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Archive for the ‘Telecom and Networking’ Category

Future of Mobile Slides

Saturday, May 19th, 2012

IGNITION WEST: Future of Mobile article constains an interesting slide set that puts together a deck on the current trends in mobile. The slide set by BI Intelligence service looks closely at the growth of smartphones and tablets, the platform wars, and how consumers are actually using their devices.

Android will be the OS of the future because it is implemented by more and more hardware makers! But Apple has done an impressive job of hanging in there. And, thus far, developers have not rallied around Android in the same way as iOS.

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According to this production the number of PCs does not seem to be decreasing in the future. The growth of PCs seems to continue to grow at current rate. In addition to this are the bigger growth in mobile and tablets. Post-PC revolution seems to be so that PCs don’t go away, just a larger number of new smart devices are taken into everyday use.

High power PoE and HDBaseT

Wednesday, May 2nd, 2012

Power over Ethernet (PoE) offers convenience, flexibility, and enhanced management capabilities by enabling power to be delivered over the same CAT5 cabling as data. This technology is especially useful for powering IP telephones, wireless LAN access points, cameras with pan tilt and zoom (PTZ), remote Ethernet switches, embedded computers, thin clients and LCDs.

The original IEEE 802.3af-2003 PoE standard provides up to 15.4 W of DC power (minimum 44 V DC and 350 mA) supplied to each device. The IEEE standard for PoE requires Category 5 cable or higher (can operate with category 3 cable for low power levels).

The updated IEEE 802.3at-2009 PoE standard also known as PoE+ or PoE plus, provides up to 25.5 W of power.

Although 2009 standard prohibits a powered device from using all four pairs for power, some vendors have announced products that claim to be compatible with the 802.3at standard and offer up to 51 W of power over a single cable by utilizing all four pairs in the Category 5 cable. The trend for power demands seem to be up.

Compliance to Power-over-Ethernet safety standards is critical when moving beyond 60W (EE Times)and Compliance with POE safety standards is critical when moving beyond 60W (EDN) articles tells that the current generation of standards-based technology enables up to 60 watts of power to be delivered over four pairs of cabling, which also improves efficiency when compared to earlier two-pair solutions. Compliance with POE safety standards is critical when moving beyond 60W.

As the industry moves toward delivering even more power over the CAT5-or-better cabling infrastructure, system designers and network administrators alike, need to understand various emerging technology options. Some new options can bring expensive and cumbersome deployment complications and, potentially, safety risks.

Some manufacturers have touted their own 100W-per-port solutions or even 200W/port solutions that are not safe. The use of a standard Ethernet-cabling infrastructure for a single port delivering greater than 100W is simply not safe under the NEC standard. The only safe approach for powering devices over Ethernet cabling is to follow IEEE802.3at-2009 specifications. Moving beyond the LPS requirement (sub-100W/port LPS requirement of IEC 60950-1:2011) to greater-than-100W/port implementations requires that the cables be protected with special flame-resistant conduit. A metal enclosure is required if the total PD load is greater than 100W for information data equipment, or greater than 15W for TV and audio equipment.

One standardized 100W solution is one used by HDBaseT Alliance. HDBaseT Alliance is develops 100W power specifications for products that transport uncompressed, high-bandwidth multimedia content, 100BaseT Ethernet, power, and various control signals through a single LAN cable. The key differences between the HDBaseT-powering approach and those from other independent manufacturers pursuing higher power levels are that it:

  • Complies with the section 33.7.1 of the IEEE802.3at-2009 standard, which mandates that all PSEs conform to International Electrotechnical Commission (IEC) 60950-1:2001 specifications including classification as a Limited Power Source (LPS) carrying no more than 100 volt-ampere (VA) – or 100W – per port without the need for special over-current protection devices, and
  • Performs Powered Device (PD) detection followed by PD classification to determine a PD’s consumed power level prior to its ignition.

