Everyone Secretly Hates Your Friendly Reminder Email

Everyone Secretly Hates Your “Friendly Reminder” Email After starting out as a fun and hip medium of communication that gained popularity in the 1990s, email has grown one of the most reviled forms of communication.While everyone hates email, it is still the most widely used form of communication at the workplace, and you can’t really avoid it in the modern world.Over the more than two decades that email has become a natural part of the modern workplace, people have developed some basic rules of email etiquette to guide the use of the medium.Still, some people have found ways to use email as a subtle tool for passive aggressiveness in certain situations.One of the times when people commonly use email as a tool for passive aggression is in situations where they need to send email reminders. Source: ExpertSenderPicture this scenario: You sent an email to a colleague a couple days ago requesting some information that you need to include in a report you are working on.The report is due in a few days’ time, yet the colleague has not sent the information you requested.They did not even acknowledge receiving your email. If they don’t send the information on time, you will miss the deadline for submitting the report, so you decide to write an email reminding them of your request.At this point, you are probably very annoyed with your colleague, but because you want to maintain an air of professionalism, you send them an email with the following message:“Just sending you a friendly reminder to please furnish me with the information about xyz.”Admit it. You have done such a thing one or two times. I know I have.Even if you haven’t, I am willing to bet that you have received such emails from a work colleague, and I can bet you weren’t exactly happy with this reminder.T here are several situations that might require you to send an email reminder.Reminding a client about a late payment, reminding a colleague about something they haven’t done that can affect the whole project, reminding a vendor or supplier about a late shipment, reminding someone about an upcoming milestone, reminding someone about something they had promised or were supposed to do but haven’t done, the list is endless.When most of us find ourselves in such a situation, our automatic reaction is to send a “friendly reminder.”Even though we are angry at the recipient of reminder (why can’t they do what they were supposed to without having to be reminded about it?), we figure that sending the friendly reminder will disguise our annoyance and allow us to maintain an air of professionalism.Put simply, the friendly reminder is an attempt at asking for something we should have already received in a polite, non-confrontational manner.While the intention of sending the friendly re minder is to be polite and professional, it might be sending the wrong message.The friendly reminder reeks of cowardice and insincerity, and most of the people you send the friendly reminders to might be secretly hating you for that.They know you are displeased because of having to send a reminder, and therefore your thinly veiled polite reminder does not cut it.Therefore, you need to stop sending these friendly reminders â€" from today.Below are some reasons why the friendly reminder might be doing you more harm than good.IT MAKES YOU LESS CREDIBLEYour choice of words when communicating, whether in person or in writing, has a huge impact on how your message is perceived by the other party.According to Georgetown University professor Deborah Tannen, who is also the author of Talking from 9 to 5: Women and Men at Work, the words you use in your communication can boost or deflate your credibility.Some of the words that lessen your credibility include hedge words and apologetic words.W hat comes into your mind when someone says something like, “I’m pretty certain about xyz” instead of “I am certain of xyz” or “I think we might want to do this” instead of “we need to do this.”In both cases, using the word “pretty” and the phrase “think we might want to” takes away from the message being passed. It makes whoever is saying these words seem wishy-washy, like they are not sure of what they are saying.Such words are an expression of self-doubt, which can make whatever you are saying seem less credible.The same applies when you use overly apologetic words such as “I’m sorry.”Consider someone saying something like “I’m sorry, but I don’t think that is the best approach” vis-à-vis saying “I don’t think that is the best approach.”Using the phrase “I’m sorry” softens a person’s position and makes them feel less authoritative. Who are you more likely to listen to? Of course the one who gives their opinion without being ap ologetic about it.Just like the above situations, using the words “just a friendly reminder” is a way of hedging your message and being apologetic about what you are trying to say.It minimizes the impact of your message and makes it less credible, giving the recipient of your email a reason to disregard what you are saying. If you want to be taken seriously, drop the phrase.Instead of “just sending a friendly reminder,” simply “send a reminder.”Your message will be direct and clear, and the recipient of the email won’t have to deal with an insincere, thinly veiled attempt at politeness.IT MAKES HIGHER-UPS VIEW YOU AS A PUSHOVERNormally, when people are communicating with someone who outranks them in the organizational hierarchy, they tend to use more subordinate language.If your boss forgot to send you something that you need to accomplish your work, you don’t want to sound like you are being bossy to them, so you decide to just send a friendly reminder to politely a sk them for whatever it is they forgot to send.However, this is the wrong approach, since it makes you seem like a pushover, like someone who cannot assertively stand up for themselves.You don’t have to be a pushover just because you are dealing with someone senior to you. It is possible to be polite while still being assertive.Remember, you are asking for something that you need in order to get your job done, not a favor.Therefore, even if you are emailing your boss, drop the “just a friendly reminder” phrase. Dropping the phrase will make you look more professional.IT INCREASES THE CHANCES OF YOUR MESSAGE BEING IGNOREDSometimes, email can become overwhelming.The average office worker receives 121 emails every single day, according to DMR reports.When you add unread emails from the previous day, it becomes a very high number that need someone’s attention.At the same time, there are only 8 hours in a workday.Within these 8 hours, not only is a person supposed to read, work o n the requests and reply to these emails, they also need to accomplish other work related tasks.In order to get all the important tasks completed within the constraints of time, people resort to prioritization, working on the important and urgent stuff first and leaving other stuff for later.When you email someone with “just a friendly reminder,” it trivializes your message, and if the recipient is busy, they are more likely to ignore your message and leave it for later after finishing the important stuff first.If you want to get a quick response, you need to drop the phrase and directly ask for what you need.Similarly, avoid using other apologetic phrases, such as “I hate to bother you with this again” or “sorry for pestering you with this, but…”Simply state what you want, and if it is urgent, don’t be afraid to say so.HOW TO WRITE AN EFFECTIVE REMINDER EMAILWe have seen some of the reasons why you need to stop just sending friendly reminders to your colleagues.But then, how do you write and effective reminder email without trivializing your message or making yourself look like a pushover?Below is a tutorial on how to do exactly this.Email Subject LineThe subject line is one of the most important parts of a reminder email. While most people know not to skip the subject line, many don’t know the right thing to write here.But think about this â€" you email’s subject line is the first thing your recipient will see once they receive your email.If your recipient has a lot of emails in their inbox, the subject line is what determines whether they will open your email or not.According to HubSpot, 35% of email recipients decide whether to open an email or not based on the subject line.If you follow the normal route and use “Friendly Reminder” as your subject line, the recipient might easily decide that the message is not very important, even without opening your email.If you want the recipient to act on your email with the seriousness it deser ves, you need a subject line that grabs their attention and communicates the seriousness or urgency of your reminder.For instance, you could write a subject line like “Response Required: Q2 Sales Reports” or “Urgent: Project ABC.”Sometimes, if you don’t want to send a separate reminder email, you can add the word “Urgent” to the subject line of your original email and resend it to the recipient of the email.SalutationAfter writing the subject line, most people do not care about the salutation of their email. They jump right into the email body.However, if you want your reminder email to be received well, you need to use a proper salutation, addressing the recipient by their name if possible. If you are well acquainted to the recipient, you can salute them with a simple “Hello Martin.”If you are well acquainted to the recipient but still know their name, you should use a more formal salutation, such as “Dear Martin.”If you do not know the recipient’s name, you can address them by their position, for instance, “Dear Project ABC Team Leader.”Email BodyHaving written a great, attention catching subject line and used a proper and appropriate salutation, you can now move on to the body of your email, which should cover your actual reason for sending the reminder.The body of your reminder email can be broken down into several parts:First sentence(s): While we said that you need to avoid the friendly reminder phrase, this does not mean that your message needs to be harsh. Therefore, it is always a great idea to start your email on a positive note.Find something positive to say to the recipient as the opening line of your email. If you can’t think of something relevant, you can use a friendly statement such as “I hope you are doing well.”Main Message: This is the part where you communicate the reason behind your message. You want this part to be as clear as possible. Don’t beat around the bush.Explain what it is you are reminding the person about (a late payment, overdue work, a late shipment, requested information, etc.) and when it should have been delivered.Call to Action: After explaining what you are reminding them about and when it was due, make it clear to the recipient what you’d like them to do. Of course, when you send a reminder, you expect them to take some action to remedy the situation.If you are expecting the person to send you some work, make this clear and mention when you need the work. In the case of something like a late shipment, you might decide to ask to request a refund instead.The clearer your expected action is, the easier it is for the recipient to actually do what you want.Since you are assuming that the recipient is already busy (probably why they didn’t respond to your initial message), you should try to keep the body of your reminder email as short as possible.Closing Your Reminder EmailFinally, you need