Ok, so maybe you are starting to give in to the idea that, employees bringing personally owned tablets at work, is indeed not a fad and you have to deal with it. You have decided on a BYOD strategy that protects company and network resources, while (mostly?) satisfying user appetite for connectivity anywhere from any device.
Great! Now. Is your 802.11n wireless network capable of delivering the user experience that is associated with these new sleek gadgets?
If you thought your network is “good enough”, then think again. This client wave is about to disrupt everything in multiple ways.
First, more devices on the network translate to significantly higher demands for bandwidth. In many cases bandwidth requirements can grow exponentially because the ratio of user to devices is no longer 1:1 but 1:2 and often 1:3. We therefore expect to see network utilization significantly rise over time.
Second, tablet form factor now allows users to truly be mobile. Unlike laptops, users can now walk/move and be productive at the same time. This new type of behavior will increase the number of clients roaming between access points.
Finally, it has been observed that tablets are primarily used for content consumption (as opposed to creation), and video is one of the predominant types of content being consumed, which further complicates bandwidth issues, but also creates new challenges.
Inclusion in some government lists may not be such a good thing… for example, the government “no fly list” could be a bummer as you board your flight on your next family vacation. Yet, other government lists can make or break you when it comes to doing business with the Federal Government. Last week, the award winning Cisco CleanAir technology was placed on the all important DoD Unified Capabilities APPROVED PRODUCT LIST (DoD UC/APL). The DoD APL happens to be the official product list that DoD agencies are required to work from when making new acquisitions for network equipment such as routers, switches, WLAN, voice, video etc. With the latest Cisco DoD APL certification, the Cisco CleanAir 3500 Series Access Point becomes the first DoD approved product that supports “built-in” system level spectrum intelligence in support of mission critical wireless networks.
In some ways, the DoD APL is like an exclusive club for a select group of IT vendors –either you are a club member or you stand outside the gate. The process to get products listed on the APL is no cakewalk. First, even before products can be considered for the APL process, the products must meet a series of stringent DoD requirements and certifications such as DISA STIGS, FIPS & Common Criteria. Next, a DoD sponsor must agree to represent the vendor’s products throughout the APL certification process. The actual certification process itself involves several months of rigorous interoperability and Information Assurance compliance testing.
One of many overlooked areas where manufacturers are finding real productifity and efficiency gains is in the Warehouse. Sure, Supply Chain Agility is key to the global recovery, but some companies are still not using the best technologies to address their business imperatives.
But we don’t try to do absolutely everything ourselves. We recognize that there are other companies out there that have the same customer-centric focus that Cisco has.
Intermec is one of those companies. Cisco has been working with Intermec for years. We have joint RFID and Barcode based solutions and many of the Intermec devices are certified as Cisco Compatible interoperability tested. I recently met up with Dan Albaum, Intermec’s Senior Director of Marketing. Dan told me that the technology continues to evolve and told me about the events Intermec had set up to spread the word.
Intermec have recently announced a refreshed product lin and is running events in various cities, some events for Intermec partners to understand the value propositions for their customers, and some aimed at customers and prospects showing how the Cisco Wireless LAN compatible devices and end points can address their business care-abouts.
Wow -- I’m impressed. We have the best folks in Cisco. I’m sure of it. The best in the industry. And I don’t just mean me (he jests)!
No, really, Cisco’s innovation is ‘on fire’ as John Chambers puts it. I’m not just saying that because I work at Cisco. I’m saying it because I meet up with folks every day at Cisco who simply impress me with their down-and-out inventiveness. It might be products, processes or business architectures. Whatever it is, I’m often left thinking we have to tell our customers about that.
Innovators -- here are just a couple I found at Cisco - more where they came from! Actually Neil Dieder, Tech Leader, and Walt Shaw, Sr. Prod. Line Mgr, both from WNBU, the Cisco Wireless Networking Business Unit.