In a typical HDBaseT implementation, the PSE is installed and powered by a 50 to 57-volt DC power supply, and all PDs receive power directly over the HDBaseT link across all four pairs of CAT5-or-better cables. Additionally, core PoE technology has been enhanced for HDBaseT to use a 1 amp current for every two cabling pairs, 3-event classification to identify compliant PSEs, and identify the cable length/resistance (draw more power when required not exceeding 100W, rather than assuming a worst-case cabling infrastructure at all times). This enables HDBaseT technology to transfer of up to 100W of continuous DC power, per port, from one side of the HDBaseT link to the other.

HDBaseT is fully backwards-compatible with the IEEE802.3at-2009 PoE specification. HDBaseT also does not infringe on any of the mandated PoE safety requirements.

HDBaseT’s ability to deliver up to 100W of power (over 100m, via a single LAN cable, without any additional power source) is actually very nicely aligned with trends in energy usage and demand. The power level is more than adequate for supporting today’s typical 40-inch LED TV, which requires 70W of power. It is expected that both LCD and LED TV monitors will soon be averaging approximately one watt of power consumption per inch of screen size. Regardless of screen size EnergyStar™ 6.0 is targeting a cap of 85 W for all screen sizes.

PoE continues to evolve and offer an even wider variety of high-value power-delivery and management capabilities.

How Clean is Your Cloud and Telecom?

Wednesday, April 18th, 2012

Greenpeace report How Clean is Your Cloud? I saw mentioned in 3T magazine news is actually quite interesting reading. This year’s report provides a look at the energy choices some of the largest and fastest growing IT companies. The report analyzes the 14 IT companies and the electricity supply chain in more than 80 data center cases.

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The report contains also lots of interesting background information on both IT and telecom energy consumption. I recommend checking it out. Here are some points picked from How Clean is Your Cloud? report:

Facebook, Amazon, Apple, Microsoft, Google, and Yahoo – these global brands and a host of other IT companies are rapidly and fundamentally transforming the way in which we work, communicate, watch movies or TV, listen to music, and share pictures through “the cloud.”

The growth and scale of investment in the cloud is truly mind-blowing, with estimates of a 50-fold increase in the amount of digital information by 2020 and nearly half a trillion in investment in the coming year, all to create and feed our desire for ubiquitous access to infinite information from our computers, phones and other mobile devices, instantly.

The engine that drives the cloud is the data center. Data centers are the factories of the 21st century information age, containing thousands of computers that store and manage our rapidly growing collection of data for consumption at a moment’s notice. Given the energy-intensive nature of maintaining the cloud, access to significant amounts of electricity is a key factor in decisions about where to build these data centers. Industry leaders estimate nearly $450bn US dollars is being spent annually on new data center space.

Since electricity plays a critical role in the cost structure of companies that use the cloud, there have been dramatic strides made in improving the energy efficiency design of the facilities and the thousands of computers that go inside. However, despite significant improvements in efficiency, the exponential growth in cloud computing far outstrips these energy savings.

How much energy is required to power the ever-expanding online world? What percentage of global greenhouse gas (GHG) emissions is attributable to the IT sector? Answers to these questions are very difficult to obtain with any degree of precision, partially due to the sector’s explosive growth, a wide range of devices and energy sources, and rapidly changing technology and business models. The estimates of the IT sector’s carbon footprint performed to date have varied widely in their methodology and scope. One of the most recognized estimates of the IT sector’s footprint was conducted as part of the 2008 SMART 2020 study, which established that the sector is responsible for 2% of global GHG emissions.

The combined electricity demand of the internet/cloud (data centers and telecommunications network) globally in 2007 was approximately 623bn kWh (if the cloud were a country, it would have the fifth largest electricity demand in the world). Based on current projections, the demand for electricity will more than triple to 1,973bn kWh (an amount greater than combined total demand of France, Germany, Canada and Brazil).

The report indicates that, due to the economic downturn and continued energy efficiency and performance improvements, global energy demand from data centers from 2005-2010 increased by 56%. Estimates of data center electricity demand come in at 31GW globally, with an increase of 19% in 2012 alone. At the same time global electricity consumption is otherwise essentially flat due to the global recession is still a staggering rate of growth.

Given the scale of predicted growth, the source of electricity must be factored into a meaningful definition of “green IT”. Energy efficiency alone will, at best, slow the growth of the sector’s footprint. The replacement of dirty sources of electricity with clean renewable sources is still the crucial missing link in the sector’s sustainability efforts according to the report.

