Should I install wifi or only Wired LAN for my home

Its a no-brainer. Wifi is a MUST today and tomorrow.

Almost all devices are being wifi enabled rather than being ethernet enabled. Mobile device (Laptop, Smartphones, tablets, gaming consoles, etc) feature only Wifi. Fixed device like smart appliances, TV setop box etc are all wifi enabled even though they may have an additional LAN port. Even PC motherboards are coming with both integrated Wifi and LAN.  The common/ubiquitous network connectivity interface therefore is Wifi.

- Suman Kumar Luthra @ APRC-P3 Telecom Sub-committee

But then why most telecom committee members insist on wired LAN connectivity to every room ?

Problem:
Despite all the simplicity and ubiquity of Wireless LAN (Wifi), the technology implementation for consumer devices suffers from a few key disadvantages:

(1) Poor Real world Throughput

(2) Limited Range

(3) Random Instability

Real world throughput is effected by many factors such as interference with neighbors wifi network (remember this is unlicensed spectrum use and all wifi routers use the same spectrum which is actual carrier/pipe for data),  attenuation by walls and other devices, EM interference etc. battery powered mobile device less antenna power  [often fewer antennas(1), less gain ones (embedded), less transmit/receive power) to conserve battery life, but this has a very negative impact on throughput achievable per device.

Similarly the signal strength falls of as the distance between Wifi Router/AP and the client device increases. The hard concrete walls and household items offer tremendous resistance to the wifi signal  propogation and progressively weaken it as we move away from the router in any direction.

Wifi links are also not stable. Their is variable latency (jitter) in transfering data and sometimes links go up and down (when router switches channels)

The short buck story is you may not see more than 1/3th the speed rated in the best case with inconsistent results in time & space. This is diametrically opposite of what you see with Wired LANs.

Here is a third party illustration of the speed gap betweeen promise and real-world delivery:

Solution:

On the contrary, Wired LAN ports on switch and client device are rated as 1 Gigabit and they can do simultaneous 1 gigabit upload and download on each port at cable lengths less than 100m. Which means an 8 port switch capacity is actually 16 Gbps simultaneous throughput whereas wifi is limited to 150 mbps per router antenna in case of 802.11n or 450 mbps per router antenna in 802.11ac. Also this antenna level router bandwidth is shared between ALL clients and therefore the practical throughput seen by each client is way less and dependent on what other clients are doing (unlike wired ethernet). A bridge solution for high throughput is to use multiple access points which use wifi for short range and backhaul wifi signal over Wired LAN (especially useful for duplex penthouses and large 4 BHKs)

A certain kind of device in home today like PC, NAS, TV setop box need high bandwidth and this makes wifi unsuitable as carrier. Their is no fixed place where we can constrain these devices to be put in every home and therefore the committee members recommend that:

(1) Every Bedroom has atleast 1 LAN port for data and they all terminate in one switch area

(2) Living room TV location(and every TV location in Bedrooms/kitchen) has 1 LAN port

(3) Additional LAN ports maybe placed wherever deemed fit for other high bandwidth applications (like CCTV camera, additional TV points, wifi access points, etc) or for redundancy

This would give you sufficient flexibility to integrate multiple access points/routers and integrate high bandwidth devices in future. In essence this prepares you for any eventuality and gives you upgrade paths for future as your needs evolve.

- Suman Kumar Luthra @ APRC-P3 Telecom Sub-committee

Wait a minute. I just saw a 1900 Mbps, 3200 mbps and even 5300 mbps Wifi Router. They are much faster than wired Ethernet. Right ?

Not exactly.

Fiction:

1. I throw $300-$400 at these routers and I get a wifi router 2 to 5 times faster than wired Gigabit Ethernet

Facts:

