Now let's take a little closer look at TCP, and let's talk about the Transmission Control Protocol. Now TCP is one of the core Protocols in the TCP/IP Suite, and as a matter of fact, is one of the two original, if you want to call them, charter members of TCP, and TCP is actually a compliment to the Internet Protocol, that's in TCP/IP as well. Now TCP as it turns out, really is the foundation of most Internet applications, and we'll talk about Internet applications in a little more detail in some other places in the course, but when you're thinking Internet application, think world wide web. We think of the world wide web as a separate network whatever, and it's not. It is a functionality that happens on all of these interconnected computers all over the world, and we just know the application, or the functionality in these browsers, as the world wide web. Email is an Internet application. We just type email addresses, and send them off, and magically they arrive, and people respond to us. And the underlying Protocols in the TCP/IP Suite are making that magic happen for email. And then of course file transfers. Now what exactly does TCP do for us? Well it provides reliable, pay attention to that word, reliable ordered delivery of data packets. Now it works with IP, or the Internet Protocol to break the data down into smaller chunks which we call packets, and then it establishes a session, or it establishes a connection. It dials the number if you will, with the destination computer. And then it sends the packets. Now probably the most unique thing about TCP that you need to remember, and we're back to that word reliable, is it verifies the delivery on the destination. And if it sees that it's putting the packets together, and it's numbering them and putting them back into order, it sees that one of the packets has not been received, it will kind of wait for a few minutes, and there's a functionality called a TCP Window, that once we go past a certain point, and it hasn't received that particular packet, it assumes it got lost, or damaged out on the network, or whatever, and it will re-request that particular packet. So it makes sure that our entire message or all of our data gets there, and it can be a reassembled properly. And I've already mentioned that it re-orders packets on the destination, if they're out of order, and most often, they will be. Now did I mention reliable? And I know I'm beating a dead horse here, but when you think TCP on the Exam, and in real life, think reliable delivery OK? And you could also call that Stateful. Now here's a little diagram, and you want to watch this as it pertains to TCP, and then as we move through other videos and talk about other Protocols, think back to this basic animation. We have two computers and I want to send the message, this is a test, from this computer to this computer, and I'm going to use TCP to do that. Now, the first thing that happens, TCP is going to work with the IP Protocol and break that sentence down into shorter packets. Now this is an over simplification, but notice, our original statement, this is a test, has now been broken down into four discreet packets. It then establishes that session across the network, across the wire, to the destination PC, and then it moves that stuff across the wire. And notice, it has arrived on the other side, but if you'll also notice, that the packets arrived out of order. These might have taken different routes, they might have got caught in network congestion in the routers, but anyway one arrived before the other, and TCP will re-order these, to get it back in the right order. And then that is has been delivered. So that's what TCP does, it takes care of all that functionality, but this little part about, and I didn't put it in the animation, but if we never receive the A here, if we never receive this datagram, TCP would have send a message back to the source PC, and said hey, I didn't get this particular datagram, can you re-send it? And it would say sure, and it would re-send it, and it would come, and TCP would re-order, and make sure everybody's in the right order, and then the message would be here. So that's a good rough view, simplistic view of TCP, and if you can understand that TCP is reliable, and that it's breaking things into packets, moving them across the network, making sure everybody gets there, putting them in order, then you know what you need to know at this point about TCP.
TERMS & CONDITIONS OF USE
BY SUBSCRIBING TO THIS SERVICE, YOU ARE CONSENTING TO BE BOUND BY AND ARE BECOMING A PARTY TO THIS AGREEMENT, THE TERMS AND CONDITIONS OF WHICH SHALL PREVAIL IN GOVERNING YOUR RIGHTS OF USE. BY CLICKING THE "BECOME A MEMBER" BUTTON, THE INDIVIDUAL OR ENTITY LICENSING THE PRODUCT ("YOU") IS CONSENTING TO BE BOUND BY AND IS BECOMING A PARTY TO THIS AGREEMENT. IF LICENSEE DOES NOT AGREE TO ALL OF THE TERMS OF THIS AGREEMENT, THE BUTTON INDICATING "BECOME A MEMBER" MUST NOT BE SELECTED, AND LICENSEE MUST NOT INSTALL OR USE THE SOFTWARE.