a final sentence and your email signature to close off your reminder emai l. Here, you want to once again end on a positive note.Since you are assuming that the recipient is going to respond to your email and take the desired action, you can end by thanking them in advance for their action.The closing part of your email should match the tone of the rest of the email.If you are well acquainted to the recipient and therefore used an informal tone, your closing should be informal as well.Similarly, if the rest of the email has a formal tone, keep your closing formal as well.SAMPLE REMINDER EMAILIf you stick to the above pointers when writing your reminder email, you will end up with an email like the one below.To: Edgar PierceSubject: Response Required: Data For Q2 ReportHello Edgar,I hope you are doing well.I am working on the Q2 report which is due at the end of the month, and I wanted to remind you that I am still missing your data, which I need for the report. Below is what I still need from you:Q2 Sales DataQ2 Client Growth DataPlease send these by Frid ay, March 19th at the very latest.Thanks in advance for your help.Kelvin KiogoraOperations Manager.As you can see, the above example uses a subject line meant to catch the attention of the recipient, uses an appropriate salutation, starts with a positive opening line and quickly moves on to the body of the email.In the body, the sender is pretty clear on what they need from the recipient.There is no room for misinterpretation.Most importantly, the sender doesn’t use the phrase “just a friendly reminder,” which would have been insincere and probably made the message seem less important.The sender remains polite and professional without watering down their message. The sender then mentions when they need the data and closes on a positive note by giving thanks for the anticipated cooperation.WHEN TO TRY OTHER METHODSEmail is a great way of communicating at the workplace, mainly because of its ease of use and convenience.When you need to remind someone of something, email is the e asiest way to communicate your reminder to the person.Sometimes, however, your email reminders might go unanswered. If you find that you have sent more than one reminder email and have not gotten any response, yet you urgently need something from the person, it might be time to try other methods of reaching out to the person.In such situations, one of the best approaches is to pick up the phone and call the person. The phone is much harder to ignore compared to an email.Calling the person also conveys the urgency of the matter. If you decide to call the person, there are some basic phone etiquette guidelines to keep in mind. These include:Call during business hours: The thing with email is that you can send a quick message at any time. If you just remembered something you need on your commute home after work, you can type up a message on your smartphone and send it. The recipient can then respond to it at their own convenience, either immediately they get it or when they get to work the following day. However, when it comes to phone calls, don’t do this, even if you have the person’s mobile number. That’s basically forcing someone to deal with work issues after work, and they aren’t likely to be thrilled about that. To avoid starting off on the wrong foot, only make such calls during business hours.Remain friendly and courteous: While you might be annoyed about your emails getting ignored and having to call the person, remain friendly and courteous during the call. Don’t show your anger, and don’t make any accusations or issue threats. You are more likely to get a positive response by maintaining a professional attitude.Keep it short: You are not calling to find out how the person’s day is going or how their weekend was. They are probably busy, and asking about irrelevant stuff is wasting their time. Get right to the point about what you need.Aside from picking the call, there are other ways of reminding someone about something they need to do.If you are in the same office, you can simply walk over to their office or desk and ask them about whatever it is you need.Alternatively, you could send a calendar invite for a 10 minute meeting with the person.The meeting invite will loom on their calendar unless they decide to click ignore on the meeting request. If they accept the meeting, you can then request whatever it is that you need.Sometimes, despite your best efforts to get the other person to respond, and despite trying different methods, some people will never give you the response you need.At the same time, you need to accomplish something whose success hinges on their response, and you can’t just drop the project.If you find yourself in such a situation, what you need to do is to send a final follow-up message requesting for whatever you need and explaining your next steps in case you get no response.For instance, if Edgar Pierce fails to respond to our email example above, and other subsequent follow ups, Kelvin migh t send a final reminder with the following line added just before the closing line.“If I don’t receive the data by deadline, I will have no other choice but to move forward and finalize the report with a note explaining that your contributions were never received.”WRAPPING UPNext time you need to remind someone about something, avoid the natural impulse to “just send a friendly reminder.”This only waters down your message, and your colleagues might be secretly resenting you for it.Instead, follow the guidelines outlined in this article to send a polite yet assertive reminder email that will be treated with the seriousness it deserves.

Drinking Water Out Of Bottled Water - 1191 Words

Most American see bottled water as a necessity, even though bottled water did not exist numerous years ago. Drinking out of a water bottle has become the customary drinking source for most Americans. We have become reliant on plastic waste. Water is life sustaining, so many of us would think that drinking water out of a bottle is harmless. Unfortunately it is not, there have been hints of PET and BPA in the plastic containers we are drinking out of. Both PET and BPA can stimulate sever health consequences. Not only are we putting our life in jeopardy by drinking out of bottled water but our planet as well. Plastic bottles don’t just vanish into thin air. Most Americans don’t recycle, so most plastic bottles end up on streets, rivers, lakes, canals, streams, or oceans polluting our planet. Not only is bottled water way more expensive than tap, it also contains the same water quality as tap water. In other words we’re just paying for the names on the plastic bottle s. Rather than paying for quality, our tap water can produce just about the same value as bottled water. Bottled water is not all it is made out to be. We all need water to survive, especially when up to 60% of the human body is made of it. Water is without question necessary to our planet. Approximately 75% of the earth’s exterior is covered by water, but only 1% of that is drinkable. Therefore, clean drinkable water is not as easy to get as it may seem. Representative Dennis Kuchinich from Ohio states that,Show MoreRelatedThe Choice Of Bottled Water Over Tap Water Essay1247 Words   |  5 PagesChoice of Bottled Water over Tap Water First, water is an important resource for consumers and the environment. 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Significance of the Court Case of Gideon v. Wainwright

Gideon v. Wainwright was argued on January 15, 1963 and decided on March 18, 1963. Facts of Gideon v. Wainwright Clarence Earl Gideon was accused of stealing from the Bay Harbor Pool Room in Panama City, Florida on June 3, 1961. When he asked for a court appointed counsel, he was denied this because according to Florida law, court appointed counsel was only provided in the case of a capital offense. He represented himself, was found guilty, and was sent to prison for five years. Fast Facts: Gideon v. Wainwright Case Argued: Jan. 15, 1963Decision Issued: March 18, 1963Petitioner: Clarence Earl GideonRespondent: Louie L. Wainwright, Director, Division of CorrectionsKey Question: Does the Sixth Amendments right to counsel in criminal cases extend to felony defendants in state courts?Majority Decision: Justices Black, Warren, Brennan, Stewart, White, Goldberg, Clark, Harlan, DouglasDissenting: NoneRuling: The Supreme Court ruled that under the  Sixth Amendment, states must  provide an attorney to any defendants in criminal cases who are unable to afford their own attorneys. While in prison, Gideon studied in the library and prepared a handwritten Writ of Certiorari that he sent to the United States Supreme Court claiming that he had been denied his Sixth Amendment right to an attorney: In all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial jury of the State and district wherein the crime shall have been committed, which district shall have been previously ascertained by law, and to be informed of the nature and cause of the accusation; to be confronted with the witnesses against him; to have compulsory process for obtaining witnesses in his favor, and to have the Assistance of Counsel for his defense. (Italics Added) The Supreme Court led by Chief Justice Earl Warren agreed to hear the case. They assigned Gideon a future Supreme Court justice, Abe Fortas, to be his attorney. Fortas was a prominent Washington DC attorney. He successfully argued Gideons case, and the Supreme Court unanimously ruled in Gideons favor. It sent his case back to Florida to be retried with benefit  of a public attorney. Five months after the Supreme Court ruling, Gideon was retried. During the retrial, his attorney, W. Fred Turner, was able to show that the chief witness against Gideon was possibly one of the lookouts for the burglary itself. After only one hours deliberation, the jury found Gideon not guilty. This historic ruling was immortalized in 1980 when Henry Fonda took on the role of Clarence Earl Gideon in the movie Gideons Trumpet. Abe Fortas was portrayed by Josà © Ferrer and Chief Justice Earl Warren was played by John Houseman. Significance of Gideon v. Wainwright Gideon v. Wainwright overruled the previous decision of Betts v. Brady (1942). In this case, Smith Betts, a farm worker in Maryland had asked for counsel to represent him for a robbery case. Just as with Gideon, this right was denied him because the state of Maryland would not provide attorneys except in capital case. The Supreme Court decided by a 6-3 decision that a right to an appointed counsel was not required in all cases in order for an individual to receive a fair trial and due process in state trials. It was basically left up to each state to decide when it would provide public counsel. Justice Hugo Black dissented and wrote the opinion that if you were indigent you had an increased chance of conviction. In Gideon, the court stated that the right to an attorney was a fundamental right ​for a fair trial. They stated that due to the Due Process Clause of the Fourteenth Amendment, all states would be required to provide counsel in criminal cases. This significant case created the need for additional public defenders. Programs were developed in states around the country to help recruit and train public defenders. Today, the number of cases defended by public defenders is huge. For example, in 2011 in Miami Dade County, the largest of the 20 Florida Circuit Courts, approximately 100,000 cases were assigned to Public Defenders.