1. A 1800 mbps router is 802.11 ac based with 3 MIMO antennas. It can do maximum 450 mbps per antenna with 802.11 ac (1350 mbps total in 5 Ghz band plus 450 mbps 802.11n in 2.4 Ghz band) but only 150 mbps  per antenna in pure 802.11n which is spread across all clients. In mixed mode this throughput limit is further reduced. 
2. Most clients have one antenna only and the good ones (iPad, Laptop, big tablet, expensive smartphone) may have two and only low-gain antennas. You are never going to see the type of theoretical throughput in (1).
3. Most clients are still 802.11n and only the latest and greatest from Samy and Fruit company may have 802.11ac with 2 antennas. So you are capped theoretically to 300 mbps on 802.11n and 900 mbps on 802.11ac devices). 
4. The signal strength drops off as distance increases from router to client and therefore speeds also drop off. This does not happen in gigabit ethernet till 100m cable length with cat6 cable
5. in an Multi-Dwelling (MDU) environment like apartment complex a lot of homes are clustered on one block/tower and each wifi router faces interference from neighboring flat (up, down, same floor units) and this limits the real world throughput considerably. Please do not look at bench-marking sites and derive throughput conclusions. That is a controlled lab environment test report.

In contrast an 8 port GbE wired LAN switch has 1 Gbps capacity in each direction per port (same on client machines) and 16 gbps totally. This is something the Wifi gear marketing brochures conveniently hide. Bottom line is don't look at Wifi Speeds advertised on routers and client devices and compare it with wired speeds. You will be greatly disappointed if you ever try to take things to that level in real life.

- Suman Kumar Luthra @ APRC-P3 Telecom Sub-committee

What are your recommendations for LAN cabling

Technical Assessment:

Lan cables have four conductor pairs (8 wires) arranged in twisted pairs. Refer the nomenclature below for cables:

In the local market you would get 2 types of cables readily viz. cat 5e and cat6 and two cable types on demand viz. cat6a anbd cat7. Also two types of cables based on how they handle crosstalk between pairs and EMI between cables viz. shielded or unshielded. Plus you may see some non-standard grades like cat 6e/6+ etc. So which one to use ?

1. First of all avoid shielded cables (F/UTP, S/UTP, SF/UTP, F/FTP, S?FTP, ertc) of any grade. They are required in High EM environments like Hospitals, industrial environments, data centers, etc where their are lot of densly packed equipment d that *constantly* emits EM radiations. They are absolutely not required in most offices and almost all homes, unless ofcourse you are running a diagnostic lab from your home. cat7 is shielded by default and that strikes it of the list. In general only U/UTP cable (un-shielded twisted pair) should be used as they satisfy residential need completely
2. Cat 5e can do 100 mbps Ethernet till 100m and 1000 mbps (gigabit) Ethernet till 33m. Most cables  in apartment are less than this length but a few in 4 BHK/Penthouse may exceed this. this cable type cannot support the upcoming 10 gigabit Ethernet. So its better to avoid this also with an eye on future though it is just good enough as of today.
3. That leaves cat 6 UTP, 6e/6+ and cat6a.  Cat6 UTP can do gigabit Ethernet till 100m and 10GbE till 33m safely and often upto 55m based on cable quality. For 3 BHK it is probably future safe as each cable will most likely not exceed 33m.  Cat 6e/6+ (an enhancement over cat6 with 30-40% more headroom in performance parameters over cat6 UTP) can do 10 GbE upto 55m safely (perhaps slightly more). So is safer for large 4 BHks and penthouses. The price difference of cat6 compared to cat 5e is no more than 20-30%., while cat 6e/6+ will cost you 20% extra over regular Cat6 UTP
4. Cat 6a UTP cable is rare in market and is considerably thicker (i.5 times the diameter & and more stiffer) than Cat 6 UTP. This posses significant challenges in laying the cables as thgicker conduits are required with better bend radius. In US the costs are 20-35% more than cat 6 UTP, but in india, its more than 2 times costly (possibly a consequence of no local manufacturing and only import). As of 2016 beginning, it makes  little sense to invest (that too for 4 BHK/PH), but this may change in future. It also seems as little overkill as cat 6a jacks and connectors are required which are almost 10 times more expensive 

The telecom committee therefore recommends cat 6e/6+ cabling for 4BHK/PH and at-least cat 6 UTP for 1/2/3 BHK  homes (better if you can go for cat 6a).  4BHK/PH can use cat 6 UTP if the wiring electrician recommends that length are lesser than 33m.

Price and Availability:

Cat 6 UTP is readily available off the counter for Rs 4500-5500 for a 305m box (based on brand) and Rs. 1700-800 for 100m box (only Dlink sells 100m box). You may but shorter lengths by paying 10-15% extra per meter from local electrical and computer shops or you can buy a box and sell remaining to others or few of owners can get together and share if lesser lengths are required. 

