The Challenge of Scaling a Wireless LAN 31-08-2008 GTM 1 @ 18:11
systemas —Philippe Hanset is wondering about the intersection of the Slingbox and the campuswide wireless LAN at University of Tennessee at Knoxville, where he's senior networking engineer.
A vendor has been industriously selling the Slingbox to incoming students, who set it up in their dorm rooms where they have cable TV service. The WLAN then lets them stream TV programs to their notebooks anywhere on campus. Imagine a hit like "American Idol" streaming wirelessly to hundreds of student notebooks.
"This could be challenging," Hanset acknowledges, with masterful understatement.
The development is typical of the new scaling challenges facing WLAN administrators as WLANs continue to grow in size, in number of users, and in more demanding applications. With big WLAN deployments, higher education is a kind of ground zero for many of these issues. (Compare enterprise WLAN products.)
Early WLANs focused on growing the number of access points to cover a given area. But today, many wireless administrators are focusing more attention on scaling capacity.
That focus is a broad one, calling for a deeper understanding of what access points are capable of, and paying more attention to scaling back-end systems, servers and networks.
The Rise of High-Density WLANs
"We've been used to 20 to 50 wireless users in an area, with another 20 to 50 maybe 50 or 100 feet away," says Brad Noblet, a former college IT director, at Dartmouth and Harvard, who's now an independent consultant. The assumption: few users, who wanted just e-mail access or Web searching.
Low-density WLANs are giving way to high-density ones, with new challenges for network administrators. "When we first put this [WLAN] in three years ago, there were few wireless clients," says John Turner, director of network and systems at Brandeis University, in Waltham, Mass. "Now everyone has a laptop."
The scaling challenges include ensuring adequate wireless, and wired, bandwidth for the applications being served to wireless users. "These scaling issues are becoming more and more apparent where lots of folks show up and you need to make things happen," Noblet says.
What has to happen is that lots of clients have to associate with an access point, get an IP address, be authenticated, get enough bandwidth (wireless and wired) for their applications, and behave themselves as network citizens.
Emphasize Capacity, Not Access
Noblet urges network administrators to configure access points for performance (or capacity), rather than for access. He's found some access points are configured without any limits on the number of client associations. If a large group of users coalesce around an access point, they'll find slow associations or none at all. "What it's really about is understanding the throughput performance of a particular data stream," Noblet says.
But everyone agrees that capacity planning at the level of the access point is more art than science. "When I speak on this topic, I always emphasize that we, the IT professionals, not the vendors are the ones who best understand the user and application scenarios we'll be dealing with in our deployments," says Dan McCarriar, assistant director of network services at Carnegie Mellon University (CMU) in Pittsburgh.
CMU is about halfway through an 802.11n deployment using gear from two vendors, Aruba for academic areas and Xirrus for residence halls. Xirrus packs a WLAN controller along with four, eight or 16 Wi-Fi radios into a single oversized "smoke detector" like package, called an array, with sectorized antennas to prevent interference. The result lets CMU plug a single array into a high-density area, without having to do complex microcell planning and administration.
Keeping Up With DHCP
In some cases, DHCP servers can't keep up with a flood of clients. "We're definitely seeing this," says Turner. But CMU's DHCP servers are able to keep pace. The key is designing the centralized IT infrastructure for these kinds of services, which are used by both wired and wireless clients, so it can scale quickly and easily.
In the future, Turner plans to create a more seamless mobile experience across the campus by tying location and mobility services into DHCP. "The DHCP server is not aware that someone has disconnected," he says. "We might be able to do something between the central WLAN controller and DHCP so we're not holding addresses for people who are never coming back."
The University of Tennessee at Knoxville has run into a slightly different DHCP problem, says Hanset, from the school's network services group: Some returning student notebook PCs or "rogue" access points in dorms act as DHCP servers themselves, serving out useless DHCP leases to requesting clients. The school blocks these hosts at switch ports or the Aruba WLAN controller.
Another scaling issue is that once clients are issued IP addresses, they may end up keeping them far longer than needed, so they can't be reissued to newly arriving clients on the same subnet. In some cases, addresses can be exhausted.
