slow wireless speeds and other transfer issues

[dazeman27]

So here’s my issue:

I’d like to get a NAS and connect it to my router and be able to access it from two laptop wireless N for backups and data access. I’d prefer decent speeds, but the goal is to not have to run CAT5E wires in the house, so I’m sure I’ll sacrifice some speed for that luxury.

Here’s my setup:

1) ATT Uverse 2-wire modem/router acting as gateway and running into Linksys WRT160N router

2) HP laptop with Windows 7 32bit (only has G network adapter; planning to upgrade to ASUS laptop with draft N or full N card)

3) ASUS laptop with Windows 64bit (has draft N 150Mbit adapter)
* note laptop only got 65Mbps connection until changing router to auto 20/40Mhz instead of locked at 20Mhz

ROUTER SETTINGS:

Mixed mode G/N, auto channel, auto 20/40Mhz, WPA2

Problems:

1) I cannot get the homegroup to work wired or wireless. It worked a few days ago and then stopped and it just says that “Windows cannot create a homegroup” on both computers when I try.

To get around this for testing speeds, I put both computers in a workgroup and mapped the network drives for each.

TRANSFER SPEEDS:
1) wireless on both laptops 2 feet from the router = around 1.2MBps

2) wireless on draft N laptop and wired on G laptop = around 8MBps

3) wireless from G laptop and wired on draft N = around 2MBps

4) netgear wireless N adapter in G laptop (130-250Mbps) to wireless draft N laptop = 1-2 MBps

5) wired to each = around 10MBps

I think that the 10Mbps is a good speed for the wired since the router is only 100Mbps so that’s my bottleneck….and the HP laptop is only 100Mbps too.

I think there must be something wrong with the G laptop since I can only get 2MBps wireless. Seems like I should be able to get around 4-6 from 2 feet away.

Also don’t understand why I can only get 1.2MBps with both wireless from 2 feet away. I’m hesitant to invest in a new laptop only to find that having N on both still gives me unacceptable speeds.

Not sure why I only got 8MBps with the wireless draft N card…thought with perfect signal level I should be able to get around 12-15 or something. Still wondering if I get two laptops with draft N 150Mbps if I’m going to have these speed issues…or if the 1.2MBps is a consequence of the G speed and bandwidth being cut in half with two wireless connections talking to eachother or something.

I’d like if a network expert could share their thoughts on my issues and what some realistic wireless speed expectations might be. If it’s realistic to have a Synology NAS connected to a gigabit router upgrade and accessed by wireless draft N. Seems like I should be able to get around 10-15 MBps if I’m close enough to the router which seems like a good enough speed for playing home media and making backups/sharing files between users.

All my experience is in programming, so I’d love some advice. I do plan to wire my house eventually ( have the knowledge for making cables) but I’m in the military, so I don’t typically stay in a house very long and I’m about to have a baby, so I’d rather not kill a Satuday.

Please don't respond in saying that I need to wire the house. I realize that this will give me a better network, but I'm not interested in doing it right now and there shouldn't be a reason why I can't get decent speeds for a NAS with two wireless in my opinion.

Thanks

Mike

 

[dazeman27]

Oh, another issue is that when I switched to auto 20/40MHz in the router, I cannot choose the channel and my connections for the draftN and G laptop are dropping every once in awhile. When I set it to 20MHz only and select a low channel like 3 that no one else is using and my microwave doesn't interfere with, I get no problems.

Are there better routers that would allow me to do mixed mode, broadcast the 2Ghz and 5Ghz and select the channels for each without auto settings. If I enable the 20-40Mhz I lose my channel selection option on the Linksys and I have to assume that my neighbors routers are killing my connections.

I also tried setting router to N only, but didn't see speeds change from mixed mode and if I change to 20Mhz and select a channel, the ASUS laptop only gets a 65Mbps connection. I guess it has to use both bands. Also, my Xbox and the ASUS laptop are apparently only on the 2Ghz frequency N, so I can't use 5Ghz only...not that my router has that option

 

[thiggins]

Check for newer Linksys firmware. Current Linksys routers (and any others I've seen) don't disable channel selection in either mode.

