of 2^bits in an octet. There are 8 bits in an octet (X.X.X.X).

 

.0 is your netmask, .1 is usually your gateway, and .255 is usually your broadcast.

This is true however you can have a non-standard subnet mask in a network.  For example, I can configure my Class C network at home to use a Class B subnet mask of 255.255.0.0 instead of a 255.255.255.0.  That's a classless network.

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On 9/28/2013 at 7:31 PM, Mkvarner said:

Nice thread, 10.0.0.1 is also used sometimes as standard gateway on some routers (at least some Zyxel routers).

 

You could also add some information about static leases :)

any ipv4 ip can be used as gateway


Net Neutrality Is Key!

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There are some considerations to be made when connecting devices using ethernet cables.
Unless one or more device has a smart network card that can flip the cable for you, this is the cables for the different setups.

 

Router -> Router - Crossover          PC -> PC - Crossover

Switch -> Switch - Crossover           PC -> Router - Straight

Switch -> Router - Crossover          PC -> Switch - Straight

 

Straight cable is the normal cable, that you would find 10 different lengths of in a store.
While Crossover cables, used to be used alot before, and still has to be used sometimes.
Depending on the network card in the switch/router/PC.
There are some switches that do not have this ability, which i noticed when trying to add a switch to my setup at the dormroom.
These switches are usually a layer 2 switch, this refers to the TCP/OSI model that defines how people categorize the internet and its applications

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On 27/04/2016 at 3:14 PM, Holen said:

There are some considerations to be made when connecting devices using ethernet cables.
Unless one or more device has a smart network card that can flip the cable for you, this is the cables for the different setups.

 

Router -> Router - Crossover          PC -> PC - Crossover

Switch -> Switch - Crossover           PC -> Router - Straight

Switch -> Router - Crossover          PC -> Switch - Straight

 

Straight cable is the normal cable, that you would find 10 different lengths of in a store.
While Crossover cables, used to be used alot before, and still has to be used sometimes.
Depending on the network card in the switch/router/PC.
There are some switches that do not have this ability, which i noticed when trying to add a switch to my setup at the dormroom.
These switches are usually a layer 2 switch, this refers to the TCP/OSI model that defines how people categorize the internet and its applications

Nowadays almost everything has auto-mdix ports on it... I would say it's mostly a non-issue TBH. 

 

Even if we had to manually do it, PC -> Router is actually crossover and Router -> Switch is actually straight. Crossover is used when two devices tx or rx on the same pins to allow them to properly talk to each other. 

PC - tx 2/4 rx 3/6
Router - tx 2/4 rx 3/6
WAPs - tx 2/4 rx 3/6
Switch & Hubs - tx 3/6 rx 2/4


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Can someone go into a little more detail about this section with me?

 

Add another router, access point or repeater – This one is pretty self-explanatory. One thing you need to remember though is that with repeaters and range extenders, each extra device (device as in networking equipment, not device like a phone or laptop) will cut your bandwidth in half. If both your router and your extended are rated for 300Mbps, then you will only get 150Mbps of theoretical bandwidth (and then about half of that in real world bandwidth). If you connect two routers with a cable then both will work at full speed.

 

Ok so I have a Nighthawk ac1900 located in my downstairs living room. Off that I have a 50ft eathernet running upstairs to a switch (couple gaming pc's) and another 50 footer going to the bedroom next to the living room (couple more pc's). Currently I also have a music Studio that's detached from my house in my back yard that is running off a netgear ac1200  extendwr that is using the 5ghz band to supply a wired connections to a pc. Guess my question is the extender cutting 1/2 our bandwidth to our entire network (gaming pcs ect)? Sorry if I sound stupid, I am not much of a networking guy and this all don't make sense to me. 

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Posted · Original PosterOP
8 hours ago, Bion1985 said:

Can someone go into a little more detail about this section with me?

