CHAPTER 1
BASIS THEORY
Transport Layer
A. UNDERSTANDING
Transport layer or the transport layer is the fourth layer of the OSI network reference model and the heart of the whole protocol hierarchy. The task of this layer can provide reliable data transport and the effective cost of the computer source to the destination computer, which does not depend on the physical network or networks that are used. Without transport layer, the whole concept layer protocol that uses tone aka no avail.
Layer or layers that set the connection from one end to the other (computer to computer pengirn receiver) and also the build logic connection between the sender and the recipient host in the network. This layer, too, who manage and implement a reliable transport service antarjaringan transparent to layers above it (upper layer). The function of this layer include flow control, error checking, and recovery.
B. LAYER TRANSPORT SERVICES
Transport layer is responsible for providing services that can be relied upon to the protocols that lie above it. The services referred to include:
• Set the flow (flow control) to ensure that the device that transmits data is not sent more data than can be handled by the receiving device.
• Sort the packets (packet sequencing), which is done to change the data that would be sent into segments of data (this process is referred to the process of segmentation / segmentation), and thus has features to putting it back together.
• Handling errors and features an acknowledgment to ensure that the data has been submitted correctly and will be sent again when the data did not reach the destination.
• Multiplexing, which can be used to combine data from bebeberapa source to send data through a single point only.
• Establishment of a virtual circuit, which is done to make the connection session between two nodes that want to communicate.
Examples of protocols that work at the transport layer is Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) which is available from a collection of TCP / IP.
1.1 the role of the transport layer
The purpose of the Transport layer is the transport layer provides segmentation of data and control data needs to go back into the various streams of communication. This - a key point to note is:
• Keep track of communication between the source and destination host application
• Segmentation and manage their data - each data. Reassembling (collecting back) segments of the stream data applications
• Identify a variety of different applications
• Track Any Communication
Each host can have several applications that communicate across the network. Each application will communicate with one or more applications on the remote host. This is a transport layer task to maintain multiple streams of communication between the application.
1.2 SegmentasiData
Each application makes streaming of data to be sent to a remote application, this data must be prepared to be sent to all media on the part that can be controlled. Transport layer protocols describe the data services segment of the Application layer. This includes the necessary encapsulated in each data. Each application requires a data header data to be added to the transport layer to indicate the communication associated with it.
1.3 SegmenReassembling
At the reception hosts, each data can be directed to the appropriate application. In addition, each data must be reconstructed into a complete data stream for use in coating applications. All the Transport Layer protocol describes how the header information on Transport layer is used to restore data to a stream that is passed to the application layer.
Identification Applications in order to generate data streams into the appropriate application, the transport layer must identify the destination application. To comply, the Transport layer provides applications that have been identified. Dialing Protocol TCP / IP is identified by a port number. Any software that will be accessed by the network given a unique port number in the host. This port number is used in the transport layer header to indicate the application of related data. Transport layer is a link between the application layer and lower layer in charge of the transmission network. This layer receives data from a variety of different communication thereafter forwarded to the lower layer that can be managed as a multiplexed on the media.
Applications do not need to know the operational details of the network used. Because the application produces data that is sent from one application to another, regardless of the destination host, media type is passed by data type, and part taken by the data, congestion on the bridge, or the size of the network. In addition, the layer beneath it are not aware that there are some applications that send data on the network. The function of these layers is to send data to the appropriate device. Then it sort out the transport layer - part before sending to the appropriate application.
Kind - kind of Data Requirements: Due to various applications have different requirements, there are several transport layer protocols. For some applications, the segment must arrive in a very specific sequence in order to successfully processed. In some cases, all data must accept any protocol to be used. In other cases, applications can tolerate some data loss during transmission on the network. At the time of network convergence, the need for different application transport layer requires communication on the same network. A variety of different transport layer protocol has rules for handling various data requirements.
Some protocols only provide an efficient basis functions for sending data between the application accordingly. This type of protocol is useful for delay-sensitive data. Transport layer protocol describes the process that provides additional features, such as ensuring a reliable delivery between applications. At the time of additional functions to provide better communication to the Transport layer between the application has additional overhead and create greater demand on the network.