Are you quoting Megabits/sec or MegaBytes/sec in your first post and how are you measuring transfer rates.

Single stream N (150 Mbps) devices have a maximum 65 Mbps link rate in 20 MHz mode. You get 150 Mbps link rate only with 40 MHz channel bandwidth. This is the same on either 2.4 or 5 GHz bands.

 

[dazeman27]

Thanks for the reply. I suspected as such with the 20Mhz only, but wasn't 100% sure on the facts behind that concept.

I'm referring to Bytes when I write MB and bits when I write Mb. I used the correct terminology, so the numbers that I wrote reflect the actual speeds that I was getting in bytes. I was transferring a 2GB movie file to obtain the speeds for my tests. I performed all the tests wired and wireless with both laptops right next to the router and two 6 ft CAT5E cables. In all my tests I only can obtain around 800KB - 1.3MB per second transfer speeds when connected between the laptops wireless. I checked the channels and no one was using channel three in the area so that's what I was on. Both computers registered "excellent" for the connection. And the transfer between the wired HP laptop and the wireless ASUS N was much faster.

 

[thiggins]

No offense intended on the Bytes vs. bits question. Many posters confuse the terms, so I needed to clarify.

Wireless to wireless speed will always be 1/2 wireless to wired because the radio must receive then transmit, cutting available bandwidth in half.

So you are getting 6 - 8 Mbps on a transfer between a wireless N client and wireless G client. From your first post:

2) wireless on draft N laptop and wired on G laptop = around 8MBps
This is 64 Mbps, which is pretty good for close-range N.

3) wireless from G laptop and wired on draft N = around 2MBps
This is 16 Mbps, which is a bit low, but still in the ballpark for close-range G

The slowest link in the chain will determine your speed. And since you are running a mixed N/G network, the N client must slow down to G speed to not risk collision.

Using the retransmission rule of 50% throughput reduction, and the G speed as the limiting factor, your net speed of ~1 Mbps is the expected result.

 

[dazeman27]

ok, thanks for the feedback. I guess that's a little disappointing that 8MBps is a good speed for wireless N at that distance. So, I guess that if I had 2 wireless N laptops (upgraded), I could possibly expect to see transfer rates of around 4-5MBps. Still not great, but at least it's better than what I'm getting.

Just out of curiosity; they're always advertising that N can be potentially 300Mbps or now they're saying even 450 with the new routers. Is this by using both frequencies simultaneously or something? Just wondering how it works. If I get a laptop that's full 300Mbps then maybe I can see some decent speeds to a NAS.

Also, I guess since you're saying that two wireless clients cut the transfer rate in half, then a wireless laptop to a wired NAS should be able to get at least the full 8MBps right? I realize there's a lot of factors that go into determining this and it depends on individual interference and usage, but I'm just curious. If my wife and I can both see the NAS at around 8MB+ then I think that would be a feasible solution for storage and backups and sharing.

Any theories as to why I drop connections on my laptops frequently when utilizing the 40MHz channel as opposed to the 20MHz? Do you think it's just the channel number we're on when I go to auto with 40MHz or is there something else going on?

I'll probably upgrade my laptop soon and purchase a NAS so I can conduct some real world experiments, but I just wanted to perform a little troubleshooting before I spent a bunch of money to fully understand the realities of wireless.
Thanks

 

[thiggins]

Reading through this should answer most of your questions: SmallNetBuilder's Wireless FAQ: The Essentials .

Available wireless bandwidth from a single access point is shared by all clients associated with it.

40 MHz bandwidth in 2.4 GHz can eat up most of the available channels. APs are supposed to back off to 20 MHz mode if they encounter traffic in the expansion channel (that's why it's labeled "Auto 20/40").

Could be that the clients and/or AP don't like the fast switching between 20 and 40 MHz bandwidth and drop connection and have to reassociate.