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The global telecoms sector is also growing rapidly. Rapid growth in use of smart phones and broadband mobile connections mean mobile data traffic in 2011 was eight times the size of the entire internet in 2000. It is estimated that global mobile data traffic grew 133% in 2011, with 597 petabytes of data sent by mobiles every month. In 2011, it is estimated that 6 billion people or 86.7% of the entire global population have mobile telephone subscriptions. By the end of 2012, the number of mobile connected devices is expected to exceed the global population. Electronic devices and the rapidly growing cloud that supports our demand for greater online access are clearly a significant force in driving global energy demand.

What about telecoms in the developing and newly industrialized countries? The report has some details from India (by the way it is expected that India will pass China to become the world’s largest mobile market in terms of subscriptions in 2012). Much of the growth in the Indian telecom sector is from India’s rural and semi-urban areas. By 2012, India is likely to have 200 million rural telecom connections at a penetration rate of 25%. Out of the existing 400,000 mobile towers, over 70% exist in rural and semi-urban areas where either grid-connected electricity is not available or the electricity supply is irregular. As a result, mobile towers and, increasingly, grid-connected towers in these areas rely on diesel generators to power their network operations. The consumption of diesel by the telecoms sector currently stands at a staggering 3bn liters annually, second only to the railways in India.

What is the case on other developing and newly industrialized countries? I don’t actually know.

NOTE: Please note that that many figures given on the report are just estimates based on quite little actual data, so they might be somewhat off the actual figures. Given the source of the report I would quess that if the figures are off, they are most probably off to direction so that the environmental effect looks bigger than it actually is.

Secret world of submarine cables

Saturday, April 14th, 2012

Links between cities and cables that run alongside roads and into houses and officers are certainly impressive — and without them we wouldn’t have high speed internet. The secret world of submarine cables article tells that Internet’s largest and most important champions are the privately-owned submarine cables that orbit the Earth. The submarine telecommunications industry has deployed the core of the global fiber grid by setting up full duplex telecommunications solutions between continents. Across these cables, which span distances of up to 13,000 km, terabits of information squirt from one side of the planet to another. These fiber optic cables are just three inches thick, and have total capacities of between 40Gbps and 10Tbps. These solutions rely on fiber-optic cables, equipped with high reliability submerged repeaters, which are DC-powered through subsea cable from power feeding equipment in the shore stations.

The generation of submarine fiber-optic cables that revolutionized trans-oceanic telecommunications a decade ago is being retired prematurely. New Life For Undersea Fiber article tells that once the marvel of the telecom world, the first undersea fiber optic cables have reached the point of telecom obsolescence some years ago. The downfall of the first generation of submarine fiber-optic cables was their need for repeaters-devices that boosted the signal strength periodically to enable the information-carrying light waves to span the whole ocean. Early fiber repeaters had to convert faint optical signals to electronic form so they could be amplified, then convert the electrical signals back into light.

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In the late 1980s, a new kind of optical fiber was developed that could amplify weak optical signals. An optical fiber amplifier can simultaneously amplify dozens of optical channels since they do not convert each channel into electronic signals separately. Optical fiber amplifier is a section of optical fiber that is doped with a rare-earth element such as erbium or praseodymium and powered with pump laser. Optical fiber amplifier was a huge improvement because it can amplify many signals at different wavelengths at the same time. DWDM is a real boon for oceanic optical fiber cables, allowing the increase of bandwidth without laying new cables undersea. In fact, the utilization of DWDM technology for submarine cable design is trending toward less fiber pairs per cable, significantly reducing the costs associated with intercontinental connections. Many of these use 80 DWDM channels at up to 10 Gbps per fiber pair.

A common sea-going fiber type specification is G.654. Rarely used terrestrially, G.654 fiber is a modified version of the G.652 fiber specification. With G.654, attenuation loss of optical fiber (less than 0.2 dB per km) is reduced to the minimum. Fiber amplifiers still require electrical power, which is fed to them through insulated copper cables, essentially superoceanic electrical extension cables that run down the length of the fiber cable.