 

Add another router, access point or repeater – This one is pretty self-explanatory. One thing you need to remember though is that with repeaters and range extenders, each extra device (device as in networking equipment, not device like a phone or laptop) will cut your bandwidth in half. If both your router and your extended are rated for 300Mbps, then you will only get 150Mbps of theoretical bandwidth (and then about half of that in real world bandwidth). If you connect two routers with a cable then both will work at full speed.

 

Ok so I have a Nighthawk ac1900 located in my downstairs living room. Off that I have a 50ft eathernet running upstairs to a switch (couple gaming pc's) and another 50 footer going to the bedroom next to the living room (couple more pc's). Currently I also have a music Studio that's detached from my house in my back yard that is running off a netgear ac1200  extendwr that is using the 5ghz band to supply a wired connections to a pc. Guess my question is the extender cutting 1/2 our bandwidth to our entire network (gaming pcs ect)? Sorry if I sound stupid, I am not much of a networking guy and this all don't make sense to me. 

It does not cut the bandwidth for the entire network. It only cuts the bandwidth for wireless devices that are within range.

 

Wireless works by using something called "collision avoidance". What this means is that wireless devices will only send data while no other device is sending data (because if two devices send data at the same time then there would be a collision and both packets would become corrupt).

Since your repeater works by listening on a message, and then send the same message out again, twice the amount of packets has to be sent (first to the repeater, and then to the router, instead of straight to the router). This means that there will be twice as much waiting time for everyone who wants to send packets (and thus, half as many unique packets with data can be sent at any period of time).

 

Only devices which are within range of the PC (which is sending/receiving data) and the range extender will be affected. The rest of the network will not.

 

 

It is also possible to avoid this by using different frequencies/channels for the PC->Repeater, and Repeater->Router.

So for example if you use 2.4GHz between the PC and the repeater, and 5GHz between the repeater and router, then it will not cut your bandwidth in half (although you will be limited to the slowest link).

 

 

 

An easier way to think about it would be this: Your WiFi range extender can handle 1200MBps. Half of that will be used for communicating PC->Repeater, and the other half will be used for Repeater->Router. So PC-Repeater will be 600MBps maximum, and Repeater->Router will be 600MBps maximum. So despite the extender being rated for 1200MBps, you will only be able to use 600MBps of it.

 

 

There is a lot more to it than that, but hopefully this post made it a bit more clear to you.

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6 hours ago, LAwLz said:

It does not cut the bandwidth for the entire network. It only cuts the bandwidth for wireless devices that are within range.

 

Wireless works by using something called "collision avoidance". What this means is that wireless devices will only send data while no other device is sending data (because if two devices send data at the same time then there would be a collision and both packets would become corrupt).

Since your repeater works by listening on a message, and then send the same message out again, twice the amount of packets has to be sent (first to the repeater, and then to the router, instead of straight to the router). This means that there will be twice as much waiting time for everyone who wants to send packets (and thus, half as many unique packets with data can be sent at any period of time).

 

Only devices which are within range of the PC (which is sending/receiving data) and the range extender will be affected. The rest of the network will not.

 

 

It is also possible to avoid this by using different frequencies/channels for the PC->Repeater, and Repeater->Router.

So for example if you use 2.4GHz between the PC and the repeater, and 5GHz between the repeater and router, then it will not cut your bandwidth in half (although you will be limited to the slowest link).

 

 

 

An easier way to think about it would be this: Your WiFi range extender can handle 1200MBps. Half of that will be used for communicating PC->Repeater, and the other half will be used for Repeater->Router. So PC-Repeater will be 600MBps maximum, and Repeater->Router will be 600MBps maximum. So despite the extender being rated for 1200MBps, you will only be able to use 600MBps of it.

 

 

There is a lot more to it than that, but hopefully this post made it a bit more clear to you.

Thank you, that helps me understand a bit better. Unfortunately my repeater/extender must operate on the same channel as the main router so I can not use a different channel. The repeater/extender is using the 5ghz band to supply the outside pc with Internet. But will this work, can I just reduce the range/power of the repeater/extenders broadcast so it don't broadcast a signal that will reach the main home?