C. QUALITY OF SERVICE
The primary function of the transport layer is to improve the quality of services provided by the network layer. If the service network layer without defects, then the transport layer are burdened easy task. Conversely, if network service is not good, then the transport layer must bridge the gap between what users want and what the transport layer provided by the network layer.
Although at first glance seems sepetri service quality are vague concept, but the quality of these services can be determined by a number of specific parameters.
These parameters are
1. Connection establishment delay
The amount of time between when the request transport connection with the receipt of confirmation by the users of transport services. This delay includes processing delay at the transport entity elsewhere. As with any parameter - the size of the delay parameter, the shorter the window, the better service
2. Estabilishment Conection failure probality
Opportunity for connection is not formed within the maximum time delay formation, for example in relation to network congestion, lack of space on the table and other internal problems.
3. Throughput parameters
Measuring the amount of user data bytes transferred per second. Byte is measured in a certain time interval. Throughput is measured separately in each direction of traffic of 0 respectively.
4. Transit delay
Measure the time between when a message sent by the transport user on the computer resources and time the message was received by the transport user on the destination computer. As with throughput.
5. Residual error ratio
Measuring the number of messages lost or damaged as part of the total messages sent. In theory, the speed residual error must be zero, because it has a duty transport layer to hide all errpr network layer. whereas in prakeknya, this ratio may be a certain small value.
6. Transfer failure probability
Measuring the extent to which services the transport layer to function in accordance with what is expected. When the transport connection established, should disepkati first output level, transit delay and residual error rate. The probability of failure time data transfer gives tanggang thus put in provisions that have been agreed this will not be fulfilled during the observation period.
7. Connection release delay
The amount of time is wasted between the time of initial release by the computer connection and the release of the source computer to the recipient.
8. Coneccton release failure probability (probability of failure to release the connection)
Part of the business release of connections that have been determined.
9. Parameter protection
Provide a way for users to specify the use of transport in the transport layer provides protection against third parties who are not eligible (tappers) who tries to read or modify data that would be transmitted.
10. Parameters priority
Provide a means of transport user to indicate that a few more clubs disbanding his connections with other connections. In times of congestion, this parameter determines that high priority connections served earlier than a low-priority connections.
11. Parameters resilience
Gives the probability that the transport layer itself spontaneously end the connection in relation to the internal congestion problems.
D. ROUTER
Router is a computer network tool that sends data packets through a network or the Internet to the destination, through a process known as routing. The process of routing occurs at layer 3 (network layer such as the Internet Protocol) stack of the OSI seven-layer protocol. Router is a reliable way of finding the device on a complex interconnection situations. Routers can perform selective traffic segmentation. In an internetworking where there are many protocols, the routers can select the type of protocol that should be used in a path that passes.
1.1 Functions
The router serves as a liaison between two or more networks to carry data from one network to another. Different router with a switch. Switch is a link multiple tools to form a Local Area Network (LAN).
Analogy Router and Switch
As an illustration of differences in the functions of routers and switches is a street, and the router is a link between road. Each house is on the road that has an address in a particular order. In the same way, the switch connects a wide range of tools, where each instrument has its own IP address on a LAN.
Routers are very widely used in technology-based network protocol TCP / IP, and router types that are also called IP Router. In addition to the IP router, there is another AppleTalk router, and still there are several other types of routers. The Internet is a prime example of a network that has a lot of IP routers. Router can be used to connect many small networks into a larger network, called the internetwork, or to divide a large network into several subnetworks to improve performance and also facilitate its management. Routers are also sometimes used to mengoneksikan two networks that use different media (such as wireless routers in general than he can connect a computer with a radio, he also supports connecting computers with UTP cable), or different network architectures, such as the Ethernet to Token Ring.
Router can also be used to connect LANs to a telecommunications service such as leased line telecommunications or Digital Subscriber Line (DSL). Routers are used to connect LANs to a leased line connections such as T1, or T3, often referred to as an access server. Meanwhile, the routers used to connect local network to a DSL connection is also called the DSL router. Routers of that type typically have a firewall function to perform packet filtering based on source address and destination address the packet, although some routers do not have it. The router has packet filtering features are also called packet-filtering routers. Routers typically block traffic in a broadcast transmitted data so as to prevent a broadcast storm which can slow network performance.
