Career Counseling - Nursing

About Nursing Profession
Nursing is one profession in which the element of service to humanity is very strong. It is a
service dedicated to the relief of human pain and suffering and prevention of diseases. The
profession has attained the stature of both an art and a science.
All across the world, nursing is seen as one of the noblest professions. In a hospital, from the
general ward to the operation theatre, nursing is the most important component of patient care.
Contrary to popular belief, nursing is not a second choice career for those unable to gain entry in
a medical college. The two professions, though complementary, require separate skills and
temperaments. Where the doctor's contact with the patients is fleeting, nurses are expected to
establish and maintain a relationship with them.
The basic eligibility for a B.Sc. in Nursing is a 10+2 with Biology, Physics and Chemistry.
The basic eligibility for a course in General Nursing & Midwifery (GNM) is also 10+2 with Biology,
Physics and Chemistry.
Every state has arrangements for training of nurses. The following courses are offered by a
large number of hospitals / institutes spread all over the country.
• B. Sc. Nursing (4 years)
• General Nursing and Midwifery (GNM) -Course (3 years)
• Auxiliary Nurse / Midwives (1 - 1/2 years)
• Multipurpose Health Workers (Male & Female) (1 year)
Personal Attributes Required
Nurses have to be compassionate; they have to have sympathy for the sick and the old, without
sentimentality and a willingness to perform what many consider menial tasks.
Nursing is a very demanding profession which calls for a great deal of personal commitment.
Nurses need.....
-To be alert, observant, show initiative and be able to act decisively
-Physical and mental stamina
-Tact, patience and sensitivity
-Maturity and a sense of humour
-Communication skills for dealing with patients, their relatives and members of staff.
Nurse’s Work
Their work covers a range of functions and responsibilities that vary with the levels of qualification
and the working environment. Some nurses concentrate entirely on bedside care, while others
manage whole groups of people. The main functional areas of nursing include - general nursing
in hospitals, nursing homes, sanatoriums as well as schools. Industrial nurses render first aid and
provide preventive and other services under an Industrial Physicist, Psychiatric nurses work with
emotionally disturbed and mentally handicapped patients, and midwives look after mothers and
children, from early pregnancy until about four weeks after the birth of the baby.
Nurses everywhere are involved in the crucial tasks of dispensing medication, keeping records of
the patients' progress, setting up and operating medical equipment, administration and several
other routine chores.
Career Guidance for HSC students on 22nd June, 2003
Working Conditions
The types of hospitals vary widely from large general hospitals with a number of specialized
departments and wards, out-patients and accident and emergency departments, to much
smaller specialist units treating patients with particular health problems, e.g. orthopedic and
geriatric units. Some of the other older buildings, however, are dark and comparatively dismal.
Most hospital nurses are based in one particular ward at a time but may quite regularly move
around escorting patients to X-ray or operation theatre for example.
Job Prospects
There are various job opportunities open to those who take up Nursing:
• In various hospitals / clinics and health departments,
• In the railways and public sector medical departments,
• In private hospitals / nursing homes / clinics etc,
• Teaching / research in concerned areas of specialization.
Nursing service is primarily wage paid oriented. However, there is scope for selfemployment
also. There are opportunities to work on a part-time or daily basis in homes, private
clinics, maternity centers and nursing homes as private nurses.
Future Prospects
Anywhere in the world, the demand for qualified, skilled nurses is ever present. In India, as the
government attempts to widen the availability of health services, this demand for trained nurses
continues to grow.
The existing nurse-patient ratio ranges from 1:10 to 1:50 in most government hospitals. With
projected requirements of 1:3 and 1:5 in teaching and non-teaching hospitals, the country needs
at least another 6.6 lakh nurses by the year 2004. For those who feel that caring for people is
their vocation, there will always be work available.
1. Institute of Nursing Education, Byculla, Mumbai- 400001 Training College Of Nursing,
J.J.Hospital, Dist.Mumbai State-Maharashtra Phone No:-3735555 Ext;2355
Courses Offered:-
Affiliation:-Under Govt.Undertaking
10+2 Science,
Preferably with
3 yrs 130
Contact Person: - Mrs. S.D.Bhore-Principal
2. Leelabai Thackersey College of Nursing (Affiliated to S N D T Women's University), 1
Nathibai Thackersery Road, Mumbai- 400020
50 4 years B.Sc. Nursing
Candidate should have pass 12th standard examination with Physics, Chemistry and Biology as
compulsory subjects with 60% marks (50% for SC/ST/OBC candidates).
Minimum age is 16 years on 31st December of the year of admission.
Career Guidance for HSC students on 22nd June, 2003
Selection is made on the basis of merit of the qualifying examination, aptitude test and Interview.
The test consists of English, General Knowledge, Nursing Practical Test, Science and Maths
Application Form and Prospectus can be obtained in the month of March from the Principal on
payment of prescribed fee and last date for submission of form is in the month of May/June.
3. College of Nursing, Wanles Hospital, Miraj Medical College Centre, Miraj- 416410
4. Bharati Vidyapeeth's College of Nursing (Affiliated to Bharati Vidyapeeth Deemed
University), Katraj-Dhankawadi, Pune- 411043
30 4 years B.Sc. Nursing
Candidate should have pass 12th standard examination with Physics, Chemistry and Biology as
compulsory subjects with 50% marks in one attempt.
Free Seats- 50%.
Payment Seats- 50%.
Age should be minimum 17 years.
Selection is made on the basis of merit of the qualifying examination and interview.
Application Form and Prospectus can be had from the college on payment of the prescribed fees.
5. College of Nursing (Affiliated to Pune University), AFMC, Pune- 411040
6. College of Nursing, Armed Forces Medical College Wing, Sholapur Road, Pune-411040
30 4 years B.Sc. Nursing
Candidate should have pass 12th standard examination with Physics, Chemistry and Biology as
compulsory subjects with 50% marks. Only unmarried female candidates are eligible. Divorcees
or widows or those legally separated and without encumbrances are also considered.
SC/ST- 2 Seats.
NCC Grade II trained- 1 Seat.
Age should be between 17 to 25 years.
Selection is made on the basis of merit of the qualifying examination and aptitude test.
Examination centres are in different parts of the country depending on the number of candidates.
Candidates should apply on the printed format published in the leading newspapers. Completed
applications should reach the DGMS, 4B, AG's branch, Army Headquarters, Room No.47, LBlock
Hutments, New Delhi-110001 in the month of August/September and last date for
submitting the Application Form is in the month of October. Test conducted in the month of
February/March, followed by interview in the month of May/June.
Career Guidance for HSC students on 22nd June, 2003
Probationer Nurses are recruited for training in the following military hospitals:
Army Hospital, Delhi Cantt.
Command Hospital, Central Command, Lucknow.
Military Hospital, Jullundur Cantt.
Military Hospital, Secundrabad
I.N.H.S., Ashwini, Bombay.
Air Force Hospital, Bangalore.
B.Sc. (Nursing) : B.Sc. (Nursing) trainees Trainees are recruited for B.Sc. (Nursing) Course of the
duration of four years.
Armed Forces Medical College, Pune conducts this course.
Psychiatric nursing is emotionally more demanding. The specialization course includes the study
of human development and behaviour, deviations from normal behaviour, psychophysical
disturbances and principles and practice of psychiatric nursing.
Some of the renowned training institutes in Psychiatric Nursing are :
AIIMS, New Delhi
The all India Institute of Physical Medicine and Rehabilitation at Mumbai conducts a one-year
post-graduate course in rehabilitation techniques for nurses (general) with three year experience.
Salaries in government hospitals are governed by fixed scales but in the private sector hospitals
and nursing homes, there is more frequent upward revision. The most lucrative prospect in
nursing continues to be exodus to the Gulf countries where salaries are very high. At home
nurses who take on assignments of personal care of bedridden or otherwise ill patients in their
own homes earn very high fees while being removed from taxing hospital schedules. Taking fulltime
care of a patient is not an easy task which is why fees for personal nursing are exorbitant.
Promotions depend upon experience and ability. In the highest positions in hospitals and other
large institutions, the responsibilities become more administrative in nature. Teaching and
research are also very good options for trained nurses and may be taken up alongside nursing
duties. At present, there is a shortage of trained nursing personnel in all spheres.
Q. Do nurses have specific duty hours?
A. Duty hours of nurses are generally in shifts which are continuously rotated so that every
nurse has equal quotas of day and night duty. Day or night nurses, while on duty, have to be
alert and vigilant with regard to the needs of their patients. They have to be fresh and cheerful
while going about their work.