The Little-Known Secrets to Gre Argument Essay Topics Answers

The Little-Known Secrets to Gre Argument Essay Topics Answers Up in Arms About Gre Argument Essay Topics Answers? The first element of the essay we'll analyze is the way that it succeeds in identifying and examining the pieces of the argument that relate to the endeavor. Practice brainstorming plenty of different essay prompts from the ETS website to become accustomed to coming up with examples that you may use to support your viewpoint. The intro needs to be short and sweet. You simply must be in a position to be comfortable with a couple examples, and be sure you can effectively relate them to your analysis. Likewise, the writer is optimistic about the state promise to wash the river. Be aware that you're NOT being requested to present your own views about the topic. You should not provide your own views about the subject, or refute the topic. If you consider the statistics below, you must concur with me. Other individuals think that college students should base their selection of an area of study on the access to work in that area. It's also imperative that you are ready to get together with students from various backgrounds. To start with, the student should comprehend the argument completely. What Does Gre Argument Essay Topics Answers Mean? You just want to say that the argument is unwarranted for a lot of reasons. If you only wind up discussing two key questions or assumptions from the argument, it's perfectly fine to wind up with two body paragraphs, but you need to bear in mind that in case you have time, there may be a third avenue of the argument that's well worth explo ring. It's possible that while explaining your stand, you divert from this issue and begin discussing another problem. Whether the writer is correct in maintaining his thought or he's mistaken and ignores some vital issues that could render the argument baseless in some circumstances. Up in Arms About Gre Argument Essay Topics Answers? When it isn't explicit, you're losing points! The point here is to understand what you're going to write before writing it. For each prompt you opt to outline, come up with three or more points of analysis and a couple sentences to explain the value of each point. So, there's no use in trying to game the e-rater. The scenario will always be shown in the very same form. Notice that there's no correct or wrong answer here. Though the response may start to tackle the assigned task, it delivers no development. An answer to any other issue will get a score of zero. Who Else Wants to Learn About Gre Argument Essay Topics Answers? Some phrases a re highlighted to assist you find the structure of the essay and the way that it responds to the particular directive. There's a lot that could be judged from the written essay. At that time, you can begin writing full length practice essays. Essay writing is definitely thought to be part of academic life and essay writing demands certain abilities or the region of the writer. Just be certain to save your essay into a distinct document on your computer so that you may return and read and score it afterwards. Following are a few of the suggested sociology essay topic for those students that are unable to choose a great topic for their assignment. Academic writing should be quite precise. What kind of essays will be there and what's predicted to be written. More creative suggestions on how to receive your essay graded here. The argument essay is deemed difficult by nearly all of the students. It is different from the normal essays that you have been writing as well as from the issue essay asked in the same section of the test. There are 176 possible topics you are going to be requested to write about on the GRE Argument essay, and they all are offered for free internet. There are quite a lot of websites that can help you in evaluating your essays and also in supplying you with useful GRE sample essays. The very first issue to do before you get started searching for GRE sample essays is to comprehend what the Analytical Writing test section is about. Not only do you have to read through GRE sample essays, but you must also look for topics on which you may write GRE sample essays yourself and have them evaluated. In each one of the 3 body paragraphs of your essay, you should talk about the 3 leading elements of the argument that go to show your point. In conclusion, the statement isn't logical since there are a few errors in it. When you check at two sentences, the outcome isn't suitable for the cause. The second sentence should give your reasoning.

Comparing themes in Recitatif and This is What It Means to Say, Phoenix, Arizona free essay sample

The relationships we see within Toni Morrison’s â€Å"Recitatif† and Sherman Alexie’s â€Å"This is What it Means to Say Phoenix, Arizona† are very complex, however, whether we’re examining a mother and daughter, or two childhood friends, it is clear our theme deals with the security and solidarity of relationships. Toni Morrison’s â€Å"Recitatif† depicts the complex relationships that two girls in foster care, Twyla and Roberta, have with their mothers. Twyla’s mother and Roberta’s mother share a tragic flaw their conditions prevent them from caring for their daughters. However, their conditions do differ Twyla’s mother’s condition may be self inflicted. Twyla’s mother is a prostitute, and she may drink or do drugs heavily in the way that we see her sloppily greet Twyla: â€Å" and she smiled and waved like she was a little girl looking for her mother not me. † (Morrison 370) â€Å"Mary dropped to her knees and grabbed me, mashing the basket, the jelly beans, and the grass into her ratty fur jacket. † (Morrison 370) Roberta’s mother may suffer from conditions out of her control she seems as though she is mentally ill. Roberta’s mother obsessively holds her Bible and refuses to shake Twyla’s mother’s hand. We can also note that these conditions never cease each time Twyla and Roberta’s lives intersect, they mention that their mothers never got better: â€Å"Did I tell you, my mother, she never did stop dancing. † (Morrison 370) The relationships Twyla and Roberta maintain with their mothers can be seen as dysfunctional solely on the fact that the girls are in a foster home. However, the mothers’ visit at St. Bonny’s gave me a slightly different feeling these dysfunctional mothers love their daughters very much, in very different ways. While Mary’s sloppy entrance mortified Twyla, their embrace is a very secure, happy moment for Twyla: â€Å"I could have killed her†¦ But I couldn’t stay mad at Mary while she was smiling and hugging me and smelling of Lady Esther dusting powder. I wanted to stay buried in her fur all day. † (Morrison 370) We can see Roberta’s loving relationship with her mother during the same visit at St. Bonny’s: â€Å"Her mother had brought chicken legs and ham sandwiches and oranges and a whole box of chocolate-covered grahams. Roberta drank milk from a thermos while her mother read the Bible to her. † (Morrison 370) This loving dynamic almost made me forget that Roberta was living as a foster child. I tried to ignore that Roberta’s mother may have gone the extra mile out of guilt or compensation Roberta was happy, and was too young to analyze the gesture further anyway. In Sherman Alexie’s â€Å"This is What It Means to Say Phoenix, Arizona†, we analyze the relationship between Victor and Thomas. Victor and Thomas were friends in their early childhood, but had a falling out at fifteen years old. The falling out was a drunken fist fight initiated by Victor, leaving Thomas badly beaten up. We might believe that Victor acted aggressively towards him out of embarrassment he wanted to show the boys in their neighborhood that he wasn’t friends with Thomas, because Thomas was an outcast: â€Å"All the other Indian boys stood around and watched it happen. Junior was there and so were Lester, Seymour, and a lot of others. † (Alexie 326) We might also credit their falling out to the fact that they have such different cultural beliefs. Thomas is extremely unique he tells odd stories, and believes nature can speak to him: I heard it on the wind. I heard it from the birds. I felt it in the sunlight. (Alexie 326) While those may seem like characteristics of a mental patient, Thomas takes his beliefs from a traditional Native American culture. Victor’s cultural beliefs stray from that lifestyle, and eventually led him off of their reservation. We see how different their beliefs are during their conversation on the Fourth of July: â€Å"‘You know’ Thomas said. ‘It’s strange how us Indians celebrate the Fourth of July. It ain’t like it was our independence everybody was fighting for. ’ ‘You think about things too much,’ Victor said. ‘It’s just supposed to be fun. ’† (Alexie 326) In their short interaction, it is clear that Thomas has an identity that is more aligned with the Native Americans who were put onto reservations and do not feel American in the cultural sense of the word. Thomas doesn’t feel that the Fourth of July applies to him. Victor, on the other hand, is simply enjoying the excitement of the fireworks, fun, and celebration. Victor doesn’t put much stock into the thought that Native Americans do not have their freedom in the way the Fourth of July presents it. The two stories represent a similar theme: the influence of our relationships as we mature into adults. Twyla and Roberta’s relationship influences they way they interact with each other as adults. While Victor didn’t have much of a relationship with his father, the trip he takes to retrieve his father’s remains becomes an emotional journey. We can also compare these stories in their use of flashbacks and flashforwards which are explained by Jan Schmidt in our Legacies textbook. Flashbacks and flashforwards provide â€Å"dramatic impact, irony and double meanings† (Schmidt 1346)