1.2 Types of routers
In general, the routers are divided into two types, namely:
• static router (router static): is a router that has a static routing table that in the settings manually by network administrators.
• dynamic router (router dynamically): is a router that has a dab to make dynamic routing tables, by listening to network traffic and also to interact with other routers.
1.3 Router vs. Bridge
How it works similar to a bridge network routers, ie, they can forward the data packet network and can also divide the network into multiple segments or merge network segments. However, the router runs on the third layer of the OSI model (network layer), and use the addressing scheme used in layers, like IP addresses. Meanwhile, the bridge network runs on a second layer of the OSI model (data link layer), and use the addressing scheme used in that layer, the MAC address.
Then, when using a network bridge do and when to use a router do? Bridge, should be used to connect the network segments that perform the same network protocol (for example: IP-based network segment with other segments of the IP network). In addition, the bridge can also be used when inside there network protocols that can not do routing, such as NetBEUI. Meanwhile, the router should be used for connecting network segments running berebeda network protocol (as well as to connect the IP network segments with IPX network segment.) Generally, the router is more intelligent than the bridge network and can increase network bandwidth, given router not forward broadcast packets to the destination network. And, the use of routers is most often done when we want our network connects to the internet.
1.4 Purpose Router
Routers are network devices that are used to divide the protocol to the other network members, with the router then a protocol can be shared to other network devices. Examples of its application is that if we want to divide your IP address to members of the network then we can use this router, the router features is the facility DHCP (Dynamic Host Configuration Procotol), by setting up DHCP, then we can divide the IP Address, other facilities of the Router is the NAT (Network Address Translator) that can allow an IP address or an internet connection be shared to other IP addresses. For example, if on a network device (computer) has the IP address 192.168.0.1, then the other computers to communicate, must be given an IP Address with the Network Identification with the Host Identification 192.168.0 and 2-254, for example 192.168.0.10, 192.168.0.11 and onwards.
Problems will arise when the network device that is connected very much (usually in the top 20 devices), an administrator will be forced to get around to setting up IP addresses for each host, therefore we can use the Router.
Router Types:
1. Application Router
Router application is an application that we can install the operating system pad, so that the operating system will have capabilities such as routers, examples of this application is Winroute, WinGate, SpyGate, WinProxy and others.
2. Router Hardware
Hardware is a hardware router that has the ability sepertiu router, so the hardware can be transmitting or sharing IP addresses and to sharing the IP Address, in practice this hardware router used to share Internet connection on a space or area, an example of this is the access router point, the region can get Ip Address and Internet connection is called the Hot Spot Area.
3. PC Router
Router is a PC operating system that has the facility to divide and mensharing IP Address, so if a network device (pc) connected to a computer will be able to enjoy an IP Address or Internet connection that is spread by the Operating System, the example of the operating system that can be used are all client server-based operating systems, such as Windows NT, Windows NT 4.0, Windows 2000 Server, Windows 2003 Server, MikroTik (Linux Based), and others.
1.5 The reason for the use of routers
With the use of network layer protocol, the router has the miraculous advantages of the bridge to consider:
1. Bridge uses only a subset of the overall topology (spanning tree), while the router to use the best path that is physically located between the source and destination addresses.
2. Easily adjusted if there are changes in the overall network topology.
3. Large whole network is not limited.
4. Bridge reject packets that are too large to be forwarded, while the router is not.
5. Busyness is a sub-network does not affect the overall network.
CHAPTER 2
CASE STUDY
A system with the router using the Internet protocol (IP) at every router and host of each network. Protocol is to wrap the transmitted data. Examples of the data transmission process is wrapped with an IP protocol Dapa seen a picture:
There are 4 types of relationships relative to the router stations namely;
1. The station is connected to a network that is connected directly to the router.
In the picture above, all the stations beginning with SO is on a network that is connected directly to router R1.
2. The station is in a connected network router that is connected directly with the active router. Router is connected is called a neighbor router. In the example above, for example the active router is R1, then R2 and R4 is a neighboring router, and all stations beginning with S1 is called is a leap (one hop) from R1.
