Wifi network buying guide for December 2014

Wifi network buying guide for December 2014

Inspired by reading all those Tom’s Hardware reviews, if you need to upgrade your hardware and can’t wait for full 802.11ac Wave 2, then here are your options. Smallnetbuilder.com seems to have the best reviews of these things. Most of the big sites don’t cover this in too much detail, but I find that for wireless and for NAS and other things for SOHO, it is perfect:

Wifi Access Points: To MU-MIMO or not

Access points fundamentally depend on clients to support their new features. So the 802.11ac transition is here. Most clients now support it. The big question is when to migrate to 802.11ac wave two (the feature name is MU-MIMO, so neither of these are consumer friendly names.

802.11ac background

802.11ac which supports what are called 3×3 which means three antennas and three streams going to each client. That is how you get to these amazing network bandwidths. For instance with the old 802.11n the maximum was 150Mbps in a 20MHz channel, so you could get up to 450Mbps if the client had three antennas in it and you burned up 60MHz of bandwidth. That only works at 5GHz and range is the big issue when you do this.
In the 802.11ac world, we use SU-MIMO which means single user multiple input and multiple output. The industry tries to capture the available bandwidth by saying that you are at AC450 if you get 450Mbps in the best, best case. So when you analyze bandwidth, you have to know how many antennas the receiver has and how many channels you are using (the more channels, the more interference potential). For a single antenna (1×1, which means 1 transmit and 1 receive), the maximum in 2.4GHz is 150Mbps in 20MHz (and that’s highly theoretic given how noisy 2.4GHz is in most buildings in the real world) but with 5GHz there is much more bandwidth, you you can actually get 467Mbps out of 80Mhz.
Here is how the math works:

  • 802.11n in 40 MHz is 150Mbps
  • 802.11ac in 40MHz at less than 10m is 200Mbps by switching to 256-QAM which means each signal carries 8 bits rather than 6 bits (normally there are 64 coding points)
  • 802.11ac in 80MHz and less than 10meter is 433Mbps. But you need lots of clean bandwidth and it only runs at 5GHz (and yes, I don’t understand where the extra 33MHz comes from).
  • 802.11ac in 80MHz at less than 10 meters with MIMO. If you have multiple antennas, then you can actually beam steers, so if you have 3×3 MIMO on both sides, ou get to that incredible 433×3=1200. If you have 4×4 MIMO then out get to 1800.

The big issue is that wifi access points is that only one client is talking to the access point at any one time. What this means is that the maximum throughput is the max of your router and the fastest client that you have. So if you only have 1×1 AC433 smartphones, you are not going any faster even if you have a infinitely fast AC3200 router. The terms are really deceiving too since AC3200 refers the maximum bandwidth across all the bands in the best possible case. No single client will see all that bandwidth and bandwidth decreases with distance anyway.
Given all this, what’s a person to do or think, well the main thing is that all this theoretic capacity is well, theoretic. There are two other big variables:
a) Range. How good an antenna system is a big issues. For instance Unifi Pro is just an 802.11n system with 3×3 antennas (450Mbps maximum), but it has incredible range which is what matters in many circumstances
b) Client compatibility. Since you are limited to the SU-MIMO clients right now, the most to MU-MIMO won’t happen until the big client change. This time we waited until the client switched before moving to 802.11ac and that probably makes some sense now.
c) Zero Handoff. In large installations, the clients decide when they move from one AP to another, so you can ‘hang’ for a long time on an AP that is far away. We had these problems when we were all Apple Extreme. Ubiquiti came up with a zero handoff scheme where all the APs use the same Mac id, they look like one big antenna and it is managed at the AP level. The result is much smoother handling and you don’t these bizarre drop offs but unfortunately this doesn’t work for UAP-AC or the UAP-AC Outdoor. Sad! One of the issues with Zero Handoff is that it requires that all APs be on the same frequency, so you don’t want them to be too close together as they will cause interference. The UAP-AC also doesn’t support wireless uplink so all need a hard ethernet connection. The main reason is that UAP AC uses Broadcom while the older ones used Atheros.

Extending SU-MIMO with Xstream.

The last thing is that there is a standard war going on right now with Broadcom delaying their move to MU-MIMO and instead doing something called Stream. They use different techniques for maximizing bandwidth.
So the big move is to MU-MIMO which allows multiple simultaneous client-to-AP transmissions. So one solution is MU-MIMO the math is for a 4×4 router made by Quantenna or QCA (Qualcomm Atheros), you get a total a capacity denoted as AC2300:

  • 5GHz: 256-QAM = 433K/stream x 4 80MHz streams = 1733 Mbps
  • 2.4Ghz: 256-qam x 3 6stream = 600Mbps

Broadcom isn’t doing 4×4 MU-MIMO, but is doing something called XStream in the interim. What this is basically putting two 5GHz radios in a single box, so you can get 3×3 across both 5GHZ bands (there are actually two sets). No one client ever sees 3×3, but it is like having two access points in one.
However all of this is kind of moot because there aren’t any 4×4 MU-MIMO client shipping anyway.
Also unintuitively as new 802.11ac router will speed up existing 802.11n clients by 50-200%. I’m not sure why, but those are the results.