The 13 Characteristics of Successful People (by Jeffrey J. Mayer)

I got this email today which I would like to share with you.

I've spent many years studying successful people and have identified the skills, talents, and characteristics that enable them to succeed. As you look at and study these skills, talents, and characteristics, you'll realize that you possess many of them yourself. Some of these skills and talents are more dominant than others and will play a greater part in your being, or becoming, a success in the business of life. These are the things you do well. The things you do easily and effortlessly. These are your strengths. When you find you need a skill or talent you don't have, just go out and look for a person or group of people with the skills, talents, and training you need. Skills and talents that complement your own. These people will become your teammates, colleagues, co-workers, professional advisors, and friends. With these combined skills and talents organizations grow, prosper, and become successful.

These are the five things you'll find every successful person has in common:

1. They have a dream.
2. They have a plan.
3. They have specific knowledge or training.
4. They're willing to work hard.
5. They don't take no for an answer.

Remember: Success begins with a state of mind. You must believe you'll be successful in order to become a success.

The following is a list of the skills, talents, and characteristics you'll find in successful people:

1. Successful People Have a Dream. They have a well-defined purpose. They have a definite goal. They know what they want. They aren't easily influenced by the thoughts and opinions of others. They have willpower. They have ideas. Their strong desire brings strong results. They go out and do things that others say can't be done.

Remember: It only takes one sound idea to achieve success.
Remember: People who excel in life are those who produce results, not excuses. Anybody can come up with excuses and explanations for why he hasn't made it. Those who want to succeed badly enough don't make excuses.

2. Successful People Have Ambition. They want to accomplish something. They have enthusiasm, commitment, and pride. They have self-discipline. They're willing to work hard and to go the extra mile. They have a burning desire to succeed. They're willing to do whatever it takes to get the job done.

Remember: With hard work come results. The joy in life comes with working for and achieving something.

3. Successful People Are Strongly Motivated Toward Achievement. They take great satisfaction in accomplishing a task.

4. Successful People Are Focused. They concentrate on their main goals and objectives. They don't get sidetracked. They don't procrastinate. They work on the projects that are important, and don't allow those projects to sit until the last minute. They're productive, not just busy.

