Category: Networking
March 26th, 2008
55W PC power supply powering the dual-core computer
Most computer builders in the world think I’m nuts for endorsing the use of 330 watt power supplies for a high-end performance computer. Conventional “wisdom” says that anything under 500 watts is inadequate for an enthusiast PC. “My power supply is bigger than your power supply” seems to be a typical mindset for many people but I’ve always had just the opposite desire to say that “my supply is smaller than yours and it works great”. So when I started building mainstream dual-core computers with 220 watt 80 Plus power supplies, people were shocked that I would even consider such a small power supply. But since I was able to build a 50W peak power dual-core computer, why not use an even smaller power supply in the sub-100 watt range?
Pictured above is the open frame fanless AC input open frame 55 watt FSP055-50LM power supply from Sparkle Power Inc with an MSRP of $39. Typically when power supplies are this small, people often use DC input power supplies with an external AC brick. Not so with this model as it’s an all in one with the standard AC power connector you get on a normal ATX PC power supply. It’s so small that it doesn’t even bother with a fan or metal casing; you have to a system-level fan yourself and provide the bracing and shielding in your computer chassis. The really nice thing about this solution is that the entire power supply including the AC conversion part is not much bigger than a DC power supply but you don’t need an external brick.
Using this 55W power supply, I took a dual-core Intel E2140 along with the bundled ECS945-GM motherboard I bought for $90 and built a computer with it using default clock speed and voltages. Unfortunately since it was missing a 4-pin power connector for the motherboard, I had to hot-wire a 4-pin CPU power connector from an older power supply to this unit to make it work. That means 2 12-volt yellow cables and 2 black ground cables had to be soldered in to place and taped up. Since these cables are safe for 10 amps each which translates to 120 watts per cable, I’m not even close to overloading the cables.
Once the computer came up, the power consumption at the plug peak out at 70W which means the output power is around 52W at 75% efficiency which is 3W under the peak output of the power supply. That is cutting it a bit close but it shows the extreme worst-case of what this PSU can handle.
In reality, the 55W PSU isn’t practical for a mainstream dual-core computer although it would be more than powerful enough for an Intel D201GLY with Celeron 115, D201GLY2 motherboard with Celeron 120, or the Via low-power ITX platforms. The upcoming Intel Centrino Atom platform with the Atom-Diamondville CPU peaks at around 4W TDP so they’re even easier to power.
The bottom line is that this is a nice little power supply for small embedded solutions but you’ll want to stick with the bigger 80 Plus closed-frame models like the Sparkle SPI220LE 220W or the SPI270LE 270W if you’re building a mainstream PC. Note that the SPI models are 1U power supplies so you’ll either need a very custom case or one that uses 1.75″ thin power supplies.
March 24th, 2008
Fixing the unfairness of TCP congestion control
Bob Briscoe (Chief researcher at the BT Network Research Centre) is on a mission to tackle one of the biggest problems facing the Internet. He wants the world to know that TCP (Transmission Control Protocol) congestion control is fundamentally broken and he has a proposal for the IETF to fix the root cause of the problem.
The Internet faced its first congestion crisis in 1986 when too much network traffic caused a series of Internet meltdowns when everything slowed to a crawl. Today’s problem is more subtle and lesser known since the network still appears to be working correctly and fairly. But underneath that facade and illusion of fairness, a very small percentage of users hog most of the Internet’s capacity suffocating all other users and applications.
Solving the first Internet meltdown crisis
In October of 1986, the Internet began to experience a serious of “congestion collapses”. So many computers were piling their traffic on to the network at the same time that the network came to a grinding halt and no one got any meaningful throughput. By mid 1987, computer scientist Van Jacobson who is one of the prime contributors to the TCP/IP stack created a client-side patch for TCP that saved the day. Every computer on the Internet - roughly 30,000 in those days - was quickly patched by their system administrators.
Jacobson’s TCP stack patch worked by causing a computer to cut the flow rate of its TCP stream in half as soon as it detects any packet loss. Packets are lost whenever the routers relaying them receive more packets than they can forward and the router begins to randomly drop packets across the board. But whenever a computer sees an acknowledgement that its packet arrived successfully, it quickly and continually increases its flow rate with every acknowledgement until it experiences another packet drop at which time it cuts its throughput in half again. This became known as the AIMD (Additive Increase Multiplicative Decrease) algorithm where the sending computer is constantly probing for the maximum allowable bandwidth by repeatedly increasing throughput until it crosses a line and gets knocked down.
Jacobson’s AIMD algorithm also allowed a new TCP stream to open up and quickly rise to equilibrium where it attains the same flow rate as all other TCP streams. Conversely when a TCP stream ended transmission, the extra bandwidth freed up would be evenly distributed amongst the remaining streams. Van Jacobson’s patch was so successful that it became a part of the TCP standards and it hasn’t fundamentally changed for over 20 years and according to Bob Briscoe, Jacobson’s algorithm is the “fifth most cited academic paper in all of computer science”.
Under Jacobson’s algorithm which sought out to balance the flow rate (throughput) of each TCP stream, the system was more or less fair to everyone who wanted to use the network so long as everyone used an equal number of TCP streams. Since people typically used one TCP stream at a time and people had limited usage on those time-sharing computers in the 1980s, Jacobson’s algorithm was adequate for the problems of that era. While it was possible for someone to open two FTP downloads or uploads at a time and get double the total throughput than anyone else, this wasn’t a big problem when applications and operating systems were mostly limited to text and computers were limited to academic and large corporate institutions. But as time went on and as the number of applications and users grew, it was only a matter of time before the fairness of the system would be exploited.
March 20th, 2008
HDMI survival guide for home theater
There’s a lot of money to be made in the HDMI cabling and switch aftermarket and unfortunately that means a lot of consumers are getting tricked in to paying outrageous prices. I’ve spent quite a bit of time helping my friends set up their home theaters recently and I thought I’d share that knowledge with my readers. If you’re tired of paying high hundreds of dollars for HDMI switches and HDMI cables, read on.
What is HDMI?
HDMI is a high speed digital interface for the transmission of high quality digital audio and digital video. So if you plug your DVD player, your PlayStation 3, your satellite or cable TV box, or even your computer up to a modern HDTV with a single HDMI cable, then the sound and picture will all work. The HDMI plug only has a single small connector so it’s nice and simple. Before HDMI, you had to hook up three separate connectors for just the video and two additional RCA plugs for stereo sound. Instead of the two RCA plugs, you could also use an S/PDIF optical cable for the sound but it still adds a lot of cable complexity and clutter compared to a single HDMI cable.
Why are there different HDMI types?
There are 4 basic versions of HDMI. You have 1.0, 1.1, 1.2, and 1.3 and you can get a quick summary of the capability of each version here. The easy answer is the higher the number, the better. If you’re shopping now, try to stick with the HDMI 1.3 devices if you can.
Do I need monster HDMI cables?
No, HDMI monster cables are simply a monster rip-off. If a cable is HDMI certified, it will by definition offer you a perfect digital signal. Despite the fact that the electrical signals traversing an HDMI cable degrade as a cable gets longer, it will still offer perfect digital transmission so long as the signal loss or distortion is within a certain tolerance. Analog cables might benefit from extra thickness and insulation because there’s not much you can do to fix analog signal loss or distortion other than to amplify and maybe filter the signal a little to mitigate the bad side effects. But when it comes to digital technology, the signal is either all there or it isn’t. There is zero measurable difference in the digital signal quality between the $6 HDMI cable and the $60 monster HDMI cable.
Where do I buy cheap HDMI cables?
There are lots of online vendors that can be found via a quick Google search of “HDMI 1.3 cable”. These cables suppliers have always been reliable in my experience and they’re many times cheaper than the local retailer. Here’s a few examples I compiled.
