Today's iOS 7 downloads an unprecedented challenge for IT

Updating Apple's OS and apps, managing bandwidth, app glitches all on menu

When iOS 7 becomes available today it will be an unprecedented challenge for enterprise IT groups: hundreds, or thousands, of iPhone and iPad users will be ready and oh-so-willing to download over the air the expected 130MB file at once.

As iOS matures, and more and more iPhones and iPads proliferate in the enterprise, IT groups are rethinking how to cope with what is now a vendor- and user-driven process for the dominant mobile platform.

The most pressing concern for some companies will be the expected surge in bandwidth demand once users are alerted to iOS 7 being available, expected at 1 p.m. EDT. A variety of vendors and users say they’re not expecting problems on the local networks, including the wireless LAN. But companies that lack a caching arrangement could find that their WAN connection clogs up and bogs down.

IOS 6 was a 130MB file and it’s expected that iOS 7 will be at least that size. In addition, at least some apps will have been updated for the new OS. According to data collected by Cisco, the average iOS app size is 23MB, almost as large as the average Windows application. Clearly that covers a very wide range of actual app file sizes. Cisco cites data from Nielsen showing that the average number of apps per iOS device is 41.

[ALSO: The best new features of iOS 7]

Multiply that by the number of iOS devices per user on the corporate network and you’re looking at a lot of data being shifted in a relatively small time frame. Cisco has calculated what it calls the “network tax” created by software updates. For the fourth generation iPad, and assuming 4GB of “business user traffic” per month, Cisco estimates that the iPad network tax is nearly 638MB per month, or 16 percent of the monthly total. Clearly that’s an average, not a hard and fast number every month: the OS updates are once or twice per year. App updates are more frequent, on average accounting for 8 percent of the “tax.” The other contributors are iCloud backup, and iCloud sync between Apple devices.

The impact of iOS 7 is likely to be greater this year because of increased penetration of the iPhone and iPad in the enterprise. Software vendor JAMF, for example, has about 225 employees, all of them with either a MacBook Pro or MacBook Air. But each one also has an iPad, either full-size or mini, and almost all of them have iPhones. All told, 225 people account for about 750 devices under management, the majority of them iOS devices, according to Jason Wudi, JAMF’s chief cultural officer.

Caching is a way to minimize the tax on the enterprise WAN connection. Cisco’s Integrated Services Routers have modules for caching the iOS 7 download on a hard disk in response to the first user request for it, says Chris Spain, vice president of product management for Cisco’s wireless business unit. Every additional employee iOS 7 update is handled locally by the cache over the LAN and WLAN.

Apple iOS devices are not alone in inflating these bandwidth demands. Spain points out that the Google Chromebook laptops automatically check for a firmware update every time they boot up. For a school or university deploying Chromebooks, that amounts to hundreds or even thousands of megabytes.

JAMF itself will be using Apple’s own caching service via OS X, Apple’s desktop and server operating system. The pending OS X Mavericks server release, version 10.9 will offer expanded use of Caching Server. Previously, only Mac App Store updates could be mirrored. Mavericks extends this to iOS 7 devices. Computerworld columnist Ryan Faas, in his detailed walk-through of the Mavericks release, says Apple apparently also will support hosting apps as well as updates. “That will be a powerful addition to any app management system that Apple offers,” he says.

But the potential challenges are not only to the network. Unlike with past corporate standards like BlackBerry phones and Microsoft Windows laptops, corporate IT lacks the power to control or even defer iOS downloads. Users receive an alert on their iPhone or iPad that the new OS is available and can choose to download it right then. And the same goes with apps.

Cisco, other WLAN vendors, as well as MDM vendors are adding applications to give IT groups much greater visibility into these traffic patterns, down to the application level.

“We have seen in the past that within three days of availability, more than 50 percent of the [enterprise] users have upgraded,” says Thomas Lippert, senior product manager for mobile, at Sophos, a mobile device management (MDM) vendor. “Enterprise IT needs to live with that and prepare itself.”

In a separate study, app management vendor Crittercism found that 80 percent of all iOS users upgrade within three months.

Radically redesigned, iOS 7 is the biggest change to the iPhone and iPad user interface since the firmware was introduced in mid-2007 on the first iPhone.

“From the testing we have done with iOS pre-release software, most enterprise-related IOS functions should continue to work,” says Matt Vlasach, director of mobile products, Unwired Revolution. “Core iOS enterprise capabilities, such as Mail, Contacts, and Calendars via Exchange Active Sync, appear to be stable. But as we have seen with previous iOS releases, even minor ones, there may be hidden bugs in the code or environmental-specific issues that may impact service availability to end-users.”

There’s been a realization that more testing in advance of the release is increasingly important. Many IT groups have joined Apple’s developer program to gain access to the iOS 7 beta releases since June, when it was unveiled at Apple’s Worldwide Developer Conference. They’ve been testing the OS and apps on existing hardware, sometimes taking advantage of Apple’s “golden master” release to run a complete final test.

“Unless IT has been testing their enterprise apps on pre-release iOS 7 devices, and updating accordingly, app functionality is a toss-up once the user upgrades,” Vlasach says.

One solution: Simply tell your users to delay their update until IT has fully vetted and approved the new firmware and the critical enterprise apps that rely on it. “This is actually surprisingly effective to keep the majority of enterprise users from upgrading, especially when the potential for downtime is made clear,” Vlasach says.

Some apps need to be rewritten to support the 64-bit processor, and iOS implementation, introduced in the iPhone 5S. Cisco, for example, is rewriting its AnyConnect VPN client for iPhone 5S for that reason. But it’s also warning employees that AnyConnect will not work on devices that upgrade to iOS 7 because “Apple changed the way VPN works” in the new release. Employees are being required to manually launch the VPN connection from within the AnyConnect client.

As a result, Cisco IT currently warns employees “There are some known issues, so at this time we do not recommend upgrading to iOS 7.”

The extensive changes to iOS 7 extend to the underlying OS frameworks that apps rely on. It’s possible these changes, if undetected by pre-testing review, could cause problems, “ranging from minor UI glitches to complete app crashes,” says Unwired Revolution’s Matt Vlasach.

Enterprises have been testing updated applications from their mobile device management vendors, who have been racing to fully support iOS 7 on day one of its availability. JAMF Software’s Casper Suite is just one of several that will “full support” iOS 7 on Wednesday, according to the vendor. Citrix XenMobile MDM (formerly Zenprise) is another.

Some enterprises are beefing up help desk resources and iOS 7 expertise, expecting app glitches and that the extensive iOS UI redesign might prove confusing for some users.

But those users are in many companies the front line of support, says JAMF’s Jason Wudi. “In a lot of enterprises, the support team for users is actually their peers,” he says. “They go to them first, before they go the help desk. It’s usually very quick.”

Right now, “make it quick” is probably the very prayer being raised by IT groups across the country.

John Cox covers wireless networking and mobile computing for Network World.http://twitter.com/johnwcoxnwwjohn_cox@nww.com

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