At the University of Tennessee, these address leases are limited to two hours, at Brandeis, to just 30 minutes. Both institutions make use of Aruba's virtual LAN pooling, which associates a pool of addresses to a given VLAN. It's an efficient and effective tool, says Turner, but network administrators still "have to think carefully about this."
Carnegie Mellon currently has a flat WLAN, essentially configured as one campuswide subnet, with one large pool of addresses. The university is planning to carefully segment the network, probably into several geographical zones, once the 11n rollout is completed. Then, address exhaustion could become an issue if not properly managed and monitored, says Scott Ambrose, CMU's manager of network design and development.
Ambrose plans to collect a mass of statistics on such things as average number of devices on the network and peak numbers of users, and the locations of the access points they associated with. All that data will go into planning the size and number of zones, and how to allocate the available IP addresses to each one.
Scaling for Multimedia
Multimedia use is surging, and 802.11n is expected to make it surge still more. All these universities are configuring their wireless LANS for multicast support, to minimize bandwidth demands where possible. Users in effect tune into a single multicast stream (analogous to viewing broadcast TV) rather than each one receiving his or her own separate, unicast stream. "You have to look at your application and ask 'what am I trying to serve here?' " Noblet says. "That will dictate whether you have to make use of a unicast or multicast transport."
"We enabled multicast everywhere we can," says the University of Tennessee's Hanset. But with that, to further improve performance, the university also disabled the slowest WLAN data transfer rates, of 1M and 2Mbps. "So every broadcast packet is sent at 5.5Mbps," he says.
Test everything, says Carnegie's McCarriar. "Support for multicasting [by vendors] is all over the map," he cautions.
11n is No Silver Bullet
These users are all adopting or evaluating 802.11n, which promises five to six times more throughput than existing 802.11abg WLANs. The additional capacity will be very welcome, but all agree that 11n won't eliminate the need for careful, thoughtful, end-to-end capacity planning.
"It guarantees faster speeds, but it doesn't prevent one bandwidth hog from taking most of that," says Hanset. "I'd like to have a 'fair-share' mechanism in the WLAN, so that can't happen, especially in high-density areas."
Hanset also cautioned that 11n throughput can be dramatically affected by inadequate upstream links and, in the University of Tennessee's case, power injectors. Tests showed an Aruba 11n access point delivering 80M to 90Mbps, but 160Mbps with a gigabit connection and gigabit-capable power injectors," he says.
In many migrations, enterprises simply are replacing existing 11abg access points with 11n devices. But if the 11n products are making use of the 5GHz frequency, because there are more channels and less radio noise, some tweaking will be needed, warns Brandeis' John Turner. That's because 5GHz signals don't propagate as well as those in the 2.4GHz band.
"We've seen where we've installed an 11n access point and expected great performance in the 5GHz band," he says. "But you walk behind two walls and your signal vanishes. It's not dead-simple."
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del.icio.usFour Free Wikis You Should Try 31-08-2008 GTM 1 @ 18:09
systemas —As Wikipedia grew in popularity, becoming the eighth most visited site on the Web, many companies decided to purchase and build wikis internally to help enable better communication, knowledge sharing, collaboration and project management between employees.
There are several free Web 2.0 offerings which help users who are new to wikis get their feet wet without installing software on a computer. We take a look at a four of them here:
1. Wiki: Google Sites (part of Google Apps)
Where it came from: Google Sites was built upon Google's acquisition of Jotspot, one of the companies that realized early on wikis had a future as a technology for the workplace.
Getting started: Signing up merely requires a Gmail account. When you sign into Gmail, click on the "More" tab and then "Sites" and you're into the app. You will be prompted to "create site" and you'll be able to decide rather quickly how you want to arrange things as they give you a few templates to choose from. A good starting off point is the web page view.
Ups: Have as many users as you want, and you can make the site publicly accessible if you wanted to take it beyond the corporate walls. Very easy editing tool that looks largely like what you'd use in your e-mail program, or a basic word processor. Like all the wikis mentioned here, you don't need to know how to write software code.
