TCP/IP Protocol Suite Chapter 2 The OSI Model and
Outline THE OSI MODEL LAYERS IN THE OSI MODEL TCP/IP PROTOCOL SUITE ADDRESSING TCP/IP VERSIONS
The McG 2.1 THE OSI MODEL
Figure 2-1 OSI Model
Layered Architecture Within a single machine Each layer calls upon the services of t below it For example, layer 3 uses the services by layer 2 and provides services for la
Layered Architecture (Cont. Between machines Layer x on one machine communicate x on another machine This communication is governed by a rules and conventions called protocols
Layered Architecture (Cont. As the message travels from A to B pass through intermediate nodes These intermediate nodes usually invo the first three layers of the OSI model As shown in the next slide
The McG Figure 2-2 OSI Layers
Peer-to-Peer Processes The processes on each machine tha communicate at a given layer are c peer-to-peer processes Each layer in the sending device ad own information to the message it from the layer just above it At the receiving machine, the mess unwrapped layer by layer
The McG Headers are added to the data at layers 6, 5, 4, 3, and 2. Trailers are usually added only at layer 2.
The McG Figure 2-3 An Exchange Using the OSI M
The McG 2.2 LAYERS IN THE OSI MODEL
The McG Figure 2-4 Physical Layer
Physical Layer Physical characteristics of interface Interface between the devices and tran media The type of transmission media Representation of bits Define the type of encoding (how 0s a changed to signals)
Physical Layer (Cont.) Data rate The number of bits sent each second Synchronization of bits The sender and receiver must not only same bit rate but must also be synchro bit level
Physical Layer (Cont.) Line configuration Be concerned with the connection of devic media Point-to-point configuration Two devices are connected through a dedicate Multipoint configuration A link is shared between several devices Physical topology Define how devices are connected to make For example, mesh, star, ring, or bus topol
Physical Layer (Cont.) Transmission mode Define the direction of transmission betwee Simple mode only one device can send Half-duplex mode two devices can send and receive but not at the s Full-duplex mode Two devices can send and receive at the same ti
Data Link Layer Transform the physical layer to a re Make the physical layer appear erro the upper layer
The McG Figure 2-5 Data Link Layer
Data Link Layer Framing Divide the stream of bits into frames Physical addressing only one hop Flow control Error control Detect and retransmit damaged or lost Prevent duplication of frames
Data Link Layer (Cont.) Access control Determine which device has control link at any given time
Node-to-Node (Hop-to-Hop) D The McG Figure 2-6
Network Layer Be responsible for the source-to-de delivery of a packet possibly acros networks (links) Data link layer take care of the delive packet between two systems on the s network (links) Network layer ensures the delivery o from its point of origin to it final des
The McG Figure 2-7 Network Layer
Network Layer Logical addressing Physical addressing in the data link la the addressing problem locally If a packet pass the network boundary Routing We need another addressing system to d source and destination systems
The McG Figure 2-8 End-to-End Delivery by the Netw
Transport Layer Be responsible for source-to-destina to-end) delivery of the entire messa Network layer only oversees the end-t delivery of individual packets Oversee both error control and flow the source-to-destination level
The McG Figure 2-9 Transport Layer
Transport Layer Service-point addressing Service-point address: port address The network layer gets each packet to the co computer The transport layer gets the entire message t process on that computer Segmentation and reassembly
Transport Layer (Cont.) Connection control Connectionless Connection-oriented Flow control End to end flow control The flow control, however, at the data link l a single link
Transport Layer (Cont.) Error control End to end error control that makes sure th entire message arrives without error (dama duplication) Error correction is usually achieved throug retransmission The error control, however, at the data link across a single link and applies to a single
The McG Figure 2-10 Reliable End-to-End Delivery of end-to-end delivery by the transport layer
Session Layer Session layer is the network dialog It establishes, maintains, and synchron interaction between communication sy
