Two Data Connections

By Andrew Garcia  |  Posted 2007-07-05 Print this article Print

Internet The iPhone offers two data connections: the ponderously slow wireless WAN using AT&Ts EDGE network and a Wi-Fi radio for use with available wireless networks. The EDGE network lived down to the hype, proving frustratingly slow for anything more than a simple Web search under most conditions and downright unusable in others. In fact, during my tests, I experienced several lengthy periods during which I was unable to connect to anything at via the AT&T EDGE network, even though the iPhone informed me that my cell coverage was solid. Given the sudden onslaught of half a million plus new wireless data users on AT&Ts network, the outages and poor performance didnt surprise me, but Im not confident that things will improve significantly after the initial crush calms down to a more consistent pattern.
Indeed, Apple has anticipated the iPhones WWAN shortcomings and designed EDGE to be the fallback connection type for iPhone data usage. As long as the user has left the Wi-Fi radio enabled, the device first will first check for available and accessible nearby Wi-Fi connections before connecting to the EDGE network. However, since most customers will want mobile data access outside the confines of known Wi-Fi networks at home or at work, they will either need to contract a hot spot Wi-Fi vendor, hope for a free municipal network or suffer through EDGEs slowdowns. In truth, even the iPhones Wi-Fi performance was at first a disappointment. I found the Wi-Fi connection to be snappy when using an Apple stores unencrypted network. At the Apple store, Wi-Fi worked easily, allowing me to browse the Web and download e-mail, weather or YouTube videos with little trouble. But at home, performance was erratic, and I consistently received error messages saying, "Cannot locate server." I learned that the iPhone has some DNS resolution problems in certain circumstances. Specifically, the iPhone has trouble communicating with certain home routers that act as a local DNS proxy. To solve this problem, I needed to configure the iPhone with a static IP address and DNS server information, with the DNS setting pointing to my ISPs upstream DNS servers, rather than the local proxy. With this fix in place, Wi-Fi performed as expected. The iPhone Wi-Fi radio is an 802.11b/g unit—a Marvell low-power chip set (as recent disassembly demonstrations have shown). This means that there wont be any secret draft 802.11n capabilities to be released down the road as Apple did previously after its Intel-based MacBooks had been available for some time. This comes as no surprise, however, as the low-power consumption draft 11n market is still quite immature. The iPhone also includes an Airplane mode—a simple way to quickly disable all the devices radios while allowing the user to take advantage of the iPhones music and video capabilities. I could enable Airplane mode via a single slider bar that lives on the devices Settings page. One of the big questions for IT administrators is whether they should allow iPhones to connect to corporate wireless networks—whether or not they intend specifically to support the adoption and usage of the iPhone. The iPhones Wi-Fi security limitations could hinder this idea, however, as the iPhone only supports the Personal flavors of WPA and WPA2 (plus WEP), but not the 802.1x-enabled Enterprise security variations. Performing initial reconnaissance on a Wi-Fi-connected iPhone, I also discovered that the device does have some open network ports that an attacker could discover. Specifically, I found that the iPhone leaves open TCP ports 110 (POP3) and 25 (SMTP), as well as UDP (User Datagram Protocol) port 5353 (Apples Bonjour). The Nmap scanner with which I tested could also determine that, indeed, the iPhone is running a variant of OSX. Media With Apples already successful history with portable media players, it is no surprise that the best part of the iPhone is its iPod-like functionality. Whats more, the iPhone really raises the bar and gives a clear indication of where I expect their media-only players to go down the road. Since external controls such as the iPod touch wheel are a thing of the past for the iPhone, Apple needed to rethink how users interact with their media libraries. Like the contact database, the media library contains an index down the right side of the screen for quick access to a certain letter. Otherwise, users navigate from the touch screen to access what they want. The items in the library fly by with a flick of the finger. And for a visually stunning effect, turning the iPhone to landscape mode switches to a view of the album covers of all the songs on the device, simulating the effect of thumbing through an old-fashioned record collection. Video is also quite nice on the iPhone. The iPhone supports H.264 encoded video (as long as the file uses Low Complexity AAC audio, instead of High Efficiency Audio), making for a nice picture. When video is playing, the screen automatically switches to landscape display mode. The earphone/microphone jack is recessed deep into the top of the iPhone (to avoid damage when the plug is forcibly removed, which means customers will need to buy an adapter to use with existing headphones or headsets. Apple sells $20 headphone adapters in its stores and online. The 2.0-megapixel camera is fairly bare bones. There are no zoom or manually configurable lighting options, and the camera does not do video, only still photos. The picture viewer was quite nice, however, allowing me to easily scroll through albums via the touch screen. Senior Analyst Andrew Garcia may be reached at or at his blog at

Andrew cut his teeth as a systems administrator at the University of California, learning the ins and outs of server migration, Windows desktop management, Unix and Novell administration. After a tour of duty as a team leader for PC Magazine's Labs, Andrew turned to system integration - providing network, server, and desktop consulting services for small businesses throughout the Bay Area. With eWEEK Labs since 2003, Andrew concentrates on wireless networking technologies while moonlighting with Microsoft Windows, mobile devices and management, and unified communications. He produces product reviews, technology analysis and opinion pieces for, eWEEK magazine, and the Labs' Release Notes blog. Follow Andrew on Twitter at andrewrgarcia, or reach him by email at

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