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Best Beginner Acoustic Guitar Guide
I've been playing acoustic guitar for almost 20 years now and the acoustic sound is one of my favorites. It's clean, natural and pleasing to the ears.
Acoustic guitars are a great starting point for most beginner guitarist. They offer incredible tone and don't require additional equipment like amplifiers and cables. The problem is that there are literally hundreds of options for acoustic guitars at music stores, so what's going to give you the best "bang for your buck"?
Below is a helpful comparison chart of the Top 5 Acoustic Guitars for beginners followed by a guide to help you choose what's right for you.
Top Beginner Acoustic Guitars
Beginner Acoustic Guitar Buyers Guide
When it comes to acoustic guitars, there are still many variables that you need to keep in mind as you look to purchase either for yourself or someone you love. To make this easy to consume, I've broken up these different characteristics as such:
- Size of the guitar: full size, jumbo, or 3/4?
- Type of wood: it affects the quality of your sound
- "Action" of the guitar: how easy is it to play the guitar?
- Guitar finish: does it look shiny or natural?
- Electronics: can you plug it into a sound system?
- Brand: buy name brand or not name brand?
Size of the Guitar
As you shop around for the best budget guitar, size should be one of the first things you think about. Is this guitar for a child? A grown man? Somebody with fat fingers?
Acoustic guitars have many different-sized bodies (thin-body and jumbo being the extreme) and there are even some acoustic guitars that are miniature in size for kids. You first need to determine what size is needed for the height of the person.
The size of the guitar also affects the sound it creates. A larger-body guitar as a more full sound with more bass while a smaller, thin guitar will tend to lose much of the bass, making it sound a bit higher in tone.
Type of Wood
Once you've narrowed down the size guitar you want, the next step is to figure out what your budget will allow you to purchase. The majority of what makes the prices of guitars so different is the quality of construction and type of wood.
Most guitars are made of three different woods: one for the top (usually a spruce), the back & sides (usually the same wood) and the neck/fretboard (usually rosewood). For the purposes of a beginner, a simple spruce top with maple back and sides will produce a great sound.
One more key characteristic of woods is whether it is a laminate or a solid wood. Less expensive guitars use what is known as a laminate wood while the more expensive guitars use a solid piece of wood. The solid wood produces a better sound and is a better investment but most beginner guitarist won't be able to tell a difference at first.
Guitar Action or Playability
The action of a guitar is usually defined by how far the strings are set from the neck of the guitar. The closer they are (without actually hitting the frets and buzzing), the easier it is to play since you don't have to press your fingers down so hard.
Generally speaking, the more expensive the guitar, the better the action or "playability". Some beginner acoustic guitarist begin on a guitar with poor action and either get discouraged and quit or build up their finger strength quickly.
Others invest more money up front to begin on a guitar with better action. You can usually get your chords to sound better in a faster amount of time in this way.
Guitar Finish
The type of finish on the guitar has absolutely no affect on how it sounds, so this is all a matter of preference! Some people prefer a glossy finish (so that it shines) while others like more of a natural, flat look.
There are also some specialty finishes that will set your guitar apart from all the others. One of my favorites is what as known as the "sunburst" finish that is darkened around the edges. If you prefer, there are some guitars you can buy that are solid color finishes, the most popular being black and red.
On-Board Electronics
If you plan to be playing as part of a band or foresee any need to plug your guitar into a sound system, you will likely need to buy an acoustic-electric guitar. These are guitars that are the same as every other acoustic guitar except that they have the option to be plugged in directly.
As a side benefit, some electronic components actually come with a tuner, like what you see to the right.
Most beginner guitarist won't have the need for electronics but it's nice to have available. If you decide against electronics now (to save money, perhaps) and then find you need to plug in later, there are what is known as soundhole pickups that you can purchase that will do the trick.
Name Brand? New or Used?
When it comes to buying a beginner guitar, it's tempting to want to buy used. I would recommend against that, only because beginner guitars are already cheap and there are so many unseen problems with used instruments that could get you in trouble.
When it comes to name brand, take a step back and remember why you want to buy a guitar. What fits your style best? What has the best playability? Name brands (Fender, Yamaha, Takamine, Epiphone, etc) are reliable options that offer great value for beginners. Don't get disappointed with a no-name guitar that sucks!
23 Responses to Best Beginner Acoustic Guitar Guide
I have attempted to use different guitars as a beginner.
I would like a 3/4″ body with low action and good mid to low bass. I am willing to spend up to 200.00 for an acoustic and would like to know the one you would suggest?
Also I would be carrying the guitar with me when I travel one Harley.
p.s. I have little patients when it comes to my slow progress, any "helpful" suggestions?