- 3 foot HDMI 1.3a cable $5
- 15 foot HDMI 1.3a CL2 rated cable $24
- 25 foot HDMI 1.3a CL2 rated cable $42
- 30 foot HDMI 1.3a cable $64 (bought for friend’s project)
- 60 meter (197 feet) HDMI 1.3a CAT5e extender kit $199
<Next page - Can I split or switch multiple input/output HDMI sources?>
March 16th, 2008
Japan's ISPs agree to ban P2P pirates
Four of Japan’s largest Internet provider organizations have come to an agreement with copyright holders on how to tackle the illegal file trading on P2P (Peer to Peer) networks. Comprised of about 1000 major and smaller Japanese Internet providers, the four organizations agreed to target flagrant copyright violators by first warning them and then banning them if their behavior doesn’t change.
According to the Daily Yomiuri Online, the Internet providers two years ago attempted to disconnect users anytime they detected the use of Winny (a popular Japanese P2P application) or any other file-sharing software. But that ran afoul of the Japanese Ministry of Internal Affairs and Communications because of concerns of privacy and the providers abandoned that practice. This time the Internet providers seem to have learned from the past and they’re going to be much more targeted by going after the most obvious transgressors of illegal file trading.
When the copyright owners see a list of IP (Internet Protocol) addresses downloading their copyrighted content, they’ll send that list of violators to the ISP (Internet Service Provider) and the ISP will warn and then ban the copyright infringers if necessary. This method doesn’t involve any of that politically dreaded DPI (Deep Packet Inspection) since the copyright owner merely needs to look for their own content on the popular file trading sites and ask for a list of peers by merely participating in the file trade. Not only does this method avoid privacy concerns, it also happens to be the most practical if not the only way of attacking the problem since many file trading applications are already completely encrypted against packet snooping.
Update 5:40AM - Just to make myself extra clear since many people refuse to believe that we are not talking about deep packet inspection here. P2P in Japan like the latest “Perfect Dark” application (successor to Winny and Share) is already fully encrypted at both the protocol and data level. That’s encryption is completely bypassed since the content owners merely need to download the Winny, Share, and Perfect Dark and look for their own content that’s being pirated. Then all they need to do is connect to it as if they were a user and then download the content to see if it is indeed their content. Then they already have a list of IP addresses that participated in that file exchange. There’s no decryption, key cracking, or deep packet inspection going on here.
Japan is considered one of the most connected broadband nations on the planet with widespread 100 Mbps broadband service. Many people in this country believe that by simply offering more capacity, there would be no need to manage the network since congestion problems would be gone. But Japan teaches us that no matter how much capacity you throw at the problem, congestion will always be a problem and the vast majority of it will be caused by P2P traffic.
At the iGrowthGlobal Panel on Network Management on Capitol Hill (my recap here), I met Haruka Saito who is Counselor for Telecom Policy from the Embassy of Japan. Mr. Saito was my fellow panelist and he shared the following data with the congressional and FCC staffers in the audience. He presented the following data from the Japanese Ministry of Internal Affairs and Communications which had been studying the issue of Net Neutrality in Japan for more than a year.
[Updated 3:15PM - I had incorrectly stated that 1% consumes 63% of all traffic because I read the charts wrong. The corrected text is in bold below.] As you can see, the utilization levels especially for uploads are dangerously high and that P2P traffic absolutely dominates both upload and downloads by a very large margin. Winny, WinMX, and Share (a successor of Winny) dominates the P2P usage. From this data, the P2P users that make up 10% of all Internet users in Japan hog ~75% of bandwidth resources and 1% of all Internet users in Japan consume 63% of that 75% share. That means just 1% of users consume 47% of all the Internet traffic in Japan. It’s no wonder the ISPs in Japan want a solution that cuts off the most egregious illegal file traders who also happen to be the biggest bandwidth hogs.
March 5th, 2008
AT&T's degrading service and my landlord's ban on Comcast
With all the negative attention headed towards Comcast lately, AT&T’s problems seem to be slipping below the radar. Unfortunately for me, those problems are first hand for me as I’m personally suffering degradations in speed. As if getting 1200 Kbps downstream on a so-called 1500 Kbps service and all those outage problems (example here and here) weren’t bad enough, my AT&T DSL service has declined. I suppose I could count myself lucky compared to my Mom’s neighbor who only got 320 Kbps service after AT&T unilaterally and without permission “upgraded” his bill to the 1500 Mbps service without upgrading his performance. Seem my DSLReports.com speed tests below.
The results above were performed at the nearest locations to my home and they were performed on idle servers with barely anyone using them. That pretty much confirms the problem is on AT&T’s end and possibly on the last mile. My Mother’s so-called 768 Kbps service only delivered about 330 Kbps but after the AT&T fixed some wiring problems outside the house, the performance went up to about 600 Kbps. I’ll have to call AT&T and see if they can do anything about my problems when I get back home.
It’s gotten so bad with my service that I’m actually starting to yearn for some of those “evil” TCP resets from Comcast to grace my router. Even more frustrating is that Comcast might actually be offering DOCSIS 3.0 with 15 Mbps downstream and 2 Mbps upstream in my area, but I live in one of these draconian housing complexes that force us to pay for bundled inferior analog cable service even though I don’t use it. The FCC has ruled against these types of exclusive contracts but I don’t think that can overturn my current situation. I think I’m finally motivated enough that I want to start a petition with the neighbors to demand the right to use Comcast. I’ll definitely have to bring this up the next time I go to Washington DC before Congress and the FCC.
Some people have told me that I should have looked at the contract before I moved in but it really isn’t that simple. There are about a thousand homes in the same multi dwelling unit and we don’t have much of a choice on where we live when an old and small home in Silicon Valley is $650,000. I do find it ironic that I’m now begging and fighting for the right to get Comcast service while others are fighting to kill Comcast.
This isn’t to say that Comcast is always good and AT&T is always bad although I’ve always gotten much better service from Comcast when I actually had a choice between the two. But it is so critical that we have competition between the two so that they have to fight for my business. The way it stands now, AT&T pretty much knows that I have no other game in my area and they have zero incentive to deploy U-Verse in my neighborhood let alone fiber-to-the-node like Verizon’s FiOS service.
What’s even more frustrating is that this isn’t a rural area problem since I’m in the heart of Silicon Valley with about 4000 homes jammed tight in a two block by two block neighborhood. It would be a Verizon FiOS installer’s dream deployment with homes packed so tightly together. With my landlord out of the way, I’d have DOCSIS 3.0 15 Mbps service to choose from and AT&T would prioritize jumping in here with U-Verse service. These are the real problems facing consumers today and not whether a few bandwidth hogs get throttled or not and I hope others will join me in a worthwhile cause.
March 3rd, 2008
A geek's trip to Capitol Hill on Network Management
I appeared before congressional and government staffers on Capitol Hill for a panel on Network Management sponsored by iGrowthGlobal. This was my first time in Washington DC and while it was a little cold for my Californian bones, it was a beautiful city and seeing the capitol of the nation was certainly a worthwhile experience. One thing that struck me was how large and spread-out the Capitol was with so many Government buildings several miles apart.
The panel was moderated by Scott Wallsten, VP for Research and Senior Fellow of iGrowthGlobal. I met Mr. Wallsten at the Net Neutrality summit held at University of San Francisco last month where the two of us presented on separate panels. The rest of the panelists for this event were:
- Melvin Ammori, General Counsel, Free Press
- David Burstein, Editor, DSLPrime
- George Ou, Editor at Large, ZDNet
- Haruka Saito, Counselor for Telecom, Embassy of Japan
- Christopher S. Yoo, Professor of Law and Communications, University of Pennsylvania
Christopher Yoo -
After a brief introduction by Scott Wallsten who explained that the order of the presentations will be reverse alphabetical order, Christopher S. Yoo kicked off his presentation. Professor Yoo explained that networks, like roads, aren’t built for everyone to use them at the same time. Yoo gave the example that if a person wants to know how fast he can travel on a freeway, he wouldn’t know until he got there because we can’t predict exactly how many other people will be on the road at the same time. Yoo explained the difficulty in projecting network capacity and that we can’t always be right when determining whether more capacity or network management was the answer. Sometimes more capacity is the answer, sometimes network management is the answer and we shouldn’t lock ourselves in to one solution or the other.