Cat6e/6+ retails for Rs. 6500/- to Rs. 8000/- for a 305m bundle. Its only on order, may not come in shorter lengths (less than a 305m box) and you may need to wait 1-2 weeks for delivery. Cat 6A costs 12500/- to 14500/- plus tax. It maybe available in some shops, but mostly its on order like cat 6e/6+.

Note: There are not many home applications today that demand 10 GbE (its not mass market technology for home but common in data center) and therefore prices are insane. 10 GbE port costs upto $200 per port and upwards of $1500 for switches. At-least for next 5 years their seems to be little use case of having a 10GbE LAN in residential environment. Even 4K or 8K video encoded with H.264 may not be able to stress a link more than 100 mbps. 3D does not exceed 2 times of 2D digital video (often 1.4 times only).

- Suman Kumar Luthra @ APRC-P3 Telecom Sub-Committee

I do not understand the Home network setup. Can you elaborate ?

Please refer to the illustration below:

This is a typical home network for data. make a note of these key points:

1. The ONT (analogous to modem in DSL network) which is the termination point of service provider  and gateway to home network. 
2. The ONT is connected to a Router, In most homes this is a Wifi Router and that is sufficient for the home network (no use of wired clients). 
3. Many ONTs come with integrated router functionality (single box for simplification), but it rare for such boxes to give top-notch performance as they feature entry level routers for cost optimization.
4. An  router will typically have 4 Ethernet LAN ports. So you can connect upto 4 devices directly to it.
5. In case you have a complete and comprehensive architecture as we suggest, its likely your total LAN ports exceed 4 and you need all LAN cables to terminate in a STAR point to a switch area and connected to a LAN switch. One port of this switch is then plugged into the router to give internet access to all wired devices.
6. In case you have large home, you need one or more additional APs and you could plug them into the router (or switch also ...)
7. It is not necessary to buy an install all active equipment at one go. You could just get a Broadband connection, get a a router + Modem and then add switch and AP if you need it later. But the cabling infrastructure has to be made ready in advance. 

Please note that in case you have a very simple requirement to use Wifi only for Internet (WAN access), Want to use Wireless AP instead of router, not use very high speed data plan,  and not share large amounts of data in your (W)LAN, then you can connect the switch directly to the ONT (not use Wifi/Wired router), connect the AP to the switch. In this case the ONT will create the DHCP based subnet for your home network.

Feel free to comment here or write to :

telecom[dot]aprp3association[at]gmail[dot]com or 

adarsh-pam-retreat+telecom[at]apnacomplex[dot]com

in case you have any query or need further advice/suggestion.


- Suman Kumar Luthra @ APRC-P3 Telecom  Sub-Committee

What is Wifi Mesh networking

Its just 2017 and the blog is facing any onslaught of the technology obsolesce life-cycle already. Wifi Mesh networking is emerging technology for Home networking gaining traction:

http://in.pcmag.com/eero/111441/guide/the-best-wi-fi-mesh-network-systems-of-2017

http://bgr.com/2017/02/14/best-mesh-wifi-system-2017-mesh-network-router/

It is similar (in consumer view) to a our multiple AP architecture (or even a traditional one router multiple range extender architecture), except that the APs use wireless links for Backhaul as illustrated below:

The advantages are pretty obvious. Being wireless, its drop dead easy to retrofit into existing homes where no wired networking cabling is done (just need power socket not data port). Plus the units gel well with home decor, Secondly multiple paths facilitating load balancing and redundant path for data. And thirdly their is an integration of Smart Home technologies (Zigbeee, Zwave, etc) and Consumer Wifi mesh kits which opens the Wifi Router/AP OEMs to Internet of Things (IoT) domain.

For large home, mesh networking Wifi performance sits between 

(a) Multiple-AP/Router with wired LAN backhaul

(b) Single router or Single router - Multiple Range extender

architectures. 

Eero, Luma, Orbi, Ubiquiti, Google Wifi, Plume are major mesh Wifi networking gear manufacturers who are getting a lot of attention from consumers worldwide.

- Suman Kumar Luthra @ APRC-P3 Telecom Sub-committee

What is PoE ? I have a PoE device and how do we integrate it ?