"VTC" refers to Virtual Training Company,
"You" refers to the user or subscriber.
"Software" refers to the VTC training content and software.
2. LICENSE: VTC hereby grants to You a worldwide, non-royalty bearing, non-exclusive license to use the Software according to the provisions contained herein and subject to payment of the applicable subscription fees.
3. RESTRICTIONS: You may not do any of the following:
Save the Software to Your hard disk or other storage
medium; permit others to use the Software except as specified by addendum;
modify, reverse engineer, decompile, or disassemble the Software; make
derivative works based on the Software; publish or otherwise disseminate
the Software. VTC, Inc., VTC Online University, and the Virtual Training
Company site is owned and operated by VTC, Inc. as a corporation of
All materials on this site are the property of VTC unless otherwise specified. No material from these pages may be copied, reproduced, republished, downloaded, uploaded, posted, transmitted, or distributed in any way. Modification of the materials or use of the materials for any other purpose is a violation of U.S. copyright law and other proprietary rights. For purposes of this Agreement, the use of any such material on any other web site or networked computer environment is prohibited.
4. FEES: The rights granted under this Agreement
are effective only upon payment of the subscription fees, which are
strictly non-refundable other than as expressly provided herein. The
term "monthly subscription" is defined as any 30 day period.
The term "yearly subscription" is defined as one 365 day
period. A yearly subscription ends on the same numerical date as it
began (example July 28, 2004 to July 28, 2005).
The VTC Online University is access to every VTC training tutorial in our library. You pay a flat fee for access to these titles. You are billed according to your renewal selection below, and can renew monthly, yearly, or in any other increment offered. If you choose to be billed monthly, you will be billed every 30 days for the subscription until you request the subscription be cancelled. Our terms of service state that you must cancel a monthly subscription at least two business days before your renewal date. These two days give us enough time to ensure that you will not be charged again.
5. LIMITED WARRANTY: VTC warrants that the Software, if operated as directed, will substantially achieve the functionality described. VTC does not warrant, however, that Your use of the Software will be uninterrupted or that the operation of the Software will be error-free or secure. In addition, the security mechanisms implemented by the Software have inherent limitations, and You must determine that the Software sufficiently meets Your requirements. VTC also warrants that the media containing the Software, if provided by VTC, is free from defects in material from the date You acquired the Software. VTC's sole liability for any breach of this warranty shall be, in VTC's sole discretion: (i) to replace Your defective media or Software; or (ii) to advise You how to achieve substantially the same functionality with the Software as described; or (iii) if the above remedies are impracticable, to refund the subscription fee You paid for the Software. Only if You inform VTC of Your problem with the Software during the applicable subscription period will VTC be obligated to honor this warranty. VTC will use reasonable commercial efforts to repair, replace, advise, or refund pursuant to the foregoing warranty within thirty (30) days of being so notified. If any modifications are made to the Software by You during the warranty period; if the medium is subjected to accident, abuse, or improper use; or if You violate the terms of this Agreement, then this warranty shall immediately terminate. This warranty shall not apply if the Software is used on or in conjunction with hardware or software other than the unmodified version of hardware and software with which the Software was designed to be used as described.
THIS IS A LIMITED WARRANTY, AND IT IS THE ONLY WARRANTY MADE BY VTC OR ITS SUPPLIERS. VTC MAKES NO OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NONINFRINGEMENT OF THIRD PARTIES' RIGHTS. YOU MAY HAVE OTHER STATUTORY RIGHTS. HOWEVER, TO THE FULL EXTENT PERMITTED BY LAW, THE DURATION OF STATUTORILY REQUIRED WARRANTIES, IF ANY, SHALL BE LIMITED TO THE ABOVE LIMITED WARRANTY PERIOD. MOREOVER, IN NO EVENT WILL WARRANTIES PROVIDED BY LAW, IF ANY, APPLY UNLESS THEY ARE REQUIRED TO APPLY BY STATUTE NOTWITHSTANDING THEIR EXCLUSION BY CONTRACT. NO DEALER, AGENT, OR EMPLOYEE OF VTC IS AUTHORIZED TO MAKE ANY MODIFICATIONS, EXTENSIONS, OR ADDITIONS TO THIS LIMITED WARRANTY.