Save the Children (UNICEF)

Interplanetary Internet from NASA’s experiment The WritePass Journal

Interplanetary Internet from NASA’s experiment   ABSTRACT Interplanetary Internet from NASA’s experiment   ABSTRACTCHAPTER 1: Introduction1.1 Background and Context1.2   Motivation to DTN:1.2.1 Challenged networks/environments for Internet1.2.2 Challenges due to Mobility1.3 DTN concept: Solution to Challenged environments and mobility2.4 DTN Denial of service attack (DoS): Motivations1.5 Objectives of Project1.6 Overview of Dissertation:CHAPTER 2: States2.6 Routing in DTN **2.6 Threats in DTN2.7 Denial of Service Attacks:2.8 Resource consumptionCHAPTER 3: My proposed approach to DOS in DTN3.1 Introduction3.1 Scenario3.2 Background/Review of Security and DOS in DTN In Literature3.3 Attack Model3.4 Authentication3.5 Routing Model3.6 Mobility Model3.7 Attack types3.8 Assumptions3.9 Proposed Resilience Mechanism3.10 Simulation model and parametersResult Matrices:One Simulator (used for simulation)Work doneOne simulator test runsFuture workCHAPTER 4: Conclusion4.1 Project Work Plan5: ReferencesRelated   ABSTRACT Internet has already revolutionized the way we live and work, but it is still in its infancy in some areas to provide ubiquitous connectivity in future. To solve the problem of Ubiquitous connectivity in communication challenged areas Delay Tolerant Network (DTN) provides an opportunistic networking architecture. Opportunistic networks represent a class of networks where end-to-end continuous connectivity between source and destination is intermittent [1]. There are variety of challenged areas like areas as high latitudes, war prone areas or disastrous scenario where environmental considerations create impossibility for conventional mobile telephony and satellite coverage is inadequate or economically infeasible or because of infrastructure deployment constraints, or power source availability, or because of government policy decisions do not allow access. Moreover, DTN seeks to address the technical issues in heterogeneous networks to use every possible feasible access method to provide internetworking among existing types of wireless or wired networks like Internet, Mobile and WLAN [7]. Integrating DTN capabilities with the existing TCP/IP based Internet it aims to deliver Internet-like communications even for long variable delay, asynchronous as well as interrupted heterogeneous environment where existing transport protocol and congestion control mechanism have limitations [1].   Basic DTN architecture by IETF RFC   involves use of ‘Bundle protocol’ which allows communication over multiple hops by means of ‘custody transfers’ and  Ã‚   messages   in DTN are routed in   store-and-forward manner on each node[2]. Research and development going on over last ten years has set out some challenges that need more focus before DTN becomes a day to day reality. In this Interim report I am focusing on Denial of Service (DoS) attacks due to open channel and multi-hop DTN transmission characteristics which can limit its full utilisation. First I will review the state-of-art in context of DTN security and attacks at present then I will analyse possible DoS attacks in DTN and their countermeasures. I will present a comprehensive resilience mechanism to address the identified attacks, focusing on a critical metrics of performance. I will propose a simulation model and demonstrate the effectiveness of the newly proposed techniques through simulation using ONE simulator.    CHAPTER 1: Introduction 1.1 Background and Context The emergence of the idea of Delay tolerant networking started in late 1990 as ‘Interplanetary Internet’ from NASA’s experiment of deep space, high delay, store-and- forward networks [5]. That early work focused on protocols suitable for very long propagation delays of deep- space- interplanetary communications. Other early work includes military specific Disruption-Tolerant Networking due to scenarios of long delayed links, broken or intermittent links. Extending initial work purpose in 2002-03 researchers looked at other applicable scenarios, like terrestrial wireless networks, wireless sensor networks and other local area networks, where communication opportunities were not much certain. DTN has shown its suitability and strength to applications having long or unknown delays due to frequent disconnections and for interconnecting various heterogeneous networks, which commonly is not   a conventional IP-based network. The development of wireless communication technologies made the Internet ubiquitously. Within the vision of ‘any time anywhere’ networking, efficient internetworking among existing types of wireless networks is inevitable. Integrating DTN networks as another access method into the existing network infrastructure allows the Internet to reach people who are hundreds of kilometres, or more away from existing infrastructure.   Although Internet has already revolutionized the way we live and work, but it is still in its infancy in some areas. Challenges faced by current Internet Today’s Internet is based on end-to-end network connectivity based TCP/IP protocol model. It makes certain fundamental assumptions like continuous source destination   connectivity, end – to- end low delay paths, low transmission error rate and bidirectional symmetrical data rate which applies a number of constraints to its reachability[1][5]. So the overall vision [6] of Future Internet should be to provide ubiquitous and pervasive networking for the users and applications in well-connected regions with keeping in mind communication challenged areas. The current Internet must develop to be more able of dealing with new evolving forms of content and their consumption but there are many challenges in the wide range of application requirements related to network heterogeneity as well as by the growing number of non-TCP/IP networks and mobile devices. 1.2   Motivation to DTN: 1.2.1 Challenged networks/environments for Internet Some regions are called ‛communications challenged’ because they have little or negligible infrastructure that is required to support modern wireless and wired Internet communications. These Challenged environments are very heterogeneous and have characteristics [1] [5] such as End-to-end path may not exist creating Intermittent connectivity Node reachability and density may be Predictable (Planetary dynamics, scheduled vehicles, message ferries) Unpredictable (Sparse sensor networks, data mules, vehicular) Semi-predictable (animals, vehicles, etc.) Large, unpredictable,   variable delays for transmission (deep space- moon: 3s, Mars: 2min, Pluto: 5h) Asymmetric/ asynchronous data rate which may be very low (acoustic underwater modems: 1 bit/s–few Kbit/s) High bit error rate (wireless, underwater, satellite) Using different transport protocols in different parts of the network making interactive communication impossible/ inefficient or unreliable Environment having very large round trip times (deep space, military or remote area communication) Many of the challenges have been tried to address using Performance Enhancing Proxies (PEPs) which try to solve high delay low bit rate links performance but it still demands end-to-end connection. 1.2.2 Challenges due to Mobility Mobility may create potential disconnection in end-to-end connectivity which produces challenges for current TCP/IP based Internet in form of: Communication link availability (not ubiquitous due to movement Limited Transmission range Communication link specially interactive communication link   may be costly due to frequent movement of nodes Link may be unavailable due lack of battery power or storage Although Ad-hoc and Peer-to-Peer networks may solve the problem to some extend but there are limitations due to not enough mobile nodes available or willing nodes or nodes with incompatible devices. 1.3 DTN concept: Solution to Challenged environments and mobility DTN aims to provide solution for challenged environment where no end- to-end connection is available or it is disrupted. Delay Tolerant Network is a network over underlying heterogeneous networks having opportunistic encounter driven ‘store, carry and forward’ approach to provide connectivity on hop-by-hop basis.   Most discussed     current approach to DTN is centred on an overlay protocol called the bundle protocol (BP).[11] 2.4 DTN Denial of service attack (DoS): Motivations DTN transmission is open channel and multi-hop which makes attacks in such situations an easier task. Traditional mechanisms to mitigate these attacks are not well sufficient to challenge environments where nodes are not connected for long periods of time and direct end-to-end communication is not possible and resources are scarce. Most of the solution available so far in literature address security in general and does not give attention to Denial of Service aspects in DTN. DoS is the most common attack in Internet communication and in DTN environments due to   longer delays DoS attempts will be   more effective. So there is need for more research explicitly considering DoS at all times. 