PoE stands for power over Ethernet where the same cable is used for carrying both data and DC power to power the equipment. In normal case data and power cable is separate and you may have situation where you need an IP device to be mounted but have no power outlet nearby (like CCTV camera locations).  Typically Wireless AP and IP camera (incl. CCTV) are the devices that are PoE enabled and many homes will need one or both. Then there are others like VoIP phones, Video Door phones etc that may be powered via PoE. PoE is especially useful for ceiling mounting devices (in false ceiling) or a separate housing near the ceiling. Many small switches used for extending ports are also powered by PoE

The main PoE standards comprise IEEE 802.3af (PoE) amd 802.3at (PoE+) which can supply 15.4 and 30.8W respectively over Ethernet cable to any device. Typically all IP cameras are PoE while many high end Wifi AP (with multiple antenna) may need PoE+. 

To power and use these devices the LAN cable must run from the point of device location to a star point, just as any other data point. At the star point you either need to connect to on of:

(1) PoE/PoE+ Injector per PoE port, the data port of which is connected to LAN switch and Power adapter cable to an AC plug source.
(2) PoE/PoE+ Mid-span Injector - This is an array of PoE injectors (used especially in CCTV applications) to provide a lot of PoE ports without creating the cabling mess that accompanies each POE injector (3 cables). Generally these are rack mount devices.  They may come in 8, 16, 24 or 48 port capacities mirroring the ports typical;ly found on LAN switches.

(3) Separate PoE/PoE+ switch one port of which is connected to your LAN switch/router and all other ports provide active (auto-sensing) PoE output

You may familiarize yourself with these devices through the following video:

NOTE: It is extremely important to ensure that the Power grade of PoE device (i.e PoE or PoE+) must match the capability  of injector and switch, otherwise it may fail to provide sufficient power to power the equipment. You should also ensure that the injector and device support same standard. For eg., 24V and 48V non-802.3af compliant injectors are also used by some vendors like Ubiquiti and Cisco for their APs. Similarly there would be other incompatibilities like fast Ethernet or gigabit Ethernet power injection, active or passive injection etc.


- Suman Kumar Luthra @ APRC-P3 Telecom Sub-Committee

Should i buy a PoE or PoE+ switch

First its important to note that a POE (802.3af complaint) switch should be able to supply upto 15.4W per port  while a POE+ (802.3at compliant)  switch can supply 30.8W of power per port. A good switch should be able to supply almost near to a multiple of these power ratings for as many PoE ports they feature.

Second most devices that work on PoE like IP camera, Video phone, IP Phone, small extension switch and common AP needs only PoE and not PoE+. Only very high end AP (with multiple antennas and radios plus high end CPU)  or high end PTZ camera (which anyways are gross overkill for home use) will need PoE+. This is as things stand today (2016 beginning)

So the recommendation is that once you have decided to go for a switch buy the cheaper and more commonly available PoE switch and if you run into a device which needs PoE+ in near future, just use the supplied PoE+ injector or buy one.


- Suman Kumar Luthra @ APRC-P3 Telecom Sub-Committee

I am confused on whether should buy a PoE switch or injector.

Please use the following principles:

1. If you have 1/2 PoE device you are better off buying PoE/PoE+ injector and connect them to your router or LAN switch (least cost and manageable cable mess)
2. If you have 3/4 PoE device, it is better you buy an 8-Port  PoE switch with 4 PoE Ports and 4 non-PoE ports.  Please make sure of switch data speed (100 mbps/1000 mbps) matching
3. If you have more than 4 PoE devices or are planning to have them soon, please go ahead an buy an 8-port PoE/PoE+ switch. They are expensive starting Rs. 7000 (Digisol) to about Rs. 16000 (Cisco) based on brand
4. If you are in greenfield mode and setting everything up, you can try to buy a switch that has 4 PoE ports and 4-20 standard Ethernet ports. 

Their is also the Midspan injector device,. You should buy that (its a little hard to find in market in India) if you need a lot of PoE/PoE+ ports and already have an existing investment in a large capacity non-PoE LAN switch

PoE (802.3af) is expensive and you pay for the simplicity of having only one wire carry both data and DC power. If PoE was not there you have the additional headache of providing power point near to device mount location or running a 2 pair electrical wire safely to that location. what's worse is that  PoE+ (802.3at)  is rarer. 

