JOURNAL OF TELECOMMUNICATIONS, VOLUME 29, ISSUE 2, FEBRUARY 2015 12

Automated Teaching Step-by-Step the Operations of TCP/IP Model (A-Step-TPC/IP)

Jameson Mbale and Mali Orient

Abstract In the telecommunication industry, the operations of TCP/IP protocols play an instrumental row in the transmission of information in the form of packets or frames from one network to another. To start with, at the source host, a transmittable message was composed and passed through the various protocol layers where headers, such as TCP, IP and network were added or attached. Whereas, at the receiving host, the same headers were consequently removed until only the original mes-sage reached the destination. Such a process was absolute to visualise by the students for they did not tangibly see the mecha-nism involved. It was in view of that the Automated Teaching Step-by-Step the Operation of TCP/IP Model, in this work abbrevi-ated as A-Step-TCP/IP, was conceived to simplify the understanding of the concepts involved in this operation. An experiment in form of a test was done, by dividing a class into two groups. The Control Group which did not use the model as teaching aid had fifty three point three three percent (53.33%) failure rate. For the Regular Group, all the students had hundred percent (100%) passing rate. Such results proved the effectiveness of the model.

Index Terms Step-TCP/IP, headers, protocol layers, transmittable message.

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1 INTRODUCTIONHE Automated Teaching Step-by-Step the Operation of TCP/IP Model, in this work abbreviated as A-Step-TCP/IP, was envisaged to simplfy the teach-

ing/learning of the concepts involved in this operation. The model gave a clear mechanism which showed the transmission of message in the network from the sender to the receiver. The model demonstrated step-by-step the mechanism in which the message was passed down the protocol layers, and the headers were added. Conse-quently, as the message was passed upwards, the corre-sponding headers were detached or removed.

The A-Step-TCP/IP simulation model was developed using the JAVA programming language. When the user ran the simulation prompted for the message to be keyed in. Thereafter, the system displayed the whole process of adding and detaching headers as discussed above. Also, a clear A-Step-TCP/IP flow chart showing the composing and movement of the message was discussed in detail in this work.

1.1 Statement of the Problem In the sub-Saharan region the telecommunication teach-ing resources are very scarce especially in the remote ter-tiary institutions. In some of these institutions, they learn such technologies but the equipment involved is not available. Hence, in the absence of both the technology infrastructure and the teaching aids it becomes absolutely difficult to the learners who are encountering such a sce-

nario for the first time. These students have no clue of where to start their conceptualisation of the new concepts they are encountering without any tangible evidence. As such, teaching of high level sophisticated technology like that of telecommunication becomes a challenge. For in-stance, teaching the concepts Operations of TCP/IP which deals with the transformation of unseen transmittable messages, further the adding and detaching of headers becomes obsolete to the learners. It is in view of that the A-Step-TCP/IP model was conceived to provide simula-tion which would illustrate step-by-step the concepts in-volved. and movement of the message was discussed in detail in this work.

1.2 Organisation of the Paper In The paper was organised in the following parts: Sec-tion 1 introduced the A-Step-TCP/IP model, highlighting the mechanism involved in the operations of TCP/IP pro-tocols. The similar models done by other researchers were discussed in Section 2. The implementation of the model was demonstrated in Section 3, where the snapshots of simulation were displayed. Section 4 gave a comprehen-sive flow diagram of the A-Step-TCP/IP system, by show-ing the movement of the transmittable message. Section 5 discussed the analysis of the test results that was given to the two groups to assess the effectiveness of the model. Section 6 summarised the functions and benefits of the A-Step-TCP/IP as a teaching model. accompany your final submission. Authors are responsible for obtaining any security clearances.

2 LITERATUR REVIEW The operation of TCP/IP has been discussed by other scholars. Hence in this work the authors will not re-event the wheel, but provide a simulation teaching aid which

Jameson Mbale is with the Copperbelt University, Department of Computer

Science, Box 21692, Jambo Drive, Riverside, Kitwe, Zambia. Mali Orient is with Copperbelt University, Department of Computer Sci-

ence, Jambo Drive, Riverside, Kitwe, Zambia.

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would help the learners conceptualise the concepts of the operation of TCP/IP.