1.5 Objectives of Project Study of delay tolerant network (DTN) architecture, its concepts and Bundle layer and how they differ from current networks, giving more emphases on security and attacks.   First I will review the state-of-art in context of DTN security and attacks at present then I will analyse possible. Identify the common DoS attacks and their countermeasures, focussing   on a scenario of communication in delay tolerant networks comprising mobile nodes. To design develop and test some resilience mechanism mechanism to address the identified attacks (nodes with address spoofing, false authentication and packet flooding), focusing on a critical metrics of performance using Simulator Simulation result will show how performance of a DTN network suffers when no Resilience scheme is used. 1.6 Overview of Dissertation: First I will review the state-of-art literature review in context of DTN architecture, security and analyse possible DoS attacks in DTN and their countermeasures. Then (in Ch-3) I will present an attack model and resilience mechanism for DoS attack. In next sections will follow ONE simulator overview and future work in direction of achieving objectives of project with Gantt chart and finally conclusion and references. CHAPTER 2: State-of-The-Art and Literature Review 2.1 Introduction DTN aims to provide usable Internet-way communications for long variable delays, asynchronous as well as interrupted heterogeneous environment where existing transport protocol and congestion control mechanism have limitations [1]. 2.2 Delay Tolerant Network history and Overview Delay Tolerant Networks (DTNs) have become a hot research topic among researchers and academicians since it was proposed by Kevin Fall in 2003 SIGCOMM seminar paper [1]. Vinton Cerf who is recognized as â€Å"one of the fathers of Internet† contributed in designing and defining its reference   Architecture [2] in DTNRG for IETFdraft of   RFC-4838. Basic DTN architecture by Internet Research Task Forces Delay-Tolerant Networking Research Group (IRTF DTNRG) involves use of ‘Bundle protocol’ which allows communication over multiple hops by means of ‘custody transfers’ and  Ã‚   messages   in DTN are routed in   store-and-forward manner on each node[RFC-5050]. 2.3 Delay Tolerant Networking Definition and Contexts of DTNs in Literature A delay- or disruption-tolerant network has been defined in several ways in literature. In [1], the DTN is defined as challenged networks, which may not follow the assumptions of the Internet. In [2]RFC-4838 describes it as   occasionally and opportunistically -connected networks that may comprise more than one   different   set of protocols. It includes a hop-by-hop transfer of message for reliable delivery. A DTN as stated in [5] was defined as a network of regional networks, where it serves as a store-and-forward overlay on top of (and providing interoperability between) regional networks (Internet, the MANETs, sensor network or any other network). 2.4 Constraints in Delay Tolerant Networks Node Constraints includes (a) Limited Memory (b) Limited and unreliable Power and Energy (c) limited transfer time for messages. Network Constraints are (a) Unreliable Communication (b) Collisions and latency Physical Limitations are (a) Unattended after deployment (b) Remotely managed Link constraints  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚      (a) long and varying delays (b) changeable mobility pattern of devices In Opportunistic networks such as Sensor/Actuator networks that use scheduled intermittent connectivity (to conserve power), because they have extremely limited node power, storage memory, and CPU processing capability. In Vehicular networks which use opportunistic (unpredictable) contact for message delivery. In Satellite networks having   medium delays or periodic connectivity In Terrestrial wireless networks that connect mobile devices, including PDAs etc. In Underwater acoustic (sensor) networks having frequent interruptions with moderate delays. Outer (deep)-space networks (InterPlaNetary (IPN) Internet project). Military Ad-hoc Networks such as a military battlefield where systems operate in highly hostile environments having mobility, bad environmental factors, or regulations causing disconnections like intentional jamming. In Rural villages or developing regions low cost and remotely located networks that non-interactively and occasionally communicate with the Internet. For example remotely located schools, kiosks and computer centres are linked on occasional basis using satellite and data mules or local transport infrastructures. In sparsely connected ad hoc networks where some wireless devices or networks may fall outside the required communication range of each other. 2.5 Major DTN Applications and Examples Example of Projects involving DTN: [6,7] Diesel net. Haggle, Interplanetary Internet, BBN’s SPINDLE project,   FirstMileSolutions SeNDT Sensor Network with Delay Tolerance, Saratoga and HTTP-DTN, SNC Project, N4C Project, ZebraNet, FidoNet, SUMOWIN, Shared Wireless Infostation Model (SWIM) at Cornell, The Mindstream Project at the University of Waterloo School of Computer Science, Time Equals Knowledge (TeK),World Wide Web Offline Explorer (WWWOFFLE), Bytewala DTN, Chianti, IBR-DTN etc. 2.6 Routing in DTN ** Traditional routing protocols operate under the assumptions of continuous connectivity, low delay and very low packet loss rate but in case of DTN opportunistic and disconnected links new routing protocols and system architectures are required to be developed. There are various types of DTNs based on their characteristics, but allows great flexibility for routing protocols in these networks based on their specific requirements. There are several DTN routing schemes proposed in the literature. Four major ones could be Epidemic routing: Epidemic routing simply makes multiple copies of packets to flood the network in a hope that any one of them will be delivered to the destination. This protocol performs best in terms of packet delivery and latency when network bandwidth and storage are unlimited. But it is not the case in practice. PROPHET: estimates delivery predictability to destinations using the history of encounters. MaxProp: computes a rank for each packet in terms of delivery probability and sorts packets in the transfer buffer accordingly. Upon transfer opportunity, packets are replicated in the order of their ranks Spray-and-Wait: follows a flooding scheme, but limits the total number of copies per packet. 2.6 Threats in DTN To understand the topic I will first examine the terminology, then the definitions of threats and DoS followed by discussion why DoS is potential problem in DTN. Security and attack literature reviews are given in next chapter. Threat: [20] Any circumstance or event (such as the existence of an attacker and vulnerabilities) with the potential to adversely impact a system through a security. Attack: Attempt to gain unauthorized access to a service, resource, or information, or the attempt to compromise integrity, availability, or confidentiality. It is irrelevant to success, which may or may not. Non DTN node threats:   The first set of threats considered were those coming from network   Ã‚  Ã‚  elements which are not directly part of the DTN.   As an overlay   Ã‚  Ã‚  network, bundles typically traverse multiple underlying networks.   Any vulnerability in the bundle protocol can be exploited at any of those network elements [13]. Denial of Service (DoS): Classically, the definition of denial-of-service (DOS) involves three components: authorized users, a shared service, and a maximum waiting time [20][13]. In DoS Authorized users are said to deny service to other authorized users when they prevent access to or use of a shared service for longer than some maximum waiting time. More generally to denial-of-service in DTN: The result of any action that prevents any part of a DTN from functioning correctly or in a timely manner so that intended user cannot use it.   It is directly a breach to availability [20]. 2.7 Denial of Service Attacks: [3]In addition to the basic resource consumption threats mentioned above there is also a range of denial of service (DoS) attacks which must be considered in the DTN context. DoS attacks can be mounted at any layer, from physical to application. In a DTN environment, the generally longer latencies involved will probably act to make DoS attempts more effective. As with all networks, security mechanisms will themselves create new DoS opportunities.   Therefore whatever services and mechanisms are defined for DTN security should explicitly consider DoS.   For example, mechanisms which involve certificate status checking (via some protocol to a key) based on received messages create new DoS opportunities since such lookups consume resources on both the receiving node and the key server. Common DoS attacks: Attacks that are common to DTNs are Dropping of packets, Flooding the network with unnecessary spurious packets, Spoofing a different node’s address to intercept all the packets destined to that node, orrupting routing states and Counterfeiting network acknowledgments Resource consumption (Battery exhaustion, creating routing loops) 2.8 Resource consumption Due to the resource-scarcity that characterizes DTNs, unauthorized   Ã‚  Ã‚  access and use of DTN resources is a serious concern.   