WARNING: A lot of PoE devices are not compliant to 802.3af or 802.3 at. So while buying the device make sure the device and injector/switch are supporting same power standard. Very frequently when good brands go for deviations (Ubiquity/Cisco) from 802.3af/at, they also supply their power injectors along with the device. Make sure yoiu use them and not plug them into a PoE/PoE+ switch/injector.midspan.

- Suman Kumar Luthra @ APRC-P3 Telecom Sub-Committee

Why the builder has left networking cables handling from wall outlets and can this be fixed ?

Its most probably a cost cutting measure from the builder to skimp on the communication wiring. Though the common reason given by engineers is that if they put wall sockets it causes attenuation and degrades performances. 

The Telecom sub-committee has tested Ethernet cables (transfer rate) with multiple keystone jack connectors (two) introduced in a single patch chord and found that their is some truth in the attenuation argument (you can read on the internet) but no truth in the conclusion that it degrades performance (we found a drop of 0.015% only which is to be ignored as measurement error). Wall jacks, patch panels, etc are widely used in enterprise and data center which are much more sensitive to performance unlike home network and hence their is another way of validating our assertion and test result as opposed to the builder's argument.

Anyways, we should fix this. the electrical outlet system is Legrand Arteor in the project. Legrand Arteor has Cat 5e/Cat6 UTP modules available readily in local market, along with flush metal boxes and faceplates. Please get them as per  the number of open data point outlets and get them sealed like any other electrical outlet. You may do the same for switch side also or buy 19" inch rack with patch panel to cover the switch area (in the same rack depending on size, you may put a switch, router, NAS, UPS etc).


- Suman Kumar Luthra @ APRC-P3 Telecom Sub-Committee

Are their ways of improving wifi coverage and speed without using a wired LAN and multiple access points ?

Technology Perspective:
Wifi was designed to be great at sharing an internet connection between multiple, never as a substitute for Wired LAN at exchanging data between two devices in the same network. With xDSL speeds in India evolving slowly from 2mbps to about 16 mbps (2 MB/s), Wifi speeds were just sufficient enough for sharing an internet connection and as a bridge to wired fixed like Broadband.

With FTTx (Fiber Optics), the broadband speeds have jumped to 20mbps, 30 mbps, 60 mbps, 100 mbps and even 1 Gbps in some cities. This has suddenly created 5-50 times speed jump for internet access speeds. Wifi simply could not evolve that fast [Its typically 3X with each technology (a, b, g, n, ac) change]. So today Wifi speed is a bottleneck for getting high speed broadband access from any *single* device.


Requirement:

In APR, Broadband speeds have reached 100 mbps and in many other parts on India 1 Gbps broadband is being offered uin under Rs. 3000 per month. So WAN to LAN connectivity max speed is 120 mbps to 1 Gbps today. If any wifi device wants to tap into this speed the wifi link must also support a throughput of at at-least 100 mbps today and possibly 1 Gbps or more in the near future,

Limitation:

We have not seem any router and client combination that can do such speeds on wireless network. So at this point of time, trying to bridge the Wireless wired speed gap is an exercise in vain. Wifi started (with 11 mbps and 54 mbps speed) as a good technology for sharing Internet connection (mostly narrow-band or early xDSL broadband implementations) between multiple device and the home. It never was great at sharing lot of data quickly between two devices, just simple to use. But Today Wireline Broadband (primarily due to FTTx) has far outpaced even the fastest throughput that Wifi can offer and therefore it is no longer by itself a great choice for sharing a high speed wireline internet connection. 

Temporary Solutions:

Some options do exist on how to improve wifi coverage and speed and are reported to work well sometimes doubling the speeds. They are:

1. Check if your router's antenna can be replaced by High gain omni-directional antennas (5dB, 8 dB, or higher) especially if your devices are placed at longer distance from router. Make sure your router supports this and then buy only compatible model. High gain antennas work surely for outdoor Wifi at great lengths if you have line of sight between device and AP/Router
2. Use of directional antenna (incl. Yagi antenna) to replace your router's antenna if signal is weak in on edirection
3. Use hacks like these below:
1. https://www.youtube.com/watch?v=ED5vl6IYto0
2. https://www.youtube.com/watch?v=lG5cEik2ABY 
3. https://www.youtube.com/watch?v=mYr0PCbLSHk
4. Use a Wifi Repeater or range extender. The repeater has to be placed somewhere we you get a good signal rather than somewhere where your signal strength is poor, so that it can extend the good signal to the area where it is poor. They come in Rs. 1000-3000 range and many Wireless router/AP can also be configured as range extenders. Please however note that the range extender will half the speed available at the place point point. 