6. PROPRIETARY RIGHTS: VTC reserves all proprietary rights in and to the Software, is protected by copyright and other intellectual property laws and by international treaties. VTC, Inc.
Trademark Notice: VTC, Virtual Training Company,
Inc., The VTC Logo, and VTC Online University, are trademarks of VTC,
Inc. All other company and product names may be trademarks of their
The information contained herein is subject to change without notice. Copyright © 1995 - 2005 VTC, Inc. All rights reserved.
7. TERMINATION: This Agreement shall automatically terminate if You fail to comply with the restrictions described herein. Your obligations to pay outstanding subscription fees shall survive any termination of this Agreement.
8. LIMITATION OF LIABILITY: UNDER NO CIRCUMSTANCES
AND UNDER NO LEGAL THEORY, TORT, CONTRACT, OR OTHERWISE, SHALL VTC
OR ITS SUPPLIERS OR RESELLERS BE LIABLE TO YOU OR ANY OTHER PERSON
FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES OF
ANY CHARACTER, INCLUDING WITHOUT LIMITATION, DAMAGES FOR LOSS OF GOODWILL,
WORK STOPPAGE, COMPUTER FAILURE OR MALFUNCTION, OR ANY AND ALL OTHER
COMMERCIAL DAMAGES OR LOSSES. IN NO EVENT WILL VTC BE LIABLE FOR ANY
DAMAGES IN EXCESS OF THE AMOUNT VTC RECEIVED FROM YOU FOR A LICENSE
TO THE SOFTWARE, EVEN IF VTC SHALL HAVE BEEN INFORMED OF THE POSSIBILITY
DAMAGES, OR FOR ANY CLAIM BY ANY OTHER PARTY. THIS LIMITATION OF LIABILITY SHALL NOT APPLY TO LIABILITY FOR DEATH OR PERSONAL INJURY RESULTING FROM VTC'S NEGLIGENCE TO THE EXTENT APPLICABLE LAW PROHIBITS SUCH LIMITATION. SOME JURISDICTIONS DO NOT ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THIS EXCLUSION AND LIMITATION MAY NOT APPLY TO YOU.
9. Links To Other Materials: Linked sites found at the VTC site are not under the control of VTC, and we are not responsible for the content of any linked site or any link contained in a linked site. VTC may change links based solely on our discretion, and we reserve the right to terminate any link or linking program at any time. VTC does not, by linking to sites, endorse companies or products to which it links and reserves the right to note as such on its web pages. If you decide to access any of the third party sites linked to this site, you do this entirely at your own risk.
Forums, and Chat are not always screened by VTC, and we are not responsible for the content of any public or open forum content at the site. VTC may change these public forums based solely on our discretion, and we reserve the right to terminate any forum at any time. VTC does not, by allowing these forums, endorse companies or products which may be mentioned in these forums, and reserves the right to note as such on its web pages. If you decide to access any of the public forums in this site, or linked to this site, you do this entirely at your own risk.
9. GOVERNING LAW & DISPUTE RESOLUTION: This Agreement is governed by Virginia law. All disputes between You and VTC shall be finally resolved through arbitration in Winchester, Virginia. This site is controlled by VTC from its offices within the United States of America. VTC makes no representation that materials in the site are appropriate or available for use in other locations, and access to them from territories where their content is illegal is prohibited. Those who choose to access this site from other locations do so on their own initiative and are responsible for compliance with applicable local laws. You may not use or export the Materials in violation of U.S. export laws and regulations. Any claim relating to the Materials shall be governed by the internal substantive laws of the Commonwealth of Virginia, USA.
VTC may revise these Terms at any time by updating this posting. You should visit this page from time to time to review the then-current Terms because they are binding on you. Certain provisions of these Terms may be superseded by expressly designated legal notices or terms located on particular pages at this Site.
If you have any questions regarding this policy,
or your information specifically,
you may email us at:firstname.lastname@example.org.