Recommendations

No one is doing a lot of testing and it varies by client and so forth, but performance wise, Smallnetbuilder.com at least has a chart measuring first 2.4Ghz Up and Dow link Throughput. I include routers on this list as well. Ironically routers have more function (which you can disable), but are cheaper as they are higher volume:

  1. Linksys AC1750 Pro. AC1750. $247. 128.7 for 2.4 and 505 Mbps for 5Ghz. Top rated for AC1750 routers
  2. Ubiquity Unifi UAP-AC. AC1750. $250. 131Mbps 2.4 and 475 5Ghz. Rated #2 overall for AC1750 with about the same speed, but the software definitely works better and it is Linux based. So even without Zero Handoff, it might be worth it.
  3. Linksys EA9200 AC3200 Router. $400. 157 2.4 UpDown Throughput and 462 Up/Down for 5GHz. So even with the fancy new Broadcom Xstream and dual 5GHz radios, it doesn’t show much in single client performance. That makes sense, the dual radios only make sense if you have multiple clients. It’s interesting to see that if you just buy two Unifi UAP-ACs and tune them to different frequency, you get about the same effect, with more flexibility.
  4. Cisco Wireless N WAP561. $264. N900 system 151Mbps 2.4Ghz and 258 for 5Ghz. and interesting to see that is true that an 802.11n system can be faster than most 802.11ac and pretty close to the theoretic maximum.

Then if you can resist the bleeding edge, the choices are:

  • ASUS RT-82 uses the Quantel 4×4 MU-MIMO (multiuser MIMO) as does the Netgear R8000 Nighthawk X6. But of course there are no clients to take advantage of it.
    .

TL;dr here is what is recommended:

  • Unifi Pro AC. This is “only” a 3×3 system, but for $300, you get zero handoff and support for current clients. The next push to GigWifi is going to take a while and a few $300 APs are not that much to throw away when the time comes. The main reason is the reported range of the thing and the unifi multiple AP software. Plus these are Linux devices so we can look into them and it uses POE so it is easy to deploy.

Wifi Client devices

The main issue is that it doesn’t make sense to buy much more capacity than you need. The good news is that most of the modern iPhones, iPads and MacBooks are well equipped for the future. And you can get small USB Adapters to upgrade existing hardware if you really want.
Here’s a list of what Apple supports (there are a zillion hardware vendors, but this is a rough sample):

  • MacBooks before 2013. They had 450Mbps 802.11n that is 3 antenna systems.
  • MacBook Pro Retina (2013). Since 2013, the MacBooks are using 3-antenna 802.11ac so they can get 1.3Gbps in 5GHz with 3x20MHz channels. Each 20MHz channel has more capacity because they are using more points in the modulation. In the best case, you get much lower bandwidth and you have to share that connection so in tests you get about 615Mbps out of a 1.3Gbps channel. Also at 30 feet, the bandwidth drops significantly to just 290Mbps so don’t; believe everything that you read. Much depends on the antennas in the box and what is in the way.
  • MacBook Air 2013. These use 2×2 802.11ac, so they get a theoretically 867MHz in 5GHZ with 2x20MHz channels. Similarly there is a downgrade so you get 537Mbps out of 867. Notice that at close range, the 802.11ac results for 3 or 2 channels isn’t that different. As a comparison, a 1Gbps ethernet does give you 941Gbps of true throughput. At 30 feet, you get 252Mbps so a steep drop.
  • iMac 2013 and later. Like the rMBP you get 3 antennas, but they are larger and much better places, so in a real world benchmark, you while you get 605Mbps at 10 feet, by 30 feet, you are still at 461Mbps.
  • iPad Air. Uses MIMO like the MacBooks and iMacs in 2×2, so you get double the throughput of or 300MBps in 2.4 and 866 in 5GHz in the most optimistic case (80MHz channels, 256-QAM).
  • iPhone 6 and 6 Plus. They use 802.11ac and are theoretically 3x faster and can do about 280Mbps in the real world again with a 1×1 antenna.
  • iPhone 5 and 5S use 802.11n. In the real world, they can do about 100Mbps. They dual band 802.11n at 2.4/6GHz with up to 150Mbps available so that means a 1×1 antenna (1 receive and one send) inthref=”http://www.networkworld.com/article/2159913/smartphones/faq–iphone-5-and-5ghz-wi-fi.html”>40MHz channel.
  • AC580 USB Wireless Adapters. Most desktops have wireless already, but if they don’t getting a simple dongle is not a bad way to go. These are 1×1 802.11ac clients and are rated at AC580. The conclusion that the Edimax EW-7911UTC and Trendnet TEW-804UB are the winners if you are only in 2.4GHz with longer range and more throughput and are as good as the ASUS USB-AC51. But don’t get the Buffalo WI-U2-433DM or the Linksys AE6000 under any circumstances. But for the tough 5GHz transmit test, ASUS USB-AC51 wins at close ranges with 160Mbps, but then the Trendnet TEW-804UB catches up and lasts longer. Net, net the TRENDnet TEW-804Ub is the winner unless you know you are going to be close to a 5GHz AP in which case, the ASUS USB-AC51 at $40 is going to have higher performance.