Haruka Saito -
Next up was Mr. Haruka Saito from the Embassy of Japan. Mr. Saito explained that Japan had been studying and debating the issue of Network Neutrality in Japan for about a year and a half and he offered a lot of hard data gathered in Japan. Japan is one of if not the most connected nation in the world when it comes to broadband deployment with 100 Mbps fiber deployments and despite this abundance of capacity, even I was shocked that they were running in to congestion problems.
When the traffic chart was broken down in to color-coded regions showing application usage, P2P easily ate the lion’s share of resources and dwarfed everything else on the chart. Mr. Saito went on to explain that 1% of the users primarily through P2P consumed around 50% of the total capacity and this pretty much mirrors every other study I’ve seen elsewhere in the world regardless of capacity. The debate in Japan was who was going to pay for this excessive usage and whether the heaviest users should start paying more money.
George Ou -
Next up was me and I gave a presentation based on my Comcast versus Vuze and Comcast before the FCC article. After Mr. Saito’s presentation, it certainly made my job a lot easier showing my charts on how BitTorrent and P2P were effectively the primary bandwidth hogs. I explained that the vast majority of all web applications like Web surfing, YouTube, Apple iTunes video downloads, Xbox Live Marketplace video downloads, and other applications like email almost never use any upstream capacity. Even though there are applications like Skype High Quality Video Conferencing which can fully saturate the upstream pipe, its duration is relatively short which significantly lowers its average load on the network.
I then explained that Vuze using the P2P model shifts nearly all of its server, storage, and bandwidth costs to its customer’s computer and the broadband providers while all other video distribution services pay for their own distribution costs. Then I explained that Cable networks and Wireless networks are shared-medium networks that are constrained in capacity and that they weren’t built nor sold to be content servers for the rest of the Internet. Wireless networks are even more scarce in terms of capacity because of the scarcity of spectrum and many of the smaller ISPs would be put out of business if the Government made rules banning P2P throttling or P2P blocking. Without those smaller wireless ISPs that cover the rural areas that the larger companies don’t want to cover, those Americans living in rural America would be cut off from the Internet and possibly even their phone service. We have plenty of choices on getting content but few choices on broadband carriers and the Government must keep this in mind when making network management policies.
David Burstein -
David Burstein went up next to give his presentation though he didn’t actually have a presentation ready so he improvised the presentation. After indirectly but clearly referring to Professor Yoo as an “idiot”, Burstein told the audience that if only Comcast would upgrade to DOCSIS 3.0, then there wouldn’t be any need to manage the network. That seemed to fly in the face of the hard network traffic data that Mr. Saito presented indicating that even a 100 Mbps per home dedicated fiber network would have congestion problems due primarily to P2P traffic. Burstein continued to insist that a measly DOCSIS 3.0 network (which is 120 Mbps shared between a few hundred users) would somehow be immune to congestion problems.
Even stranger was Burstein’s testimony that it would only cost Comcast 10 cents per user per month to upgrade everyone to DOCSIS 3.0. When pressed where he got such a number, Burstein Then he admitted it was only a guess but insisted that until someone proves him wrong, then everyone should laugh in the faces of his doubters. I didn’t bother challenging Burstein on the spot since there were so many other things I wanted to say, but I will respond to him here.
If we take Burstein’s estimate at face value, then we would have to believe that a DOCSIS 3.0 CMTS (Cable Modem Termination System) along with a ~250 DOCSIS 3.0 cable modems could be had for a cheap total of $50 for the entire neighborhood per month. Now bear in mind that the typical DOCSIS 2.0 modem costs about $60 and a CMTS is about the size of a 40U rack and falls under the category of very specialized networking gear. A more common Cisco switch half the size would easily cost a quarter million dollars so it wouldn’t be surprising if a CMTS costs upwards of half a million dollars. With 500 users on a CMTS loop (Cable TV with typically half of them subscribing to cable broadband), the costs will at least be $1000 per user for just the CMTS and we haven’t even begun to look at the costs of upgrading the surrounding infrastructure to support the higher capacities and the cable modems.
[Update 3/4/2008 - Dave Burstein has asked me to issue a correction that he stated it was 10 cents per user PER MONTH. I do apologize for my error, but it doesn't really change the fact that the correct number from Burstein has little to do with reality. At 10 cents per user per month, it would take 10,000 months or 833 years to break even on a minimal $1000/user investment.]
Marvin Ammori -
Marvin Ammori from the Free Press went up and also improvised a presentation. He kicked it off with a cheap shot saying how he was glad that Professor Yoo and I didn’t bring a busload of chair warmers and attempted to paint the two of us as industry shills. Ammori then went on to build a straw man argument that he thought my position was that YouTube didn’t pay their fair share of the Internet. Ammori obviously never saw my article from last year where I ripped Ed Whitacre’s statements that Google didn’t pay their fair share on Internet connectivity. After Ammori finished his presentation, I let my displeasure be known that I spoke as a proud American citizen who was in Washington DC for the first time with no one paying me to speak.
One other interesting tidbit was the fact that Mr. Ammori who admittedly never heard of the word “BitTorrent” up until a few months ago claimed that BitTorrent will only do 4 upstream sessions. Since Ammori told us that he heard it from Professor Edward Felton [waiting for Ammori's clarification on who he heard it from], somehow that overturns my testimony that BitTorrent was a bandwidth hog that opened 10s of upstream sessions. The reality was that certain BitTorrent clients will default to 4 upstream sessions for each torrent, but multiple torrents meant multiples of 4. The other interesting claim that Ammori made was that BitTorrent was intelligent and kind enough to back off when your neighbor was trying to use something like a web or email application. Where exactly Ammori got this information wasn’t clear, but I’d like the Free Press to show me some documentation for a protocol that no one has ever heard before.
[UPDATE 3/4/2008 - Ammori emailed me that he didn't say it was from Ed Felton despite the fact that he mentioned Ed Felton's name in the closest proximity to as far as my memory is concerned. Ammori writes in his email that he had named David Reed, David Clark, and Ed Felton as the three expert witnesses he cited, but has so far refused to clarify which one told him that BitTorrent maxes out at 4 upstream sessions. Strangely, Ammori seemed a lot more confident of his source when testifying before the government to bolster his claims and discredit mine but now he refuses to clarify his source when he is shown to be wrong. At this point I don't know if Ammori was given the wrong information or didn't understand what he was told, but either way he gave bad testimony.
Instead of offering clarification, he took a few more shots at me the same way that he attacked Richard Bennett implying that we're somehow not qualified and that we're "brought in" by Comcast which has no truth. Then just as he did at the panel last Friday, he insists that his sources are better even though none of his sources have disputed anything I or Richard Bennett has said. Richard Bennett is one of the pioneers of the Internet and he's written some very informative and articulate articles on this matter and he's also faced off with Ed Felton in podcasts. You can hear the podcast for yourself but I think you'll find that Richard Bennett held his own against Ed Felton and Richard has far more expertise on this particular subject matter.
During his presentation, Ammori also tried to discredit the data I showed where P2P seeding was pretty much the only application that hogged the upstream. In the context of the hard data presented by Mr. Saito from the Japanese Ministry of Internal Affairs and Communications showing that P2P was undoubtedly the upstream and downstream bandwidth hog, it was shocking that Ammori would try to continue disputing that fact. Ammori basically argued that we can't really know if the charts I used (copy here) are legitimate or not and he made a habit of trying to discredit me with no factual data to counter. It will be interesting to see if he's willing to explain exactly which expert he was citing.]
