Whether you are among the 8,000 attendees participating at Cisco Live Milan in-person or among our many virtual attendees catching the live web broadcast, you’ll find lots to help you with your mobility-related projects.
By Lisa Garza, Cisco Service Provider Marketing, Mobility Solutions Everything old is new again, and that’s true for voice over Wi-Fi. When Apple announced support for Wi-Fi calling on the new iPhone 6 this fall, a new hype cycle was born. In the most extreme cases some industry players are claiming the resulting death of residential licensed small cells. As in most technology introductions, the truth will unfold over time as the technology is applied in the real world. If voice over Wi-Fi were a simple panacea, then we would all Read More »
In today’s highly mobile society we try to stay as connected as we possibly can, whether that be for instant messaging, email, or keeping up with our favorite TV shows and movies. This obsession for connectivity has stressed the wireless infrastructures that are installed by many organizations. Because of this many organizations are looking to update their systems that support 802.11n technologies or even the older 802.11a/b/g standards. As a consultant it is one of my jobs to help a customer understand the new technology inside and out and make sure their networks are deployed accordingly. One of the major topics discussed when going over 802.11ac is throughput. 802.11ac brings with it a substantial jump in throughput, but there is a price to pay in order to achieve those higher data rates.
Let’s go over a basic first, in wireless technology we use a frequency, or channel, to send our signal from the client to the station (access point). Think of this channel as a lane on a highway or freeway. A single lane carries so many cars per hour. Now if we add another lane in the same direction we can carry double the amount of traffic. This is repeated for each lane that you add. 802.11n and 802.11ac both allow us to combine multiple lanes to act as a single wide lane, allowing for larger traffic to pass. These channels are reflected as 20MHz, 40MHz (2 lanes – 802.11n and 802.11ac), and 80MHz (4 lanes – 802.11ac).
Ok, so we get the hole channel concept now right? So what’s the big deal then if we start combining these channels? Channels = capacity in the wireless world. A channel only has so much bandwidth to provide, you can’t create more, it’s a very finite resource. When our goal is to support hundreds of client devices in a large university auditorium for example, we want more channels as this gives us more overall capacity. If I were to deploy a true 802.11ac network for a university in an auditorium that requires say for example 6 access points I will end up with channel reuse when I avoid DFS channels in 5GHz. The channel reuse will degrade the performance of those access points using the same channel. Now if I deploy the same 6 access points with 40MHz channels I no longer have to worry about channel reuse in that auditorium. Read More »
Today, Cisco, Aquantia, Freescale and Xilinx announced the founding of the NBase-T Alliance. Key goals of the alliance are as follows:
- Promote collaboration and dialogue for developing technology to enable speeds greater than 1Gbps on existing Category 5e and Category 6 cabling infrastructure.
- Work in conjunction with standards bodies to standardize speeds greater than 1Gbps on existing Category 5e and Category 6 cabling infrastructure.
The IEEE 802.11ac Wave 1 standard has already delivered 1 Gigabit wireless speeds to enterprise access networks. Soon, the industry will introduce 802.11ac Wave 2 products that could deliver wireless speeds up to 6.8Gbps. Similarly, products based on 802.11ad standard could deliver speeds up to 7Gbps. And the 802.11ax standard while in its formative stages has a goal to quadruple the throughput in the 5GHz band. Other emerging technologies such as Li-Fi could also facilitate access networks in the multi-gigabit range for the Internet of Everything.
Ever since the much anticipated 802.11ac standard was ratified and supported by Enterprise class access points (AP), I’ve asked myself the question that perhaps other network and Radio-Frequency (RF) engineers have: how much of the theoretical 1.3Gbps 802.11ac data-rate can I really deliver to my users and what is the overall throughput experience when I deploy at scale or in high-density (HD) scenario? On the surface, it may seem intuitive that I should allocate 80MHz to my 802.11ac radios to achieve the best throughput BUT as it turns out, this approach has limited scale and may lead to less total throughput than a smaller 40Mhz channel – so in this case; less may be more!
This is due to the fact that while in a single-cell (AP) scenario (say 5000 sq. ft) it is realistic to expect most capable devices can reach 1.3Gbps (1Mbps of throughput) with 3 spatial stream (SS) & 80MHz (e.g. MacBook Pro) and 433Mbps (300Mb/s of throughput) with 1 SS & 80MHz (e.g. iPhone 6) BUT this throughput degrades quickly in a multi-cell environment where co-channel-interference (CCI) from neighboring APs can dominate. So we need to look at the primary CCI contributors, which are: Read More »