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Making Wireless, Not Ethernet, the Heart of the Network
GMGruman writes "As mobile devices enter the workplace and latch on to Wi-Fi networks — along with devices such as HVAC sensors and videoconferencing that most people don't even realize use Wi-Fi — the typical wireless LAN is unable to cope. What needs to happen, argues Aberdeen Group's Andrew Borg, is a rethink of the wireless LAN not as a casual adjunct to the wired LAN (the typical mentality when they were first set up) but as the corporate LAN itself."
So what? What is relevant is what those devices are doing. Anyone who needs to pull boatloads of data needs to sit the hell down, and at that point, you can serve them with a wire.
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
High latency, low throughput, and a shared collision domain.
What's not to like?
Ye cannae change the laws of physics!
Seriously, though... wireless has serious inherent disadvantages. Susceptibility to interference, a single collision domain, much lower bandwidth in the analog sense. It's good for mobility, but if you try to run a whole site-LAN on wireless it just wouldn't work - even if you utilised the 800MHz, 2.4GHZ and 5.0GHz bands all at once. Maybe if you put little 60GHz nodes in every room, but it'd be far too expensive.
One of the advantages of a wired network is that the data only leaves the premises at well defined locations that you control. With wireless networks it floats over the aether in all directions. And before you can say "encryption will protect me", think about how easy it would be to build a transmitter running on the same frequencies as the wireless network and sit that just outside the company and pointed inwards - instant denial of service attack with zero traceability.
I am Slashdot. Are you Slashdot as well?
Printers? Video surveillance? HVAC? Electric meters? Why are these things using WiFi, when they rarely move and are always plugged into an external power source?
Palm trees and 8
These are the three things that WiFi still can't compete in against a wired network.
Even the most secure wireless is still much more susceptible to attack then a wired network. Even with the most modern access control and protection methods (which are neither cheap nor convenient) the sheer massive avenue of attack WiFi presents creates a problem for many large corporations. Ask JPMorgan Chase how much WiFi connectivity they have. Or pretty much any US Government building.
Even if you do as the article suggests and call in an expensive contractor to map out the best locations for access points, you have to find out if it's even feasible to run network and power to that location. Even with the best-possible placement you are going to have dead zones, and the size and location of dead zones will vary depending on the devices used. My Toshiba laptop got service in places a virtually identical Macbook did not- let alone the poor wireless reception most mobile phones and devices provide. So you have to deal with irate users, and try to find places to install additional access points to cover the dropped zones.
When I worked for a small non-profit K-12 school, during teacher inservice days I always had to install 2 additional access points in the gym so that the teachers could all connect on their laptops, as the single AP currently serving the gym was not sufficient. Even then, transferring any large file from the server or online either brought the network to a standstill or required tethering each machine to an ethernet cord to do the transfer. Most high-tech oriented conferences, the wireless is all but useless if it's available publicly, due to the hundreds of devices all connecting within a limited frequency space and bandwidth. There is just not enough bandwidth in a small space available to deal with more then a handful of data-rich connections. Spread across multiple spheres of AP reception the problem is reduced, but not eliminated! My bedroom is WiFi-connected only due to wiring constraints and connecting from my laptop to my server via VNC or to copy files is very... very... slow. And really, try having a LAN party over wireless- I can run hundreds or thousands of network cables through a small room and connect everything I need for nearly any project or task inexpensively, and know that the network will be robust. Working with WiFi in anything other then a solo arrangement is a lesson in frustration.
TL;DR - Until security protocol and access control methods are more robust and available; until tools to design, implement, and test wireless networks are more plentiful and robust; and until bandwidth availability is not on par with but exceeds that of standard CAT5- wireless is but an adjunct, a convenient add-on to the main structure of a wired network in a business. ... err, not that I'm impassioned about it, or anything.
What needs to happen, argues Aberdeen Group's Andrew Borg
So a Borg is giving suggestions as to how Earth's networks are to be set up?
Careful now, people.
The three laws of thermodynamics:(1) You can't win. (2) You can't break even. (3) You can't even quit.
The limitations of a shared medium preclude its being the "core" of any LAN that is actually seeing sustained use.