5. Successful People Learn How to Get Things Done. They use their skills, talents, energies, and knowledge to the fullest extent possible. They do the things that need to be done, not just the things they like to do. They are willing to work hard and to commit themselves to getting the job done.

Remember: Happiness is found in doing and accomplishing, not in owning and possessing.

Anecdote: Many years ago I was asked: "Jeff, do you like pleasing habits or pleasing results?" As I pondered that probing question, and squirmed in my chair like a worm at the end of a hook, I felt as if I had painted myself into a corner. A few moments later I answered: "I like pleasing results." From that moment on my life changed. I began to do the things that were difficult, because they enabled me to achieve my goals.

6. Successful People Take Responsibility for Their Actions. They don't make excuses. They don't blame others. They don't whine and complain.

7. Successful People Look for Solutions to Problems. They're opportunity minded. When they see opportunities they take advantage of them.

8. Successful People Make Decisions. They think about the issues and relevant facts, give them adequate deliberation and consideration, and make a decision. Decisions aren't put off or delayed, they're made now!

SuccessTip: Spend more time thinking and planning before you make your decision, and you'll make better decisions.

SuccessTip: When you don't get the expected results from the decision you've made, change your course of action. Decisions should never be carved in stone.

9. Successful People Have the Courage to Admit They've Made a Mistake. When you make a mistake, admit it, fix it, and move on. Don't waste a lot of time, energy, money, and/or other resources trying to defend a mistake or a bad decision.

Remember: When people are wrong, they may admit it to themselves. If they are handled gently and tactfully, they may admit it to others and even take pride in their frankness and broad-mindedness. But people become very defensive and angry when others try to cram their mistakes down their throats.

10. Successful People Are Self-Reliant. They have the skills, talents, and training that are needed in order to be successful.

11. Successful People Have Specific Knowledge, Training, and/or Skills and Talents. They know the things they need to know to be successful. And when they need information, knowledge, or skills and talents that they don't possess, they find someone who does possess them.

12. Successful People Work with and Cooperate with Other People. They have positive, outgoing personalities. They surround themselves with people who offer them help, support, and encouragement. They are leaders.

13. Successful People Are Enthusiastic. They're excited by what they're doing, and that excitement is contagious. They draw people to them because these people want to work with them, do business with them, and be with them

Application calendar - Study Abraod

18 months before beginning your studies in the US:
 Begin your search of possible US colleges or universities that you would like to attend. Read through college reference guides and visit college websites. Also talk with your relatives and friends who have studied in the US. Request information from 10 to 20 different schools so that you can make a good decision on where to apply.
 Register and start preparing for the TOEFL and other entrance tests (such as the SAT or GRE).
 Continue to work hard at your subjects at school. Good grades in the courses you are taking now will count heavily in the admissions decisions.
15 months before:
 Take the TOEFL and other entrance tests. Most universities require you to take the test before December, so taking it now gives you an opportunity to take it again in November and improve your score.
12 months before:
 Send letters to colleges you have selected requesting applications and information, or obtain this information and necessary forms from their websites. You should choose: (a) one or two schools that you really like, but may be too difficult to get into; (b) two or three that you also like and which you think will accept you; (c) one or two which may not be your favorites, but you are quite sure will accept you.
 Identify two or three teachers or other people whom know you well and ask them to write recommendation letters for you.
 For undergraduate applicants the best references are teachers and your school principal. Family friends, religious counselors, and others should be used only if they know you very well and can speak specifically about your academic goals and potential.
 Graduate students should obtain letters from their teachers or professionals in their field whom they have worked with and who can speak specifically about their academic potential and relevant accomplishments.
 Ask the schools you have attended to start preparing your transcripts. These are official school documents that show the courses you have studied and the grades you have received in those courses.
 If your previous TOEFL, SAT, or GRE scores were not satisfactory, register for the test again.
11 months before:
 If you have not yet received the application forms you requested from the schools you wrote to, send another letter repeating your request.
 Study the applications you have received. Note carefully the deadlines on each of them. Remember to allow time for delays in the mail.
 Ask your schools to send certified copies of your academic transcripts to each of the schools where you are applying.
 Ask your teachers to write their letters of recommendation for you. Give them the forms provided by the schools and a stamped, addressed envelope for each letter they will be mailing.
 Undergraduate students should write their application essay. This essay is an important part of the application. It should reflect who you are and what you feel is important. Try not to repeat information you have provided in other parts of the application, but instead work to make the essay unique and personal. Get comments on it from an English teacher. For more information on writing your essay, refer to Personal essay.
 Graduate students should write their statement of purpose if the schools have indicated that they require one. This is an important part of the application. You should show in your statement how your education so far has created a foundation for your goals, and how your proposed coursework in the US will help you achieve those goals. You should be as specific as possible about your research interests and past accomplishments.
 Make photocopies of the applications and begin to fill in the required information on the copies. You will later transfer the information to the originals. If any questions confuse you, seek help from your teachers, or from someone who has studied in the US.
10 months before:
 Complete your essays and application forms, including the financial aid application forms, using the originals (not the copies). Type or write by hand very neatly and carefully. The finished applications will be your introduction to the schools, so you want to make them look good. Keep a copy of the completed applications for your records. Mail the originals by airmail in time to meet the deadlines.
 Take the TOEFL and other exams again, if you need to improve your scores.
 Check with your teachers and your school to make sure your recommendations and transcripts have been mailed in time to meet the deadlines.
9 months before:
 It is not unusual for schools to request more information or resubmission of something you have already sent. Respond promptly to any requests you receive.
4-5 months before:
 You will start hearing decisions from the schools. Contact the admissions office at any school that you do not hear from.
 Accept only one school's offer, and let the other schools know of your decision. Ask the school you have chosen to attend to send you the I-20 form.
 Make housing arrangements.
 Apply for a passport if you do not already have one.
3 months before:
 Get a visa application form from the US embassy or consulate nearest you. For a complete description of the visa application process, go to Immigration.
 Make travel arrangements. Schedule your trip so you arrive at least 15 days prior to your school’s orientation.