In [1] he discussed a service data unit (SDU) as all data from an application that have to flow down through all five layers at the sender, and up all five layers at the receiver to reach the correct process on the other system. He illustrated that each layer on the sending system adds information to the data it receivesd from the layer above and passes it all to the layer below. He also talked about the protocol data unit (PDU), where each layer on the receiving system unwraps the received message. He even cited an example of the data link layer where it removed the wrapper meant for it, used it to decide what it should do with that data unit, and then passed the remainder up to the network layer. His overall emphasis on the receiv-ing end was that each layer examined, used, and stripped off the information it needed to complete its task, and passed the remainder up to the next layer until the origi-nal message was received.

Also, in [1, 2] they discussed the importance of encap-sulation of one layers information inside another layer as a key part of how TCP/IP works. They pointed out that each layer used encapsulation to add the information its peer needed on the receiving system. They gave an ex-ample of the network layer which adds a header to the information it received from the transport at the sender and passed the whole unit down to the data link layer. They also highlighted that at the receiver, the network layer looked at the control information, usually in a head-er, in the data it received from the data link layer and passed the remainder up to the other layers for further processing.

In [3] he demonstrated the operation of TCP/IP by cit-ing a practical example. He named the sender as host A, from the source network and receiver as host B, at the destination network. He began by pointing out that at host A, the sending process generated a block of data and passed it to TCP, where it appended control information known as the TCP header, forming a TCP segment. He then illustrated that the TCP handed each segment over to IP, which appended a header of control information to each segment to form an IP datagram. He further high-lighted that the network access layer appended its own header, creating a packet or frame which was then trans-mitted across the subnet-work to router in this case named J. He also explained that the packet header con-tained the information that needed to transfer the data across the subnet-work. He further discussed that when the data was received at B, the reverse process occurred, such that at each layer, the corresponding header was removed, and the remainder was passed through to the next higher layer, until the original user data were deliv-ered to the destination in the Application. In [4] he discussed both encapsulation and de-capsulation as one of the important concepts in protocol layering in network. He explained the encapsulation process that

occurred at the source in the network as the data moved downwards along the layers where headers were added. He pointed out that the Application Layer dealt with the message, which had no header. He said this message was then passed through to the Transport Layer where the TCP header was added forming a user datagram or TCP segment, which contained the identifiers of the source and destination application programs and the infor-mation that was needed for the end-to-end delivery of the message, such as information needed for flow, error con-trol, or congestion control. He further stated that the user datagram was then handed to the Internet Layer where the IP header was added, forming the datagram which contained the addresses of the source and destination hosts and some more information used for error checking of the header, and fragmentation information. He also indicated that the datagram was passed through to the Data Link Layer where the network header was added, forming the frame which contained the link-layer ad-dresses of the host or the next hop (the router). He then explained that the frame was passed through to the Phys-ical Layer where it was transformed into bits that trans-ported to the next network. He pointed out that it was at this next network where the de-capsulation took place at the destination host. He emphasised that it was at this stage where the process was the reverse of the other such that in this case headers were removed or detached as data was delivered to the next-higher layer protocol until the original message reached the Application Layer. Au-thors are responsible for obtaining any security clearanc-es.

3 THE IMPLEMENTATION OF A-STEP-TCP/IP MODEL

The A-Step-TCP/IP Model is illustrated in Figure 1, demonstrating the automated functional mechanism of encapsulation and de-capsulation of data by adding and detaching the headers in the next lower and higher proto-col layers respectively. The A-Step-TCP/IP Model is com-posed of two vertical downward and upward operational and functional partitions or components, in this work referred to as Source-host-Network Process (SHNP) and Destination-host-Network Process (DHNP).

Figure 1. Snapshot: The A-Step-TCP/IP Model Interface

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The SHNP, component, is at the source host (the sender), where the user composes the message. The composed message is entered by the user in the input box, and presses the send message button to commence the simula-tion of the TCP/IP operation in transmitting the data. As the message is passed through and reaches the next layer, a particular header is added. When the message arrives at the physical layer it is converted into bits where it is transmitted through the media to the next network at the destination host, in this work referred to as DHNP. At the next network, the bits are transformed back into the frames and the message is passed through upwards lay-ers. At each level the prefixed header is detached until the original message reached the Application Layer. At this level the user is prompted to press the receive button in order to get the original composed message. Samples of snapshots were taken during the simula-tion of the A-Step-TCP/IP Model. Figure 2 illustrated an example of demonstration run on the model. At this junc-ture, the user keyed-in the information to be composed into a transmittable message. In this case, at the SHNP, the user keyed in the following message: Assignment due 31st January 2015 as demonstrated in Figure 2.