But the MOST IMPORTANT TRICKs that will do 90% of the job will be to

• Try to put your router/AP in a central location or closer to where high speed access happens AFAP. It is not the default location provided by builder therefore, unfortunately needs cabling modifications
• Try to mount your router/AP near the ceiling with antennas facing downwards rather than conventional deployment where we place router on a raised platform on the floor. This is useful as devices face less attenuation from household objects in top to down direction and many clients will get LOS to router/AP. But again this needs wiring changes

Long term (possibly Permanent) solution:
Refer this Q&A (http://home-network-aprc-p3.blogspot.in/2015/10/what-is-future-of-wifi-technology-and.html)


- Suman Kumar Luthra @ APRC-P3 Telecom Sub-Committee

Why do we need UPS for Internet connection and how to integrate it ?

Current Deployment Situation:

In APR Phase III Condominiums, the current plan is to get intercom and Broadband over FTTH only. We decided to drop xDSL completely because of the extreme asymmetry in upload and download speeds. Refer below URL for my 8 mbps Airtel Broadband performance:

 http://www.speedtest.net/my-result/a/1558822516

With FTTH we usually get half the download speed as upload speed. Also intercom and voice as per current plan will also be delivered using FTTH. So for these services an ONT device will either be placed inside home or in the shaft and from which CATV, cat6 and telephone patch chords (cable)  will be drawn. 

Requirement:

When utility power fails, we want to have intercom continuity (if it fails it may take 5-15 min to get enabled after power comes back). Also most subscribers would want Broadband to continue so that their online sessions on video, chat, browsing, sync etc are not aborted suddenly due to networking failure.  The facility has DG power backup and the power would come back in 5-60 seconds anyways, but we still need to protect against the short sub-minute outage. Which means the ONT, Router, switch etc must be put on UPS backup which can support 1 min standby time. If the service provider puts shared ONT in shaft he will provide batter y backup for it. But if teh ONT is inside your home, then you need to take care of it. 

Concrete Solution:

Their are two ways to proceed on this:

1. Ensure that the ONT, Router, Switch etc are in one place (preferably in a nice rack unit) and connected to an offline UPS like APC back-UPS Model No. APC BX600CI-IN (available for Rs 2000-2200 locally) and turn the battery saver mode off if outages are longer than 1 min. We have verified that this can support upto 1 hour backup for low power device and will solve the issue for 90% plus of the residents. It has also supports Automatic Voltage Regulation (AVR) and Surge Protection when on utility mode and is the best bang for buck as far as UPSes go ...
2. A few residents want clean power for *ALL* their sensitive electronic device and deploy online (double conversion), Offline or Line interactive UPS at a phase level by connecting a high capacity UPS (2-3 KVA) to main Distribution box of flat.  This is also a very good (albeit expensive solution) but will ensure your TV, fan, LED lights, one refrigerator, etc which is put on one phase can continue to operate whenever power fails apart from just your communication equipment. besides protecting them from surges and over-voltages.

Feel free to write to telecom[dot]aprp3association[at]gmail[dot]com if you need more clarifications/details. 

- Suman Kumar Luthra @ APRC-P3 Telecom Sub-Committee

Which Wifi Router I should buy ?

This is a very hard question to answer as everyone's needs are different. And there are so many types of consumer products available in market from  prices starting Rs. 800/- to Rs. 30,000/- while enterprise ones go from $500-$1300 USD. Besides their is a huge gap between the promised theoretical speed labels on the packing box and what is practically achievable when deployed.