Wired Ethernet: 10GB future proof

The gigabit ethernet is pretty standard these days. It is about $10 a port, so you can get an amazing unmanaged router of 24 ports for $300 or so. However, for the additional management, you get LADP which is a link aggregation protocol. While this doesn’t increase the available bandwidth, it does give you fail over and if you have a file server with two ports, then you can server more clients.
These things are switches, so that means that every client sees every other client and gets the full 1Gbps. This is quite different than Wifi where you share with other clients and if you’ve got lots of other businesses, the noise floor rises and you get even less. Still amazingly, 900Gbps is actually reasonably slow these days, it equates to about 100MBps in effect transfer speed. And with SSDs, you can easily get 500MB-1GBps (5-10x) that performance.
The translation is that it’s time to start thinking about 10Ghz Ethernet even for a small business particularly if you’ve got lots of video you are moving around. In the old days, you had to get fiber optics or something exotic, but today, for runs of less than 30 meters, you can use Cat 6e which is cheap and easy and still get this high performance.
Now of course, most client devices don’t have 10Gbps adapters, so this is more about talking server to server or machine to machine, but for video work it makes much more sense to get to 10Gbps. And in the old days, hard disks were limited to about 125MBps anyway just because of disk rotational speed. But with the advent or RAID0 and much faster SSDs, we are way past this.

Wired Ethernet client

The vast majority of systems support gigabit ethernet out of the box.
To get to 10Gbps ethernet, you need to get a special adapter card and direct PCI Express. For servers that means getting a PCI Express card that is 1 lane (10Gbps is a pretty good match). For laptops that doesn’t make much sense as they don’t have PCI Express and and USB 3.0 isn’t fast enough (it is 4.8Gbps in SuperSpeed), so laptops all about gigabit ethernet.
Gigabit ethernet adapters on USB 3.0. So what do you need for a gigabit adapter on a laptop? First, you really need USB 3.0 as the 4.8Gbps is of course much faster than 1Gbps where the real world performance is more like 100 MBps.

Net, net for wired ethernet

As a rule of thumb for:

  • Fast ethernet (which isn’t fast any more) of 100Mbps, you can use a USB 2.0 adapter (100Mbps using 480Mbps)
  • Gigabit ethernet you need at leastUSB 3.0 (1Gbps using 4.8Gbps)
  • 10Gbps, you need at least PCI Express 1 lane (10Gbps using 10Gbps).

3 Comments

  1. Think there’s a typo in the penultimate paragraph: “For laptops that doesn’t make much sense and USB 3.0 isn’t fast enough (it is 4.8Gbps inSuperSpeed). So for gigabit adapter you need USB 3.0. ”
    I think it should be USB 2.0 in the first instance, unless I’m missing something.

    1. Yes it’s a confusing a paragraph. I rewrote to so that it is clear USB 3.0 (4.8Gbps) isn’t fast enough for 10Gbps ethernet.
      Thanks
      Rich
      —–
      Dad, if you want to make it down this steep bump run, you can’t be timid. You have to just have to attack the hill. You can’t stop, slow down, you have to attack. Calvin Tong. Double black diamond, off-piste run somewhere on Whistler-Blackcomb, February 2011. —–
      tongfamily.com | fb.me/richtong | @richtong | +1-206-963-9029 | +86-137-6184-9029

  2. You are right, this was super confusing! I just corrected, it should say, “10Gbps ethernet for laptops doesn’t make much sense. You can’t put in a PCI Express card. USB 3.0 at 4.8Gbps can’t keep up.
    Instead for a laptop, you can get gigabit ethernet and this is sized nicely with for USB 3.0.

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