Figure 2. Snapshot: Demonstrated the Keying-in of Message and

Headers Added When the user started keying-in the message, the Press to Send Message button was automatically active as demonstrated in the figure. Once the Press to Send Mes-sage button was pressed, the system started running and the headers were being added: at transport layer, TCP header, Internet Layer, the IP header, and Data Link Lay-er, the Network header as shown in Figure 2. As the process continued, at the Physical Layer, the data was transformed into streams of bits as demonstrat-ed in Figure 3.

Figure 3. Snapshot: Demonstrated Message Transformed into Bits at Physical Layer

From the SHNP, the stream of bits: 1100100001110111101111101110000110 were transmitted through the media to the next network in this work re-ferred to as DHNP and demonstrated in Figure 4.

Figure 4. Snapshot: Bits Transmitted to DHNP and Headers Dropped

as Data Moved Upper Layers At the DHNP, from the Physical Layer, the bit streams were transformed into the frame in the Data Link Layer. As the frame moved to the Internet Layer, the Network header was detached remaining with the datagram. Also, as the datagram was moved to Transport Layer, the IP header was removed remaining with the TCP datagram or TCP segment. The TCP datagram was passed through to the Application Layer and the TCP header was dropped remaining with the original message as demon-strated in Figure 5. Then the dialog window prompted the message that You have 1 new message. When the user pressed OK, the Press Read Message button was active. As the user pressed the later button, then the orig-inal message Assignment due 31st January 2015 ap-peared on the output or read window as demonstrated in Figure 5.

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Figure 5. Snapshot: Original Message Received by the Recipient at DHNP

4 DATA FLOW DIAGRAM FOR THE A-STATE-TCP/MODEL

As discussed in earlier Sections, Figure 6 demonstrated the flow of the information from the SHNP where the message was composed and passed through downwards from one layer to another and at each level a particular header was added. Similarly, at DHNP, the message kept on flowing upward and at each layer the headers were dropped until the original message reached the destina-tion.

Start

InformationExists

Yes

TansmitMessage

Add TCP Header

Yes

Add IP Header

Add Network Header

Transform into Bits

Compose(d) Message

Exit

No

No

ApplicationLayer

Yes

No

TransportLayer

InternetLayer

Data LinkLayer

Yes

Yes

Yes

PhysicalLayer

PhysicalLayer

Drop Network Header

Data LinkLayer

InternetLayer

TransportLayer

Drop IP Header

Drop TCP Header

YesNo

No

No

No

Yes

Yes

Yes

Yes

No

No

No

No

Figure 6. A-Step-TCP/IP Flow Chart

When the system was started, it checked whether there was any information to be sent from SHNP to DHNP or not. If there was no information, then the process was terminated. However, when the information was verified to be existed, it was passed through to the Application