During the informal panel debate after everyone had spoke, I brought up the fact that Comcast gives you web space to post content which operates 10 times faster than any BitTorrent seed. This apparently wasn’t good enough for Mr. Ammori and he felt that this was somehow impinging on his right to free speech since he couldn’t serve out high-definition video content from his own home. Never mind the fact that we’re in a unique time in history where for the first time user generated content on YouTube can have a huge impact on the election. Anyone can put up a political ad on YouTube and get millions of people to watch it if the video was clever enough, but the fact that Ammori couldn’t serve it in High Definition from his own home was somehow a violation of his first amendment. But the fact of the matter is that you can serve HD video from your own home if you pay for a commercial-grade Internet connection that allows you to host servers. What you don’t have the right to do is buy a cheaper residential-grade Internet connection, hog the scarce resources by serving content to the whole world and violate the terms of service.
So to sum it up, it was knee deep in politics experience but it was all worthwhile. I felt honored that I had contributed something to my Government and my Nation.
[Update 3/4/2008 - Since this post is obviously being told from my viewpoint, I will be happy to link to any of the other speaker's blogs rehashing their experience if they write anything regardless of whether I agree with them or not.]
February 26th, 2008
FCC hearings: Comcast versus Vuze
The FCC held its hearing on Comcast’s Network Management practices at Harvard University yesterday. Vuze executive Gilles BianRosa whose company filed one of the two FCC complaints against Comcast reportedly told the FCC yesterday that BitTorrent does not hog bandwidth. Since most Internet experts would dispute that claim, I generated the following hard data on the bandwidth consumption of various applications that run on the Internet.
Note: Richard Bennett who was an expert panelist at yesterday’s hearings informed me that BianRosa claimed that BitTorrent didn’t exceed the contracted limit. That however ignores the explicit “no server” clause in the terms of service and no broadband service was built to be fully saturated 24×7. This is why commercial grade T1 lines that offer less than half the speed of broadband connections costing 8 times less are $400 per month.
Bear in mind that the data below is in reference to upstream (upload) bandwidth consumption in kilobits per second since that is the focus of these FCC hearings. Also note that applications like web surfing hardly use the upstream at all since it’s primarily your clicks and URLs that are being transmitted to tell the web server where you want to go.
The following is a graph of the above chart
* Corporate VPN telecommuter worker using G.722 codec @ 64 Kbps payload and 33.8 Kbps packetization overhead
** Vonage or Lingo SIP-based VoIP service with G.726 codec @ 32 Kbps payload and 18.8 Kbps packetization overhead
*** I calculated that I Sent 29976 kilobytes of mail over the last 56 days averaging 0.04956 Kbps
It is interesting to note that before the advent of P2P applications, Broadband users were primarily downloaders and rarely did they ever upload. It is for this reason that Broadband networks were built asymmetrically and heavily favored the downstream. Servers in data centers with commercial-grade Internet connections served and transmitted content and consumers consumed that content by downloading them.
If you’re downloading video from a service like Apple iTunes, Microsoft Xbox Live Marketplace, Netflix, or YouTube, you’re only downloading and not uploading anything. Those services pay a lot of money for their own datacenters filled with servers, their own bandwidth, and/or they pay services like Akamai to cache and distribute their content over the entire Internet.
Vuze on the other hand uses a different business model where they don’t pay for their own bandwidth and they expect their users to contribute their upload bandwidth to make the service work using the BitTorrent protocol. Vuze basically gets free distribution because they enlist their own customers to be their servers and bandwidth providers using their own computers and broadband connections. So instead of paying for commercial distribution, Vuze offloads their bandwidth on to the broadband providers.
<Next page - Exacerbating the Cable and Wireless spectrum scarcity>
Disclosure: Many people have asked me for the source of the data so I will put out the following disclaimer. As I already indicated in the first paragraph of this article, I am the original source of those charts and graphs. I’ve written extensively on VoIP bandwidth consumption as the former Technical Director of TechRepublic. Before TechRepublic, I built and designed networks for a living. I worked on the routing, the switching, and the traffic engineering of Intranet and Internet based networks. The in-use bitrates I cited are detailed and include packetization overhead and they can be independently verified.
February 23rd, 2008
Why Satellite Internet service is so slow
I was reading in the news today about an experimental geosynchronous communications satellite being launched by Japan and I got to wondering about why Satellite Internet service has such horrendous latency and is so slow. So I drew up a little diagram above (click to see full resolution) and did some calculations on the distance traveled and how long it takes for light to take the four-way journey. That’s because you have to go up to the satellite, then back down to the service provider, then back up to the satellite, and finally back down to you. Seeing that circle represent the planet Earth gives you some perspective how far and high a geosynchronous orbit is.
Here are some interesting numbers I compiled and estimated
- 35,780 kilometer geosynchronous altitude
- 12,756.32 kilometer diameter of earth at the equator
- 12,715.43 kilometer diameter of earth at the poles
- 299792.458 km/s is the speed of light in a vacuum
- Just the speed of light delay is between 477 ms to 556 ms delay
- With equipment delay and congestion, we’re looking at 500 ms to 1000 ms delay for satellite Internet service.
- ~199862 km/s is the speed of light in glass
(assuming glass is 1.5x slower than in vacuum) - 39.6 ms theoretical ping from California to New York
- 80 ms is the realistic ping from California to New York
- 90.8 ms theoretical ping from California to Germany
- 180 ms is the realistic ping from California to Germany
- 100.8 ms theoretical ping from California to China
- 200 ms is the realistic ping from California to China
February 15th, 2008
The $330 IPCop/Copfilter firewall 25 watt appliance
A lot of you probably already know my disdain for desktop anti-virus because of how sluggish it makes your computer and how it actually becomes more of a liability in terms of security. I’ve talked about how wonderful it would be if you could run your anti-virus at the gateway to protect all of your computers. The one thing I couldn’t really offer up until recently is how you actually implement this with a practical and relatively cheap solution.
One of the things a lot of people did was to take an old computer that made a lot of noise and probably takes a lot of power which adds up on the electricity bill. Another option was to buy a $600 embedded appliance which is too expensive. The third option which Justin James attempted was to order something all the way from China which took nearly 2 months along with a steep money transfer fee and shipping costs. I got so desperate that I even thought the Apple TV would make a nice low-power cheap appliance only to find out that the EFI BIOS was going to be a pain to deal with.
A year has passed and I’m happy to inform you that the bad old days are over and you can finally buy a low-cost low-powered x86 appliance for a little over $330 with no gimmicks or hacks. Enter Logic Supply’s Perimeter B4 appliance for $291 which includes 3 gigabit ports and 1 FastEthernet port as shown in the picture above and below which I got a chance to review. It’s an all metal chassis that can be mounted on the wall or just placed in the corner somewhere. [See gallery for a closer look.]
This particular model came with a 2.5″ hard drive and 512 MB RAM, but the current model being sold only has 256 MB RAM and 256 MB flash. I’m not sure why they no longer offer the hard drive and more memory option on their website but you might be able to custom order it. If not, you can buy 512 MB of DDR2-533 memory for $9 including shipping and a 20 GB 2.5″ hard drive for $29 including shipping. This is the recommended amount of memory you’ll need for running IPCop/Copfilter and the hard drive is perfect for transparent caching which speeds things up immensely. If you spend $14.38 including shipping for 1 GB of RAM, that would give you more room to grow.
The noise level in this device is moderate with the three small fans inside (1 for CPU and 2 for chassis). It’s a lot quieter than your 1U Cisco switch or router and quieter than some PCs, but it’s no silent enough for under-desk operation in my opinion and you might have to make some modifications to the fan to slow them down. You can generally replace the yellow wire leading up to the fan with the red wire which cuts the voltage from 12 to 5 volts and that will significantly slow down the fan. The temperature seemed to be low enough that you could reduce the speed of the fan. I did complain to Logic Supply that they should implement variable speed fans that only speed up and make noise when the system is getting too hot.
Inside the chassis you’ll find a standard mini-ITX Jetway J7F2WE-1G motherboard with 1 GHz Via C7 processor which is plenty of performance for a gateway device like this. Typical power consumption was around 25W so it should cost about $22 a year to operate 24×7 at 10 cents per kilowatt*hour.