Hey Brad, with that budget I would suggest the Yamaha FG700S listed above. It fits your price range and has decent action (you shouldn't expect awesome with a $200 budget) and overall good tone. Hope that helps!
If you're a beginner, it can be hard to know where to start. Buying a first guitar can be confusing, frustrating, and difficult.I think the Taylor GS BBT Guitar is great. I absolutely love the sound it makes.
My grandson, a very gifted 3 year old is getting either a 1/2 size acoustic guitar or a ukelele for his birthday. I want to buy him an electronic tuner. What would be the best one to purchase.
I'm a bit confused – what are you looking for, a guitar or a tuner? Or both?
Josh, I'm looking for a tuner, my son's buying the guitar or ukelele. I'm not sure what he's getting.
Hi Josh,
I am trying to but guitar for my husband for Christmas. He has played in the past but I would say he is still a beginner. Is a Fender Squire Acoustic a good choice? I have about $200 to spend. Thanks
Hi Staci, thanks for your comment! I'm glad you're looking at a possible guitar for your husband. With a budget of around $200 to spend, your options are limited but I certainly think that the Fender Squier acoustic and the Fender FA-100 aren't bad options to get him back in the saddle. Once he gets into it more, though, he'll want to upgrade in the next year or two (just warning you! 🙂
Hello, I'm a complete beginner but would rather not buy something to cheap. In fact and if possible I'd like something for a beginner yet good enough to get me through intermediate levels should I excel fast. I'm contemplating the Taylor Big Baby (maybe e model) and the Seagull S6 original / Seagull S6 Mahogany Deluxe.
Second part of this is that I'm also going to buy an electric guitar as well, I know perhaps it sounds weird but I really like both acoustic and electric sounds.
I'm looking at the Epiphone Les Paul Standard or Les Paul 100?, Epiphone G-400 PRO, or one of the Fender Squire Strat models. I'm not entirely sure of the exact sound I'm looking to create on an electric which is why I'm all over the place with my options. Perhaps whichever of the models that will allow me to experiment with all sounds and not be limited if that makes sense. Thank you.
Hey Alex, thanks for your comment!
As far as acoustic guitars go, I don't think you can go wrong with either the Seagull or the Taylor Big Baby. You might even look at the Taylor 100 series, although at that point you're getting a bit more expensive.
Your electric selections are solid as well. I personally recommend the Les Paul Standard, although the LP-100 is a great choice as well. Either will provide some good versatility if you like the hollow-body electric. I hope that helps!
Thanks Josh.
I can't begin to explain how overwhelming and confused I am lol. It's not easy to decide on when they all look like good selections. I've also decided to look at the yamaha fg730s which made it that much more harder because I don't know how that guitar stacks up to the others I mentioned. To make matters worse I thought perhaps I pass on the acoustic for now in order to get a better Fender Strat or Les Paul. Sorry for being indecisive.
Thanks again for your help.
No problem, Alex! Thanks for your comment and I hope that you're able to make a good decision on the guitar.
I have been wanting to learn to play guitar for years I am ready to jump in. Right now I am leaning towards ordering a Takamine GD30CE. Hoping its not too much for a beginner but will last for years to come. Also hoping it fits my small female hands. I called all of the music shops and pawn shops locally on hopes of placing one in my hands for fittability but noone carries them. I am hoping if I order one that it will be a good choice. Thoughts and opinions for ordering this model since I can't find one locally?? Tia
Hey Josh,
I see that you're here to help and that's awesome. I want to mention a little bit about myself, I've been playing electric guitar, classical and acoustic. I dig them all but I'm in the market for an acoustic and having trouble finding one. I mainly play electric guitar. So that being said, should I try acoustic electric? I would like to travel with it, so preferably a padded gig bag. My price range is under 400. It would mean a lot to get some feedback many thanks.
Hello sir
I reside in uae planning to buy a guitar . I am total beginner nd went to some shops bt lyk i was keen to buy yamaha f310 bt sum1 sd me chard brand is good for beginners. Vch 1 u suggest sir . Plz would love if u advice me as i am eager to buy
Last fall I went to a guitar shop and had the guy hand me guitars till magic happened. I did tons of research on line agonizing over every detail that I thought I wanted. First three guitars on the list didn't fit me. The guy hands me a Washburn WD50SCE and it was magic. 500.00 later it was mine!
For sound though I found a fender dg8s on an auction site for 70.00 and just can't put it down. The Washburn's my fave for playability and the full dreadnaught fender has it for sound. Someday I'll find the "ONE" That fits both categories.
Hi, I'm looking for a good quality guitar that will last me a while. I'm willing to spend up to $400, and since I'm pretty small (5'2″) I probably want something 3/4 size but with good sound quality. I'm not sure what I should go for, since I'm a beginner. Thanks!
