I need help with wireless bandwidth

[MetalPig]

I have a 50 Mbps internet connection, and a 802.11n wireless router.
If I make a wired connection I do indeed get 50 Mbps internet speed.

So why do my wireless devices get speeds that never exceed 20 Mbps?
I looked at the router settings, and in the wireless settings I found a bandwidth selector that has the options 20 and 20/40. The selected item is 20/40.
On the status screen my devices are listed with bandwidth 20M.
Laptops say they are connected to the router at 54 Mbps.

So my questions would be:
- Is bandwidth the same as speed?
- Can I get my devices to connect at a higher speed (20/40 suggests they could be at 40 instead of 20)?
- Do I need another router that lets me choose a higher bandwidth/speed?

[Dancing David]

There are many factors in that wireless rate, it also depends upon the receiving wireless card.

The signal quality and interference will matter as well, packets that are damaged/corrupted will have a 'cyclical redundancy check' that does not match the transmitted value. Then the packet is trashed and needs retransmission.

[Sam.I.Am]

I think 20/40 refers to the channels that it is using and is not a direct measure of speed (it has to do with how the wireless N standard communicates). That you are getting 20mbps is just a coincidence.

I suppose the router could be splitting its wireless resources by intentionally limiting each connection to 20mbps to ensure that each device gets its fair share but I honestly don't know. But it does seem odd that each one is listed at exactly 20mbps.

Google the router manual and read it.

[MetalPig]

Originally Posted by Dancing David

The signal quality and interference will matter as well, packets that are damaged/corrupted will have a 'cyclical redundancy check' that does not match the transmitted value. Then the packet is trashed and needs retransmission.

Signal quality is "Excellent"; the laptop is about 10 feet from the router. The PC upstairs also gets 20 Mbps.
I did read something about interference from wireless phones (DECT). There is one right next to the router. But would that cause interference when there is no phone call going on?

Originally Posted by Sam.I.Am

I suppose the router could be splitting its wireless resources by intentionally limiting each connection to 20mbps to ensure that each device gets its fair share but I honestly don't know.

I don't think so. It's not like they each get 20 out of the 50 Mbps. If one of them is downloading at 20Mbps, the others get nearly nothing.

Originally Posted by Sam.I.Am

Google the router manual and read it.

I did, but found no answers. That's why I came here

[Dancing David]

I think the technical specs would be more likely the ones you want to look at. But the way wireless works can be tricky just due to the nature of the way things are designed. So without doing a lot of research it might be easier to use an ethernet cable.

Also 50mbs is going to be a top range, most ISPs have quality controls that throttle bandwidth, unless you are paying to not be throttled and never share, my broadband is limited by what my neighbors do.

I can almost always count on 12-15 mbs, but on Friday and Saturday evenings it can slow to 3 mbs, as everyone starts streaming or watching on demand in the local area of my ISP.

So are you running graphics files or something, that you need consistent high transmission?

[TheL8Elvis]

Originally Posted by MetalPig

I have a 50 Mbps internet connection, and a 802.11n wireless router.
If I make a wired connection I do indeed get 50 Mbps internet speed.

So why do my wireless devices get speeds that never exceed 20 Mbps?
I looked at the router settings, and in the wireless settings I found a bandwidth selector that has the options 20 and 20/40. The selected item is 20/40.
On the status screen my devices are listed with bandwidth 20M.
Laptops say they are connected to the router at 54 Mbps.

So my questions would be:
- Is bandwidth the same as speed?
- Can I get my devices to connect at a higher speed (20/40 suggests they could be at 40 instead of 20)?
- Do I need another router that lets me choose a higher bandwidth/speed?

20/40 has nothing to do with the 'speed'.

I'll put the blahblahblah technical answer at the bottom, read it if you want.

In a nutshell, disable mixed mode (if enabled) and ensure that only wireless N is enabled on the router and that all your devices are using N for the max throughput.

