Popular literature on 802.11ac describes 40 MHz and 80 MHz operation (channel bonding) as doubling and quadrupling of the data rate, respectively. Every time I saw that mentioned, the following question came to my mind.
When radio transmits over 40 MHz (or 80 MHz) channel, is the total transmit power proportionally increased over 20 MHz to maintain the SNR (signal to noise ratio)? And, how is the data rate multiple with channel boding distributed over the cell?
This question nagged me like a little stone in the shoe that is impossible to ignore. My subsequent findings from the lab tests show that the popular literature is only partially true. Read on to find out why. Read more…
802.11ac, WLAN planning
Wireless packet capture has always been important to Wi-Fi professionals and support engineers for resolving network problems. With the diversity of wireless clients that is already around and which is only expected to grow with the Internet of Things (IoT), packet capture capabilities will continue to be critical. Wireless packet capture can be facilitated in the AP radios using the hardware and the driver level hooks. Read on to find out what’s under the hood.
There are two main plumbing points to get frames from wireless up to the application: one in the hardware and the other in the driver software. At the hardware level, the radio supports “Promiscuous Mode” option. When this option is activated, the hardware passes all wireless frames received on the channel where the radio is operating up towards the driver software. When this option is deactivated, the hardware passes only the wireless frames for the MAC of the radio (and the frames like probe requests & beacons based on the additional sub-settings under non-Promiscuous mode) up towards the driver software.
The driver software can operate in AP, STA, or Monitor Mode.
There is large and ever increasing assortment of enterprise access points offered by wireless vendors today. APs have different number of radios, number of streams, 11n/11ac, POE compatibility, peripherals, price, etc. While this diversity is overwhelming, have you wondered what lies in the hardware guts of these APs? What are the hardware design concepts that are responsible for rendering feature personality to the AP? How does the hardware ecosystem work among chip vendors, ODMs and AP vendors? What are state of the art hardware architectures for the 802.11ac APs? This blog post discusses key hardware concepts, such as SoC, dedicated CPU and offload architectures that are commonly found inside the APs, along with the ODM sourcing model for the Wi-Fi APs and its implications for product offerings.
What a great start to year on the industry events front – we started with NRF in January, looking forward to HIMSS and our ACTS event in February, and MURTEC in March. In NRF, high points of discussion were around Social Wi-Fi and analytics. That said, topics of security and PCI compliance were also high on the agenda prompted by the Target credit card breach that occurred just before NRF. I expect to there will be a lot of security discussions at HIMSS too.
Healthcare, Wi-Fi and HIPAA
The Health Insurance Portability and Accountability Act (HIPAA) was passed by Congress in 1996. It is enforced by the Department of Health and Human Services (HHS), and implemented by regulations of 45 CFR. Among other provisions it has rules mandating that healthcare organizations safeguard the privacy and security of patient health information.
Healthcare, WiFi Access
Netgear recently announced integration with Facebook on their APs using Facebook Wi-Fi API. Meraki and Cisco have also announced the same capability on their APs. Facebook Wi-Fi franchise is growing. It is easy to configure and get working (except when used on Cisco APs, which requires running separate CMX VM and per-AP license). That is good news for local businesses. However, does this architecture meet the requirements of mid-size to big retail enterprises? Not so fast! Let me explain.
Retail enterprises operate multiple stores across regions, states or countries. They run targeted marketing campaigns for customer engagement. This puts certain requirements on Social/Wi-Fi integration for retail enterprises, which are currently unmet with Facebook Wi-Fi integration.
1) Omni-channel marketing is essential for maximum reach
Facebook Wi-Fi allows only Facebook logins, obviously. So merchants miss out on other social channels like Twitter, Google+, Linkedin, Foursquare, etc. In addition to social logins, enterprises also want to promote brand loyalty programs when users access guest Wi-Fi. Facebook Wi-Fi does not allow this as well.
