Team Members: Bhavya K Meera B CPooja PSushma Mallesh
Agenda1. Introduction2. Description of the OSI model3. Addressing4. Working/analogy5. Demonstration6. Conclusion
Introduction1. Topic - Protocol stack and addressing2. Network Models - OSI model - Internet model3. Protocol4. Protocol Stack5. OSI model
OSI Model 1. It is an abstract description 2. Has 7 layers 3. Each layer provides services to the layer above it and receives services from the layer below it.
PHYSICAL LAYER It is the first layer of the protocol stack. Data at this layer is in the form of bits (0s and 1s). Co-ordinates the functions required to carry the bit stream over a physical medium. It defines the relationship between a device and a physical medium. Some of the protocols which function at this layer include ISDN, ATM, X.21, RS-232.
Functions : Defines the physical characteristics of the interfaces and the medium. Modulation Data rate Line configuration Transmission mode Physical topology Contention resolution
Integrated Services Digital Network (ISDN) : ISDN in concept is the integration of both analog or voice data together with digital data over the same network. It allows the transmission of voice, data, video and graphics at very high speeds simultaneously over communication lines. ISDN uses two channels for communication namely 1. B-channel (Bearer channel) 2. D-channel (Data channel)
Asynchronous Transfer Mode (ATM) : ATM is a technological system developed for both LAN and WAN and designed to handle data as well as video and voice traffic, all at the same time. ATM organizes data into fixed 53-bytes cell units and transmit them over a physical medium. Each cell has 5 bytes header and 48 bytes information field. ATM creates a fixed channel, or route, between two points whenever data transfer begins.
DATA LINK LAYER It is the second layer of the protocol stack. Data at this layer is in the form of frames. It translates the logical information into the actual electrical pulses that travel over the physical layer. It is composed of two sub layers 1. Logical Link Control (LLC) 2. Media Access Control (MAC) Some of the protocols which function at this layer include IEEE 802.5 Token Ring, PPP, ISL, HDLC.
Functions : Framing Frame sequencing Physical addressing Error notification and error control Flow control Access control
Token Ring Protocol: It is a LAN protocol defined in the IEEE 802.5. All the workstations are connected in a ring topology. A bit or token-passing scheme is used in order to prevent the collision of data between two computers that want to send messages at the same time.
Point-to-Point Protocol (PPP) : This is a full-duplex protocol that can be used on various physical media. It is meant for communication between two computers using a serial interface. Ex: a personal computer connected by phone line to a server It offers error detection mechanism.
NETWORK LAYER It is the third layer of the protocol stack. Data at this layer is in the form of packets. This layer is mainly concerned with source to destination delivery of data packets via multiple networks. Routers operate at this layer. Some of the protocols which function at this layer are ARP, RIP, IP, ICMP, IGMP.
Routing Information Protocol (RIP) : RIP is a distance-vector protocol that uses hop (node) count as its metric. This protocol is widely used for traffic in the global internet. It sends routing-update messages at regular intervals and when the network topology changes.
Address Resolution Protocol (ARP) : ARP is a network protocol which maps network layer protocol address to a data link hardware address. It is used when a host in a Ethernet network has to communicate with another host. ARP resolves IP address to corresponding Ethernet address.
Transport layer It is the fourth layer of the Open Systems Interconnection (OSI) model. It is responsible for process-to-process delivery of the entire message. It encapsulates application data blocks into data units (data gram/segments). Various protocols under this layer include TCP, UDP, ECN, DCCP and so on.
Functions of transport layer: Statistical multiplexing of data. Connection oriented communication. End-to-end reliable connection. Flow control.
Protocols of Transport layer: 1. Explicit Congestion Notification (ECN) Delivers distinguished protocol segments from the source host to the destination host solely based on their addresses. Allows end-to-end notification of network congestion without dropping packets.
2. Datagram Congestion Control Protocol (DCCP) Provides reliable connection setup. Sends acknowledgements to sender about the segments sent. Useful for applications with timing constraints on the delivery of data.
Session layer It is the fifth layer of the Open Systems Interconnection (OSI) model. It establishes, maintains and synchronizes interaction among communicating systems. Used in application environments that make use of remote procedure calls (RPC). Various protocols under this layer include PAP, PPTP, RPC, ZIP and so on.
Functions of Session layer: Dialog control. Authentication/permission. Synchronization.
Protocols of Session layer: Password Authentication Protocol (PAP) Authenticates a user to a network access server. Server sends acknowledgement based on credentials. It is used by point to point protocol.
Point-to-Point Tunneling Protocol (PPTP) Implements virtual private networks. It does not provide confidentiality and encryption.
Presentation layer It is the sixth layer of the Open Systems Interconnection (OSI) model. It is concerned with the syntax and semantics of the information exchanged between two systems. It is composed of two sub layers: CASE (Common Application Service Element) SASE (Specific Application Service Element) Various protocols of this layer include AFP, NCP, RDP, XDR.
Functions of Presentation layer: Translation Encryption Compression
Protocols of presentation layer: Remote Desktop Protocol (RDP) It is a proprietary protocol developed by Microsoft. It is also a communications protocol. Provides a user with a graphical interface to another computer.
NetWare Core Protocol (NCP) It is usually associated with the NetWare operating systems. It is used to access files, directories and clock synchronization.
