College doubles the number of Cisco access points, gains significant performance boost
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In 2006, Santa Clara University began rolling out a Wi-Fi network as a way to supplement the school’s existing production network. The initial deployment consisted of about 800 Cisco Aironet 1131 a/b/g/ access points and Cisco WiSM controllers. As expansion or renovation projects occurred, the school added some 802.11n access points, but until recently 90% of the roughly 70 buildings on campus were equipped with the older, slower technology.
Todd Schmitzer, network and telecommunications manager at SCU, says the original Wi-Fi network was designed to provide expanded ‘convenience’ access to the campus network from academic, administrative, and residence hall locations. It was never intended as a production network or the sole mechanism for people to access the campus network. It did not cover all locations (only the common occupied spaces), did not provide for high-density use (classrooms, theaters, dining halls), or provide nearly the bandwidth of the wired network.
Over time, usage grew from 3,000 unique devices/users in 2007 to more than 15,000 unique devices/users in 2012. And at peak times, simultaneous use went from 2,000 users to more than 5,000 users. In addition, “usage has shifted from convenience to production and, in many cases; it’s now the primary network for many end users,” says Schmitzer.
The school was now facing the issue of how best to upgrade the Wi-Fi network. “We debated whether it made more sense to initially install access points with 802.11ac or install access points that could later be expanded to include the newest standards,” says Ronald Danielson, CIO and Information Services vice provost at SCU. Going with 802.11n “would initially save money, while still providing a significant boost in performance,” says Danielson.
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On the other hand, “There weren’t many mobile devices shipping with 802.11ac, but we expected that would ramp up rapidly, and that many of our clients would soon have 802.11ac-compatible devices (perhaps as soon as Christmas 2013, but certainly by 2014). Couple that with the disruption to the campus caused by having to go back out in a year or two and touch each of the installed APs to upgrade to 802.11ac, we decided that installing 802.11ac at the beginning was the right way to go.”
Schmitzer notes that they immediately decided that the new network should cover all of the campus (interior and exterior), that all locations should support the high bandwidth demands for multimedia rich communications and academic applications (including voice and two-way video). It was a requirement that both 2.4 GHz and 5 GHz radios would be used and that the design should ensure adequate coverage to provide low latency and jitter free transmission in the 5-GHz radio frequencies.
“The 802.11ac was not initially a requirement of the plan or design,” says Schmitzer, “But since 802.11ac utilizes the same frequencies as initially planned for, our design easily accommodated 802.11ac. Given our goal to install a superior and, now, primary Wi-Fi network, we felt that 802.11ac provided a significant enhancement to all our new requirements: high density use, higher bandwidth, and improved access.”
The plan calls for nearly 1,900 Cisco 3600 access points. The additional density is designed to deliver improved coverage, particularly in high-occupancy locations, like classrooms.
The school currently has about 95% of the access points installed and the entire project is expected to be completed by April.
No Deployment Issues—No Learning Curve
Schmitzer adds that the implementation of 802.11ac involved no additional requirements. SCU designed its new Wi-Fi network to support 2.4 GHz and 5 GHz radios — plus high density, high bandwidth, low jitter, and low latency — from the onset, so adding 802.11ac had negligible impact. There were some minor software/firmware issues, as expected with any newly released equipment; but no learning curve. From an end-user perspective, there is even less of a learning curve because the devices negotiate the best connection the network can provide.
Schmitzer says that during deployment of the interior upgrade, they encountered a few concerns, only one of which was technical. For example, he explains, with the higher density of access points required, equipment visibility becomes greater, so the awareness and concern of the faculty, staff, and students of potential electromagnetic radiation exposure increased. In addition, the architectural concerns, especially for outdoor placement on some of our historic buildings, have been noted, because maintaining the campus aesthetic is a high priority for SCU.
“Given that each AP can now support a significant increase in bandwidth and that the number of APs for the interior network nearly doubled, concerns have developed about network aggregation to network distribution to network core uplink capacities. We aren’t experiencing any significant issues now, but it’s an area we will be monitoring closely going forward,” adds Schmitzer.
Performance Gains & Benefits
“In our limited test of the AC access point, we have seen extensive performance improvements,” he adds. “We experienced over a five-fold improvement in bandwidth for an average laptop between the 802.11n radio and the 802.11ac radio.”
Schmitzer explains that their experience with 802.11ac performance and the metrics stated have been in test scenarios. Given the small volume of AC devices available at the time, the team conducted simulated tests, where they used standard laptops with Netgear USB 802.11ac adapters.
“As part of an early stage of our project, we wanted to understand what an AC radio would add to the performance of our wireless design, a design that was done to support 5 Ghz radios and AC,” says Schmitzer. “We designed for 802.11ac, but initially didn’t know if we were going to actually pay for 802.11ac now as part of this project. So, we did a test. These tests were done using a single 802.11 a/b/g/n Cisco 3600 AP with AC module installed (same as the model that we have deployed). This AP was temporarily added to our infrastructure.”
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“Next we ran tests using the same laptops with built-in 802.11n radios, then again, using the same laptops with an external/USB 802.11AC radio to eliminate computer hardware impacts to the performance results. The tests were done on our production network with other (non-testing) clients connected to the AP and network. The performance characteristics were gathered and compared and that is where we came up with what we expect the performance gains would be when our deployment was complete. It was not a scientific number but, we feel, it is a realistic number. We used this performance increase number to justify the expense of 802.11ac now and to communicate the upcoming upgrade to our community.”
“We connected all these devices to the wireless network where clients of various capabilities were also connected and compared traffic performance,” says Schmitzer. “However, we won’t know how things “REALLY” improved (other than the anecdotal reports of improvements from our users) until probably mid-year, when we’ll get a chance to do more testing with 802.11ac-based APs installed everywhere. Plus, one of our limiting factors, currently, is an over-utilized Internet connection (which will be upgraded this spring).”
Looking ahead
“Bandwidth is like memory — you never have enough for very long,” says Danielson. “I’m not sure the wireless standards’ process can keep up with expectations. We believe that we’ve architected our new network to provide great coverage and bandwidth across this campus, and 802.11ac is a critical part of that architecture. But I think we’ll have to continually monitor how well we are meeting expectations, and I predict we’ll be reinforcing the wireless infrastructure on campus within two years, as hotspots of use develop, and demand overwhelms capacity in localized areas. And then we’ll be tracking future standards with great interest.”
Sartain is a freelance writer. She can be reached at julesds@comcast.net.
