In my last blog on 5 GHz spectrum, I discussed the recent FCC ruling that permitted outdoor access points to use the U-NII 1 band (5150-5250 MHz).
But the story doesn’t stop there. As mentioned last time, there are significant technical challenges to using the 5 GHz band. It is not cleared spectrum. It contains incumbent uses that are important for national security and public safety. Therefore, it is imperative that Wi-Fi not create harmful interference to these incumbent systems. Cisco will not settle for less.
On the topic of interference, a particularly interesting component of the same FCC ruling that opened the U-NII1 band for outdoor AP’s is that it also re-opened the Terminal Doppler Weather Radar (TDWR) band (channels 120, 124, 128) with new test requirements for DFS protection. Hold on, let’s backtrack a bit before diving into what this means:
What is TDWR?
In brief, Terminal Doppler Weather Radar (TDWR) “is a Doppler weather radar system used primarily for the detection of hazardous wind shear conditions, precipitation, and winds aloft on and near major airports situated in climates with great exposure to thunderstorms in the United States.” TDWR uses the frequency band from 5600-5650 MHz which is why wireless network equipment needs to be proven to “do no harm” to TDWR. If you’re curious for more information on TDWR, then please click here and/or here.
A Brief History
Many of you reading this will recall that the FCC closed the use of the TDWR band several years ago as the result of numerous reports of wireless equipment creating interference with TDWR. Read More »
Tags: 802.11, 802.11ac, access point, AP, band, bandwidth, capacity, certification, channel, co-channel, device, DFS, DFS protection, doppler, emission, emissions, equipment, FCC, Firmware, GHz, gigabit, HD, high density, interference, Mhz, operation, procedure, radar, radio, requirement, ruling, spectrum, tdwr, test, weather, wi-fi, wifi, wireless
Northern Kentucky University is among the fastest growing universities in Kentucky. It hosts over 15,000 students with about 13,000 undergraduate and 2,000 graduate students. The goal of the wireless program at NKU is to provide secure, robust and ubiquitous wireless access throughout the campus, both indoors and outdoors. This ensures that students always stay connected and feel at home. The classrooms are equipped with smart technology to ensure that the teachers can benefit from technology when collaborating with students. The IT team has blanketed the libraries, the classrooms, the dorm-rooms as well as the outdoor areas with Wi-Fi. In the previous blog in 2012, we described how the Cisco 7.5 release allows networks to recover with no client re-authentication in the rare event of your primarily wireless LAN controller goes down.
At a Glance:
Located in: the Highland Heights Kentucky
Number of students: 15,000 of which about 2000 stay in residence halls
Number of teachers/staff: 2000
# WLAN clients: Approximately 8500 concurrent clients
Access-Point Model and Units: 1200 units of AP models including AP702W, 3502, 3602, 3702, 1550 and a few older Access Points which are being phased out
Controller Model and Units: 2 Pairs of WiSM2 operating in 18.104.22.168
Switch Models: Various models 2960, 3650, 3850, 3750X and 6500
Prime Infrastructure: 1.4.2
Mobility Services Engine: 7.6
Deployment Details: We talked to Christopher Johnson, the Senior Infrastructure Systems Analyst II at Northern Kentucky University to capture some of his thoughts around their choice of this solution and the associated benefits. Read More »
Tags: 11ac, 802.11, 802.11ac, access point, AP, application, AVC, bandwidth, CCIE, client, control, controller, device, gigabit, graduate, kentucky, LAN, mobile, mobility, nku, prime, professor, re-authentication, smart, staff, student, switch, system, teacher, technology, university, video, visibility, wi-fi, wifi, wireless, WiSM2, wlan
A lot can change in 25 years. At the first Cisco Live (then known as Networkers conferences) in 1989, 200 geeks gathered for the inaugural event. Fast forward to three weeks ago, when we welcomed a whopping 25,000 attendees into the arms of our namesake, beautiful San Francisco.
We heard there was some interest in how the network performed at the show, so I wanted to share some of the interesting statistics about the network at Cisco Live! I shudder at the thought of the ancient network from 25 years ago. So here we go:
Wi-Fi Client Devices
This year we saw 30,705 unique devices, with 7000 in the theater for John Chambers’ keynote.