Specifically, the following can consume DTN resources and be considered threats   Ã‚  Ã‚  against a DTN infrastructure [13]: 1.   Access by unauthorized entities, 2.   Unauthorized applications controlling the DTN infrastructure, 3.   Authorized applications sending bundles at a rate or class of   service for which they lack   permission. 4.   Unauthorised bundle content modification -tempering 5.   Compromised network elements, be they DTN nodes or not. In addition to these threats, DTN nodes can act to assist or amplify  Ã‚   such resource consuming behaviour as follows: Forwarding bundles that were not sent by authorized DTN nodes. Generating reports not originally requested (e.g. if a bundle has been modified) Not detecting unplanned replays or other misbehaviours. DoS prevention: As described above, denial-of-service is a breach of the security characteristic of availability. Along with availability, confidentiality and integrity are the primary concerns of security. DoS cannot be prevented because most attacks leverage the use of routing and other network activity but there are countermeasures to mitigate it like: Spread spectrum techniques (using network coding) Proper authentication using either Public-key cryptography (computationally expensive) or Fast symmetric-key cryptography must be used sparingly Currently work has been done using Identity based cryptography (IBC) or Hierarchical based cryptography (HIBC). DTN Security Requirements: [5] According to DTNRG The emphasis of DTN security is on protecting the DTN infrastructure from unauthorized access and use Prevent access by unauthorized applications, Prevent unauthorized applications from asserting control over the DTN infrastructure, Prevent authorized applications from sending bundles at a rate or class of service for which they lack permission, Promptly detect and discard bundles that were not sent by authorized users, (early detection within infrastructure rather than at destination), Promptly detect and discard bundles whose headers have been modified Promptly detect and disable compromised entities Secondary emphasis is on providing optional end-to-end security services to bundle applications. CHAPTER 3: My proposed approach to DOS in DTN 3.1 Introduction In this section I summarise my analysis of previous work done in the areas of security and attacks in DTN, especially Denial of Service in DTN. Also I identify conditions that are can materialise an attack materialise. Then I show that based on these conditions the attack effectively happening in a representative model, with a set number of nodes and chosen network topology, routing schemes and security scheme. I also demonstrate that security and privacy are crucial in DTN and using cryptographic techniques we can secure DTN. I assert that because of constrained nature of DTN, participants have limited access to Trusted Authority. In view of these constraints, I propose a model based on a symmetric and asymmetric key cryptography to mitigate DOS attacks in DTN. My model is based on prior creation and distribution of keys to participants at setup stage, where each trusted participant knows keys of others. 3.1 Scenario My scenario is based on IETF DNRG architecture on Delay tolerant network. There are multiple operating groups in this DTN. Each group has its own trusted and well known registering agency/organisation which can work as an affiliation agency or service provider. These could be any mobile service provider or any company which will register its employees and knows them prior or any university/school/hospitals which can register members by verifying their identity and credentials. This means that members of this group are now trusted and known and are not malicious. With this set up we have limited authenticated participant nodes and we can avoid any malicious activity by unknown/ untrusted nodes. Such network is a special DTN and can also be useful for example in a conflict zone where participation by anonymous nodes is not desired. I consider a scenario in which these mutually trusted DTN mobile nodes exchange messages within its group (using PDA/Bluetooth devices/mobile phones) with one another after authentication phase is successful. Fig1: Used Scnario 3.2 Background/Review of Security and DOS in DTN In Literature Here I will discuss solutions and reviews based on literature survey on DTN security and DOS attacks. There is a particular lack of research papers addressing DOS attacks in DTN. Most work is based on assuming that routing or security mechanism of DTN will prevent DOS to some extent. Nevertheless these schemes can never underlie the necessity of authentication protocols. Farrell and Cahill [11] review the current state of DTN security work inspired by Internet. They identify and analyse threats for DTN and the security requirements in bundle protocol. Then they discuss open issues in bundle security and implementation issues in DTN security as follows. (1.) First set of threats are from outside network due to being overlay nature of DTN. (2.) modification of messages or bundles in transit for malicious purposes. (3.) Unauthorized use of scarce DTN resources like replay attacks and (4.) denial of service which can be mounted on any network layer, and (5.) confidentiality and integrity threats like changing the destination in bundle. The author propose for DOS that firstly using random values instead of counters for identifying messages will make it hard to guess valid message content. Secondly, accepting only fresh authenticated messages and dropping all others will be advantageous in mitigating attacks. Thirdly, authors point that networks and security protocols themselves can create new DOS if not carefully designed. I am building on the second concept in my proposal i.e. exchange message after successful authentication. Moreover, Farrell and Cahill [11] propose that security architecture is needed in which security services can be provided both on hop-by-hop and end-to-end basis, and additionally between two intermediary nodes in the middle of a route. They also mention that several open issues remain in DTN security like the implementation cost and level of complexity should not rise too high, since typically complicated solutions are not secure in practice. Another big open issue is key management [11][12] briefly addresses security services on an end-to-end basis (e.g. confidentiality and DoS), but does not go into specifics nor considers the case of initial communication between two nodes without any prior security context. [13]The Delay Tolerant Networking Research Group (IRTF-DTNRG) has produced an Internet draft for bundle security protocol specification [12] and an additional draft [13] explaining the security overview and design choices made in the specification. The draft which is near completion describes security headers that can be added to bundles to provide different security services. Security Blocks in Bundle security Specification: According to RFC draft [13] there are four types of security block that can be included in a bundle. These are the (1.)Bundle Authentication Block (BAB), (2.) Payload Integrity Block (PIB), (3.) Payload Confidentiality Block (PCB) and (4.) Extension Security Block (ESB). The BAB is used to assure the authenticity and integrity of the bundle along a single hop from forwarder to intermediate receiver. The PIB is used to assure the authenticity and integrity of the payload from the PIB security-source, which creates the PIB, to the PIB security-destination, which verifies the PIB authenticator. The PCB indicates that the payload has been encrypted, in whole or in part, at the PCB security-source in order to protect the bundle content while in transit to the PCB security-destination. PIB and PCB protect the payload. The ESB provides security for non-payload blocks in a bundle. ESB therefore is not applied to PIB or PCBs, and of course is not appropriate for either the payload block or primary block. Extension Blocks Bundle Payload Primary Blocks (Time Stamp, Life Span, Flags, Source EID, Destination EID, Report to EID, Custodian EID) Security Blocks (optional) BAB, PIB, PCB, ESB Each security block contains source and destination information and a cipher-suite defines the algorithms that should be used to process the received security headers. The security-sender and the cipher-suite information together determine the choice of keys. Different combinations of these four security headers can be used simultaneously. The need to authenticate bundles using Security blocks is very useful to protect against denial-of service (DOS) attacks against a bundle agent’s resources, but need more insight knowledge how to implement it. In [14], [15] (Seth and Kate) authors discuss the challenges of providing secure communication (i.e., confidentiality) in DTN and suggest employing Identity-Based Encryption (IBE) to let a source derive the destination public key from some associated identity string, e.g., an e-mail address. In [14] Seth