[…] Beginner Acoustic Guitars […]
Thank you for the the clear well-written article. Your recommendations supported with your personal experience was eye opening. I am emailing this to my 12 year old and then we are going guitar shopping. Thanks so much
[…] Beginner Acoustic Guitars […]
Hi. I have 2 guitars in my possession, a Carmen acoustic and an Academy acoustic. The Academy is brand new the Carmen is older and without strings at the moment. I have searched for info on both guitars with no luck. Can you tell me which is the better guitar and why. I want to learn how to play on one of them. the Academy is a bit smaller and fits me better.
[…] Beginner Acoustic Guitars […]
What about the cut on the guitar? Should that be considered? I have been learning guitar for last 4-5 years on a very basic no-name guitar and finally got to a stage where i can sing a few songs. I don't know if that makes me a beginner or an intermediate. I play regularly for the last 8 months or so. I am looking at Yamaha guitars and the F310 seems to be a good one based on the reviews but it does not have a cut. I am not sure about 100C. Can you please suggest some options for my level which i can use to learn and graduate to the next level. Budget is around $200-$300.


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Tuesday August 23, 2011
George Michael not only wowed fans on the first date of his tour but also revealed his split with partner Kenny Goss and his troubled past.
The singer welcomed the audience to "a very different evening with George Michael".
Accompanied by a symphony orchestra, the star played a sell-out concert at the Prague State Opera House.
The intimate venue provided the backdrop for covers of My Baby Just Cares For Me and True Faith as well as for the opportunity to come clean about his relationship.
He admitted he and Kenny have broken up - just months after denying rumours of a split.
The star told fans that his love life has been a lot more turbulent than he has admitted publicly.
The disclosure comes after George took to Twitter and went on live TV in March to say rumours of a split were "lies".
He told fans: "In truth, Kenny and I have not been together for two and a half years."
The Faith singer said he loved his ex, adding he was sorry for any pain he had caused his former partner.
George thought it was better to be honest about the real situation, adding: "This man has brought me a lot of joy and a lot of pain."
He said the break-up had prompted him to write a song called Where I Hope You Are.
Michael also paid tribute to singer Amy Winehouse, who died last month. He said it was unbelievably heartbreaking that there would be no more music from her.
In the interview for the tour programme, he further spoke of getting into trouble with the law, saying he deserved to be jailed last year for crashing his Range Rover after smoking marijuana.
He said he felt going to jail was karma, adding: "I had a bill to pay and I thought that prison was a logical conclusion to a very long, dark chapter."
There are currently 65 shows on the European leg of Symphonica - The Orchestral Tour, with 19 dates scheduled for Britain.
The first nine weeks will see him take in Spain, Germany, Italy and France before hitting British soil on October 25 for a performance at the Royal Albert Hall.
Photo: © Getty

subset: commoncrawl


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The May 2 fight between Floyd Mayweather and Manny Pacquiao generated $72,198,500 in ticket sales, a new boxing record.
The May 2 fight between Floyd Mayweather and Manny Pacquiao generated $72,198,500 from the sale of 16,219 tickets, a new boxing record for ticket revenue, ESPN's Dan Rafael reports.
ESPN's Darren Rovell reports that the $4,451 in average ticket value is also a record.
Mayweather defeated Pacquiao by unanimous decision in a bout billed "The Fight of the Century." The fight was expected to be the richest in boxing history.
• BISHOP: Mayweather wins fight but will never have victory he wants most
Days before the fight, tickets were averaging nearly $7,000 on the secondary market.
The #MayweatherPacquiao gate record included 46 comps and 9 unsold tickets. #boxing— Dan Rafael (@danrafaelespn) May 12, 2015
Of tix sold for #MayweatherPacquiao's record gate, 1,226 were in the $10k category and 1,594 in the $7,500 category. #boxing @darrenrovell— Dan Rafael (@danrafaelespn) May 12, 2015
- Alex Putterman


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These names crack me up. This whole collection has me blushing a little but this one is the cheekiest!
Barielle I Got A Headache is a great warm brown with golden bronze shimmer. Interesting base color but the shimmer really steals the spotlight. I tried to really capture it in the picture below.
This was the first set of swatches I could edit without much trouble with color balancing. Hopefully the others will follow soon!
Thanks for looking.
Barielle polishes are 3 free and cruelty free. Polishes retail for $8/each but a set of 5 is $25. This polish is included in the Nude & Naughty collection available here.