Here I detached the hard drive and the Gigabit Ethernet daughter card. The hard drive is a standard 2.5″ PATA IDE hard drive mounted on a metal holder. There is only one DDR2-533 slot for memory so make sure you buy enough memory.
The system comes with a 10/100 FastEthernet interface on the motherboard and a 3-port gigabit Ethernet card which uses three Realtek RTL8110SC network processing chips all compatible with Linux and BSD. Note that the CPU in this appliance isn’t fast enough to turn this thing in to a gigabit router but it’s plenty fast as a gateway device. This particular daughter card actually uses the strange 120-pin plug (see gallery for higher resolution image) in the picture above.
IPCop and Copfilter are free Open Source applications and Justin James has a simple guide on how to install IPCop here if you want to get started right away. I’ll be following up with a more detailed guide.
February 13th, 2008
Comcast traffic management issue before FCC
Today is the deadline for the FCC call for comments on the Comcast traffic management case brought about by a formal complaint from the Free Press and Public Knowledge. As a former network engineer who designed networks and servers and as someone who has written extensively on these matters, I thought I would summarize the issues in a clear and concise manner.
Background
Independent groups last year found that Comcast was sending TCP RESET packets to BitTorrent seeders at various times of the day to cut back the number of upload sessions they could have. A BitTorrent seeder is someone who is not downloading but acting as a dedicated and peer-to-peer file server. BitTorrent downloads or uploads while downloading were not affected. Various groups complained that this was possibly illegal protocol discrimination using forged TCP RESET packets while Comcast maintained that this was reasonable network management to assure fair distribution of bandwidth to all their users.
The upstream contention problem
A typical Cable broadband network such as Comcast operates under the DOCSIS 1.1 standard which offers 10 mbps of upstream bandwidth and 40 Mbps of downstream bandwidth bandwidth shared amongst the neighborhood. Since the typical user has a static upstream cap of 384 kbps, it would be possible for 26 BitTorrent seeders and/or BitTorrent uploaders to completely jam the upstream pipe rendering the entire network unbearable. Since a typical Cable broadband company provisions between 50 and 400 users (typically somewhere in the middle) per cable loop, it is possible for ~10% of the users can jam the entire upstream network which ultimately affects downloads as well since services can’t be asked for. This is further complicated by the fact that DOCSIS networks use a reservation system for upstream traffic on a collision network. Too many requests for upload slots and the requests collide and no one gets to transmit anything.
Accusations of discrimination
Some have complained that this was content discrimination. But Comcast does not discriminate based on content; Comcast discriminates against excessive upstream usage that chokes up their entire broadband network. The EFF complains that this was “protocol discrimination” against BitTorrent and other P2P (peer-to-peer) applications, but it is a fact that BitTorrent and P2P are the biggest upstream bandwidth users. Since BitTorrent seeders who only continuously upload throughout the day can be reasonably classified as dedicated servers, they actually fall under prohibited services under Comcast’s TOS (Terms Of Service).
Blocking versus delaying
Comcast says they’re merely delaying BitTorrent seeders from uploading to their peers while their critics say they are blocking. It is true that Comcast blocks BitTorrent seeds when the broadband network is very busy, but they do allow BitTorrent seeding at most other times of the day. Network Engineer and Internet pioneer Richard Bennett explained this best in his comment to the FCC that since BitTorrent and other peer-to-peer applications all have the ability to resume transmission at where they left off, temporary blocking of seeders effectively acts as a delaying mechanism. The file eventually gets served to the remote party outside of Comcast’s network intact.
Consumer versus commercial Internet connection
The reality is that Comcast customers were never blocked, throttled, or delayed from receiving any services; they were delayed from offering hosting services (BitTorrent seeding) that were technically prohibited to begin with under the terms of service. Comcast’s consumer broadband service technically doesn’t have to act as a commercial hosting service to other customers in and outside of Comcast’s network so the fact that they permit seeding most of the day seems like a reasonable compromise. Furthermore, BitTorrent users who are downloading are continuously uploading during the download without any delaying action so it isn’t as if Comcast refuses to participate in P2P uploads.
Blocking of Lotus Notes
Comcast’s network management mechanisms did have a bug in them that accidentally blocked Lotus Notes traffic, but this issue was fixed months ago when the issue was first brought to the attention of Comcast. All software and hardware implementations have bugs and we expect the service provider to act in good faith and repair the problems as soon as possible. In this particular case, Comcast appears to have acted quickly and properly by fixing the problems that blocked Lotus Notes.
The complaint to the FCC
The Free Press and Public Knowledge filed a formal complaint to the FCC to immediately enjoin Comcast from these network management practices before the merits are decided and the facts weighed. This is an unreasonable request since Comcast customers would be harmed by network traffic jams due to the lack of any traffic management. The Free Press and Public Knowledge also demanded fines of $195,000 per infraction which would amount to over $2 trillion dollars if we counted every Comcast customer. This is obviously impossible since it exceeds the gross revenue of any corporation in the USA.
February 7th, 2008
RBAC problems wipe out AT&T DSL in California
If things weren’t bad enough last night with the computer problems I had, things got worse when AT&T decided to do an unannounced maintenance. This was sort of similar to the massive network outage last year where the network goes down but they don’t even bother to tell their own first level support. You call in to tech support and they tell you jump through a bunch of hoops and crawl under the table to find your cable modem model numbers and detach your router and all the usual nonsense. Then they tell you that they might have to send a tech over the next day and how they won’t charge you if the problem isn’t on your end. Well I knew the problem wasn’t on my side so I demanded to be escalated to level 2 support where they confirmed my suspicions.
It turned out that AT&T was doing a 6-hour (12AM to 6AM) “maintenance” on a dozen of their California RBAC (Role Based Access Control) systems this morning which is their PPPoE authentication servers. This is exactly what I suspected since my DSL light was still on indicating that the link to the DSLAM was operational. The last place I lived two years ago my AT&T (SBC back then) DSLAM would die once a week so I know a DSLAM outage when I see one. This kind of service is ludicrous to me because if you’re doing this kind of authentication system maintenance, there should be redundant systems in place or they should simply let everyone on the network even if they can’t authenticate. It’s not like anyone can steal DSL access that easily anyways and we’re talking a short period of time. I’ve run my authentication servers for many years without ever having an outage and it’s ludicrous that AT&T would put their users through this nonsense.
In light of past cases where AT&T doesn’t tell level 1 support about these maintenance and outage issues and putting their customers through tech support hell, this seems to be a systematic breakdown in AT&T’s support infrastructure. I don’t know what it’s going to take to knock some sense in to AT&T’s customer support, but this just isn’t acceptable. It not only frustrates the level 1 support team and makes for unnecessary work on to the maintenance department; it’s just plain bad customer service.
February 7th, 2008
Podcast discussion on network management policies
I spent a little time chatting with some folks at the Technology Liberation Front doing a podcast today “Network Management Redux“. Sorry if I sounded a little groggy in the recording after the computer problems and AT&T DSL problems that kept me up all night.
I’ll be inviting some guests from some Washington Think Tanks for some of our own podcasts later on.
February 7th, 2008
First experiences with Vista SP1 RTM
[UPDATE 1/12/2008 2:55PM - Looks like my fellow blogger Ed Bott may have pulled through and found the answer in the quotation below. The lesson in this is to always update the motherboard BIOS when upgrading to a new OS. This shouldn't be too much of a surprise since this same rule applies to upgrading memory and CPUs as well.
Ed Bott: 2.07 (BIOS for IBM Thinkpad T60) is ancient, and according to the changelog Vista support was added in 2.09, so your BIOS is not Vista-compatible. The most up-to-date BIOS is 2.20:]
[UPDATE 1/12/2008 2:55PM - It looks like the IBM ThinkPad T60 lockups may have something to do with Vista SP1 after all. It locks up within 30 seconds when I boot the Vista SP1 fresh install DVD or when I boot Windows Vista that was upgraded to SP1 from a different DVD. My IT person loaded Windows XP on the laptop and it runs smoothly. He will load Windows Vista without SP1 and see if it is stable as well. More updates to come. Update 3:15PM - Looks like Vista without SP1 crashes too. This reminds me of the lone desktop machine I had last year that ran fine for a year on XP but was never able to load a fresh install of Vista without it crashing. This could be one of those hardware problems that only manifest itself when being taxed more by something like Windows Vista. Either way, we're trying to get to the bottom of this and this laptop is going back to where we bought it from.]