Unrepeatered Submarine Fiber Optics Systems represent a new market opportunity for existing and new players in the market. As the technology has developed the capability of unrepeatered undersea fiber optic links continues to increase, opening up new markets where only the cable is placed underwater and the electronics are located in a benign environment on the shore. Unrepeatered systems also require less investment and lower cost for installation and operation. Hence, many smaller players are now able to enter the market. Similar to the repeatered long distance systems, unrepeatered systems are being driven by the unprecedented growth of the internet.

Both old and new ways of sinking a cable into the Pacific, Atlantic, Indian, and even Arctic Oceans requires a billion-dollar logistical feat that requires months or even years to enact. The secret world of submarine cables article has nice map of cables. Read more about optical submarine cables on Wikipedia. Undersea cable system: Technical overview & cost considerations is also good reading.

Managed Ethernet Infrastructure for show control

Sunday, March 18th, 2012

John Huntington’s Entertainment Technology Site blog has an interesting article series on using Ethernet on show control applications. The articles concentrate on Gravesend Inn haunted attraction, that is a pretty good reflection of the progress of networking technology in the field of entertainment control. Back in 1999, was built around around hard wired sensors/closures and by 2011, almost every single control system was moved fully onto out integrated, managed, VLAN’d network.

Managed Switch/Routing Ethernet Infrastructure for The Gravesend Inn, Part I talks about the evolution of the network for the Gravesend Inn, and gaves a little background on VLANs and managed switches.

Managed Switch/Routing Ethernet Infrastructure for The Gravesend Inn, Part II talk more about the specifics of the implementation of the Gravesend Inn network.

How I’m Being Followed on Web

Friday, March 2nd, 2012

I’m Being Followed: How Google—and 104 Other Companies—Are Tracking Me on the Web is a voyage into the invisible business that funds the web. Who are these companies and what do they want from me? Even if you’re generally familiar with the idea of data collection for targeted advertising, the number and variety of these data collectors will probably astonish you. Right now, a huge chunk of what you’ve ever looked at on the Internet is sitting in databases all across the world.

Many different companies want to know as much about me and what’s on my screen as they possibly can, although they have different reasons for their interest. To be clear, these companies gather data without attaching it to your name (most of the companies do not know names of the people they are following); they use that data to show you ads you’re statistically more likely to click. That’s the game, and there is substantial money in it. Some of the best minds of my generation are thinking about how to make people click ads (think for example how many highly talented people Google has). The online advertising industry argues that technology is changing so rapidly that regulation is not the answer to queasiness about all that data going off to who-knows-where.

The bad news is that people haven’t taken control of the data that’s being collected and traded about them. At the moment there is a fascinating scrum over what “Do Not Track” tools should do and what orders websites will have to respect from users. Do Not Track signals a user’s opt-out preference with an HTTP header. Several large third parties have already committed to honor Do Not Track, but many more have been recalcitrant.

It’s now time for us to watch the watchers. Track Who’s Tracking You With Mozilla Collusion. Collusion is a Firefox browser add-on that lets you track who’s tracking you across the web for behavioral targeting purposes. There is a demonstration put up at collusion.toolness.org, which takes you through five popular websites and visualizes the data collection companies that track you across them. From there, you can download the add-on if you want to see the tracking visualization of your own browsing behavior evolve in real-time.

collusion

Collusion looks to offer more transparency to users by creating a visualization of how your data is being spread to different companies as you navigate the web. Each time it detects data being sent to a behavioral tracker, it creates a red (advertisers), grey (websites) or blue dot on the visualization and shows the links between the sites you visit and the trackers they work with. Mozilla has created an online demo to show just how quickly your data ends up in the hands of dozens of different companies as you move on popular web popular sites.

If you need the source code, it’s all at github.com/toolness/collusion. For some more details take a look at Toolness Blog posting on Collusion. This is an interesting experiment to track on who is tracking you. Collusion is about alerting users to tracking that’s happening without their consent. Very interesting! The more access to metrics the better.

Tell your IT problems in time

Monday, January 30th, 2012

Our society relies increasingly on information technology (IT). In such a society, it is important that we, as citizens, trust and are satisfied with services utilizing IT. Unfortunately, IT problems in the use of services are part of our daily lives and. And they are frequently reported by the mass media.