Here are some grades of Routers/APs based on application domain:

(1) Consumer Grade  - Belkin, Tp_link, Dlink, Asus, Linksys, tenda etc (FROM $20-$400)
(2) SOHO/SMB Grade - Ubiquiti (Typically $100- $200) - The best option for advanced users
(3) Enterprise Grade - Cisco/Meraki, HP/Aruba ($500-$1000) - Only for offices and workplaces with high density of WiFi Users
(4) Carrier Grade - Ruckus Wireless ($1000+). Suitable for WiFi Hotspots deployed by fixed line carriers

(3) and (4)  offer enterprise features which most users do not need, are hard to configure and therefore these routers are an overkill for the home environment besides being ridiculously expensive. Even though some of the radio performance and technology in them is extremely suitable to high density scene like apartment.  Therefore home users must straddle the lines in (1) and (2) based on what their needs are.

 Let see some evaluation criteria and then they to make a decision (sorry I cannot cut a long story short on this one):

Router capability (Speed label and Antennas):

Refer the illustration below:

802.11g (obsolete) used to support 1 antenna and work at a peak theoretical speed of 54 mbps.

802.11n (mature) supports 3 antennas and can work at 450 mbps max (with all 3 antennas)

802.11ac (emerging) supports 8 antennas max. With each antenna it can do upto 450 mbps per antenna (commonly its 3 and 1350 mbps). Or 3 times 802.11n

The above are all theoretical speeds, Real world we can get at max (varies from deployment to deployment greatly based on interference from neighbor) about 30MB/s (or 240 mbps) and 90 MB/s  (or 720 mbps) with a 3 antenna configuration. 

Most important to note is that the above speeds are cumulative for the router not per client. So to really tap  this speed a client must have the max. no of antennas. If their are two clients with max. no of antennas then speed of each is half of above, if 4 then its just one fourth (and if all are operated simultaneously).

Client Capability:

Lets see the client antenna situation on various devices:

• WiFi USB Dongle - Typically 1 or 2 antennas
• Smartphone - Typically 1 antenna to improve battery life and save space.
• Tablet (iPad) - Frequently 2 Antennas
• Laptops - Frequently 2 antennas (3 on desktop replacements)
• PCI card on PC - 1-4 antennas depending on the model you buy

What this means is that if your client has N antennas then it can reach only 54, Nx150, Nx450 mbps speed (with 802.11g, n and ac respectively) theoretically (or 1/3rd of that in real life). 

So if you have a 802.11ac smartphone (likely with one antenna), you will not exceed 30 MB/s transfer rate in real life. With 802.11n this would be capped to 10 MB/s


Additional features:
USB ports (for connecting Hard disk/pendrive, Dual WAN, Media servers, Print serever etc. These are needs of a few power users and for those few these decisions can come after you have settled on an option based on client & router speed

To summarize, do as under:

1. Skip 802.11g altogether. Technology is obsolete. all 802.11n and 802.11ac have backward compatibility with 802.11g, so that  takes care of older devices
2. Based on the type of client support you have and their number go for either 802.11n or 802.11ac (remember that ac routers are expensive while n routers are very cheap). 
3. Their is little using buying 802.11ac router when you have no 802.11ac client. You might consider a replacement when you have those clients and need the faster speed absolutely (not that feature is by default). With time both clients and router prices will drop (every 6 months or so as new models emerge)
4. If you are small family its unlikely you will be having more than 2-3 simultaneous clients downloading data using though many more many connect and therefore you do not need more than 1 or 2 antenna device.
5. Then of-course your need for extra value added features (USB drive, Media server, Printer etc)

For most people the heaviest bandwidth applications is to watch 1080p HD video streams and that requires no more than 10 mbps (little  1.25 MB/s) even with 3D. At max two such streams will be played in home simultaneously and therefore 20 Mbps is the max speed one needs from Wifi (and Broadband connection too ...). Therefore I generally believe a 2-antenna 802.11n router [eg. TP-Link TL-WR841N or TP-Link TL-WR841(N/HP)]  is the best bet for most of the homes. Anything more is luxury or just for bragging rights.

Personally I have a small family of two adults and one kid, with max two devices being used at a time have a Rs. 800 1-antenna 802.11n router and a Rs. 17000/- 3-antenna 802.11ac one,  and I am equally happy with the Rs. 800/- one. That's what made motivated me write this post to prevent others from unnecessarily blowing their wallet in a heavily depreciating asset.

- Suman Kumar Luthra @ APRC-P3 Telecom Sub-Committee