|802.11n was developed as a range and speed booster, employing multiple antennas and two or more radios to work over greater distances (sending a stronger signal, having better receiver sensitivity) and at greater speeds (improved encoding, multiple spatial paths, double-wide channels). That’s fine for laptops, desktops, and routers, but it’s hard to cram that much radio technology into a battery-powered mobile device without making the time between charges unusably brief.
Glenn Fleishman, Does the iPhone Need 802.11n?
That’s where single-stream 802.11n comes in. With single-stream 802.11n, only a single radio and single antenna are used…
…802.11n’s single stream encoding is 65 Mbps, where 30 to 50 Mbps of throughput is possible. So you lose wide channels, antenna diversity, and multiple streams, but could gain 50 percent or more in net throughput.
|Streaming is the better solution when your clips are more than a few minutes long, when you want to enable interactive applications like video search or linking deep into a file, or you want to collect statistics on what’s actually being watched.
Larry Bouthillier, Streaming vs. Downloading Video: Understanding The Differences
Streaming is the way to go when you want to control the impact of video on your network, or when you need to support large numbers of viewers. And of course, it’s the only way to do live webcasts and multicasting.
|When you type a command in Windows PowerShell, you are invoking a specific, small-scale object that has a very specific purpose. Yes, you can invoke command line applications, too. You can also invoke GUI applications. But your old DOS batch files won’t run anymore. Why? Windows PowerShell is not about text processing, it’s about object handling.
Payton Byrd, What is Windows PowerShell?
|The Internet engineering community says its biggest mistake in developing IPv6 – a long-anticipated upgrade to the Internet’s main communications protocol – is that it lacks backwards compatibility with the existing Internet Protocol, known as IPv4.
Carolyn Duffy Marsan, Biggest mistake for IPv6: It’s not backwards compatible, developers admit
I just finished reading Carolyn Marsan’s piece, Google: IPv6 is easy, not expensive. Google, you see, has moved to IPv6. IPv6 operates in much the same way as IPv4, but with one very important distinction — IPv6 assigns IP addresses of 128 bits instead of IPv4’s 32 bits and that really increases the total number of possible Internet addresses.
Carol reports that Google engineers worked on the IPv6 effort as a 20% project – meaning it was in addition to their regular work. So far, the U.S. has been lagging behind other countries with IPv6 — mostly because we can — but now that Google has come on board, that may hurry things along.
What really caught my interest, was a sidebar that linked to an article where Carol did a bang-up job explaining the REAL issue that is holding up IPv6. Simply put, the developers mis-judged how adoption would really occur. They may have shot themselves in the foot by not making IPv6 backwards-compatible with IPv4, but It’s not their fault — it would have been cost-prohibitive, complicated and illogical in some ways.
(Explaining it to myself) It would be like your television station broadcasting in both analog and digital for awhile and then gradually fading out analog broadcasts as people replaced their old analog sets with new digital ones. It seemed like a logical, practical plan.
The IETF developers designed IPv6 to run in a dual stack. That means that IPv4 and IPv6 would run side by side for awhile and then IPv4 would gradually be faded out.
They didn’t foresee a scenario where IPv4 devices would stick around for years, some vendors wouldn’t bother upgrading their products to be IPv6-compliant and some administrators would just shut off the IPv6 part of the dual stack in an effort to keep things simple.
Since IPv4 isn’t fading away as the engineers had thought, they are going back to the drawing board to help IPv6 addresses be understood by IPv4 devices.
Carol says the transition mechanisms include:
* Dual-Stack Lite, a technique developed by Comcast that allows for incremental deployment of IPv6. With Dual-Stack Lite, a carrier would give new customers special home gateways that take IPv4 packets from their legacy PCs and printers and ship them over an IPv6 tunnel to a carrier-grade network address translator (NAT).
* NAT64, a mechanism for translating IPv6 packets into IPv4 packets and vice versa. A related tool, dubbed DNS64, allows an IPv6-only device to call up an IPv4-only name server. These two tools would allow an IPv6 device to communicate with IPv4-only devices and content.