1 Great Upcoming site
All about educating others.Join us and introduce a category for your country
A comprehensive site have a look
A chinese Student website.Good information.Plz do visit
Accreditation directory
Accreditation deatils
All About GRE
Loads of info, sample essays, word roots etc to help u prepare for GRE
All About TOEFL
General Info on TOEFL n Word Roots
All About US Admissions
Excellent site outlining the application process of US Admissions
Application process
Various Articles
Best toefl resources
The following site has the best resources for TOEFL prep.
Check for the professors
Comprehensive info
Abroadplanet is a community of international students studying in the USA. It provides comprehensive and free information about everything international students need to know about studying and living in the United States of America. You'll also get free web pages, forums, and lots of other stuff that no international student should be without.
Comprehensive site like I20fever
Another Good site for analysis and forum
Fiancial aid site 3
Guide to Financial Aid
Financial aid 1
Search 600,00 scholarships
Financial aid 2
Free college scholarship and financial aid searches.
GMAT students
In this web site you can find last 4 years ranking of top American Research Universities. You may compare universities' activities.
Gmat students
Best B school analysis
Good site for TOEFL .
This site provides good stuff for TOEFLVOCAB of 3000 words, which are used with simple sentences.This vocab helps in preparing for GRE too.
Gre and toefl
Good site to practice
Gre and toefl
Online prep site, good for Vocab but inefficient
Gre and toefl
This is a great website about almost all English exams.
Gre and toefl prep
This web site has great free resources about TOEFL, GRE, GMAT, etc. You also may find some essay and writing samples in this web site.
Gre and toefl prep
This web site presents some free resources for TOEFL preparation. It has some great links to other free web sites about TOEFL.
Gre and toefl prep
This web site could help students who are preparing for GMAT and GRE.
Gre planing chart
Gives a timetable for the planing
Gre prep
This Forum has great free resources about TOEFL, GRE, GMAT, etc. You also may find some essay and writing samples in this web site.
Gre prep
This web site could help students who are preparing for GMAT and GRE
Gre preparation
Good source of information about Gre
Gre preparation
This groups is for those who are taking the GRE exam after 1st October 2002. The pattern of GRE exam is changing from 1st October with the addition of a writing Assessment test.
Gre target score 1600!
An article in Rediffmailnews
Gre toefl and IELTS
books,papers ,material All Free
Guide to US
Covers all the topics
Have alook
Professor Advice for students
Helps finding Univ as per your score
A link which can give you a rough idea of univ as per your score
url for Indian Student Association of the univs in USA
India student assoication link
Usefull information about the places
Link about Science
Science Information
List of Universities
U can find lot of info about Univs of USA n beyond
PHD guys
How to be a good graduate student
PHd students
some tips on Writing a successful proposal
Performance on Gre
Check this site if u want to know how u performed in the GreCAT
Peterson's Education Portal
Peterson's Education Portal – Colleges, Graduate Programs, Financial Aid
Princeton Review's Best 351 Colleges Rankings
Rankings by Princeton review on untraditional grounds
Ranking of world 500 top universities 2004
American ranking of world universities
Regarding univ and research
In this web site you can find last 4 years ranking of top American Research Universities. You may compare universities' activities.
Research related site
NAtional Association of Graduate-professional students survey
Sop preparation Tips
Another Website about SOP
School finder 1
Information about engg schools
School finder 10
This web site categorizes United States' universities by states.
School finder 11
Good website to narrow down universities based on your Program
School finder 12
Search Tool by Program and Location
School finder 13
Practical Info about Studying Abroad
School finder 14
Features listing of all Private & Public Colleges, Community Colleges and Universities in US organized by Name, State and Program. Includes links to Institution's Profile and Website. Also includes resource on College Ranking and Best Schools
School finder 15
Your Graduate school guide|- Search Graduate programs,prospective grads,schools,application
School finder 17
Graduate School Shortlisting Search (NOT very Comprehensive n Reliable)
School finder 18
Some Weird Criteria for Rankings! College Guides By Students For Students
School finder 19
Alphabetical listing of All AmericanUniversities
School finder 2
Information about schools
School finder 20
Shortlisting by Program and Location
School finder 23
Schools by states and canadia states aswell
School finder 3
About schools
School finder 4
School finder 5
School finder 6
Searching univ and colleges
School finder 7
School finder 8
information on more than 700 universities, colleges and career colleges in Canada, including admission requirements, costs, programs and contact details.
School finder 9
You may use this web site for searching your appropriate university by providing your desire keyword, major, and state.
School info
some feedback from students regarding universities
Some financial Documents
Smaple documents
Some paper presentations
U can rate uni's acc. to u'r parameter here
Some sites information
Univ website page
Student abroad guide
Good site for students going abroad
Students review site
Well not explored much to give details
Study Abroad Information Source
Little info of everything!
Survey site
National society of experimental Education
Technical Journals
Institute of Engg India
Technical writing
Proposal for grants
The official site of i20fever by naveen
u can analyse ur self and make the univ selection and know the pakka i20 univ's and discuss that in forums
UNITI Foundation
The non profit organization supported by US to help students inthe whole process.
USA Clocks
Univ listing
EE and CE univ list
University selection
Feedback of students about univ
Visa Fundae
Personal observation of the website author
Visa Interviews
Link provides all the application available under one umberella
Visa in The Hindhu
Article published in New paper cotnain general tips.Published in the Hindhu
Weekly tips are good
Good tips use freely available material.Must read the weekly tips article
abc of going to US
Contains A to Z info of going to US
application process
U.S site
good site for gre & word pronounciation
this is a good 1 to check it out , but the vocaboly software is the best , just check it in messanges ,& download it ull find gre at-ease
good website which gives brief ideas abt universities of ur course
just all u need to have is i20fever & this web url then just go on choosing univ's according to ur need
yahoo group 2
yahoo group 3
good info in the database

