802.11n, 5GHz WiFi, HP dm1z and other things learned configuring my new Cisco Linksys E4200 wireless router

I thought I knew the details of WiFi and WiFi home networking pretty well. Turns out I was fairly ignorant on the details.

Current Router
My present router is a Linksys WRT54GS. I've had it for about 7 years. It's OK, it supports b/g over 2.4GHz. Generally it works but it drops connections, fails to accept connections, or data throughput would just turn into a crawl. I had to power cycle it often to correct these issues and this was annoying. 802.11n has been around for a while and I've heard good things about it, and I heard good things about 5GHz WiFi too. I figured it was time to upgrade my home wireless router as I now have multiple devices that support 'n' including the dm1z.

New Router
Initially I thought of buying a n-only 5GHz router. This with the WRT54GS would give me a two router set up to get the new+legacy coverage. But I decided against this and started looking for a single unit that met my criteria:

• Support for all the WiFi letters a/b/g/n
• Dual band (2.4GHz + 5GHz)
• Ethernet ports
• USB port so I can plug in and have a networked hard drive

I decided on the Cisco Linksys E4200. It's pricey ($179) but any dual band wireless router with a USB port is $150+ so I figured I get the top of the line for a bit more (plus the unit just looks sharp).

New Wireless Router Install
The first Linksys E4200 I got was a dud and I had to return it. The second was fine and the basic setup was painless. But I wanted different SSIDs for each band and to get the network drive going so this requires going into the 'advanced' settings, mostly straightforward though not exactly a painless process. I had to instant chat with Cisco support but they turned out to be nearly worthless so I mostly figured things out on my own. Anyway, I'll talk about my E4200 selection process set up woes later, overall it is a good wireless router.

So now I have a dual band wireless router. I assumed I'd connect my b/g only devices to the 2.4GHz band (b/g only works on 2.4GHz) and my 'n' devices on the 5GHz. Well, assumptions make an ass of you and me they say. As I connected my devices I learned a few thigs in the process of building up new WiFi home network that I did not fully understand prior.

Connecting to the New Wireless Router
Here's what I will be connecting to the router:

• Dell Latitude E6500
• HP Pavilion dm1z
• iPhone 4
• iPhone Original
• Dell Latitide c400
• Xbox
• USB Hard Drive

Dell Latitude E6500
My main laptop has a WPAN/UWB card and it does connect to the 5GHz SSID I created. I set up the router to have only 'n' on 5GHz with WPA2 security.

HP Pavilion dm1z
My dm1z supports 'n' but only on 2.4GHz. I assumed the dm1z would support 5GHz WiFi but this is not the case. Why did I assume this? I don't really know, probably I'm an idiot. I guess I assumed that 'n' and 5GHz WiFi go hand-in-hand so any 'n' device would naturally support 5GHz. Be sure to verify an advertised 'n' supported device also supports 5GHz to get the max benefit of 'n'.

Dell Latitude c400
This is my emergency/guest system. It's old but still works. This unit connected fine to the WRT54GS which I set up to use WEP. I've connected this unit to WPA networks too. It runs XP SP3 and has a Dell TrueMobile 1150 Series Mini-PCI Card with the latest (and likely last) driver from Dell, version 7.86.15.638. The card supports WPA with TKIP only, it does not support WPA2 (here's a list of wireless security acronyms). I set up the 2.4GHz security to be 'WPA2/WPA Mixed Mode'. I figured the c400 supports WPA so the Cisco Linksys E4200 WPA/WPA2 mixed mode would allow me to connect over WPA. A good assumption I think but I was unable to connect. The c400 sees the network but sees it as a WPA2 network and not WPA. I try to connect anyway (I do get asked for the key) but it fails. I'm not sure if WPA-TKIP is part of the problem or if it's something else. When I run a diagnostic it says the security protocol is incompatible. I tried to change the security to just WPA but the E4200 says any 'n' devices would run at only 'g' speeds (why? and just for the 2.4GHz SSID or for the 5GHz too?). I get the same message for WEP but I would never do WEP again and deal with those long keys. Can I update the c400 driver to WPA2? I think not. I can plug the c400 into the ethernet port so it can get online and that's good enough for an emergency laptop. I'm curious why it can't connect to the E4200 mixed mode however - is it a E4200 problem or a c400 driver problem?

Connecting the iPhone and Xbox
My original iPhone supports b/g while the iPhone 4 supports b/g/n and they connected fine to the 2.4GHz SSID. I plugged in my Xbox into the ethernet port, no problem.

Connecting a USB Drive
I plugged in my Maxtor USB hard drive into the E4200 and it picked it right up. I chose to share out the entire drive and gave it a name. The laptops were able to connect to the drive on the network no problem. I then disconnected the drive to re-organize and add folders as there was some long overdue data housekeeping I had to do. I then had permissions issues with one of the new folders I created when I connected it back to the E4200 and shared it out; I could not access the folder. I did not understand this and didn't want to dig around with permissions so I disconnected the drive, plugged it into my laptop, moved the offending folder into a folder I could see when shared, and reconneceted it to the E4200. That solved it though I'll try to review this permission issue more when I can. I also need to see if I can get to the drive via FTP when I'm at work so still a bit more to do here. The speed when accessing/browsing the drive over the network is fine but copying data to/from the drive is slow. This performance is OK for me though, I'm not looking for a snappy NAS, I just need some convenient shared storage.