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About & History:
The Sydney Baha'i Centre located in Silverwater was opened officially by NSW Governor Professor Marie Bashir on Friday 17 October, 2003. The vision for the building is of a centre of excellence for spiritual and moral education, where all people of good will may explore together a common spiritual heritage, and where we may discover ways to build bridges of faith and understanding across the racial, ethnic and religious barriers which still stand in our society. The facilities and human resources of this Centre are available both to Sydney's many Baha'i communities and groups, and to the wider community. It is our hope that the Sydney Baha'i Centre will become a place of joy and hospitality, a suitable venue for hosting a variety of activities and events which promote the oneness of humanity. For all information regarding booking and reservations please contact the centre booking office on the email or phone number provided.
More about Baha'i faith:


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Scotland decriminalized homosexual acts between consenting male adults in private in 1980, 13 years after similar legislation in England and Wales. This begs the question: why was Scotland different? Queer Voices in Post-War Scotland charts the experiences of gay and bisexual men in Scotland who from within the shadows of criminality forged identities and relationships despite the apparent opprobrium of the state, religious institutions and wider society. Through the use of extensive archival research and oral histories contributed by gay and bisexual men this book charts the history of male homosexuality within Scottish society from the 19th century until decriminalization occurred in 1980.
When I began my PhD way back in 2006, the publication of a monograph was pretty low on my list of priorities. The most pressing concern was, at that time, accessing gay and bisexual men (GBM) who had experience of life in Scotland in the years before partial decriminalisation occurred in 1980. I was surprised that despite a growing historiography of the LGBT history of Britain, there was very little published which focused on Scotland. Indeed, I struggled to find any meaningful debates about why Scotland was omitted from the Sexual Offences Act 1967. The popular explanation was that Scotland was deeply resistant to change, governed by conservative Presbyterian values, and hostile social and political forces. As I was to discover this was only partly true. Scottish queer history had been somewhat neglected; and I was determined to find out why this was the case. Did Scotland have a queer history?
As this book details, Scotland certainly did have a queer history, a colourful, resourceful, and passionate history. The silence which had obscured this history was deeply engrained within Scottish culture, and this silence impacted significantly on the lives of queer Scots throughout the 20th century. Scotland did not have an Oscar Wilde and there was a lack of trials which attracted the kind of publicity afforded to Peter Wildeblood et al in 1950s England. In Scotland there were very, very few trials relating to private sex between consenting male adults, the full force of the Scots Law was focused upon the men who sought sex in the public spaces of Scottish towns and cities. As these types of offences would still be illegal in England and Wales beyond 1967 there was a dominant attitude amongst Scottish legislators that legal change was not required in Scotland. This, of course, ignored the issue of civil liberty.
My book charts the manner by which same-sex desire was discussed within Scotland from the 18th century through to the decriminalisation of sex between male adults in 1980. The book includes archival research examining sodomy trials from the 19th century to the pre-war period, queer subcultures in interwar Scotland, and examines the experiences of gay and bisexual men in post-war Scotland. Some of the main themes relate to homosexuality and religion, medicine and politics. Personal testimonies engage with the disconnection many GBM felt, their social isolation, but also the manner by which GBM made and re-made their intimate and social lives. The chapter on sexuality and religion charts how GBM of faith struggled to acknowledge both their sexual identities and their religious identities. The chapter on medicine and sexuality includes case studies of men who sought medical explanations for their sexualities and perhaps most troubling all, treatments. These were once deeply private experiences, and offering them up to an historian who they had never met before were acts of trust. Writing was both an informative and enabling experience but it was also an emotional journey.
The book also details the life of Harry Whyte – the Scot who challenged Stalin. I am extremely grateful to Harry's surviving relatives who generously offered their own recollections of Harry and shared some personal images. Their expectations were that I would treat Harry and his story with great respect, I felt privileged. It is quite extraordinary that Harry was much more open about his sexuality when living in the Soviet Union during the 1930s than he ever was as a young man living in Scotland. The book also contains an examination of queer subcultures in interwar Glasgow and Edinburgh, which greatly informed my LGBT historical maps of Scotland. I examine the formation and work of Scotland's foremost homosexual law reform organisation, the Scottish Minorities Group, and their often unacknowledged work in campaigning for LGBT rights.
Yet, I think my greatest achievement of all is down to the generosity of the 24 gay and bisexual men who agreed to participate in my research, who shared deeply emotional and private experiences of their struggles and challenges of growing up queer in Scotland. Their narratives speak of isolation, emotional trauma, but also of passion, sex, and affirmation. Despite the opprobrium these men forged ahead with their intimate lives, in at times, deeply moving narratives. What is also notable is that many of these GBM elders feel a sense of disconnection with contemporary queer experience and culture. If it's not too much of a cliche, I was equally moved and inspired by these men's stories, and their willingness to share important and personal aspects of their own histories: from ill-fated medical and psychiatric interventions and family rejection to successful and meaningful relationships, community involvement and emotional security. I found myself in a rather privileged position, being able to visit the homes of these men, to be treated to cups of tea, coffee, home baking and, on one occasion, a delicious kedgeree. There was also a great deal of trust offered; that I would faithfully re-tell their stories, that I wouldn't abuse that trust for my own ends. We oral historians are presented with wonderful opportunities to explore and analyse, but we also have undertaken a contract to treat people and their oral narratives respectfully.