History (skip if tl;dr)
Ethernet, as originaly designed by Digital, Intel, and Xerox (DIX) was a shared medium. Transceivers sat on very think cable with vampire-taps piercing the cable to provide station connections. That is 10Base5. (10Mbps, 500meter max length). An improvement in technology allowed switching to 75ohm coaxial cable with BNC connectors, three-way connectors instead of vampire taps, and allowed four repeaters instead of the previous two. (10Base2 was commonly called Thinnet, as the coax cable was much thinner than its predecessor.)
Both of those are shared-media. That means every station receives every other station's transmissions. It's half-duplex in that only one side can transmit in any one time. The concept of "Collisions" and collision-backoff intervals were employed to minimize multiple stations transmitting at the same time.
With the advents of twisted-wire Ethernet (10Base-T) and having stations "home run" to a master repeater, this didn't change much other than the way in which cable was laid. HOWEVER, it prepared the ground for the existence of "smart repeaters" which would "learn" where each Ethernet MAC address was, and only forward frames to the right ports. This switching capacity led to them being called ... switches.
NON-Shared Medium comes into existence:
Switches now allow treating the network as a NON-shared medium. For example, Alice's PC can talk to Printer Bob, while Charlies PC talkes to file-server David, and neither's Ethernet frames interfere, hold up, or affect each other. That's what wired Ethernet is like in today's "modern" network.
WiFi however is a shared medium. AT THE VERY BEST it would be like going back to pre-switch days. If Alice's PC is transmitting, neither Printer Bob nor Charlie's PC or file-server David can be transmitting. Everybody queues up, and overall throughput drops by a function of the number of transmitting stations. But wait, WiFi has other issues which means it's not "at its very best." Some of these include hidden-nodes, RFI, limitation on channel-use, and adjacency issues. Additionally, most WiFi devices will transmit at the speed of the slowest station. So if you have a 802.11b node, it will slow down the 802.11g or 802.11n traffic. In other words, a WiFi network is worse than pre-switch wired networks by a significant amount.
CORE vs EDGE:
When you design a product (and a LAN is a product... it's used by everyone in the house/office/factory,etc.) a design should be based on accomplishing the goals. With LANs that's usually HIGH throughput, LOW cost, LOW errors. For that to work, the "bottlenecks" should not be in the center of this great star cluster of communication, but at the edge.
That is why the core needs to have the MOST bandwidth. (For some 100Mbps full-duplex wired is sufficient. For some of my clients 10Gbps is not enough.) The edge, where small-bandwidth devices exist (e.g. Android Phone, iPhone, Netbook, laptops) is the ideal deployment of WiFi for three reasons:
1. These devices are mobile. It makes sense they should be able to connect everywhere.
2. These devices use little bandwidth. It is unlikely they would normally saturate the wireless network.
3. These devices typically are complementary... so if a user has BOTH an Android phone AND a laptop... it's unlikely both will be using lots of data at the same time.
Ehud Gavron
Tucson AZ
P.S. "Wireless" as used her is "WiFi" which is wireless Ethernet. So it's not really "Wireless vs Ethernet" but rather "Wireless vs Wired".
Ethernet (IEEE 802.3) defines the physical layer (layer 1) and MAC layer (lower half of layer 2). Both of those are specific to wired connections.
Wifi (802.11) defines the wireless physical layer and MAC layer. Again both of those are specific to wireless connections.
The MAC layer of both were deliberately designed to have similar frame formats, but they are most definitely not the same. You cannot simply emit a WIFI frame on Ethernet and expect it to work.
Both utilize the same LLC layer (upper half of layer 2) specified in (IEEE 802.2).
So, no Ethernet is not a Layer 2 technology, and it most definitely implies a wired connection.
Stylish sheet to fix many problems in Slashdot's D3: https://gist.github.com/801524
4 years ago I've helped to manage a mesh WiFi network for a fairly large enterprise. It covered a large building with about 1000 people working simultaneously. It was first intended as a temporary network (they had to relocate quickly, because of a fire in their old building). But it worked well enough to become the main network.
Keys to success: low-power APs with WDS, and gigabit Ethernet trunks + switches with STP. We used WPA with pre-shared password for wireless security and then IPSec for IP-level security (it was used with the wired network earlier so no setup was required).
As far as I remember, an average access point served about 15 clients. We manually set all the access points to the lowest possible power level, but apart from that we did no additional setup.