Layer. At this layer, the system tested if it was the correct one (layer). If it was not, then the process was restarted. However, once verified that it was the right layer, then the information was composed into a transmittable mes-sage in readiness for sending it across the protocol layers of SHNP in rout to DHNP. Having composed the mes-sage, again the system tested whether it was well pack-aged and worthy sending or not. If it was not worthy transmission, then the process was exited. Once certified that it was worthy sending, then the message was passed through to the next layer, in this case the Transport Layer. Like the previous layer, this one also was verified if it was the right layer. If it was not the correct layer, the process was terminated. However, once verified that it was the right layer, the TCP Header was attached or added to the message forming the TCP Segment as explained in the earlier Sections. Then the TCP Segment was passed through to the Internet Layer. Similarly, this layer was tested whether it was the right one or not. If it was not the correct one, then the process was ended. If the system verified that it was the correct layer, then the IP Header, was attached to the message, and at this juncture referred to as IP Datagram, also already discussed above. Thereaf-ter, the IP Datagram was sent to the Data Link Layer. Like others, this layer was tested to be either the right one or not. If it was not the correct one, then the process was discarded. When the system verified it to be the intended layer, then the Network Header was attached to the mes-sage, in this case known as Network-Level Packet or Frame. Then the Frame was passed through to the Physi-cal Layer. Like any other layers discussed above, equally this one was tested to check if it was the actual one or not. If it was not the actual one then the process was terminat-ed. If it was the correct one, then this layer transformed the Frame into Bits and transferred them to the other Physical Layer at DHNP as demonstrated in Figure 6. Likewise, the Physical Layer at DHNP was also tested to be the correct one or not. If it was not, then the process was terminated. Once the layer was tested correct, the data was sent upwards to the Data Link Layer. As already discussed, and as the message moved upwards, the next layers were also tested to be the right ones or not. If found not be the intended ones, similarly the processes were terminated. On the contrary, if the layers were the right ones the message was passed to the next layers where at various protocol layers the subsequent headers were removed or detached until the original composed message remained and arrived at the DHNP, marking a complete flow of the process as demonstrated in Figure 6.

5 RESULTS AND DISCUSSIONS A class of thirty (30) students was divided into two groups of fifteen (15) learners. In this work, the groups were referred to as Control and Regular. A test was ad-ministered to the two groups to compare the performance

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between them in order to assess the effectiveness of the A-Step-TCP/IP Model, as the teaching aid. The Regular Group was taught using the teaching aid, the A-Step-TCP/IP Model. During the lectures / lessons of the Regular Group, the Lecturer ran the A-Step-TCP/IP Model which provided the simulation of operations of the TCP/IP. The simulation demonstrated step-by-step the mechanism involved in this operation. From the simula-tion, the students could physically see how the infor-mation was composed to a transmittable massage. They could also see the movement of the transmittable message from one protocol layer to the next. They also witnessed how the headers were added and removed at every pro-tocol layers until the message reached the destination. During tutorials, the students from the Regular Groups practiced on the teaching aid and this consolidated their understanding of the concepts of the operation TCP/IP. By seeing the simulation, the students were able to visual-ise the whole mechanism involved under operations of TCP/IP. The Controlled Group was taught without using the A-Step-TCP/IP Model. The Lecturer just explained the concepts of Operations of TCP/IP theoretically. During the lessons, the students from this group struggled to vis-ualise how the information was composed to the trans-mittable message. Worse still they could not figure out how the headers were added and dropped as they (mes-sages) were passed through from one protocol layer to the next. The whole Operation TCP/IP concept was just abso-lute to them. When the test was administered to the two groups, the following performance was experienced. Out of the fif-teen (15) students from Regular Group, the following re-sults were recorded as depicted from Table 1a: five (5) students got Distinction, which was thirty three point three three percent (33.33%) pass rate, also as demonstrat-ed in Figure 7. Seven (7) obtained Merit, which was forty six point six seven percent (46,67%) pass rate. Three (3) managed to get Pass, which was twenty percent (20%) pass rate, and none failed the test. TABLE 1 Comparison of Test Results From Two Groups Table 1a. Regular Group Used Teaching Aid Results Distinction Merit Pass Fail No. Students 5 7 3 0 Table 1b. Control Group Did Not Use Teaching Aid Results Distinction Merit Pass Fail No. Students 1 2 4 8

Figure 7. Test Results From Regular Group

For the Control Group as shown in Table 1b, the follow-ing results were obtained: only one (1) got a Distinction, which was a six point six seven percent (6.67%) pass rate, also illustrated in Figure 8. Two (2) got a Merit, which was thirteen point three three percent (13.33) pass rate. About four (4) got a Pass, which was twenty six point six seven percent (26.67) pass rate. The majority of eight (8) failed the test, which was fifty three point three three per-cent (53.33%) fail rate.