Writing this book was an, at times, challenging undertaking: what to include, what to add, what to cut. Re-engaging with life stories was a deeply meaningful experience that moved and inspired me in equal measures. There's probably another book amongst the archival material and personal testimonies that didn't make the final cut, not through relevance but the demands of completion. So, thank you: Alastair, Brian, Chris, Colin, Daniel, Donald, Drew, Duncan, Ed, Frankie, Harry, Joseph, Ken, Morris, Peter, Robert, Samuel, Sean, Simon, Stephen, Stewart, Theo, Tom and Walter, I really, really, couldn't have done it without you.
"Queer Voices in Post-War Scotland is a groundbreaking study of the lives of non-heterosexual men in the contemporary history of Scotland. This fascinating and highly original book explores how historians of homosexuality in Britain have either neglected or ignored Scotland. And, yet, Scots Law retained sex between males as a crime long after its partial decriminalisation in England and Wales in 1967. In this often-moving account, Jeff Meek analyses the apolitical vacuum and absence of queer discourse in Scotland in the decade after 1967, caused by the Scots legal establishment not adopting the Sexual Offences Act of 1967. Through remarkable oral testimony, Meek provides a fascinating analysis of the difficulties and challenges of being a gay or bisexual man in Scotland in the period. He traces the activism of those few who did campaign for law reform in Scotland. Also, the lives and sense of isolation of gay and bisexual men in this period, and the ways in which work, religious beliefs and family life were negotiated in the face of deeply hostile rhetoric on homosexuality in Scotland are examined, in this timely and compelling book. In common with all volumes in the Genders and Sexualities in History, Queer Voices in Post-War Scotland presents a multifaceted and meticulously researched scholarly study, and is a sophisticated contribution to our understanding of the past."
John H. Arnold, Joanna Bourke & Sean Brady


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Apr 14, 2015
India To Get 36 Dassault Rafale Fighters
In a statement issued April 10 during Prime Minister Narendra Modi's state visit to Paris, the Indian premier said New Delhi would purchase 36 Rafale jets in fly-away condition "as quickly as possible," though both the Indian and French governments said further negotiations are still underway.
Modi and French President Francois Hollande agreed to conclude an intergovernmental agreement to supply the 36 Rafale aircraft under a deal that is separate from a three-year-old negotiation between Paris and New Delhi over the sale of 126 Rafale fighters under the MMRCA tender, which calls for 108 of the combat jets to be produced by Hindustan Aeronautics Ltd. (HAL) in India.
The joint statement said delivery of the 36 Rafale aircraft would occur according to a timeframe compatible with operational requirements of the Indian air force (IAF), and that the aircraft and associated systems and weapons would be supplied in the same configuration as those already tested and approved by the IAF under the MMRCA tender.
If concluded, the deal would be a boon to Dassault Aviation, which is already riding high after recently selling 24 Rafales to Egypt, to be delivered by 2019.
Etiquetas: DASSAULT, Egypt, Egyptian Air Force, FRANCE, INDIA, INDIAN AIR FORCE, MMRCA, RAFALE
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Congestions and Control Mechanisms n Wired and Wireless Networks
- Brett Booth
- 3 years ago
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1 International OPEN ACCESS Journal ISSN: Of Modern Engineering Research (IJMER) Congestions and Control Mechanisms n Wired and Wireless Networks MD Gulzar 1, B Mahender 2, Mr.B.Buchibabu 3 1 (Asst professor, cmrec, Hyderabad, india 2 (Asst professor, cmrec, Hyderabad, india 3 (Asst Professor, cmrec, Hyderabad, india ) ABSTRACT: In today s world, network is becoming compulsory technology even in a normal human life ranging from a student to a professional. In every field networks are being used. In olden days networks are formed by connecting the computer systems through cables. As the days are going on more number of computer systems are connected to the network. As a result network size gets increased and networks like LAN, MAN, WAN came into existence. Huge networks with cables has so many disadvantages like, if the cable is damaged there will be no communication between the system, and since one cable may be shared between many users the communication may become slower, and the users may put heavy load on the communicating cable than it s capacity which may cause congestion. To overcome all these demerits of wired networks wireless networks are proposed. In wireless networks there are no communicating physical cables. The system will communicate with each other by using radio or infra red waves which travels through air. The wireless networks will also suffer from so many problems like node mobility,, high error rate, long latency and even congestions. In this paper we are going to discuss various congestion control mechanisms in wired and wireless networks and their merits and demerits. Keywords: congestion, congestion control TCP, wired network, wireless network I. Introduction The main problem In todays network is slower communication, which