Usually most of the IT problems visible to society are the same ones that system and service providers perceive to be the most problematic. Compensation alone will not satisfy users when the incident creates unpredictability and uncertainty for them. After service degradation, users are eager to use the service again if they receive relevant information. Information and knowledge thus play a significant role in incidents. Users will continue to IT after the failure, using a service, most likely, when they get the problem situation in a sufficient factual information.

This is stated in a recent Finnish study, doctoral thesis Information technology incidents in the present information society : Viewpoints of service providers, users, and the mass media, which examined the users’ thinking and intentions of the services provided at the time of their IT-related problems after the failures.

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Clear information can bring significant competitive advantages over other service providers.

Computer technologies for 2012

Wednesday, January 25th, 2012

ARM processor becomes more and more popular during year 2012. Power and Integration—ARM Making More Inroads into More Designs. It’s about power—low power; almost no power. A huge and burgeoning market is opening for devices that are handheld and mobile, have rich graphics, deliver 32-bit multicore compute power, include Wi-Fi, web and often 4G connectivity, and that can last up to ten hours on a battery charge.The most obvious among these are smartphones and tablets, but there is also an increasing number of industrial and military devices that fall into this category.

The rivalry between ARM and Intel in this arena is predictably intense because try as it will, Intel has not been able to bring the power consumption of its Atom CPUs down to the level of ARM-based designs (Atom typically in 1-4 watt range and a single ARM Cortex-A9 core in the 250 mW range). ARM’s East unimpressed with Medfield, design wins article tells that Warren East, CEO of processor technology licensor ARM Holdings plc (Cambridge, England), is unimpressed by the announcements made by chip giant Intel about the low-power Medfield system-chip and its design wins. On the other hand Android will run better on our chips, says Intel. Look out what happens in this competition.

Windows-on-ARM Spells End of Wintel article tells that Brokerage house Nomura Equity Research forecasts that the emerging partnership between Microsoft and ARM will likely end the Windows-Intel duopoly. The long-term consequences for the world’s largest chip maker will likely be an exit from the tablet market as ARM makes inroads in notebook computers. As ARM is surely going to keep pointing out to everyone, they don’t have to beat Intel’s raw performance to make a big splash in this market, because for these kinds of devices, speed isn’t everything, and their promised power consumption advantage will surely be a major selling point.

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Windows 8 Release Expected in 2012 article says that Windows 8 will be with us in 2012, according to Microsoft roadmaps. Microsoft still hinting at October Windows 8 release date. It will be seen what are the ramifications of Windows 8, which is supposed to run on either the x86 or ARM architectures. Windows on ARM will not be terribly successful says analyst but it is left to be seen is he right. ARM-based chip vendors that Microsoft is working with (TI, Nvidia, Qualcomm) are now focused on mobile devices (smartphones, tablets, etc.) because this is where the biggest perceived advantages of ARM-based chips lie, and do not seem to be actively working on PC designs.

Engineering Windows 8 for mobile networks is going on. Windows 8 Mobile Broadband Enhancements Detailed article tells that using mobile broadband in Windows 8 will no longer require specific drivers and third-party software. This is thanks to the new Mobile Broadband Interface Model (MBIM) standard, which hardware makers are reportedly already beginning to adopt, and a generic driver in Windows 8 that can interface with any chip supporting that standard. Windows will automatically detect which carrier it’s associated with and download any available mobile broadband app from the Windows store. MBIM 1.0 is a USB-based protocol for host and device connectivity for desktops, laptops, tablets and mobile devices. The specification supports multiple generations of GSM and CDMA-based 3G and 4G packet data services including the recent LTE technology.