The McG Figure 2-11 Session Layer
Session Layer Dialog control Allow two systems to enter a dialog Allow the communication between tw in Half-duplex Full-duplex Synchronization Allow a process to add checkpoints (synchronization points) into a stream
Presentation Layer Be concerned with the syntax and se of the information exchanged betwe systems
The McG Figure 2-12 Presentation Layer
Presentation Layer Translation Different computers use different enc systems The presentation layer is responsible f interoperability between these differen methods Encryption Compression
Application Layer The application layer enables the us whether human or software, to acce network
The McG Figure 2-13 Application Layer
Application Layer Specific services provided by the ap layer Network virtual terminal File transfer, access, and management Mail services Directory services
The McG Figure 2-14 Summary of Layers
2.3 TCP/IP PROTOCOL SUITE
TCP/IP Protocol Suite TCP/IP protocol suite was develope the OSI model and is made of five l Physical, data link, network, transport application layers The first four layers correspond to t four layer of the OSI model
TCP/IP Protocol Suite The three topmost layers is OSI mo represented in TCP by a single laye the application layer
The McG Figure 2-15 TCP/IP and OSI Mode
Physical and Data Link Lay TCP/IP does not define any specific TCP/IP supports all of the standard proprietary protocols
Network Layer Internetworking Protocols (IP) Four supporting protocols ARP RARP ICMP IGMP
Internetworking Protocol (IP The packets in IP are called datagra Unreliable and connectionless datag protocol Best-effort delivery services Provide no error checking or tracking
Address Resolution Protoco Associate an IP address with the ph address Data in LAN are transmitted by the ph address
Reverse Address Resolution Pr (RARP) Discover a host s internet address vi physical address Used when A computer is first connected to the n When a diskless computer is booted
Internet Control Message Pr (ICMP) A mechanism used to send notificat datagram problems back to the send ICMP sends query and error reporti messages
Internet Group Message Pro (IGMP) Facilitate the simultaneous transmis message to a group of recipients
Transport Layer TCP/UDP A process-to-process protocol IP A host-to-host protocol
User Datagram Protocol (UD Add only Port numbers Checksum error control length
Transmission Control Protocol Reliable connection-oriented protoc
The McG 2.4 ADDRESSING
The McG Figure 2-16 Addresses in TCP/IP
The McG Figure 2-17 RelationshipofLayers andaddressesin
Physical Address Also called link address, the address of a defined by its LAN or WAN Ethernet: 6 byte LocalTalk: 1 byte Physical address can be either Unicast address Multicast address Broadcast address
The McG Example 1 Figure 2.18 shows an example of p addresses.
The McG Figure 2-18 Physical Addresses
The McG Example 2 Most local area networks use a bytes) physical address writte hexadecimal digits, with every separated by a hyphen as shown be 07-01-02-01-2C-4B A 6-byte (12 hexadecimal digits) physi
Internet Address Provide universal communication servi are independent of underlying physical Different networks can have different addr A universal addressing system is thus need Internet address can also be either in un multicast and broadcast 4 bytes long in IPv4
The McG Example 3 Next slide shows an example of In addresses. Network address A and physical address send data to => Network address P and p address 95 IP address does not change along the trip However, physical address changes from network to network
The McG Figure 2-19 IP Addresses
The McG Example 4 As we will see in Chapter 4, a address (in IPv4) is 32 bits normally written as four decima with each number representing 1 numbers are separated by a dot. B example of such an address. 132.24.75.9
Port Address A label assigns to a process 16 bits long
The McG Example 5 Next slide shows an example o layer communication. Process with port address j send data to process with port address k
The McG Figure 2-20 Port Addresses
The McG Example 6 As we will see in Chapters 11 and address is a 16-bit address repre one decimal number as shown belo 753 A 16-bit port a
The McG 2.5 TCP/IP VERSIONS
Version Version 4 What we current used Version 5 Only a proposal Based on the OSI model Version 6 Also called IPng (IP next generation)
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