Linux Networking-concepts

I have written a number of networking HOWTOs in the past, and it occurred to me that there's a hell of

pile of jargon in each one. I had three choices: my other two were ignoring the problem and explaining the

terms everywhere. Neither was attractive.

The point of Free software is that you should have the freedom to explore and play with the software systems

you use. I believe that enabling people to experience this freedom is a noble goal; not only do people feel

empowered by the pursuit (such as rebuilding a car engine) but the nature of the modern Internet and Free

software allows you to share the experience with millions.

But you have to start somewhere, so here we are.

(C) 2000 Paul `Rusty' Russell. Licenced under the GNU GPL.

2. What is a `computer network'? 2

2 What is a `computer network'?

A computer network is just a set of stu_ for nodes to talk to each other (by `nodes' I mean computers, printers,

Coke machines and whatever else you want). It doesn't really matter how they are connected: they could

use _ber-optic cables or carrier pigeons. Obviously, some choices are better than others (especially if you

have a cat).

Usually if you just connect two computers together, it's not called a network; you really need three or more

to become a network. This is a bit like the word `group': two people is just a couple of guys, but three

can be an `group'. Also, networks are often hooked together, to make bigger networks; each little network

(usually called a `sub-network') can be part of a larger network.

The actual connection between two computers is often called a `network link'. If there's a bit of cable running

out of the back of your machine to the other machines, that's your network link.

There are four things which we usually care about when we talk about a computer network:


If you simply connect your four computers at home together, you have what is called a LAN (Local

Area Network). If everything is within walking distance, it's usually called a LAN, however many

machines are connected to it, and whatever you've built the network out of.

The other end of the spectrum is a WAN (Wide Area Network). If you have one computer in Lahore,

Pakistan, one in Birmingham, UK and one in Santiago, Chile, and you manage to connect them, it's

a WAN.

Topology: The Shape

Draw a map of the network: lines are the

2 (network links), and each node is a dot. Maybe each line leads into a central node like a big star,

meaning that everyone talks through one point (a `star topology'):

o o o

\_ | _/




/ | \

o o o

Maybe everyone talks in a line, like so:


| |

| |

| o

| |

o |


Or maybe you have three subnetworks connected through one node:


o | o--o--o

| | |

o--o--o--o--o o

\ |

2. What is a `computer network'? 3


/ |

o--o--o--o--o o

| | |

o | o--o


You'll see many topologies like these in real life, and many far more complicated.

Physical: What It's Made Of

The second thing to care about is what you've built the network out of. The cheapest is `sneakernet',

where badly-dressed people carry _oppy disks from one machine to the others. Sneakernet is almost

always a 2 (LAN). Floppies cost less than $1, and a solid pair of sneakers can be got for around $20.

The most common home network system is used to connect to far bigger networks, called a `modem'

(for MODulator/DEModulator), which turns a normal phone connection into a network link. It turns

the stu_ the computer sends into sounds, and listens to sounds coming from the other end to turn

them back into stu_ for the computer. As you can imagine, this isn't very e_cient, and phone lines

weren't designed for this use, but it's popular because phone lines are so common and cheap: modems

sell for less than $50, and phone lines usually cost a couple of hundred dollars a year.

The most common way to connect machines into a LAN is to use Ethernet. Ethernet comes in

these main _avors (listed from oldest to newest): Thinwire/Coax/10base2, UTP (Unshielded Twisted

Pair)/10baseT and UTP/100baseT. Gigabit ethernet (the name 1000baseT is starting to get silly) is

starting to be deployed, too. 10base2 wire is usually black coaxial cable, with twist-on T-pieces to

connect them to things: everyone gets connected in a big line, with special `terminator' pieces on the

two ends. UTP is usually blue wire, with clear `click-in' phone-style connectors which plug into sockets

to connect: each wire connects one node to a central `hub'. The cable is a couple of dollars a meter,

and the 10baseT/10base2 cards (many cards have plugs for both) are about $30. 100baseT cards,

which can also speak 10baseT as well, are ten times faster, and about $100.