Application Layer: Enables the application to access the network. Services provided by the application layer includes: Network Virtual Terminal: A network virtual terminal is a software version of a physical terminal and allows the user to log on to a remote host. File transfer, access and management (FTAM): This application allows user to Access, Retrieve and Manage files in a remote computer. Mail services: Facilitates email forwarding and storage. Directory Services: This application provides distributed database sources and access for global information about various objects and services. Examples for protocols in this layer: HTTP(Hyper Text Transfer Protocol), FTP(File transfer Protocol), BOOTP(Bootstrap protocol), SSH(Secure Shell), SLP(Service Location Protocol) etc.
Hypertext Transfer Protocol (HTTP): It is an application-level protocol for distributed, collaborative, hypermedia information systems. Its use for retrieving inter-linked resources led to the establishment of the World Wide Web. User Agent: Using a web browser, spider, or other end-user tool Origin Server: Which stores or creates resources such as HTML files and images Implementation: Implemented on top of any other protocol on the Internet, or on other networks Bootstrap Protocol, or BOOTP: It is a network protocol used by a network client to obtain an IP address from a configuration server BOOTP has also been used for Unix-like diskless workstations to obtain the network location of their boot image in addition to an IP address, and also by enterprises to roll out a pre-configured client (e.g., Windows) installation to newly installed PCs Bootstrapping: Use of another device on the network to become an active IP hosts.
File Transfer Protocol (FTP): is the simplest way to exchange files between computers on the Internet Architecture: It is a standard network protocol used to exchange and manipulate files over an Internet Protocol computer network. It built on a client-server architecture and it utilizes separate control and data connections between the client and server applications. FTP can be used with user-based password authentication or with anonymous user access. Use: FTP is commonly used to transfer Web page files from their creator to the computer that acts as their server for everyone on the Internet, used to download programs and other files to your computer from other servers. You can also update (delete, rename, move, and copy) files at a server.
Physical Address (MAC Address): Usually encodes the manufacturer’s registered identification number Formulating a MAC Address: MAC -48 EUI -48 EUI -64 Finding MAC Address for WINDOWS: Start Menu – Run – Type ‘cmd’- Enter – Type ‘Ipconfig /all’(If WINDOWS XP type ‘getmac’) Finding MAC Address for LINUX: Use the ‘ifconfig’ command - /bin or /sbin directories.
IP Address: In a computer network utilizing the Internet Protocol for communication between its nodes Versions: IPV4: Uses 32-bit (4-byte) addresses, limits the address space to 4,294,967,296 (232) possible unique addresses. Each part represents 8bits of the address, hence called Octet. It may be presented in hexadecimal, octal, or binary representations Example of an IPv4 address: 184.108.40.206 IPV6: Due to rapid exhaustion of IPV4 address space, prompted the IETF to expand Internet’s addressing capability. Increased address size to 16 Octets. Opportunity to separate the addressing infrastructure of a Network segment. No need to have a complex address conservation methods as used in classless inter-domain routing (CIDR). Example of an IPv6 address: 2001:0db8:85a3:08d3:1319:8a2e:0370:7334
IP Address of WINDOWS based Operating System: Start – Run – Type “cmd” or “Command” – Press Enter/OK. An MS DOS window will open. You are now ready to send a command to your Computer. Type "netstat -n" – Press Enter List of all your active connections and IP numbers. You will see 4 fields with 4 columns with all the IP details of sites or the people whom you are connected. Type "netstat -nab" and you can see the programming details. Type Start – Run – cmd – Ipconfig, shows masked IP and IP.
IP Address of LINUX based Operating System Use the command “ifconfig”. Used at boot time to set up interfaces as necessary. It displays Ethernet IP address, Mac address, subnet mask and other information Type /sbin /ipconfig command to display IP address: $ /sbin/ifconfig
Differences between MAC and IP Address: MAC Type of a number for network devices like Assigned at the time hardware is manufactured Hardware address Hexadecimal string of numbers and letters IP Address: It uniquely identifies computers on the Internet, or on a local intranet As part of connection to a network. It is not fixed Software address It is assigned by the router every time it gets connected to the network
Apple Talk: Proprietary suite of protocols. The AppleTalk Link Access Protocol (ALAP) AppleTalk's address header Sockets Transport Layer AppleTalk names consist of three fields: (Object Name, Type Name and Zone Name. The Echo Protocol (EP) Specifications for ADSP (Apple Talk Data Stream Protocol) Apple Talk Session Protocol (ASP) Apple Talk Filing Protocol (AFP) – Specifications
Apple Talk Protocols: Apple Computers developed the AppleTalk protocol suite to communicate among Apple systems using the Local Talk interface. The Apple Talk Protocol suite includes the following protocols: AARP: AppleTalk Address Resolution Protocol DDP: Datagram Delivery Protocol RTMP: Routing Table Maintenance Protocol AEP: AppleTalk Echo Protocol ATP: AppleTalk Transaction Protocol NBP: Name-Binding Protocol ZIP: Zone Information Protocol ASP: AppleTalk Session Protocol PAP: Printer Access Protocol ADSP: AppleTalk Data Stream Protocol AFP: AppleTalk Filing Protocol
How to check IP Address on an Apple System: Apple Computer running Mac OSX - Apple logo on the top left of the screen - System Preferences - Internet and Network - Network -– Drop down menu. In case of Ethernet – Select "Built In Ethernet" – if Wireless (select “Airport). Select "TCP/IP" on the "Network" screen. Your IP Address will be shown here.
ANOLOGY Sender’s end:
Tools1. Ethereal2. Multiple Interface Watcher
Conclusion1. Basic concepts2. Description of OSI model3. Addressing4. Analogy5. Demonstration of the tools