may result due to so many reasons like client may be a slower than server or vice versa, or the communicating channel may have the less bandwidth than the requirement of the communuatingresoureces, or so many computers are connected to a single network or a server for ex: when so many clients are connected each may have their own requests and there may be only one server to fulfill these requests due to this every client needs to wait until it s request get executed, and the intermediate resources of a network like routers and swithes may be slower. Due to all these reasons network performance becomes degraded. One more problem in network is congestion, when this occurs, the communicating devices may be blocked until the congestion is cleared. II. Congestion Congestion in a network occurs when the offered load by the communicating devices is greater than the available bandwidth of the communicating mechanism. Congestion may occur either at the resources or at the communicating channel. When a fast sender is sending packets to a slow receiver its buffer or queue in which the packets are stored before processing gets filled and remaining in comingpackets get discarded. In each case the sender needs to be informed regarding the congestion either at the network or receiver so that it will slow down the process of sending packets. The congestion may be handled differently in wired and wireless networks which we discuss in following sections. III. Congestion Control In Wired Networks Form the control theory point of view, all the solutions are divided into two categories. They are open loop congestion control and closed loop congestion control.open loop solutions attempt to solve the problem by good design, to make sure congestion does not occur in first place. Once the system is created corrections ca not be made in the middle [10]. Closed loop solutions are based on the concept of feedback loop. This approach has 3 parts. 1. Monitor the system to detect when and where congestion occurs. 2. Pass this information to places where action can be taken. 18 Page
2 3. Adjust the system operation to correct the problem. Open loop congestion control algorithms are further divided into two categories. They are which acts at source and which acts at destination. The closed loop algorithms are also divided into two categories. They are implicit feedback and explicit feedback. In explicit feedback the packets are sent back from the point of congestion to warn the source. In implicit the source identifies the congestion by making local observations. Such as time needed for acknowledgments to come back. The presence of congestion means the load is greater than the resource can handle. We can increase the resources or decrease the load to control the congestion[10]. 3.1 Congestion Control in TCP In TCP congestion control, the sender window size or sender s buffer size is decided by the available buffer space in the receiver window(rwnd), as well as the network s bandwidth called as congestion window(cwnd) because if the network has low bandwidth it cannot deliver all packets sent by the source to destination. So the actual window size of the sender is minimum of these two [9]. TCP s general policy for handling congestion is basedon three phases 1. Slow start 2. Congestion avoidance 3. Congestion detection In slow start phase, the sender starts with a very slow rate of transmission, but increases the rate rapidly to reach the threshold. When the threshold is reached the data rate is reduced to avoid congestion Slow Start: Exponential Increase One of the algorithms used by TCP to control the congestion is slow start. Here initially the sender s window size is equal to congestion window(cwnd), which is equal to one maximum segment size(mss).and it is assumed that rwnd is much higher than cwnd, so that sender window size always equal to cwnd.in this it is assumed that each segment is acknowledged individually. The sender starts with cwnd=1 MSS, that it can send only one segment. After receipt of acknowledgment] for segment 1, the cwnd is increased by 1, now cwnd is 2. Now two more segments can be sent, and these two can be acknowledged, the cwnd becomes 4. Now 4 segments are sent, when acknowledgment is received the cwnd becomes 8. Figure1: Slow start If we look at cwnd in terms of rounds, we find the rate is exponential as below. Start->cwnd=1 After round 1->cwnd = 2 1 =2 After round 2 ->cwnd = 2 2 = 4 After round 3 ->cwnd = 2 3 = 8 19 Page
3 Slow start cannot continue indefinitely, there must be a threshold to stop these phase. The sender uses a variable ssthresh(slow start threshold). When the size of the window reaches to the threshold, slow start stops and next phase starts. In most implementations the value of ssthresh is 65,535 bytes Congestion Avoidance: Additive Increase In slow start algorithm, the size of cwnd increase exponentially. To avoid congestion before it happens, the exponential growth must slow down. TCP defines algorithm called as congestion avoidance, which uses additive increase instead of exponential one [9]. When size of cwnd reaches to the threshold, slow start phase stops and additive phase begins.in this algorithm cwnd size will be incremented by one only when all segments in window are acknowledged. Figure 2 : congestion avoidance If we look cwnd in terms of rounds Start ->cwnd=1 Round 1 ->cwnd=1+1=2 Round 2 ->cwnd=2+1=3 Round 2 ->cwnd=3+1=4 In congestion avoidance phase the size of the cwnd increase additively until congestion is detected Congestion Detection When congestion occurs, the congestion window size must bedecreased. The sender can guess about the congestion by the need of retransmission of the segment. Retransmission occurs in one of the two cases. 1. When a timer times out. 2. When 3 acknowledgments are achieved. In both cases threshold will be dropped to one half, called as multiplicative decrease [9] TCP Congestion Policy Summery 20 Page