It's easy to embed video, links and other forms of media. There is great version control (so that if you don't like changes that were made, you can revert to an earlier form). Easy admin controls that allow you to make someone an administrator (who has the ability to create and terminate sites), collaborators (who can work within sites), and viewers (who can merely look at what's being done but can't edit). The ability to draw from Google Gadgets (a collection of widgets offered for iGoogle, such as a map or a stock ticker) is also nice.
Downs: No real mobile app to speak of. No offline mode. Though there are no ads to look at now, that could change as Google reserves the right to put ads on its consumer apps. Only 100 MB of storage per site. Pretty stingy considering Google's big server farms we always hear about.
2. Wiki: Socialtext
Where it comes from: Since its founding in 2002, Socialtext has been in the business of bringing social software such as wikis to the enterprise. They don't make their money off ads, so the free version of Socialtext (up to 5 users) is more or less a way for them to show businesses it is worth their time and money to sign up for their enterprise version that supports more users and contains more features.
Getting started: Go to Socialtext's customer login page and click on "get your own free Socialtext wiki."
Ups: Wikis do very well at providing users with context for the content their reading and consuming, and Socialtext is very good in this regard. You can embed content from within the confines of a social software environment (such as another wiki page or blog) as well as areas of the public Web. As an example, you can embed Google search results and RSS feeds rather easily by clicking on the "insert" drop down menu. It has good mobile access and the ability to take a wiki offline. Ability to tag content for easy discovery later on. If you're enamored enough by Socialtext's wiki, and want to expand your social software usage, the company also now gives you platform in which to create a blog.
Downs: While the editing tool allows for someone to post with no coding experience (just like Google Sites), it's not as pretty looking as the Google Sites text editor and has fewer options around font types. It's only free for only up to five users.
3. Wiki: Wikispaces
Where it comes from: Wikispaces is a three-year-old San Francisco start-up that focuses on hosting wikis for everything from businesses to schools.
Getting started: Pretty easy. Go to wikispaces.com and a light green sign up box can be found in the right corner.
Ups: The free version of Wikispaces doesn't have any limit for the amount of users and offers 2 GB of storage. The WYSIWYG (What You See is What You Get) editor is cool in that you can move it around the page to where you like it best. One elegant feature allows users to embed widgets (such as a YouTube video) very easily and have it appear nicely on the page. A "history" tab allows you not only to list previous versions but to compare them as well.
Downs: No mobile access and they've got to pay the bills, so they might serve up some ads along side the application.
4 Wiki: PB Wiki
Where it comes from: Since grabbing its first round of funding in 2006, PB Wiki has been hosting wikis for schools and companies such as AT&T, Citi and Cisco (see these examples on the company's home page).
Getting started: Go to pbwiki.com and click on the red button that says "create a wiki."
Ups: PB Wikis recently released a new version of their wiki that provides a good starting off point for someone with no wiki experience. It simply has two tabs at the top: "view," which would be like a read-only form, and "edit," to make changes/edits/deletions. You can backup your wiki offline if you're worried about something happening to it. The "Insert PlugIn" button in the text editor allows you to add content like the other leading free wikis. It includes the ability to add video (such as YouTube) and Google Gadgets. You can also upload views of key productivity apps, such as a calendar or spreadsheets. While most wikis rely on tagging and search as their primary ways of discovery (which it has), PB Wiki helps you bring the old fashioned folks into the fold with optional folders. Like Google Sites, it has a nice selection of fonts.
Downs: Only free for up to three users.
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Can Seinfeld Really Sell Vista? 31-08-2008 GTM 1 @ 18:08
systemas — Tags: Vista Windows industry PC MacFor the past two-plus years, Microsoft Corp. has stood by while Apple Inc.'s "I'm a Mac, I'm a PC" TV commercials treated Windows Vista like a punching bag.
But starting next week, Microsoft will fighting back with its own ad, starring funny-man Jerry Seinfeld. And not a moment too soon.
"Microsoft let Apple have the podium and dominate the communication space," said David Graves, an analyst with Forrester Research Inc. "It's not how you would do things in politics, where it's tit for tat. So it was time for Microsoft to strike back."