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Posted · Original PosterOP
2 hours ago, Bion1985 said:

Thank you, that helps me understand a bit better. Unfortunately my repeater/extender must operate on the same channel as the main router so I can not use a different channel. The repeater/extender is using the 5ghz band to supply the outside pc with Internet. But will this work, can I just reduce the range/power of the repeater/extenders broadcast so it don't broadcast a signal that will reach the main home?

No, the extender's signal needs to reach your home. Otherwise the extender will not have a signal to extend.

 

Just leave your setup like it is right now.

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r there any other ways to check connection speed? i can't seem to watch twitch stream on source quality(4k ish kbps) as it keeps buffering, my speedtest is good on download.

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You could probably do more explaining on what PfSense is and the difference between a vanilla router and a wireless router. Too many people wall wireless access points "routers."

PfSense is great if your house has been ran with ethernet and you want to keep the good majority of your network equipment in a single location. you can then place a dedicated WAP in a more strategic location (likely one you can't get a consumer wireless router to.) 

 

PfSense as a dedicated routing box is much more powerful than any consumer router, but if you want an all-in-one box for your internet PfSense is probably not for you.

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Posted · Original PosterOP
On 8/8/2016 at 1:52 AM, Tist said:

r there any other ways to check connection speed? i can't seem to watch twitch stream on source quality(4k ish kbps) as it keeps buffering, my speedtest is good on download.

What do you classify as "good on download"?

 

 

Your download speed will vary depending on what server you connect to. It might just be that the speedtest server you are connecting to is faster than the Twitch server (depends on distance, amount of users using it, etc). I don't know of any way to test this though.

 

 

 

1 hour ago, Lord_Doge said:

You could probably do more explaining on what PfSense is and the difference between a vanilla router and a wireless router. Too many people wall wireless access points "routers."

PfSense is great if your house has been ran with ethernet and you want to keep the good majority of your network equipment in a single location. you can then place a dedicated WAP in a more strategic location (likely one you can't get a consumer wireless router to.) 

 

PfSense as a dedicated routing box is much more powerful than any consumer router, but if you want an all-in-one box for your internet PfSense is probably not for you.

I honestly think that I was fair against PfSense in my post. I explain why I don't think it is something the average home user should use, but if you are interested in the more powerful features then you should check out Ssoele's guide (which I link in my post).

 

The thing about PfSense is that if you know how to use it and has needs for it, you will not be the type of person who needs to read this thread.

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2 hours ago, LAwLz said:

The thing about PfSense is that if you know how to use it and has needs for it, you will not be the type of person who needs to read this thread.

true

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On 13/08/2016 at 1:35 AM, LAwLz said:

What do you classify as "good on download"?

 

 

Your download speed will vary depending on what server you connect to. It might just be that the speedtest server you are connecting to is faster than the Twitch server (depends on distance, amount of users using it, etc). I don't know of any way to test this though.

like 100mb and above, at day time i can watch anything fine and night can't watch anything in HD or better, like youtube, this has to be ISP fault right?

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Posted · Original PosterOP
1 hour ago, Tist said:

like 100mb and above, at day time i can watch anything fine and night can't watch anything in HD or better, like youtube, this has to be ISP fault right?

If it's only at a particular time of the day then yes, sounds like something is wrong at the ISP or somewhere between you and the ISP.

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Perhaps we should mention that only consumer grade switches are plug and play.  I know most people reading the FAQs won't care about managed switches, but just wanted to mention it so we are technically correct.


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Posted · Original PosterOP
4 hours ago, ultimatemythbuster said:

Perhaps we should mention that only consumer grade switches are plug and play.  I know most people reading the FAQs won't care about managed switches, but just wanted to mention it so we are technically correct.

Well, managed switches are plug-n-play too. None of the more advanced features, like actually being manageable, will work out of the box, but all the stuff unmanaged switches does, will work.

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