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Consumerization of IT is a hot trend that continues at year 2012. Uh-oh, PC: Half of computing device sales are mobile. Mobile App Usage Further Dominates Web, Spurred by Facebook article tells that the era of mobile computing, catalyzed by Apple and Google, is driving among the largest shifts in consumer behavior over the last forty years. Impressively, its rate of adoption is outpacing both the PC revolution of the 1980s and the Internet Boom of the 1990s. By the end of 2012, Flurry estimates that the cumulative number of iOS and Android devices activated will surge past 1 billion, making the rate of iOS and Android smart device adoption more than four times faster than that of personal computers (over 800 million PCs were sold between 1981 and 2000). Smartphones and tablets come with broadband connectivity out-of-the-box. Bring-your-own-device becoming accepted business practice.

Mobile UIs: It’s developers vs. users article tells that increased emphasis on distinctive smartphone UIs means even more headaches for cross-platform mobile developers. Whose UI will be a winner? Native apps trump the mobile Web.The increased emphasis on specialized mobile user interface guidelines casts new light on the debate over Web apps versus native development, too.

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The Cloud is Not Just for Techies Anymore tells that cloud computing achieves mainstream status. So we demand more from it. That’s because our needs and expectations for a mainstream technology and an experimental technology differ. Once we depend on a technology to run our businesses, we demand minute-by-minute reliability and performance.

Cloud security is no oxymoron article is estimated that in 2013 over $148 billion will be spent on cloud computing. Companies large and small are using the cloud to conduct business and store critical information. The cloud is now mainstream. The paradigm of cloud computing requires cloud consumers to extend their trust boundaries outside their current network and infrastructure to encompass a cloud provider. There are three primary areas of cloud security that relate to almost any cloud implementation: authentication, encryption, and network access control. If you are dealing with those issues and software design, read Rugged Software Manifesto and Rugged Software Development presentation.

Enterprise IT’s power shift threatens server-huggers article tells that as more developers take on the task of building, deploying, and running applications on infrastructure outsourced to Amazon and others, traditional roles of system administration and IT operations will morph considerably or evaporate.

Explosion in “Big Data” Causing Data Center Crunch article tells that global business has been caught off-guard by the recent explosion in data volumes and is trying to cope with short-term fixes such as buying in data centre capacity. Oracle also found that the number of businesses looking to build new data centres within the next two years has risen. Data centre capacity and data volumes should be expected to go up – this drives data centre capacity building. Data centre capacity and data volumes should be expected to go up – this drives data centre capacity building. Most players active on “Big Data” field seems to plan to use Apache Hadoop framework for the distributed processing of large data sets across clusters of computers. At least EMC, Microsoft, IBM, Oracle, Informatica, HP, Dell and Cloudera are using Hadoop.

Cloud storage has been very popular topic lately to handle large amount of data storage. The benefits have been told very much, but now we can also see risks of that to realize. Did the Feds Just Kill the Cloud Storage Model? article claims that Megaupload Type Shutdowns and Patriot Act are killing interest to Cloud Storage. Many innocent Megaupload users have had their data taken away from them. The MegaUpload seizure shows how personal files hosted on remote servers operated by a third party can easily be caught up in a government raid targeted at digital pirates. In the wake of Megaupload crackdown, fear forces similar sites to shutter sharing services?. If you use any of these cloud storage sites to store or distribute your own non-infringing files, you are wise to have backups elsewhere, because they may be next on the DOJ’s copyright hit list.

Did the Feds Just Kill the Cloud Storage Model? article tells that worries have been steadily growing among European IT leaders that the USA Patriot Act would give the U.S. government unfettered access to their data if stored on the cloud servers of American providers. Escaping the grasp of the Patriot Act may be more difficult than the marketing suggests. “You have to fence yourself off and make sure that neither you or your cloud service provider has any operations in the United States”, “otherwise you’re vulnerable to U.S. jurisdiction.” And the cloud computing model is built on the argument data can and should reside anywhere around the world, freely passing between borders.