4 Figure3: TCP congestion policy 3.2 TCP -Tahoe and TCP -Reno TCP-Tahoe is the old version of TCP. In this case cwnd size is reduced to 1 MSS. in each case of time out and 3 acknowledgments are arrived. TCP-Reno is the new version of TCP, in congestion detection phase when a time out occurs cwnd is decreased to 1MSS, and when three acknowledgments are arrived cwnd is reduced half of cwnd [8]. The reason for TCP Reno is, when 3 acknowledgments are re received means 3 packets are delivered, which means network has capacity to forward some acknowledgments. This is called as fast recovery. The following fig shows the performance evaluation of both Reno and Tahoe[8]. Figure 4: Comparison of TCP Tahoe and TCP Reno Initially the threshold is equal to 8 MSS. The congestion window increases fast exponentially during slow start, and reaches to threshold at fourth round, the cwnd increases up to 3 duplicate ACKNOWLEDMENTs occurs. After transmission round 8, cwnd is 12 MSS when the loss event occurs. At this point cwnd decreases to one half to 6. In TCP Reno the cwnd=6 MSS, and in TCP Tahoe the cwnd is set to 1MSS and then grows linearly until threshold is reached. Most TCP implementation today uses TCP-Reno algorithm and many variations of Reno algorithm have been proposed. 3.3 TCP Vegas The TCP Vegas algorithm attempts to avoid congestion while maintaining good through put[2]. The basic idea of Vegas is to 1. Detect the congestion in routers between source and destination before packet loss occurs. 2. Lower the rate when packet loss is detected. Packet loss is predicted by observing the RTT. The longer RTT means the greater the congestion is. 21 Page
5 IV. Congestion Control In Wireless Networks The TCP was designed on the assumption that, loss of data packets is caused by congestion. But in wireless networks data packets losses due to high bit rate, nodes mobility, one tomany links and link failure etc. So the conventional TCP mechanism is not appropriate for wireless adhoc networks. To the large extent TCP will reduce the network performance. This unmodified TCP is unable to distinguish packet loss caused by network congestion and transmission errors. 4.1 TCP In wireless networks In wireless links TCP reacts to packet loss as it is in wired environment, and it drops the transmission window before retransmitting the packets and initiates congestion control or avoidance mechanism. This will unnecessarily reduce the link s bandwidthutilization and causes significant performance degradation in the form of throughput[2]. It is important to improve the performance of TCP in wireless networks because many network applications may be builted up on TCP. Several reliable transport layer protocols for n/w with wireless links have been proposed to improve the performance of TCP in wireless machine The split connection approach This approach is used in indirect TCP (I-TCP). It includes splitting a TCP connection between a fixed host, and mobile host in to two separate connections. One TCP Connection is established between fixed host and base station, and other between base station and mobile host[1]. Figure 5: Split connection approach in I-TCP On the second connection there is no need to use TCP, we may use a wireless specific protocol for better performance. The advantage here is the flow and congestion control of wireless link is separated from fixed host The Fast retransmit approach This approach is used with TCP when communication resumes after a handoff. Unmodified TCP at the sender considers the delay caused by handoff process to be due to congestion, and when timeout occurs, reduces it s window size and retransmits unacknowledged packets[1]. The fast retransmit approach overcomes this problem by having the mobile host send a certain number of duplicateacknowledgments to the sender to immediately reduce it s window size and retransmit packets starting from missing one Link Level Retransmission In this approach, the n/w is divided into two parts like fixed host to base station and from base station to mobile host. For fixed host to base station wired connection is used and for base station to mobile host wireless connection is used. The wireless link implements a retransmission protocol and forward error correction method, as well as TCP implements its own end-to-end retransmission protocol [3] Snoop Protocol The n/w applications that require reliable transmission uses TCP. So we may want o improve tcp performance without changing it s implementation. The only components that we may want to control are the base stations and mobile hosts. In snoop protocol modifications are done to the routing code of base stations only. These modifications are for catching unacknowledged TCP data and performing local retransmissions as soon as loss is detected [4]. This protocol will shield the sender regarding the packetloss, or problems occurred at the wireless link. This results in increased performance of the connection without sacrificing the end-to-end semantics of the TCP[7]. 22 Page