The reported US$300-million "Windows, not Walls" campaign will kick off next Thursday, September 4, with the airing of the first Seinfeld commercial, the Wall Street Journal reported last week. No coincidence, the NFL season kicks off that night on NBC.
Little else is known, but it has been reported that French director Michel Gondry, the man behind Eternal Sunshine of the Spotless Mind, may have directed the commercial.
That didn't keep the blogosphere from weighing in. And the reaction wasn't positive, reported Brandweek .
"Microsoft doesn't like being 'cast as a stodgy oldster' by Apple's advertising and has turned to Jerry Seinfeld. Oh, so they want to be cast as late-middle-age almost stodgy oldster," one blog quoted by Brandweek said.
Advertising industry experts say that whether choosing Seinfeld, 54, is on- or off-target depends on Microsoft's ambitions.
"Who is Microsoft really trying to target? If it is the thirty- and fortysomething business community, I think he's a great choice," said Marc Ippolito, president of Burns Entertainment and Sports Marketing.
But if the goal "is to woo the college-age and younger crowd to convince them not to switch to a Mac or to switch back," said Ippolito, 38, isn't so sure. "If you're 20 years old now and the show ended [in 1998] when you were 10, that's going to seem a long time ago."
Though the sitcom is widely seen in reruns, Ippolito says the "college kids in our office talk about Gossip Girl or The Office , not Seinfeld."
Steve Hall, publisher of AdRants.com, is more blunt. "If you want to make Vista a cool operating system, give it some cool. I don't think Jerry Seinfeld does anything that's cool."
Hall, 46, says it's more than just Seinfeld's recent lack of hits. "Advertising is cool. And cool, by default, is supposed to be young."
Car ads, which tend to feature actors and extras decades younger than the target demographic, follow that maxim.
"There is one general rule that people in the auto industry swear by: You can sell a young person's car to an old man, but you can't sell an old man's car to anyone," one industry expert told The New York Times .
Choosing Seinfeld would violate that rule. The long-time bachelor and, at least according to his semi-autobiographical sitcom, "man-child", is not only a father of 3 but, as noted earlier, is 54 years old -- only a few years younger than the late Lorne Greene was when the Bonanza star began pitching Alpo Dog food in the 1970s.
Microsoft rejected younger comedians Will Ferrell, 41, and Chris Rock, 43, because it did not want its campaign to be seen as pandering to the youth market or be seen as too hip, a Wall Street Journal report said.
Noting Rock's reputation for profanity-laced standup routines, Ippolito agrees that he may have been too edgy for Microsoft. But Ferrell would've not only had broad appeal but through his many successful movie comedies, "clearly is very relevant to the twenty-something audience."
But others, such as Graves, think that Seinfeld "may be above" such an ageist rule.
"He's ageless," says marketing guru Sergio Zyman, who argues that choosing Seinfeld is consistent with what Microsoft, as the still-overwhelming market leader, really needs to do.
"I think the strategy has to be to reassure all of the consumers still using Windows that 'Hey, you're OK, you're still cool,'" said Zyman, who was chief marketing officer at Coca-Cola in the 1980s . "If you actually came up with a commercial that was kind of the reverse of the 'I'm a Mac' ones, with a cool guy portraying Windows, that'd be too much on the edge, and you're not going to get away with that."
Zyman, whose consulting firm has helped Microsoft on past launches such as Excel and the Xbox, says that Apple, as the underdog, can afford to do aggressive, "insurgent" ads. Microsoft, which still must cater to senior executives and mainstream buyers, is limited to doing "incumbent advertising."
Not that he believes that the "I'm a Mac, I'm a PC" commercials have led to a lot of actual PC-to-Mac conversions. "It's still more noise than numbers," Zyman said.
AdRants' Hall expresses a similar sentiment, though less kindly.
"Maybe Microsoft is throwing its arms up and acknowledging that the people who are going to buy and use Vista are not on the cutting-edge of anything, and that Apple users will be younger, cooler, hipper, the early adopters and the 'good' geeks," Hall said.
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