Did 2013 have to end with the somber news of a big credit card security breach? But it did! It is reported that 40 million credit cards were compromised in the security breach in stores of a major U.S. retailer Target. This is only a shade second to the earlier TJX breach in which 45 million credit cards were compromised. (After this blog was published, it was reported that the number of affected accounts in the Target breach is as high as 110 million, which would make it more that double the TJX breach!)
After any breach, and surely after the breach of such dimension, discussion on the data security issues at the retailers escalates. Earlier, the TJX breach resulted in stricter wireless PCI (Payment Card Industry) compliance requirements. The current Target breach can also trigger tightening of the compliance requirements. This breach may also prompt IT, security and compliance managers at major retailers to take a hard look at the information security aspects of the various technologies that they have deployed. Add to it the fact that retailers are aggressively deploying mobile and wireless technologies like POS, kiosks and tablets in stores. What are some of the core issues they should be looking at?
Compliance, PCI, Retail
Wi-Fi is installed after everything else in the network is already set up – switches, routers, servers, firewalls, VPNs etc. Naturally, customers rely on their Wi-Fi solution provider to alleviate any network problems that arise during the Wi-Fi deployments, even though the problems are not necessarily Wi-Fi specific.
Need Wi-Fi troubleshooting? Call up a networking Jedi!
Network issues aren’t something new in any project. However, the troubleshooting task becomes challenging when it needs to be done remotely and when there isn’t much onsite IT help. This is often the case with the distributed Wi-Fi deployments. Also, due to the heterogeneity of the network infrastructure in many environments in the distributed vertical, sometimes very stealthy network problems are encountered. Take these recent troubleshooting examples which underscore these points.
802.11ac has brought with it MIMO alphabet soup … spatial streams, space-time streams, explicit beam forming, CSD, MU-MIMO. Alphabet soup triggers questions to which curious mind seeks answers. This post is an attempt to explore some questions surrounding explicit beam forming (E-BF) that is available in Wave-1 of 802.11ac. E-BF is a mechanism to manipulate transmissions on multiple antennas to facilitate SNR boosting at the target client.
How is E-BF related to spatial streams?
E-BF is a technique different from spatial streams. E-BF can be used whenever there are multiple antennas on the transmitter, irrespective of the number of spatial streams used for transmission.
Mature cloud Wi-Fi offerings have gone through few phases already. They started with bare-bones device configuration from the cloud console and over the years matured into meaty management plane for complete Wi-Fi access, security and complementary services in the cloud.
Alongside these phases of evolution, optimizing the cost of operation of the cloud backend has always been important consideration. It is critical for cloud operators and Managed Service Providers (MSPs). This cost dictates what end users pay for cloud Wi-Fi services and whether attractive pricing models (like AirTight’s Opex-only model) can be viable in the long run. It is also important to the bottom line of the cloud operator/MSP.
Posed with the cost question, one would impulsively say that cost is driven by the capacity in terms of number of APs that can be managed from a staple of compute resource in the cloud. That is an important cost contributor, but not the only one!
In earlier blog posts on 802.11ac practical considerations, we reviewed 80 MHz channels, 256 QAM and 5 GHz migration. Continuing the 802.11ac insights series, in this post we will look at some practical aspects of MU-MIMO, which is the star attraction of the impending Wave-2 of 802.11ac.
MU-MIMO mechanics and 802.11ac standard
Illustration of 802.11ac MU-MIMO
At a high level, MU-MIMO allows AP with multiple antennas to concurrently transmit frames to multiple clients, when each of the multiple clients has lesser antennas than AP. For example, AP with 4 antennas can use 2-stream transmission to a client which has 2 antennas and 1-stream transmission to a client which has 1 antenna, simultaneously. Implicit requirement to attain such concurrent transmission is beamforming, which has to ensure that bits of the first client coherently combine at its location, while bits of the second client do the same at the second client location. It is also important to ensure that bits of the first client form null beam at the location of the second client and vice versa.