On the whole I have to say mission accomplished with my router upgrade. But I encountered some technical things along the way that I didn't fully understand. So I wanted to understand them.

WiFi 802.11n and 2.4GHz/5GHz
Firstly I needed to have a more clear understanding about WiFi details. Some info below on WiFi 'n' and 2.4GHz/5GHz.

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

To achieve maximum output a pure 802.11n 5 GHz network is recommended. The 5 GHz band has substantial capacity due to many non-overlapping radio channels and less radio interference as compared to the 2.4 GHz band.

From Linux Planet: http://www.linuxplanet.com/linuxplanet/reports/6581/1/

Performance:
Compared to 2.4 GHz, the 5 GHz band has much greater spectrum available, which leads to significantly better performance as compared to the 2.4 GHz band. In fact, the use of 5 GHz devices is really the only way to achieve the highest performance from 802.11n networks, mainly because of the need to provide adequate bandwidth for 802.11n's optional 40 MHz (rather than 20 MHz) channels. If the highest performance is an important requirement, then certainly lean toward the 5 GHz band.

RF Interference:
2.4 GHz wireless LANs can experience RF interference from cordless phones, microwaves, and other existing wireless LANs. The interfering signals degrade the performance of a wireless network by periodically blocking users and access points from accessing the shared air medium. If it's not possible to reduce potential interference in the 2.4 GHz band to an acceptable level, consider deploying a 5 GHz system. The noise floor in the 5 GHz band is generally lower compared to the 2.4 GHz band, which allows 802.11n to function at higher data rates.

And Engadget said last year "you should be running a dual-band 2.4 and 5GHz WiFi network"

So WiFi 'n' on 5GHz is best, this point is clearly a slam dunk.

Am I getting the most bang for my buck with the Linksys E4200?
The ideal situation for my home network is to have all my WiFi devices on 5GHz using 'n'. I figured I would achieve this with no problems since after all I got a high end wireless router to do exactly this. But the problem I have now is I just don't know exactly how the network is behaving. The new router has been worth it but moving to 5GHz 'n' has raised many questions for me:

• The dm1z connects to the 2.4GHz SSID but I don't know if it connects in 'n' mode or another letter. How can I find out?
• The iPhone 4 connects to the 2.4GHz SSID but I don't know if it connects in 'n' mode or another letter. How can I find out?
• Does the Linksys E4200 automatically use the fastest protocol it can on the 2.4 GHz SSIDs? So will it use 'n' when it can and downgrade at other times? What would cause it to downgrade?
• Is 'n' on 2.4GHz on the Linksys E4200 really a speed improvement over 'g' on 2.4GHz on the WRT54GS?
• Is the 2.4GHz on the Linksys E4200 better than 2.4GHz on WRT54GS (i.e. will I experience less drops)?
• Is 'n' more robust then 'g' on 2.4GHz (i.e. is it less likely to experience dropped connectivity)?
• As 2.4GHz is more susceptible to interference compared to 5GHz, will the 'n' benefits will be outweighed by signal loss issues in the 2.4GHz spectrum?
• Will 5GHz connections drop less often?
• If I conect only 'n' devices to the 2.4GHz SSID on the E4200 how do I know if they are leveraging 'n' (the 2.4GHz SSID is in 'mixed' mode)?
• Do I care if my devices connect on 'n' over 2.4 or 5GHz? Does it matter since my cable transfer speed tops out at a rate that's still in the g range? I do care since I paid for a 'n' router and want all my devices that suport 'n' to be on 'n' (dammit!)

Conclusions in re 'getting the most bang for my buck with the Linksys E4200'
My goal for my home network is to go all 'n' on 5GHz. At this point only one of my devices can connect on 5GHz using 'n'. But connections to the E4200 seem faster and more robust and the network drive feature is great.

So, the answer is I am not yet getting the most bang for my buck - but it's not the fault of the E4200 router. Not all my devices support 5GHz 'n'. My cable connection is not fast enough to even leverage 'n'. These factors will change in the future so I will be growing into the E4200 capabilities over time. The E4200 is a good unit and I have no regrets buying it, hopefully I'll get 7+ years out of it.

Epilogue
Note that a device may say it supports 'n' but this does not mean support for 5GHz. Be sure to get devices that explicitly support 'n' and 5GHz. For example, the iPhone 4 supports 'n' but on 2.4 GHz only (Apple does state this fact). For the dm1z HP wasn't exactly clear on this point. The ideal is 'n' support 2x2 - 'n' support on legacy 2.4GHz and 5GHz.

It seems I simply need to trust that the router uses the fastest possible connection option. I believe if I connect my 'g' only devices then things would go all 'g' on the E4200 2.4GHz.

I'm now somewhat future-proofed with the E4200, so as my cable provider speed increases (hah) I can gain the benefits with my faster WiFi router. I could upgrade to a faster internet package offered by my cable provider and realize these benefits with the E4200 too. My next TV will be network enabled and you really need 'n' for pushing video from a PC to the TV so I'll be covered there. And I may get a 5GHz 'n' upgrade or USB adapter for my dm1z. This would get my two main laptops on n and 5GHz, which is where you want to be.

The last key item for me to get on 'n'+5GHz is the iPhone. Maybe iPhone 5 will support 5GHz?