On the other end of the spectrum is Fiber; a continuous tiny glass _lament wrapped in protective

coating which can be used to run between continents. Fiber costs thousands.

We usually call each connection to a node a `network interface', or `interface' for short. Linux gives

these names like `eth0' for the _rst ethernet interface, and `fddi0' for the _rst _ber interface. The

`/sbin/ifcon_g' command lists them.

Protocol: What It's Speaking

The _nal thing to care about is the language the two are speaking. When two 2 (modems) are talking

to each other down a phone line, they need to agree what the di_erent sounds mean, otherwise it

simply won't work. This convention is called a `protocol'. As people discovered new ways of encoding

what the computer says into smaller sounds, new protocols were invented; there are at least a dozen

di_erent modem protocols, and most modems will try a number of them until they _nd one the other

end understands.

Another example is the 2 (100baseT) network mentioned above: it uses the same physical 2 (network

links) (2 (UTP)) as 2 (10baseT) above, but talks ten times as fast.

These two protocols are what are called `link-level' protocols; how stu_ is handed over the individual

network links, or `one hop'. The word `protocol' also refers to other conventions which are followed, as

we will see next.

3. What is the `Internet'? 4

3 What is the `Internet'?

The Internet is a 2 (WAN) which spans the entire globe: it is the largest computer network in existence. The

phrase `internetworking' refers to connecting separate networks to build a larger one, hence `The Internet'

is the connection of a whole pile of subnetworks.

So now we look at the list above and ask ourselves: what is the Internet's size, physical details and protocols?

The size is already established above: it's global.

The physical details are varied however: each little sub-network is connected di_erently, with a di_erent

layout and physical nature. Attempts to map it in a useful way have generally met with abject failure.

The protocols spoken by each link are also often di_erent: all of the 2 (link-level protocols) listed above are

used, and many more.

3.1 How Does The Internet Work?

The question then arises: how come every node on the Internet can talk to the others, if they all use di_erent

link-level protocols to talk to each other?

The answer is fairly simple: we need another protocol which controls how stu_ _ows through the network.

The link-level protocol describes how to get from one node to another if they're connected directly: the

`network protocol' tells us how to get from one point in the network to any other, going through other links

if necessary.

For the Internet, the network protocol is the Internet Protocol (version 4), or `IP'. It's not the only protocol

out there (Apple's AppleTalk, Novell's IPX, Digital's DECNet and Microsoft's NetBEUI being others) but

it's the most widely adopted. There's a newer version of IP called IPv6, but it's still not common.

So to send a message from one side of the globe to another, your computer writes a bit of Internet Protocol,

sends it to your modem, which uses some modem link-level protocol to send it to the modem it's dialed up

to, which is probably plugged into a terminal server (basically a big box of modems), which sends it to a

node inside the ISP's network, which sends it out usually to a bigger node, which sends it to the next node...

and so on. A node which connects two or more networks is called a `router': it will have one 2 (interface)

for each network.

We call this array of protocols a `protocol stack', usually drawn like so:

[ Application: Handles Porn ] [ Application Layer: Serves Porn ]

| ^

v |

[ TCP: Handles Retransmission ] [ TCP: Handles Retransmission ]

| ^

v |

[ IP: Handles Routing ] [ IP: Handles Routing ]

| ^

v |

[ Link: Handles A Single Hop ] [ Link: Handles A Single Hop ]

| |


So in the diagram, we see Netscape (the Application on top left) retrieving a web page from a web server

(the Application on top right). To do this it will use `Transmission Control Protocol' or `TCP': over 90% of

the Internet tra_c today is TCP, as it is used for Web and EMail.

4. This IP Thing 5

So Netscape makes the request for a TCP connection to the remote web server: this is handed to the TCP

layer, which hands it to the IP layer, which _gures out which direction it has to go in, hands it onto the

appropriate link layer, which transmits it to the other end of the link.

At the other end, the link layer hands it up to the IP layer, which sees it is destined for this host (if not,

it might hand it down to a di_erent link layer to go out to the next node), hands it up to the TCP layer,

which hands it to the server.

So we have the following breakdown:

1. The application (Netscape, or the web server at the other end) decides who it wants to talk to, and

what it wants to send).

2. The TCP layer sends special packets to start the conversation with the other end, and then packs the

data into a TCP `packet': a packet is just a term for a chunk of data which passes through a network.

The TCP layer hands this packet to the IP layer: it then keeps sending it to the IP layer until the

TCP layer at the other end replies to say that it has received it. This is called `retransmission', and

has a whole heap of complex rules which control when to retransmit, how long to wait, etc. It also

gives each packet a set of numbers, which mean that the other end can sort them into the right order.

3. The IP layer looks at the destination of the packet, and _gures out the next node to send the packet

to. This simple act is called `routing', and ranges from really simple (if you only have one modem,

and no other network interfaces, all packets should go out that interface) to extremely complex (if you

have 15 major networks connected directly to you).

4 This IP Thing

So the role of the IP layer is to _gure out how to `route' packets to their _nal destination. To make this

possible, every interface on the network needs an `IP address'. An IP address consists of four numbers

separated by periods, like `'. Each number is between zero and 255.

Interfaces in the same network tend to have neighboring IP addresses. For example, `' sits

right next to the machine with the IP address `'. Remember also that a router is a node with

interfaces on more than one network, so the router will have one IP address for each interface.