3. The station is on a network that is connected to the router is not the neighboring active routers. Stations that meet the purposes of this condition is called is a lot of jumps (multiple hops) from the active router. In the example, if the active router is R1, all the stations beginning with S2, entered in this category. Station S2 is 2 beginning with a leap of R1.
4. Router does not recognize the address stated on the IP protocol data grams.
CHAPTER 3
CASE ANALYSIS
When a router gets the data grams to be forwarded to the station, then the data transmission process will be conducted in accordance grams station location relative to the router, which can be explained as follows.
1. On the relations relative station of the first router, the datagram protocol wrapped in accordance with the destination LAN address of the destination station.
2. On the relations relative station router to the 2nd and, also wrapped up datagram protocol next LAN, but with the next router address.
3. On the relations relative station router to 4, error messages sent to the sender station data.
The process of sending data from the stations on the LAN A SO1 to several other stations can be explained as follows.
1. IP management module on the station SO1 build datagram with a global network address and recognize that the address is located on another LAN. Datagram packet form can be seen in the picture
IP DATA
2. IP datagram sent to router R1 with the appropriate network protocol wrapped with LAN A. symbol HA (R1) means the header protocol to the LAN A, which contains the address of R1 and TA is the trailer. It should be noted that this protocol is a protocol layer below the network (layer 3). The form can be seen in the image bundle;
H-A (R1) IP DATA T-A
3. Router R1 receives shipment and re-open parcel A LAN protocol earlier, in order to obtain the original datagram.
4. Based on the IP protocol packet, the router R1 must determine what to do. When the destination station is connected directly, for example SO 4 on LAN B, the form of packets that are sent to the LAN B can be seen Figure;
H-B (SO 4) IP DATA T-P
5. When moving a jump destination station, eg station S11 On LAN C, the form of packets that are sent on LAN B router which is intended to fit, as in the picture;
H-B (R2) IP DATA T-P
6. If the destination station is a leap, for example, station S21 on LAN E, then R1 must determine, through the router where the distance is closer (in 1 jump). In the example above, the distance to reach the destination station when passing mauun R2 R4 are the same.
7. Before the actual data transmitted on the network destination, the router may split the packet size to complete the packet size limit on the destination network. Each - each section into a separate IP datagram, then this data is queued to be distributed.
Overall the above process continues so that data transmitted is complete. Search work this way is generally done by creating a lookup table for every router path and the station, which contains information on possible destination networks and routers in between.
CHAPTER 4
CONCLUSION
Transport layer or the transport layer is the fourth layer of the OSI network reference model and the heart of the whole protocol hierarchy. The task of this layer can provide reliable data transport and the effective cost of the computer source to the destination computer, which does not depend on the physical network or networks that are used. Without transport layer, the whole concept layer protocol that uses tone aka no avail.
Layer or layers that set the connection from one end to the other (computer to computer pengirn receiver) and also the build logic connection between the sender and the recipient host in the network.
Transport layer is responsible for providing services that can be relied upon to the protocols that lie above it. The services referred to include:
• Set the flow (flow control)
• Sort the packets (packet sequencing)
• Handling errors and acknowledgment feature
• Multiplexing
• Establishment of a virtual circuit
The purpose of the Transport layer is the transport layer provides segmentation of data and control data needs to go back into the various streams of communication
PARAMETER - PRAMETR THAT DETERMINE THE QUALITY LAYANA:
1. Connection establishment delay
2. Estabilishment Conection failure probality
3. Throughput parameters
4. Transit delay
5. Residual error ratio
6. Transfer failure probability
7. Connection release delay
8. Coneccton release failure probability (probability of failure to release the connection)
9. Parameter protection
10. Parameters priority
11. Parameters resilience
Router is a computer network tool that sends data packets through a network or the Internet to the destination, through a process known as routing. The process of routing occurs at layer 3 (network layer such as the Internet Protocol) stack of the OSI seven-layer protocol.
The types of routers
In general, the routers are divided into two types
static router (router static)
dynamic router (router dynamic)
Tidak ada komentar:
Posting Komentar