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Data centers to cut LAN cord? article mentions that 60GHz wireless links are tested in data centers to ease east-west traffic jams. According to a recent article in The New York Times, data center and networking techies are playing around with 60GHz wireless networking for short-haul links to give rack-to-rack communications some extra bandwidth for when the east-west traffic goes a bit wild. The University of Washington and Microsoft Research published a paper at the Association of Computing Machinery’s SIGCOMM 2011 conference late last year about their tests of 60GHz wireless links in the data center. Their research used prototype links that bear some resemblance to the point-to-point, high bandwidth technology known as WiGig (Wireless Gigabit), which among other things is being proposed as a means to support wireless links between Blu-ray DVD players and TVs, replacing HDMI cables (Wilocity Demonstrates 60 GHz WiGig (Draft 802.11ad) Chipset at CES). 60 GHz band is suitable for indoor, high-bandwidth use in information technology.. There are still many places for physical wires. The wired connections used in a data center are highly reliable, so “why introduce variability in a mission-critical situation?”

tcpdump

Monday, January 23rd, 2012

Packet capture is one of the most fundamental and powerful ways to do network analysis.

If you think that tcpdump has been made obsolete by GUI tools like Wireshark, think again. Wireshark is a great application; it’s just not the right tool for the job in every situation.

tcpdump uses a “one-off-command” approach that lends itself to quick, on-the-spot answers. You can run it through an SSH session, doesn’t need X and is more likely to be there when you need it. And, because tcpdump uses standard command-line conventions (such as writing to STDOUT, which can be redirected), tcpdump can be used in all sorts of creative, interesting and extremely useful ways.

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You can even use tcpdump and Wireshark together by capturing the network data with tcpdump for viewing with Wireshark. To ensure that you capture complete packets, use the following command:

tcpdump -i <interface> -s 65535 -w <some-file>

tcpdump fu article introduces some of the basics of packet capture and provide a breakdown of tcpdump syntax and usage. Manual page of tcpdump lists you all the command line options you can use.

If you are embedded Linux system developer, remember that you can easily fit the tcpdump program inside a small embedded Linux system without too much problem (which is not the case with Wireshark, because it is a huge program that needs GUI and has many dependencies).

WANem network emulator

Thursday, January 12th, 2012

There are many cases when need to emulate various networking conditions and scenarios. Usually the most practical way to test the application on different networking conditions is to use some kind of WAN emulator that lets you control the various networking characteristics. WANem is a free WAN emulator suitable for this task. WANem allows the application development team to setup a transparent application gateway which can be used to simulate WAN characteristics like Network delay, Packet loss, Packet corruption, Disconnections, Packet re-ordering, Jitter, etc.

WANem is a Wide Area Network Emulator that is designed to provide a real experience of a WAN/Internet during application development and testing. WANem works over an Ethernet LAN environment. WANem is available in bootable CD and VMware virtual appliance versions at an affordable cost (for FREE!). Award winning (FOSS INDIA AWARDS 2008) WANem is built on top of Linux and many open source component. From a functionality perspective WANem hooks into the Linux kernel towards provisioning the network emulation characteristics and extends the functionality with additional modules.

Setup is pretty straight forward. WANem is normally launched through a LiveCD, which is based on a re-mastered Knoppix. Another option is to use VMware virtual appliance. I have used both versions. Both versions allow a quick and easy setup in any development environment with an intuitive web interface for purposes of configuration. You don’t need to be a network and Linux guru to use WANem because the provided easy and very quick. There are many example configurations you can easily select and you can modify them as needed.

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In advanced mode you have option to set all necessary network performance parameters you can think of. If you are a networking expert and know what are the right setting for different parameters, this is the way to go. You can see the supported settings (in advanced mode) on the picture below.

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WANem has even tool (WANalyzer is distributed along with WANem) that allow you to measure the performance of an existing real network, and then it can simulate how that network performed.

WANem has to be located between two hosts, between each we want to simulate a network link. The routing parameters which need to be configured on the clients and/or on the WANem machine. The preferred and most straightforward configuration uses a PC with two Ethernet cards and connect that between the two hosts.

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It is possible to work also with only one Ethernet card (with some limitations), but for this to work you need special configuration on the end hosts to make sure all traffic they send gets sent to the WANem machine that forwards the traffic to other host. I have personally used this approach only when I have wanted to use the virtual machine version of WANem.

Installing and Configuring WANem Virtual Appliance and Using the WANem WAN Emulator Virtual Appliance articles tells that setup is pretty straight forward. After the WANem Virtual Appliance has been started and setup in your network environment, all you have to do is to route your traffic through it.

WANem is an excellent tool.


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