So the Linux Kernel's IP layer keeps a table of di_erent `routes', describing how to get to various groups of

IP addresses. The simplest of these is called a `default route': if the IP layer doesn't know better, this is

where it will send a packet onwards to. You can see a list of routes using `/sbin/route'.

Routes can either point to a link, or a particular node which is connected to another network. For example,

when you dial up to the ISP, your default route will point to the modem link, because that's where the entire

world is.

Rusty's ISP's ~~~~~~~

Modem Modem { }

o------------------o { The Net }

{ }


But if you have a permanent machine on your network which connects to the outside world, it's a bit more

complicated. In the diagram below, my machine can talk directly to Tridge and Paul's machines, and to the

_rewall, but it needs to know that packets heading the rest of the world need to go to the _rewall, which

will pass them on. This means that you have two routes: one which says `if it's on my network, just send it

straight there' and then a default route which says `otherwise, send it to the _rewall'.

4. This IP Thing 6

o Tridge's

| Work Machine ~~~~~~~

Rusty's | { }

Work Machine o--------+-----------------o--{ The Net }

| Firewall { }

| ~~~~~~~

o Paul's

Work Machine

4.1 Groups of IP Addresses: Network Masks

There is one last detail: there is a standard notation for groups of IP addresses, sometimes called a `network

address'. Just like a phone number can be broken up into an area pre_x and the rest, we can divide an IP

address into a network pre_x and the rest.

It used to be that people would talk about `the 1.2.3 network', meaning all 256 addresses from to Or if that wasn't a big enough network, they might talk about the `1.2 network' which meant all

addresses from to

We usually don't write ` -'. Instead, we shorten it to `'. This weird `/16' notation

(it's called a `netmask') requires a little explanation.

Each number between the dots in an IP address is actually 8 binary digits (00000000 to 11111111): we write

them in decimal form to make it more readable for humans. The `/16' means that the _rst 16 binary digits

is the network address, in other words, the `1.2.' part is the the network (remember: each digit represents 8

binary digits). This means any IP address beginning with `1.2.' is part of the network: `' and `'

are, and `' is not.

To make life easier, we usually use networks ending in `/8', `/16' and `/24'. For example, `' is a

big network containing any address from to (over 16 million addresses!).

is smaller, containing only IP addresses from to is smaller still, containing

addresses to

To make things confusing, there is another way of writing netmasks. We can write them like IP addresses:

Finally, it's worth noting that the very highest IP address in any network is reserved as the `broadcast

address', which can be used to send a message to everyone on the network at once.

Here is a table of network masks:

Short Full Maximum Comment

Form Form #Machines

/8 / 16,777,215 Used to be called an `A-class'

/16 / 65,535 Used to be called an `B-class'

/17 / 32,767

/18 / 16,383

/19 / 8,191

/20 / 4,095

/21 / 2,047

/22 / 1,023

/23 / 511

/24 / 255 Used to be called a `C-class'

/25 / 127

5. Machine Names and IP Addresses 7

/26 / 63

/27 / 31

/28 / 15

/29 / 7

/30 / 3

5 Machine Names and IP Addresses

So every interface on every node has an IP address. It was realized quite quickly that humans are pretty

bad at remembering numbers, so it was decided (just like phone numbers) to have a directory of names. But

since we're using computers anyway, it's nicer to have the computer look up the names for us automatically.

Hence we have the Domain Name System (DNS). There are nodes with well known IP addresses which

programs can ask to look up names, and return IP addresses. Almost all programs you will use are capable

of doing this, which is why you can put `' into Netscape, instead of `'.

Of course, you need the IP address of at least one of these `name servers': usually these are kept in the

`/etc/resolv.conf' _le.

Since DNS queries and responses are fairly small (1 packet each), the TCP protocol is not usually used: it

provides automatic retransmission, ordering and general reliability, but at a cost of sending extra packets

through the network. Instead we use the very simple `User Datagram Protocol', which doesn't o_er any of

the fancy TCP features we don't need.

6 Di_erent Services: Email, Web, FTP, Name Serving

In the earlier example, we showed Netscape sending a TCP request to a web server running on another node.

But imagine that the node with the web server is also running an Email server, an FTP server and a name

server: how does it know which server the TCP connection is for?

This is where TCP and UDP have a concept of `ports'. Every packet has space for a `destination port',

which says what service the packet is for. For example, TCP port 25 is the mail server, and TCP port 80 is

the web server (although sometimes you _nd web servers on di_erent ports). A list of ports can be found in


Also, if two Netscape windows are both accessing di_erent parts of the same web site, how does the Linux

box running Netscape sort out the TCP packets coming back from the web server?

This is where the `source port' comes in: every new TCP connection gets a di_erent source port, so everyone

can tell them apart, even if they are going to the same destination IP address and the same destination port.

Usually the _rst source port given will be 1024, and will increase over time.

7 Dialup Interfaces: PPP

When you dial your modem to an ISP, and it connects to their modem, the kernel doesn't just shove IP

packets through it. There is a protocol called `Point-to-Point Protocol', or `PPP', which is used to negotiate

with the other end before any packets are allowed through. This is used by the ISP to identify who is dialed

up: on your Linux box, a program called the `PPP daemon' handles your end of the negotiation.