Max throughput/speed in wifi is generally in a perfect world - and yes, just having a client 10 feet away from the access point is going to guarantee you maximum throughput.

http://en.wikipedia.org/wiki/IEEE_802.11n-2009

Backward compatibility
When 802.11g was released to share the band with existing 802.11b devices, it provided ways of ensuring coexistence between legacy and successor devices. 802.11n extends the coexistence management to protect its transmissions from legacy devices, which include 802.11g, 802.11b and 802.11a. There are MAC and PHY level protection mechanisms as listed below:

PHY level protection: Mixed Mode Format protection (also known as L-SIG TXOP Protection): In mixed mode, each 802.11n transmission is always embedded in an 802.11a or 802.11g transmission. For 20 MHz transmissions, this embedding takes care of the protection with 802.11a and 802.11g. However, 802.11b devices still need CTS protection.
PHY level protection: Transmissions using a 40 MHz channel in the presence of 802.11a or 802.11g clients require using CTS protection on both 20 MHz halves of the 40 MHz channel, to prevent interference with legacy devices.
MAC level protection: An RTS/CTS frame exchange or CTS frame transmission at legacy rates can be used to protect subsequent 11n transmission.
Even with protection, large discrepancies can exist between the throughput an 802.11n device can achieve in a greenfield network, compared to a mixed-mode network, when legacy devices are present. This is an extension of the 802.11b/802.11g coexistence problem.

[The Norseman]

As was said above, but also wireless internet has a separate protocol (CSMA-CA) which differs from wired transmissions (SCMA-CD) which will slow things down due to the nature of the wireless transmission itself.

CA stands for Collision Avoidance while CD stands for Collision Detection. The avoidance portion will slow down the same connection due to that.

[theprestige]

Originally Posted by MetalPig

I have a 50 Mbps internet connection, and a 802.11n wireless router.
If I make a wired connection I do indeed get 50 Mbps internet speed.

That's because wired connections are faster. Not even 802.11n can match the speed of a decent-quality cat5 cable.

You will never get the full advertised speed of your Internet connection, via a wireless link.

What you will get via a wireless link is unparallelled convenience and ease of access, and speeds fast enough as to not make a noticeable difference during casual use.

If you're ever downloading a large file, and an extra half hour or two is really truly unacceptable, you may want to plug in first.

[MetalPig]

Wow, thanks for the answers; I will need some time to digest and experiment...

[Alareth]

Originally Posted by MetalPig

I did read something about interference from wireless phones (DECT). There is one right next to the router. But would that cause interference when there is no phone call going on?

DECT cordless phones should have no interference issues with wi-fi as the DECT standard operates in the 1.9GHz range.

It's the older 2.4GHz phones that use the same frequency range as the majority of routers

[Yalius]

You might also make sure that your wireless clients are N-capable as well. An N router with a G client won't give you anything approaching N speeds. The best I've ever gotten with wireless (Dual-band N wireless adapter --> dual-band N wireless AP --> gigabit ethernet link --> ISP-grade router --> 1.5 Gbps fiber link to Sprint backbone) gave me about 70Mbps sustained when testing to Speakeasy.net about 250 miles north. Bypassing the wireless portion gave me about 220 Mbps to the same test site.

Using an 802.11G client will max at maybe 24Mbps in perfect conditions.

[MetalPig]

I played with just about every setting on the router. Some settings slowed things down, others made no difference. I checked that my clients are N-capable (at least they say so, just like the router) and played around there, as well.
I have come to the conclusion that it's just a crappy cheap router.

Fortunately, my ISP is handing out fast wifi-router/modems (some of my cow-orkers have one and are getting speeds up to 50 Mbps). Unfortunately, they distribute them to people with slow modems first, and they can't tell me when it's my turn.

[Beerina]

Originally Posted by Dancing David

Also 50mbs is going to be a top range, most ISPs have quality controls that throttle bandwidth, unless you are paying to not be throttled and never share, my broadband is limited by what my neighbors do.

He did say he got the full speed when he connected to the same router with wires.

It's also possible the router is gracefully sharing the airwaves with other nearby routers. I don't know enough about how they operate if they share the same band or just offset to a limited extent (thus not having to share.)

[Dancing David]

Originally Posted by Beerina

He did say he got the full speed when he connected to the same router with wires.

It's also possible the router is gracefully sharing the airwaves with other nearby routers. I don't know enough about how they operate if they share the same band or just offset to a limited extent (thus not having to share.)

I was just saying that because I have seen my bandwidth get throttled heavily on Friday and Saturday evenings, so I tend to avoid big download or files at those times. It can effect the quality of Netflix, but it seems a lot of us in the neighborhood stream on Friday and Saturdays.