Which is correct?
_________ installing the patches?
a. Did you finish
b. Have you finished
|The marketplace has not been especially kind to Xen for two reasons: it was not first to market, which is an important factor for any industry, and Xen resellers do not have the power of the VMware PR machine.
Schley Andrew Kutz, Xen: An endangered species in the virtualization ecosystem?
|The IEEE 802.11 standard defines two modes of operation. Ad Hoc Mode refers to a peer-to-peer association established directly between two wireless stations. Infrastructure Mode refers to associations between a group of wireless stations and an access point (AP). Ad Hoc Mode is also referred to as an Independent Basic Service Set (IBSS) because there is no access point involved.|
|One of the things we see happening is combining video communications with social networking–what we call “visual networking,” which will change the way we do business and how we communicate with our families.
Padmasree Warrior, as quoted in America’s First CTO?
I guess we’ll have to define ‘visual networking.’
David Talbot at MIT Technology Review has an entertaining nterview with Padmasree Warrior, Cisco’s CTO. Rumor has it that she’ll be President Obama’s pick for America’s CTO.
As you probably know by now, Cisco has acquired Pure Digital (makers of the popular Flip video camera) for $159 million.
I’m not surprised by the acquisition, but I am confused that Cisco said they were adding Flip to the ‘Cisco Consumer Business Group.’ What’s up with that name? If your group is named Consumer Business Group, doesn’t that account for ummmm….everyone?
Upon the close of the acquisition, the Pure Digital team will become part of Cisco’s Consumer Business Group, which includes Linksys® by Cisco® home networking, audio and media-storage products. Jonathan Kaplan, chairman and CEO of Pure Digital, will become general manager of the combined organization, reporting to Ned Hooper, Senior Vice President of Cisco’s Corporate Development and Consumer Groups.
|Because so many ActiveX controls turn out to be malicious, Microsoft designed Internet Explorer 7 so that it displays a warning every time a site attempts to use an ActiveX control. The problem is that the casual user does not typically understand what an ActiveX control is, or what the consequences of allowing an ActiveX control to run might be.|
Experts are predicting that there’s no end in sight for ActiveX exploits. It makes sense — because even criminals want to be cost-efficient. If you’re trying to find vulnerabilities to exploit, you to make sure you can affect the highest number of people — and IE is still #1.
|Military training rooms that once would have housed purpose-built, machine-based systems now resemble internet cafes, with up to 100 standard desktop PCs in a line networked together to let trainees explore the boundaries of collaborative training scenarios.
David Braue, Behind Pretend Enemy Lines
Every once in awhile I come across some marketing term that pushes some button and I feel compelled to talk to a vendor and ask “What were you thinking?” Case in point: Microsoft’s Hailstorm. (Ironically, Hailstorm was probably Microsoft’s first venture into what we now refer to as cloud computing. I have to say, they did a much better job picking their new name, Azure. I’d rather have blue skies than hail stones ruining my garden and denting the hood of my car any day.)
But I digress.
Last week when I was posting a new BigDog video from Boston Dynamics, I went to their corporate website and saw a large graphic image for their military simulation COTS. (COTS is just an industry term for custom commercial-off-the-shelf software.)
Now, my son just entered the military and one of the things I’m interested in learning more about is how the military is using virtual worlds and simulation games for training.
I’ve seen some video clips of how the military has been using video games and 3-D simulation in centers called The Army Experience, so when I saw that Boston Dynamics had developed a COTS for training, my first thought was to read more. I was actually kind of excited.
That is, until I saw that their product is called DI-Guy.
What an unfortunate name. It pushed some button deep inside me that I didn’t even know I had.
I wrote to the company, asking why they would name their military simulation COTS DI-Guy (DIE GUY???) and a very nice man named Marc Raibert wrote back — almost immediately — to inform me that the product’s name is pronounced D. I. Guy and that D-I is a military acronym for dismounted Infantry.
I understand the name better now — but I still don’t like it.
The military is notorious for its use of acronyms. I find it hard to believe that the only good fit was DI. But what do I know? I’m just a mother.