[Update 3:55PM - Seems like a hardware issue with this specific IBM ThinkPad T60 since Microsoft tells me they have plenty of T60s that are running fine with SP1. I was trying to recover some log files for Microsoft by booting the Windows Vista SP1 fresh-install DVD and it hung there and locked up the mouse too. That would seem to at least rule out DivX and it was a mere coincidence on the exact timing of the lockup. Heck the battery on it is dead too and the screen came with some scratches so it's time this dog of a laptop goes back to the IT department.]
I completed the first two installations of Vista SP1 RTM upgrade last night on to my primary desktop computer and my first Vista laptop meant to be my new work computer. The result is a near death experience with my desktop computer, and then a real death experience with the laptop (caused by hardware and not Vista SP1). I guess I should count myself lucky that it wasn’t my main computer that died since I haven’t migrated to the laptop for work yet. I will try to get some help from Microsoft to see if we can resolve this issue.
Near death with desktop computer:
The desktop computer almost didn’t make the upgrade but finally managed to pull itself out of the gates of hell. The SP1 upgrade on both computers took more than an hour to install along with multiple reboots. When the desktop system finally allowed me to log in, it went in to non-aero mode and it refused to let me flip in to aero. The sound was temporarily messed up but I managed to get it working after I enabled the sound. 5 minutes after I logged in the Windows SP1 upgrade finally told me it was finished which seems strange since you would think the user should be locked out until everything was done. Since I couldn’t get aero running I figured I’d try rebooting but the next reboot just seemed to hang on a black screen with a working mouse pointer for 5 minutes so I tried rebooting again. On that last reboot everything finally came up and I breathed a sigh of relief. [UPDATE 3:55PM - Microsoft says they are working with the driver developers on this to smooth out the install process]
Death of a laptop:
The laptop computer on the other hand went a little smoother on the SP1 upgrade and worked fine for about two hours until I installed the latest DivX codec and the whole machine just locked up after Vista popped up the Windows experience feedback prompt. Now this laptop locks up the entire computer within 15 seconds of logging in and there’s no way I even have time to run system restore to see if I can get it to the state right after I installed SP1. All I see is a locked up Vista screen and the laptop is as useful as a bookend. It is possible that this could be a hardware issue but the laptop was working fine up until this point. [UPDATE 3:55PM - It appears to be most likely a hardware issue with this specific IBM ThinkPad T60 laptop]
I don’t know if Vista SP1 just doesn’t like DivX or if it was just a coincidence and something else is causing this problem. I have the same DivX codec installed on my desktop computer this week but it was installed before last night when I installed Vista SP1. It’s quite possible that installing this version of DivX after SP1 will kill the computer but if this is the true, Microsoft needs to issue a warning and block this codec from installing after SP1 has already installed. If you’re planning on installing SP1 on your computer, DO NOT install DivX codec after you’ve installed SP1 until after I verify what’s going on and update this blog. If you have DivX codec installed already, then it doesn’t seem to be a problem.
Minute long login times for domain connected computers
The other problem I was told that Windows Vista SP1 would fix was the minute long login times for a Vista computer joined to an Active Directory. This turned out to be false at least in my case since it still takes 55 seconds of looking at the “Welcome” message after I type in my password. This doesn’t seem to be a problem coming out of suspend mode if you’re already logged in so it would only affect you if you reboot or log off the computer, but it’s annoying as hell and it really makes me think twice before using Vista in a business environment until these issues are solved.
[UPDATE 4:05PM - Microsoft explained to me that until a laptop at least logs in once on the corporate LAN and cache the domain controllers correctly, it will exhibit a 20 second delay per each domain controller the laptop knows of. That's a neat solution and all, but I know quite a few mobile workers who never go in to the corporate LAN and they need a solution where they can simply VPN in and get all this nonsense sorted out automatically and painlessly without flying in to an office with a permanent LAN or WAN connection to the Domain Controller]
Some improvements after SP1
My desktop computer seems to be a lot healthier now after I installed Vista SP1. The Vista install seemed to have gotten corrupted to the point that IE7 was locking up left and right while I kept getting these error messages from Windows Media Center Store Upgrade Manager shown in the figure below. [UPDATE 4:15AM - Looks like I may have spoken a bit too soon and the talkback tool here still locks up IE7 pretty hard on this computer. I'm not sure if it's related to the talkback or something else on that page that's causing it. All I know is that IE7 has been locking up hard on my Windows XP laptop and Vista machine for the last month or more.]
So far that error message hasn’t popped up yet [UPDATE 3:55PM - The message popped up again and it appears I need to rebuild the database score in Windows Media Center] and IE7 seems to have stabilized now and it’s no longer locking up the CPU to 100% utilization on a single CPU core[UPDATE 3:55PM - I'm working with Microsoft to figure this issue out and will update since it's still locking up in the talkback section]
The Windows networking indicator icon shown in the screenshot below seems to be a lot more responsive in discovering your network location. It completes in a few seconds after you log in rather than sometimes wait up to a minute pre-SP1. The laptop (before it died) also exhibited the same responsive network indicator icon. [UPDATE 3:55PM - Microsoft says quite a bit of work went in to the TCP/IP stack. This seems to be a good thing.]
Windows Movie Maker for Vista still a stinker:
If you’re wondering why I even bother with the DivX codec and Dr. DivX video encoder, it’s because Microsoft’s Windows Media Encoder 9.0 is old and doesn’t support high definition HDV formats yet and Windows Movie Maker for Vista is still garbage. If you attempt to use Windows Movie Maker to encode HDV videos, it will only encode one corner of the video at standard resolution and leave out most of the rest of the video frame. [UPDATE 3:55PM - Microsoft says they can encode HDV footage without problems so the problem may be caused by some codec conflicts. They also say that Microsoft Expression Encoder ($300) will work much better, though that's quite a bit more money than I want to spend since Dr. Divx is free.] The latest version of Dr. DivX (which requires the DivX codec) will handle High Definition .dvr-ms files and let you encode in to the desired video format for DVD set-top box playback or for YouTube optimized format. I’d love to be able to encode in to the 1080p Windows Media Advanced Profile format that Windows Media Encoder 9 promises but the software simply doesn’t work.
Making things worse, I was hoping Windows Movie Maker which only comes with the Premium or Ultimate Edition would actually be a complete application by now but I would be disappointed again. The old Windows Movie Maker in Windows XP was a free download and it allowed you to select the part of the tape you want to record off your DV camcorder but HDV format wasn’t supported at all. The new Windows Movie Maker for Vista does support HDV format but it teases you by asking you if you want to “Import entire videotape or just parts?”. Then it only gives you the option to “Import the entire videotape to my computer” as shown in the screenshot below. If anyone knows of a cheap or free non-bloated HDV capture program for Windows, please tell me in the talkback.
Fortunately DivX codec and Dr. DivX works on my desktop computer since they were installed before SP1 so I will need to get verification of the problems on my new work laptop.
Now at this point it’s still to early to draw any conclusions about Vista SP1 and the problems I faced may be unique to my particular setup or hardware. It certainly doesn’t make a good first impression for me and you need to be careful anytime you install a major upgrade like this. Please check back here for updates and status reports on these problems.
February 4th, 2008
Windows Server 2008 and Vista SP1 RTM today
Microsoft has reached a major milestone today for its Windows Server and Client products. Windows Server 2008 and Windows Vista Service pack 1 have been released to manufacturing today which means they will soon be available to IT customers and consumers. Windows Server 2008 replaces the venerable Windows Server 2003 while Vista SP1 upgrades the somewhat controversial Windows Vista. If this looks like a coincidence that Vista SP1 and Server 2008 launched at the same time, it’s not. These two products share the same kernel and they were finished together and launched together by design.