6 The operation of snoop protocol can be shown as follows Figure 6: Operation of snoop protocol Data Gram Congestion Control Protocol (DCCP) DCCP is a message and connection oriented transport layer protocol, it differs from UDP because it includes congestion control and it differs from TCP, where it does not provide guaranteed reliability. DCCP is a general congestion control protocol for UDP-based applications. But DCCP provides semantics like in TCP, but does not provide reliable in order delivery, sequenced delivery within multiple streams as in SCTP. To make DCCP reliable and in-order delivery, DCCP allows the use of general TCP-friendly congestion control mechanisms like TCP-like and TCP-friendly [5]. DCCP is completely a new protocol; it is still under research that weather it can be used for real time applications practically [6]. V. Conclusion The internet communication became a daily routine. And the major problem in the network is congestion which causes slower, disturbed communication. Congestions will occur in wireless and wired networks. Since wireless network has so many advantages over wired, so it is the mostly used technology. In this paper we have discussed various congestions and their controlling mechanisms in wired and wireless networks. But in future we may have more featured, fast networks which may also suffer from congestions, so there is a need to design a reliable congestion control mechanism for secure and fast communication. REFERENCES [1] Ning Jia, Lei An, Analysis of Congestion Control Strategy for Wireless Network, Institute of Electrical and Electronics Engineers, /09/$ IEEE [2] Alhamali Masoud Alfrgani.Ali, Raghav Yadav, Hari Mohan Singh, Congestion Control Technique for Wireless Networks, IOSR Journal of Computer Engineering (IOSR-JCE), e-issn: , p- ISSN: [3] Ali Ghaffari, Congestion control mechanisms in wireless sensor networks: A survey, A survey. Journal of Network and Computer Applications (2015), [4] Alonso Silva, Patricio Reyes, Merouane Debbah, Congestion in Randomly Deployed Wireless Ad-Hoc and Sensor Networks, Institute of Electrical and Electronics Engineers, /09/$ IEEE [5] Atilla Eryilmaz and R. Srikant, Fair Resource Allocation in Wireless Networks using Queue-length-based Scheduling and Congestion Control, Institute of Electrical and Electronics Engineers, /05/$ IEEE [6] N. Thrimoorthy and Dr. T.Anuradha, A Review on Congestion control Mechanisms in Wireless Sensor Networks, International Journal of Engineering Research and Applications, ISSN : [7] Raheleh Hashemzehi, Reza Nourmandipour,Farokh koroupi, Congestion in Wireless Sensor Networks and Mechanisms for Controling Congestion, Indian Journal of Computer Science and Engineering, ISSN : [8] James E. Kurose, Computer Networking, (Pearson Education, Inc, Dorling, Kindersley(india)Pvt.Ltd) [9] Behrouz A Forouzan, Data Communication and Networking (The MC Graw-Hill Education Pvt.Lid, New Delhi(India)) [10] Andrew S.Tanenbum, Computer Networks(Pearson Education,Inc, Dorling, Kindersley(india)Pvt.Ltd) 23 Page
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text:
Saturday, June 5, 2010
How I block ads
4 comments:
- Morbus said...
Not really. Display:none doesn't download them at all. Opacity:0 or visibility:hidden will simply hide them and the site will never know (in their bills) that you didn't see them. But it will still play annoying sounds, and it will still get viruses into your computer and still your clicks and your focus and your scroll. So display:none is the way to go.
The advertising industry is rotten with spyware and adware that is damaging to the user (often against the site's consent). So I block everything that isn't Google ads, and I block everything that moves. I can't stand moving things on the web. I understand that you want attention to your banner, but I don't care. If you want me to buy your product, go sponsor some sports team or some stuff like that, don't come bothering me, cause you'll only make me loose respect for you. It's that simple. My bank? Santander, cause of F1. My favorite drink? Red Bull, cause of motor sports. My gas? Repsol cause of motor sports. My running shoes? That'd be Puma, cause of sports. And so on and so on.
Simple, really: if you want me to buy your product, pay for something I like first and don't bother me.
- June 5, 2010 at 12:39 PM
- glazou said...
let's give back to Caesar what belongs to Caesar, ie Joe Francis, former member of the Netscape Editor team. He did that in 2001 or 2002 IIRC:
- June 6, 2010 at 5:36 PM
- June 12, 2010 at 8:24 AM
Necessity is the mother of invention...................................................................
- June 15, 2010 at 11:32 PM


text:
CHARLESTON RAYS: Welcome
Welcome to another exciting season of Rays baseball!!!
Scrimmage today 4pm at Springfield Elementary. It is our first of the 2011 preseason as we strive to get ready for our run at the 2011 CMABL Championship. Come out and support your 2011 Charleston Rays!!
Wednesday, March 16
***April 18 DEADLINE***
$200 on or before that date. $225 after up until opening day. Then its $240. We must have 15 players paid in full by opening day or we will not be allowed to play this season.