et al. discuss in detail about rural area DTN and shows that traditional mechanisms including a combination of Public Key Infrastructure (PKI) and certificates issued by trusted third party are not suitable for DTN. They develop a security mechanism for DTN using Hierarchical Identity-Based Cryptography (HIBC) for creating secure channels, providing mutual authentication, and key revocation. [15] Kate et al. uses identity based cryptography (IBC) for source authentication and anonymous communication as well as message confidentiality are provided using IBC. Its main idea is to make an entity’s public key directly derivable from its publicly known identity information such as e-mail address. Eliminating the need for public-key certificates and their management makes IBC much more appealing for securing DTNs, where the need to transmit and check certificates has been identified as a significant limitation. I note that the existing techniques to secure DTNs are aimed to provide data confidentiality and authentication only. In [16] Burgess et al. suggested that some Delay tolerant networks coupled with replication-based routing protocols are intrinsically fault tolerant even without authentication mechanisms. They compare four different routing algorithms (MaxProp and its three variants) against four different attack models: dropping of packets, flooding of packets, routing table falsification and counterfeiting delivery acknowledgments. They distinguish between two types of attack; weak and strong attacks on the basis of prior knowledge of DTN scenario. One of the major themes in the paper is the two-fold benefit of epidemic-style packet dissemination in DTN routing which improves packet delivery rates and greater attack tolerance. However, this paper does not provide any attack specific simulation. In [22] authors poses the question of the necessity of authentication or the level of authentication required especially since authentication imposes overhead. Without authentication, the number of nodes willing to join the network may actually increase due to the easier deployment, resulting in better overall performance. They identify conditions for an attack and present an attack based on a combination of targeted flooding and acknowledgement counterfeiting. They suggested that generally, attacks become increasingly effective when the minimum hop count required increases. Coclusion: Identity-based cryptography requires a global trusted third party to guarantee for new nodes entering the network (by generating the necessary private keys). But IBC is no better than traditional PKI in terms of authentication and only a little better than traditional PKI in terms of encryption since network connectivity is not necessarily needed at the time of reception and decryption. In [17] authors propose a scheme that gives confidentiality and authentication to messages leveraging social contact information and past present affiliation of peers. Author evaluates the proposed scheme by analysing real-world social network data of Facebook, simulating communication scenarios, and through an informal security analysis. In [18] authors focus on DOS and describe few possible DOS attacks for DTN and propose a token based mechanism against those attacks. Authors suggest attack depends on routing protocol. Therefore, it is obvious that the routing protocol that maintains routing table like in-node states can be subject to severe DOS attacks. Spray-and-wait protocol is a stateless protocol in that nodes do not maintain any routing states; instead a tiny state is kept in each packet header. Their first approach is very trivial but second approach based on Token utilising collision count with every peer node provides countermeasures against spoofing and packet dropping in a limited scenario. There are many drawbacks in this approach for example an honest node always meets the same malicious node spoofing   the same address and   that honest node never meets with the actual address holder or any other adversary spoofing that address. In this case the honest node does not suspect this peer to be an adver sary and always follows basic Spray and will transfer message to malicious node. In [19] A. Wood very broadly discusses about DOS attack taxonomy to identify the attacker, his capabilities, and the target of the attack, vulnerabilities used, and the end result. Although, author surveys vulnerabilities and give possible defences in Wireless sensor network some of which issues are useful in gaining insight of DOS attacks in DTN. According to author denial-of-service is the result of any action that prevents any part of a network from functioning correctly or in a timely manner. It is directly a breach to availability. In [2s0] authors also use Identity based cryptography to investigate how security in DTNs can be bootstrapped and present an improved scheme for authentication of fragments. We show that DTN with replicative routing protocols are not necessarily robust under known denial of service attacks if there are no authentication mechanism in place. Under many networking settings and mobility patterns, carefully designed attacks based on well-known techniques can cause considerable performance degradation. They investigate the attack effectiveness under various settings and identify properties of the networking environment that attribute to the vulnerability of the network. They observed that routing protocols which globally floods routing metadata to guide routing decisions are more susceptible to attacks as the routing metadata can be easily spoofed. They also observed that the minimum hop count required for packet delivery plays an important role. 3.3 Attack Model My objective is to determine how performance of a DTN network suffers when no authentication scheme is used. This also depends on other variables set aside in assumptions about the security model and what attacks I want to consider. By recognise that these little variations can cause DTN to perform badly even in the presence of few attackers, for example in case of extremely low mobility of nodes and one node positions itself at a crucial location along the routing path. If that node misbehaves, by dropping or flooding bundles, DTN will perform miserably at least along that routing path. I have chosen a hop by hop authentication model where main aim of adversary nodes is to create DOS by preventing the successful delivery of packets to their intended destinations. The adversary nodes can join together to launch a coordinated attack or a standalone adversary node can perform an opportunistic attack. 3.4 Authentication Without authentication no estimation can be formed about the identities of nodes and therefore the intentions of peers can be determined. In traditional TCP/IP, data frames are transmitted to all other nodes on a network. Each receiving node checks the destination address of each frame, and simply ignores any frame not addressed to its own MAC. Because it is a local broadcast domain, MAC address spoofing is fairly easy. Attackers can spoof address of any node and can become any node at any time including the destination node of the bundle. 3.5 Routing Model While routing is important consideration and routing data exchange between nodes is an important factor, the need for peer to peer and end to end authentication cannot be precluded. In my model I am ignoring any attacks based on routing data exchange and also at application layer such as spoofing requests that floods legitimate nodes to flood each other with unneeded traffic. 3.6 Mobility Model An attacker’s mobility can be variable. It can attack all nodes that come within its transmission range or it can choose to remain in the vicinity of one node in the network for extended periods. Tailgating is also possible. [6] Burgess et al call the latter approach a parasite attack the most effective use of the attacker’s resources. 3.7 Attack types In the above situation DOS attacks are possible by misbehaving nodes. I am considering the following two: Packet Dropping: An adversary node does not replicate, forward or store a packet that is received from its peer. These nodes act like black holes in the network and impair packet propagation in the network, although routing choices such as Spray provide some resilience to such attacks, because additional copies of packets might exist at other locations. Address Spoofing:   An adversary fakes the some other node’s address when it encounters another node in the network. An unsuspecting node sends packets to this malicious node and removes packets from its queue. The unsuspecting node might also delete the packet after delivery. If the malicious node receives packets with a high replication count, the successful delivery of such packets becomes highly unlikely.   Spoofing created more problems in the network than dropping with respect to packet delivery. An attacker can also perform both types of attacks simultaneously. 3.8 Assumptions In this section I describe assumptions for my proposed resilience mechanism to prevent DOS attacks in DTN. I’m considering two schemes; one based on pre shared symmetric keys and other based on public key cryptography. There is a Trusted Authority is assumed not to be compromised and nodes can only be registered by proving their credentials. Registration Authority can be any service providing company or any local company or government organisation.   