Windows Server 2008 will have key enhancements in Virtualization both on the OS kernel side and the hosting side, but the hosting side of the equation won’t appear for another six months in the form of Windows Hypervisor. The OS kernel side optimizations come in the form of “enlightened” (AKA paravirtualized) IO optimizations for video, storage, networking, and memory. The Hypervisor will take advantage of these kernel enhancements to reduce the overhead associated with virtualization. Other virtualization vendors will most likely license or negotiate rights to these kernel enhancements in virtualization if they wish to host Windows Server 2008 efficiently. Older server operating systems like Windows 2000 and 2003 server will later be retrofitted with just the I/O optimizations but not the full kernel modifications that optimize Memory and CPU operations.
Windows Server 2008 will also have a stripped down headless operation mode called “Core installation” that increases reliability and security because it reduces the code foot print. This in turn also reduces the need for reboots because components that would normally need to be updated simply won’t be installed in the first place. Server 2008 will also have a fast kernel mode IIS web server as well as enhancements to Routing and Remote Access such as SSTP (Secure Socket Tunneling Protocol). SSTP puts a NAT- and proxy-friendly wrapper around the PPTP and L2TP protocol for trouble free VPN access.
Windows Vista will get some sorely needed enhancements on stability. The size and scope of enhancements and changes to Windows Vista over previous generation Windows XP has resulted in some major growing pains both in OS and driver stability. While many of these issues have already been hammered out, annoying problems like a minute long wait to login a Vista machine in to an Active Directory domain and slow network file copies are now fixed in Vista SP1. Other controversial features like a Windows Vista kill switch have been removed. On the usability front, the aforementioned SSTP feature in Windows Server 2008 can now be leveraged using the new SSTP client in Windows Vista SP1. In the coming weeks, I will be eager to test both of these products.
January 30th, 2008
Painful lesson in OLPC mesh networking for Mongolians
The Mongolians have had a painful lesson on mesh networking according to the OLPC current events webpage. Broadcast storms in the overly dense mesh environment along with excessive mDNS broadcast traffic seem to have crippled the Gobi desert experiment. Here’s an excerpt:
We have painfully discovered the limitations of the mesh and current collaborative software in Mongolia, where the convolution of the number of laptops with bugs #5335 (more mDNS traffic than expected) and #5007 (mesh repeats multicast too much) make the perfect storm, which prevents anybody from using the network. We will continue to improve the mesh performance, but clear guidelines are needed as to what network infrastructure to deploy under what conditions. Once a certain density of students is exceeded, a wired backbone and conventional access points will be required.
The limitations of mesh topology are well known in the wireless engineering community and I’ve raised the issue and pointed out the limitations last September. Each mesh hop you add increases the propagation delay as well as multiply the radio traffic and congestion. Performance on a mesh network is fundamentally many times slower than a non-mesh network and when the density gets high enough, the system simply breaks down.
When on a tight budget, I had always recommended the usage of a cheap $60 router running open source DD-WRT would have sufficed and you get a free router with it which you need for IP sharing anyways. The addition of a high-powered antenna would allow the access point to hear distant signals from faint clients and it will amplify the broadcast signal. A simple in-door $26 9 dBi antenna placed up high can easily cover a small school. A $60 12 dBi outdoor antenna positioned on the roof would easily cover an entire campus. If you put two centralized Access Points and large antennas on channel 1 and 11 (avoid adjacent channels because of channel bleeding) in the 2.4 GHz spectrum, you can load balance and have redundancy if one set of AP/antenna fails.
My fellow blogger and teacher Chris Dawson feels that the ability to do peer-to-peer collaboration with or without an Access Point has great potential. But peer-to-peer wireless collaboration could have been done with regular ad hoc networking technology without the expense or problems of a full 802.11s mesh implementation.
The inclusion of full 802.11s stack has been challenging. The need for a radio system that stays on and continues to forward packets even while the laptop is off added unnecessary expenditure to the OLPC XO and it unnecessarily drains the laptop batteries. When you multiply this expense and complexity across all the clients and realize that the wireless access point comes free with the router, it becomes clear that this may not have been the best design decision.
January 26th, 2008
Network Neutrality Summit at University of San Francisco
I will be speaking at the Network Neutrality Summit this morning at the University of San Francisco. They will be streaming this event LIVE at ustream.tv. Fireworks start at 9:00AM which is the panel I will be on with:
- Richard Clarke - AT&T
- Lawrence Spiwak, Phoenix Center for Advanced Legal & Economic Public Policy Studies
- George Ou - ZDNet
- Marham Erickson - Open Internet Coalition
- Timothy Wu - Columbia Law School
Hope to see you there or catch it live on the Internet.
January 18th, 2008
Don't believe the low bit-rate 'HD' lie
Update 6:00PM - Here’s what fake HD video looks like.
Last week at CES, Comcast announced their “HD” video on demand download service over its future DOCSIS 3.0 that allows 4 minute downloads of entire HD movies. Attendees at MacWorld this week were told that disk-based HD formats like HD DVD and Blu-ray are essentially obsolete because you can simply download “HD” movies from your Apple TV 2.0 box on demand. Microsoft started offering HD downloads for the XBOX360 starting in late 2006. You can even watch “HD” videos from ABC right from the web. There are even YouTube competitors that offer user uploaded “HD” content. There’s just one minor little problem, it’s not HD.
As I’ve tried to educate my readers last year with my blog “Why HD movie downloads are a big lie“, these so-called HD movies use very low bit-rates compared to even standard definition DVDs let alone something like HD DVD or Blu-ray DVD. Raw uncompressed 1080p video at 60 frames per second is about 3000 mbps so even HD DVD’s 28 mbps needs to be compressed about 107 to 1 with the H.264 or VC-1 codec. By all reasonable standards this needs to be the minimum bit-rate for acceptable loss in quality on 1080p video.
Updated 4:30PM - Standard definition 480i DVD movies are typically 5 to 8 mbps (megabits per second) MPEG-2 whereas these so-called HD wannabes weigh in at a pathetic 1.5 to 4 mbps of 720p H.264. Apple’s new HD service is capable of 4 mbps which simply isn’t enough to be considered HD. XBOX360 downloads are 6.8 mbps 720p VC-1 so they’re semi-decent borderline HD. Marketing will push the nicer sounding “720p” aspect of the video but they don’t tell you it’s way too compressed to offer good video fidelity. Blu-ray has a maximum bit-rate of 40 mbps while HD DVD offers a maximum of 28 mbps. Over the air broadcasts can be up to 24 19.38 mbps.
Modern video compression codecs like H.264 or VC-1 can hide these compression artifact problems much better than MPEG-2 video compression but there’s only so much it can do. At best you might get away 50% more compression over older compression technology but 1.5 to 4 mbps H.264 will not be better than 8 mbps MPEG-2 under most video complexity requirements. The only time 4 mbps 720p will look better than 8 mbps 480i is when the video on the screen is almost entirely stationary or it’s a low-complexity video such as animation movies. Under most normal circumstances, the low bit-rate 720p so-called “HD” video will be inferior though many companies are betting that consumers won’t know any better.
So the bottom line is that so-called “HD” video from Microsoft’s XBOX360 HD download service and Apple’s new Apple TV service or any other web download service is simply not HD by any respectable definition. These companies cannot and should not use the “HD” name with video that is lower fidelity than standard DVD. As for Comcast, there’s not much detail on it but I highly doubt it’s more than 4 to 8 mbps even on DOCSIS 3.0 because its 160 mbps total capacity is divided between 50 to 400 customers. Only FiOS technology with its massive 620 mbps per 32-user capacity and possibly U-Verse (but slower than real time) has sufficient last-mile capacity to deliver true HD movie downloads at the quality of HD DVD and Blu-ray technology.