Because there are so many dialup users in the world, they usually don't have their own IP address: most

ISPs will assign you one of theirs temporarily when you dial up (the PPP daemon will negotiate this). This

is often called a `dynamic IP address', as separate from a `static IP address' which is the normal case where

8. What Packets Look Like 8

you have your own address permanently. Usually they are assigned by modem: the next time you dial up,

you will probably get a di_erent modem in the modem pool, and hence a di_erent IP address.

8 What Packets Look Like

For the exceptionally curious (and the curiously exceptional), here is a description of what a packet actually

looks like. There are several tools which watch what packets are passing in and out of your Linux box: the

most common one is `tcpdump' (which understands more than TCP these days). Such programs are known

as `packet sni_ers'.

The start of each packet says where it's going, where it came from, the type of the packet, and other

administrative details. This part is called the `packet header'. The rest of the packet, containing the actual

data being transmitted, is usually called the `packet body'.

So any IP packet begins with an `IP header': at least 20 bytes long. It looks like (this diagram stolen

shamelessly from RFC 791):


|Version| IHL |Type of Service| Total Length |


| Identification |Flags| Fragment Offset |


| Time to Live | Protocol | Header Checksum |


| Source Address |


| Destination Address |


The important _elds are the Protocol, which indicates whether this is a TCP packet (number 6), a UDP

packet (number 17) or something else, the Source IP Address, and the Destination IP Address.

Now, if the protocol _elds says this is a TCP packet, then a TCP header will immediately follow this IP

header: the TCP header is also at least 20 bytes long:


| Source Port | Destination Port |


| Sequence Number |


| Acknowledgment Number |


| Data | |U|A|P|R|S|F| |

| Offset| Reserved |R|C|S|S|Y|I| Window |

| | |G|K|H|T|N|N| |


| Checksum | Urgent Pointer |


The most important _elds here are the source port, and destination port, which says which service the packet

is going to (or coming from, in the case of reply packets). The sequence and acknowledgement numbers are

used to keep packets in order, and tell the other end what packets have been received. The ACK, SYN,

RST and FIN _ags (written downwards) are single bits which are used to negotiate the opening (SYN) and

closing (RST or FIN) of connections.

9. Summary 9

Following this header comes the actual message which the application sent (the packet body). A normal

packet is up to 1500 bytes: this means that the most space the data can take up is 1460 bytes (20 bytes for

the IP header, and 20 for the TCP header): over 97%.

9 Summary

So the modern Internet uses IP packets to communicate, and most of these IP packets use TCP inside.

Special nodes called `routers' connect all the little networks together into larger networks, and pass these

packets through to their destination. Most normal machines are only attached to one network (ie. have only

one interface), and so are not routers.

Every interface has a unique IP address, which look like `': interfaces in the same network will have

related IP addresses, with the same start, the same way that phone connections in the same area have the

same pre_x. These network addresses look like IP addresses, with a `/' to say how much of them is the

pre_x, eg `' means the _rst two digits is the network address: each digit represents 8 bits.

Machines are given names by the Domain Name Service: programs ask name servers to give them the IP

address, given a name like `'. This IP address is then used as the destination IP address

to talk to that node.

Rusty is really bad at writing documentation, especially for beginners.



10 Thanks

Thanks to Alison, for sitting through the original terrible draft, and telling me how shit it was, in the nicest

possible way.

11 Index

_ 2 (100baseT)

_ 2 (10base2)

_ 2 (10baseT)

_ 4.1 (Broadcast address)

_ 2 (Coax, Coaxial cable)

_ 2 (Computer network)

_ 4 (Default route)

_ 6 (Destination port)

_ 5 (DNS, Domain Name Service)

_ 7 (Dynamic IP address)

_ 2 (Ethernet)

11. Index 10

_ 2 (Fiber)

_ 2 (Gigabit Ethernet)

_ 2 (Hop)

_ 2 (Hub)

_ 3 (Internet)

_ 3.1 (IP, Internet Protocol)

_ 4 (IP address)

_ 8 (IP header)

_ 3.1 (IPv4, IP version 4)

_ 3.1 (IPv6, IP version 6)

_ 2 (LAN, Local Area Network)

_ 2 (Link-level protocol)

_ 2 (Modem)

_ 5 (Name server)

_ 4.1 (Netmask)

_ 4.1 (Network address, network mask)

_ 2 (Network interface, interface)

_ 2 (Network link)

_ 3.1 (Network protocol, protocol)

_ 2 (Node)

_ 8 (Packet body)

_ 8 (Packet header)

_ 8 (Packet sni_er)

_ 1 (Packet)

_ 6 (Port, TCP port, UDP port)

_ 7 (PPP, Point-to-Point Protocol)

_ 7 (PPP daemon)

_ 3.1 (Protocol stack)

_ 2 (Retransmission)

_ 4 (Route)

_ 3.1 (Router)

_ 2 (Routing)

11. Index 11

_ 2 (Sneakernet)

_ 6 (Source port)

_ 2 (Star-topology)

_ 7 (Static IP address)

_ 2 (Sub-network)

_ 3.1 (TCP, Transmission Control Protocol)

_ 8 (TCP header)

_ 2 (Terminator)

_ 2 (Topology)

_ 5 (UDP, User Datagram Protocol)

_ 2 (UTP, Unshielded Twisted Pair)

_ 2 (WAN, Wide Area Network)