# of Unique Clients
# of Sessions
# of Unique Users
# of Unique APs
Avg Users per AP
Max. Concurrent Connected Wi-Fi Devices
There was a peak of 14216 concurrently connected device at SF this year.
Read More »
Tags: #CLUS, 10G, 802.11, access point, analytic, antenna, AP, application, Application Visibility and Control, attendee, AVC, catalyst, Cisco, cisco live, client, client composition, concurrent, Conference, control, controller, deploy, design, device, Gbps, Geek, GHz, HDX, High Availability, high density, infrastructure, IPv6, LAN, laptop, legacy data rate, mobile, moscone, mse, network, networkers, peak, peak throughput, phone, san francisco, show, switch, TBps, TByte, throughput, traffic, unique user, user, visibility, wifi, wireless, wlan
There’s been some speculation about the performance of the AP2700--just how good could our latest AP fly under stress? We were talking with Blake Krone and Sam Clements from the No Strings Attached Show, where they produce independent discussion and commentary on a variety of wireless equipment and technology across vendors. The idea came up that they could do an independent performance test on the Cisco Aironet AP2700. The guys received no compensation for the testing with the exception of arranging their travel out to Richfield, OH facility for the testing. We also provided 2 AP’s per person just in case they wanted to do some further testing.
Sam & Blake along with several Cisco TMEs loaded up an AP2700 with 100 real clients to see what happens. The testing was meant to be as real world as possible, so they did things like setup the clients at varying distances and angles, use a mix of 11n and 11ac clients, tested with CCO code (7.6MR2), and even factory reset and configured the controller then in front of Blake and Sam to show there’s no funny business. The idea being, if you had 100 clients, and wanted to do the testing yourself and repeat the results, you could. I don’t want to spoil the results, so head to www.nsashow.com/AP2700/ to check out the whitepaper.
Here’s a sneak peek at the client setup:
For full details as well as the results, visit www.nsashow.com/AP2700/
Tags: 11ac, 11n, 7.6MR2, 802.11, access point, angle, AP, CCO, CCO code, Cisco, client, device, distance, factory reset, nsashow, perform, setup, stress, test, white paper, wi-fi, wifi, wireless
Wi-Fi roaming is often a tumultuous subject. The crux of the issue is, with Wi-Fi the roaming decision is left to the client.
In the recent years, there have been great strides in improving Wi-Fi roaming with the creation of standards-based roaming technologies. Cisco first pioneered fast roaming many years ago with CCKM (Cisco Centralized Key Management), which was the foundation for 802.11r. 11r which was ratified by the IEEE in 2008, allows for fast roaming, even on a secure 802.1X SSID. With 802.11r it is possible to roam without disruption during a voice or video call.
While client support of 802.11r is largely lacking in the laptop space, there is large support in the smartphone realm. Apple iOS devices have supported 11r since iOS 6 (http://support.apple.com/kb/HT5535). The recent Samsung smartphones, such as the Galaxy S4, S5, and Note 3, also support 11r.
Note: Some non-802.11r clients can react adversely when connected to an 11r WLAN. The current recommendation from Cisco is to have a separate WLAN for 802.11r clients.
802.11k is another amendment from the IEEE that helps to improve roaming. 802.11k provides a whole slew of information to the client, which allows the client to understand the RF environment and make an informed roaming decision. This information can include channel load and AP neighbor lists.
11r and 11k help, however, that does not mean the infrastructure is irrelevant in the roaming picture. With the help of a model train, we did some testing to figure out just how much impact the infrastructure could have. We compared Cisco to one of our competitors, whom we will call Vendor A.
This video summarizes the results and shows the train in action, or continue reading for more details:
Read More »
Tags: 11r, 11x, 802.11, 802.11k, 802.11r, 802.11x, access point, AP, channel, channel load, client, dbm, device, infrastructure, rf, roam, roaming, roaming decision, RRM, SSID, standards, statistic, technologies, technology, transit power, video, Voice, wi-fi, wifi, wireless, wlan