I’m not saying that you shouldn’t buy these services from Apple, or other services that offer low bit-rate 720p video downloads, but consumers must be aware of the fact that they’re slightly worse than a 1080p up-converted DVD. Microsoft’s XBOX service is border-line HD that is slightly better than DVD but nowhere near 1080i over-the-air HD broadcast quality.
January 14th, 2008
Samsung multi-function printers scan direct to USB
Unfortunately, one of the least used features on all-in-one multi-function printers and heavy duty copier/scanner/printer machines is the scan function because it’s simply too complicated. If you’re lucky, IT will set up your email account as a preconfigured setting and they’ll teach you how to scan a document to your email inbox. If you’re geeky enough to go and figure out how to key in your own email, then you might be one of the other two people in the building that uses the scan functionality. But most people simply keep paper copies and do everything the way they’ve always done it by making more copies and storing them in a file cabinet if they’re organized enough. Well Samsung might actually change this with their direct to USB multi-function printers.
One of the features I’ve searched long and hard for is a scan-to-USB feature. I’ve asked representatives from Xerox and every other copier company that offers multi-function copiers with little luck. I’ve asked HP for this feature and no luck there either. But last week as I went through Samsung’s CES booth, I thought I’d check out their color multifunction printers and I notice a nice little USB port in the front of them. The Samsung representative explained that the USB port can act as a print source or scan destination and I thought FINALLY we’ve made scanning easy.
The color multi-function printers in question are the Samsung CLX-3160 (pictured left) and the yet-to-be-released CLX-6200. Both devices can print an assortment of document types such as PDF, JPEG, TXT, etc directly from USB memory. Both devices can also scan documents and save them directly to the USB memory. This means that instead of trying to figure out how to configure an email destination which is difficult without a qwerty keyboard or figure out how to dump to a scan to a network file share, you simply dump the scan to USB. Now you just take those stacks of documents and shove it in the feeder and it will get digitized on to USB memory!
The difference between the Samsung CLX-6200 and CLX-3160 is that the 6200 can print all four colors at the same time whereas the 3160 does color one color at a time. This means that the 6200 prints color more than four times faster than the 3160 and it also prints black and white a little faster. The 6200 will also print full duplex two-sided output automatically which cuts down paper consumption in half if only people can be educated on using it. The 3160 is available now online for roughly $450. The 6200 will launch at the end of this quarter for $200 more than the 3160 and should be well worth the price as a workgroup all-in-one. Personally I wouldn’t mind having one of these near my cubical.
January 9th, 2008
This ad brought to you via Bluetooth
I spoke to Tiffany Burns from iSign Media Corp at a CES party last night which offers some interesting if not controversial technology. This technology will send you spa, I mean advertisements to you via Bluetooth technology. Ms. Burns touted the fact that these ads were free since they weren’t eating up any cell phone time or racking up messaging charges, but my immediate reaction was what happens if the user doesn’t want to see the ad. Burns’ responded that the user can simply hit no on the yes/no dialog but I asked what if the user doesn’t even want to see these ads ever, not even the prompting. The response was to turn off Bluetooth which didn’t make me any more comfortable since people may not know or may not want to shut off Bluetooth on their cell phone.
Now I have my personal feelings about this technology but I want to hear what you have to say about this so I put up the following poll. Please feel free to comment in the talkback section too.
Loading ...December 10th, 2007
Why metered Internet is a really bad idea
The above image from Lauren Weinstein’s blog shows why metered Internet is a really bad idea and obnoxious. It shows Canadian ISP Rogers Internet altering web pages to warn you when you go over 75% of your 75GB cap. I checked on the Rogers website for the Toronto Ontario area and 1 mbps service was $33 CAD (worth more than US dollars these days) per month with a 60 GB monthly cap. That effectively means you can only use BitTorrent for about 6 days out of the month. Compared to the Australian plans which have 8GB noon to midnight caps that the EFF was touting as the “better” alternative to Comcast BitTorrent seed throttling, Rogers seems like a pretty good deal. However, it’s still nowhere near as good as the US ISPs that don’t use metered internet plans.
There are plenty of price tiers in the US that work by limiting the rate at which you can download but not the amount you can download so it’s not like everyone is forced to subsidize the big bandwidth users. You can get 768 kbps DSL plans in the US for $15/month which still allow you to theoretically download 248 GBs per month if you kept it running continuously. This offers the best compromise where Internet usage isn’t stifled by constant fears of going over the limit or what time of the day it is like your cell phone.
My AT&T DSL plan is 1.5 (good for 1.2 mbps due to distance or line quality) costs $20/month with no metering. I’ve also had Comcast in the past and they charged less than $40/month with roughly 5 mbps service and they didn’t have any gigabyte caps (excluding NNTP news server which doesn’t count as network utilization). Comcast doesn’t even throttle BitTorrent uploads or downloads, they only limit the number of BitTorrent seed connections you can serve at a time to alleviate the network load. Now is this really that bad of a trade-off to ensure that a few BitTorrent users don’t overwhelm the majority of users and make everyone suffer? Even if you throttled BitTorrent upload/downloads by 50% throughput (which isn’t being done) and “only” allowed them to download 200 GBs per month instead of 400 GBs per month, is that really so unfair?
On a related note which I also posted as an update, the EFF has responded to me and others that I have misrepresented their position in my blog titled EFF wants to saddle you with metered Internet service. I’ll let you be the judge of that so here is what they sent me and what they’re telling everyone else.
The article incorrectly states that EFF endorses legislation or regulation that would force ISPs or users to offer only metered services. The EFF report actually states that the *availability* of metered access alongside “all you can eat” plans, combined with accurate advertising by ISPs, is one alternative that might solve whatever congestion issues Comcast might be having (as the language you quote in your article expressly makes clear).
Nowhere in my blog post do I state EFF would force ISPs to *only* offer metered services? All I said was “The EFF goes as far as touting the Australian model for broadband service” as a better alternative to Comcast’s current model and I included the Australian ISP link the EFF pointed to. The plans that came up were mostly metered plans and some were very expensive unlimited plans. Peter Eckersley even sent me an email touting this page where you pay $65/month AUD for a plan that gives you 8 GB of “pre-paid data” during noon to midnight [Update 12/12/2007 - Peter Eckersley emailed me saying he sent me the wrong link and had meant to link to this page which is $20 cheaper. That's slightly better but the 8GB cap is still a horrible idea]. Since you can download 8 GBs in less than 2 hours at 10 mbps, you essentially give up using any BitTorrent from noon to midnight unless you want to pay $3/GB. Even the off-peak rates are metered so you still have to be careful to turn off your BitTorrent client after 1 hour each day. If you want 48 GB “pre-paid data”, you need to pay $120/month AUD and $3/GB over that amount.
Now consider Comcast’s offerings which permit you to download and upload unlimited data using BitTorrent with no throttling for a flat fee of $40 per month. You can easily download 100 GBs and upload 10 GBs per month or more and Comcast won’t stop you or charge you anything extra. The only thing Comcast does is occasionally scale back the number of BitTorrent seed connections (dedicated server mode) you can have even though Comcast’s TOS (Terms Of Service) prohibits servers of any kind. My ATT DSL plan is less than $20/month and I can download 8 GB per day every day and not pay a single cent on overage charges so what is the EFF thinking recommending the Australian ISP model over Comcast’s “bad” model?
The EFF says what Comcast is doing is evil and that the Australian model is the better alternative even though it’s draconian compared to what Comcast or any other American ISP is doing. It would certainly stop the BitTorrent usage during peak hours but at what price to the user? The Free Press and Public Knowledge also think metered Internet is a better alternative but they go a step further and want to criminalize Comcast’s current operating model and fine them trillions of dollars. So again I ask: Who is the EFF, Free Press, and Public Knowledge serving? The RIAA and MPAA couldn’t buy this kind of anti peer-to-peer lobbying if they tried.
George Ou is Technical Director of ZDNet. See his full profile and disclosure of his industry affiliations.
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