I really recommend 20 MHz mode in 2.4 GHz unless you are sure there are no neighboring networks. You don't really get that much more bandwidth from 40 MHz mode, it's not neighbor friendly (eats up available channels) and you actually will get lower throughput under low signal levels.

 

[dazeman27]

Thanks for the reply. I read through the post you recommended, but I still don't know if I fully understand. You're saying that the 300Mbps is not for data but other bits needed for the connection, so you'll never get anything close to that. And you recommend to go down to 20Mhz, but then I only get 65Mbps which is only 11Mbps faster than the G, so what's the point?

When I go to 40Mhz I show 150Mbps, but you're saying that I wouldn't get anything close to that...fair enough. Why am I only able to get 150 as opposed to 300 though? I'm just curious for my future laptop purchases. The ASUS laptops I've looked at only have the 2.4Ghz frequency and not both, so is that why they can only do 150 and not 300? It would be nice to do 5Ghz since my microwave likes to interfere with most of the channels in the 2 Ghz range and I have about 50 neighbors using G routers occupying most of the channels in that frequency band.

I was just wondering what kind of card would yield 300Mbps and what settings on a router could yield the maximum transfer rates, so I can make sure I buy the best router and wireless cards for my LAN.

I'll try updating my firmware to see if I can get channel options in the 20-40MHz auto setting and maybe stop dropping my connections.

Do you know what the best settings are and the best theoretical data transfer rates are that I could get from a laptop wireless to a NAS (NAS connected directly to router with 40-60MBps transfer capabilities from Synology)?

I tried reading through all the forums, but I guess I'm still not fully understanding what the best equipment to have is.

 

[thiggins]

The rates you see manufacturers quote are maximum LINK rates. Think of these like the 10/100/1000 Mbps rates for Ethernet adapters. This is the maximum speed at which bits flow through the connection.

Wired Ethernet provides the most stable and reliable connection, so the overhead for retransmitting lost packets is low. So maximum usable throughput is a high percentage of the link rate. With 100 Mbps Ethernet, you'll see maximum TCP/IP speeds in the low to mid 90 Mbps range. With Gigabit Ethernet, you can see speeds in the 700 - 800+ Mbps range.

With wireless, there is a lot more overhead. The client must constantly monitor the received signal level from the AP and adjust its link rate. There is also a much higher bit error rate due to the relative (to wired Ethernet) unreliability of wireless transmission. So maximum usable throughput is a much lower percentage of the link rate, usually 50% or less.

Maximum link rate depends on the wireless standard and, with 802.11n, the number of streams and the bandwidth mode. It does not depend on frequency band (2.4 vs. 5 GHz) Here is a quick rundown:
802.11b = 11 Mbps
802.11a/g = 54 Mbps
802.11n 1 stream, 20 MHz bandwidth = 65 Mbps
802.11n 1 stream, 40 MHz bandwidth = 150 Mbps
802.11n 2 stream, 20 MHz bandwidth = 130 Mbps
802.11n 2 stream, 40 MHz bandwidth = 300 Mbps
802.11n 3 stream, 20 MHz bandwidth = 195 Mbps
802.11n 3 stream, 40 MHz bandwidth = 450 Mbps

This gets even more complicated due to other variables that different manufacturers use. That's why some two-stream N adapters will show only maximum link rates of 117 / 270 vs. 130 / 300.

If you want a maximum link rate of 130 / 300, you need to have both client and AP that support that rate. If you see "150" in either the adapter or router / access point description or spec, you are getting a single-stream N router that will never deliver link rates higher than that.

 

[dazeman27]

awesome! That's exactly what I wanted to know. Not usually sure if something is one or two streams based on the laptop I'm looking at, but maybe if I research the wireless card for each one I can find that information.

 

[thiggins]

awesome! That's exactly what I wanted to know. Not usually sure if something is one or two streams based on the laptop I'm looking at, but maybe if I research the wireless card for each one I can find that information.

That's correct. You may have to dig for the data or even ask a sales rep. It's very hard to find this info from some suppliers, Dell, for instance.

Once you find the card type, you should be able to find specs on it. Again, anything with "150" in the name or description is a single-stream card.