Also malicious nodes cannot be registered and registered nodes are not malicious. Each node has a unique ID and I assume that all group nodes have enough power and storage capability to perform cryptographic operations. For pre pre-shared keys scheme, each node at registration phase is given a group key, which it uses for authenticating other nodes. For public key cryptography based scheme, each node is given a public- private key pair at registration phase. Also, each node maintains a table of every other node in the group and their public keys. This table is provided at registration phase. 3.9 Proposed Resilience Mechanism My proposed schemes are based on creating a mutually trusting network of nodes. Spoofing nodes cannot utilise this network because they cannot pass authentication checks. a)   Scheme based on pre-shared group key: The communicating nodes thwart potential DOS attacks of packet flooding by malicious sender and packet dropping by malicious receiver. Nodes authenticate each other before sending packets. The intention is to find if a peer is spoofing someone’s address. This is done as follows. Two nodes N1 and N2 are part of the group, which shares the group key G that they received at registration phase and wants to authenticate each other. Node N1 generates a random token RN1 and encrypts is with the group key G and sends the encrypted message G[RN1] to N2 Node N2 decrypts G[RN1] with G and sends result G’[G[RN1]] to N2 Node N1 checks whether RN1 is equal to G’[G[RN1]], if mismatch, N1 terminates further communication, otherwise proceed to next steps Node N2 generates a random token RN2 and encrypts is with the group key G and sends the encrypted message G[RN2] to N1 Node N1 decrypts G[RN2] with G and sends result G’[G[RN2]] to N2 Node N2 checks whether RN2 is equal to G’[G[RN2]], if mismatch, N2 terminates further communication, otherwise proceed to next steps N1 and N2 exchanges message. The drawback of this scheme is if pre-shared group key is compromised a malicious node can spoof any other node and coordinated attacks can be very disastrous. b)  Ã‚  Scheme based on public key cryptography: In this scheme each trusted node maintains a table of other nodes and their public keys. This list is originally provided by Trusted Authority and refreshed when subject node comes in contact with Trusted Authority opportunistically or at scheduled times. The communicating nodes authenticate each other based on each other’s public keys before sending packets. This is done as follows. Two nodes N1 and N2 are part of the group, with each having their public private key pair [NiPub, NiPvt] received at registration phase. N1 generates a random Token RN1 N1 creates encrypted Token N2pub[RN1] Using shared N2s public key and sends to N2 N2 decrypts N2pub[RN1] using its private key and responds with N2pvt[N2pub[RN1]] N1 checks whether N2pvt[N2pub[RN1]] is equal to RN1. If mismatch, N1 terminates further communication, otherwise proceed to next steps N2 generates a random Token RN2 N2 creates encrypted Token N1pub[RN2] Using shared N1s public key and sends to N1 N1 decrypts N1pub[RN2] using its private key and responds with N1pvt[N1pub[RN2]] N2 checks whether N1pvt[N1pub[RN2]] is equal to RN2. If mismatch, N2 terminates further communication, otherwise proceed to next steps N1 and N2 exchanges message. In both of these schemes one node needs to know if the bundle originates from a trusted community in order to prevent flooding attack by a malicious node and the bundle is sent to a trustworthy node in order to prevent packed dropping If a malicious node spoofs some other node’s address, it cannot decrypt the encrypted random token it received from its peer. Analysis of Proposed Mechanism: I have chosen the above mutual authentication schemes as a mechanism to prevent DOS attacks on DTN because this is a reliable way to identify malicious nodes and prevent packet flooding by rejecting packets from untrusted nodes and also prevent the risk of packet dropping by not sending packets to untrusted nodes. If a malicious node tries to send junk packets to legitimate nodes, the packets can be discarded at first contact with a legitimate node because a malicious node cannot authenticate itself to the network without pre-shared group key or public-private keys issued by Trusted Authority. There is a need to address current distribution of security information among nodes. This will involve key management and revocation issues. But this is part of more general DTN configuration management solution. 3.10 Simulation model and parameters Result Matrices: The simulation results will show that packet delivery rate decreases significantly in the presence of malicious nodes, i.e., packet droppers and/or address spoofers. The results will also show that delivery rate is increased with our countermeasures. In addition to that, I will also measure the overheads caused by the countermeasures in terms of number of copies of a single packet. One Simulator (used for simulation) The Opportunistic Networking Environment (ONE) simulator has been specially designed for evaluating DTN routing and application protocols. It is written in JAVA. It provides Generation of node movement using different movement models e.g. 1. Random Movement 2. Map based Random Movement 3. Human behaviour Based Movement Routing messages between nodes with various DTN routing algorithms and sender and receiver types. Visualizing both mobility and message passing in real time in its graphical user interface. I have run some scenarios and already Implement protocols in ONE like 1.) MaxProp   2.)Direct Delivery, 3.)   Epidemic, 4.) First Contact, 5.) PROPHET 6.) Spray and Wait I have tried to read and understand Code of different classes, I have configured ONE using Eclipse Work done Fig: Screen shot of scenario One simulator test runs Five test runs were done on One Simulator using default epidemic routing with varying number of nodes from 60 to 180 in steps of 30. Some of the results are captured in the table below Nodes 60 90 120 150 180 sim_time 165 374 541 780 1096 delivered 288 292 313 300 299 delivery_prob 0.3876 0.3914 0.4196 0.4032 0.4024 hopcount_avg 20.7396 15.2705 17.7636 15.12 12.9398 Future work I have chosen mutual authentication as a means to prevent DOS attacks because current implementation of DTN does not yet completely address the problem of address spoofing and packet dropping. Without the aid of some form of authentication either at node level or bundle level, it is difficult to discern malicious nodes. The bundle security protocol draft introduces four new security blocks in Bundle architecture (BAB, PIB) and their purposes. These blocks can be used to implement existing cryptographic techniques to provide some robust resilience against DOS and other common attacks in DTN. However this will involve development of reliable cipher suites and cryptosystems and this is an area of continued research. My further work will be mainly focused in the area of Bundle security specification. CHAPTER 4: Conclusion 4.1 Project Work Plan 5: References [1]  Ã‚   K. Fall, â€Å"A Delay-Tolerant Network Architecture for Challenged Internets,† SIGCOMM, August 2003. [2]  Ã‚   Vinton Cerf, Scott Burleigh, Adrian Hooke, Leigh Torgerson, Robert Durst, Keith Scott, Kevin Fall, and Howard Weis, Delay-tolerant network architecture. DTNRG Internet Draft, March 2003 and   IETF RFC 4838, informational, April 2007. [3]  Ã‚   K. Scott and S. Burleigh, â€Å"Bundle Protocol Specification,† IETF RFC5050, experimental, November 2007. [4]  Ã‚   K. Fall and S. Farrell, â€Å"DTN: an architectural retrospective,† Journal of Selected Areas in Communications, vol. 26 no. 5, pp. 828- 836, June 2008. [5]  Ã‚   William D. Ivancic (NASA Glenn Research Center), â€Å"Security Analysis of DTN Architecture and Bundle Protocol Specification for Space-Based Networks†, IEEEAC paper1057, Version 4, Updated 2009:10:27 [6]  Ã‚   DTN The State of the Art (http://wiki.n4c.eu/wiki/images/0/03/Proposal_description.pdf) [7] Challenged Internet Access Network Technology Infrastructure (CHIANTI March 2008) [7]  Ã‚   http://en.wikipedia.org/wiki/Delay-tolerant_networking [8]  Ã‚   L. Wood, W. Eddy, P. Holiday: â€Å"A Bundle of Problems,† IEEE Aerospace conference, Big Sky, Montana, March 2009. [9]  Ã‚   K. Scott and S. Burleigh, â€Å"Bundle Protocol Specification,† IETF RFC5050, experimental, November 2007. [10]  Ã‚  Ã‚   F. Warthman. Delay tolerant networks tutorial..tnrg.org/docs/tutorials/warthman-1.1.pdf, 2003. [11]  Ã‚  Ã‚   Stephen Farrell and Vinny Cahill. Security considerations in space and delay tolerant networks. In Proc. 2nd IEEE International Conference on Space Mission Challenges for Information Technology (SMC-IT’06), July 2006. [12]  Ã‚  Ã‚   Stephen Farrell, Susan Symington, and Howard Weiss. Delay-Tolerant networking security overview.IRTF, DTN research group, October 2006. Draft version -03; expires in Expires: January 4, 2008. [13]  Ã‚  Ã‚   S. Symington, S. Farrell, H. Weiss. Bundle Security Protocol Specification. dtnrg.org/draft-irtf-dtnrg-bundlesecurity-19.txt, Expires: September 12, 2011. [14]  Ã‚  Ã‚   A Seth, U. Hengartner, and S. Keshav. Practical security for disconnected nodes. 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