Figure 8. Test Results From Control Group

In comparison of the two groups, it is evident that the students who were taught using the teaching aid had an opportunity to physically experience the mechanism of the A-Step-TCP/IP teaching model. Through the use of this model, and from the simulation, the students were able to see the imitation of how the information was composed to a transmittable message. Also, the learners had chance to see a replica of various headers that were added at every protocol layer as the message moved downwards the process. Similarly, the students witnessed these added headers, on the reverse being removed at the same corresponding protocol layers, until the original message reached the intended destination. The use of such an animation teaching tool helped the student from the Regular Group to conceptualise or visualised the mechanism of the Operations of TCP/IP. This goes with a saying, which states that What you see is difficulty to

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forget! Hence, it is true that the demonstrated A-Step-TCP/IP teaching model, through an animation has given students a concrete visualisation of the mechanism in-volved as such they would not forget what they saw.

Contrary to what has been discussed above, the Control Group which was taught without the use of the teaching aid, faced a lot of challenges to grasp the con-cepts, as everything was in abstract or nonconcrete. Dur-ing the lessons, this group could not see the transfor-mation of the information into a transmittable message, apart from hearing it from a teacher mentioning it verbal-ly. Similarly, the learners could not figure out the features of the headers that were being added and detached from the message at every protocol layer. In fact, this addition and detaching of the headers phenomenon further con-fused the students as there were no visible and concrete objects to assimilate with. Much of teaching was just in theory.

6 CONCLUSION The A-Step-TCP/IP Model was envisaged as a teaching tool to be used during the lessons to give a tangible and physical demonstration of the Operations of TCP/IP. The Regular Group was taught using this teaching aid. These students had an abundant exposure to the mechanism involved in this model. As a result, the learners were able to clearly visualise the concepts of the Operations of TCP/IP, such that by the time they were given a test, they confidently passed it. In fact, as shown from Table 1a and Figure 7, no one failed the test in this group, they had hundred percent pass rate. The Control Group was taught without using the A-Step-TCP/IP Model. Students from this group struggled to understand the lessons as they could not visualise the concepts of the Operations TCP/IP. The lesson was taught in theory, and everything was obsolete to the students. The learners could not figure out the concepts that were mentioned verbally, without any evidence of the compo-nents or facilities involved in discussion. For instance, it was mentioned that, information was transformed into a transmittable message, but the students could not see or make sense out of it. Worse still, they were taught that the transmittable message was passed through the protocol layers and different headers were added. Further, this confused the learners for they could not figure out the physical features of the message and headers in discus-sion. Hence, this group was deprived of the practical ex-posure to the teaching aids components and its total mechanism. In that, it left the learners in a confused state where they had some difficulties to visualise the concepts presented in abstract. As such, when the test was admin-istered, more than half the group which was fifty three point three percent (53.33%) failed as shown in Figure 8.

REFERENCES [1] Protocol and Layers, TP1-Ejercicio5-ingles [2] The TCP Protocol Suit, Fujitsu Network Communications Inc.

(FNC). December, 2008, http://www.fujitsi.com/us/services/telecom/training/edservtcpip.pdf

[3] W. Stallings, Data and Computer Communications, Fifth Edi-tion. Prentice Hall, 1997

[4] Chapter 2, Network Models Jameson Mbale received his PhD Degree in Computer Science from Harbin Institute of Technology (HIT), China in 2003. He ob-tained MSc Degree in Computer Science from Shanghai University in 1966 and B.A. in Mathematics and Computer Science at the Univer-sity of Zambia (UNZA) in 1993, in Zambia. He also got the Second-ary Teachers Deploma in 1985 from Technical and Vocational Teachers College, in Luanshya, Zambia. He worked as a Lecturer and Head of Depterment for the Department of Computer Science at the University of Zambia from 2004 to 2008. He was the Founder of Zambia Research and Education Network (ZAMREN), for Zambia in 2008. He also served as a Senior Lecturer and later as an Associate Professor, Head of Department for Computer Science and Acting Director for Computer Centre at the University of Namibia (UNAM) from 2008 to 2014. He is the Founder (2010) of the Centre of Excel-lence in Telecommunications and Information Technology at UNAM. Currently, he is an Associate Professor in the Department of Com-puter Science at the Copperbelt University (CBU), in Zambia from 2004. He is also the Acting Director for Research for the Copperblet University. His research interest is in: network security, wireless networking and telecommunications and he has published many papers in these areas. Mali Orient is a student in the Department of Computer Science at the Copperblet University (CBU), in Zambia.