I speak to many customers at Executive Briefings (EBCs) and they echo my sentiment. When I talk about what we’re doing in the manufacturing industry, many of them say ‘Wow, I didn’t know Cisco did that!’ Well, I guess that’s the purpose of the EBC. Bring the customer to Cisco to tell them stuff they don’t know. Add that to what they do know and, well, they’re going to make a more informed decision.
It’s hard to choose one innovation since there are so many, but since my blogs are about manufacturing, I decided to talk about something that, on the surface is not all that exciting. Wireless Networking. Been around for years right? Right. Easy-peasy, right? Wrong! Read More »
One of the key tenets of engineering is to reduce complexity, but in doing so it is important to understand the implications. While we might try to view one technology as it relates to another to help us simplify the details, it is important that we recognise how and where they differ.
Case in point.
When it comes to wireless networks, I often talk about how there are two questions I dislike being asked more than any others:
How many clients can connect to an access point?
What is the maximum range of an access point?
The reason is that I believe they are the wrong questions. They are being asked from perspective of someone trying to relate to a wireless network as if it were a wired network. What they are really asking is “how many switch ports do I need to cover this area?”
But wireless networks are not switched networks. While each connected device in a wired network has its own physical cable, and thereby its own gigabit Ethernet link, in a wireless network, every device connected to a particular access point shares the same RF spectrum, the same total available bandwidth.
For a standard access point in today’s deployments, that means a maximum total bandwidth of 144Mbps on the 2.4GHz band with a 20MHz channel and 300Mbps on the 5GHz band with a 40MHz channel using channel bonding.
But that is an over simplification.
Those aggregate bandwidths assume each client is connected at the highest available data rate. As we increase range, however, the data rate decreases, thereby reducing the overall channel utilisation. Therefore, with fewer access points, we are not just sharing a limited amount of bandwidth with more clients, but we are actually reducing the total available bandwidth.
Interference, particularly as access points cover larger areas, becomes an even greater issue. An increase in the signal to noise ratio leads to a decrease in the maximum sustainable data rate. This again reduces the overall channel utilisation. The key here is that a wireless network’s ability to not only detect, but where possible mitigate interference is critical to its ability to sustain higher data rates and maximise the total available bandwidth in each cell.
All this assumes that the wireless clients connecting to the network are even capable of supporting those high data rates.
Most smartphones on the market today support only 802.11g in the 2.4GHz band, meaning that at most they can support 54Mbps.
Newer devices, such as the iPhone 4, support 802.11n, but only in 2.4GHz, and only with a single antenna, limiting them to a single “spatial stream”—in simple terms that means the maximum data rate they can support is 72Mbps.
This applies to tablet devices as well. While the new iPad2 supports 802.11n in both the 2.4GHz and 5GHz band, it too is limited to a single spatial stream. The Cius goes one step further with support for channel bonding in 5GHz, increasing the maximum data rate to 150Mbps.
Interestingly, we are now starting to see new access points enter the market using Atheros’ first-generation silicon supporting three spatial streams. While this increases the maximum data rate in the 5GHz band to 450Mbps, as we have just seen, this will have no impact on the multitude of mobile devices given their single spatial stream limitation.
Three spatial streams represents a key milestone for the 802.11 standard, and will become increasingly important over the next 2 to 3 years as battery technology improves and wireless chipsets incorporate better power saving designs. Of course, by that time we will be looking at access points supporting four spatial streams and 600Mbps—and again, be waiting for the mobile devices to catch up.
As we look to support these many different mobile devices entering the market today along with their high bandwidth applications, clearly the two key areas we must consider in our wireless network designs are access point density to control cell sizes, and interference detection and mitigation capabilities to ensure that we maximise the channel utilisation in each cell.
And so, I’d like to propose two different questions to consider at the start of a wireless deployment:
How many different devices do you expect to connect to the wireless network?
And what are the applications that will run across the network and what are their associated bandwidth requirements?
Wireless and wired networks fundamentally differ at the physical layer. While its not necessarily important to understand the details of RF communications, it is important to understand the implications.