4. 1978 to define a unifying standard for the architecture of networking systems International Telegraph and Telephone Consultative Committee and International Organization for Standardization (ISO) Officially rolled out by ISO as Open Systems Interconnection model by 1984. OSI Layers
5. OSI Layers 7 Layers: 7 - Application 6 - Presentation 5 - Session 4 - Transport 3 - Network 2 - Data-Link 1 - Physical “All PeopleSeem To Need Data Processing”
6. Each layer defines networking tasks Each layer communicates with the layers above and below it Layer 7 provides services for programs to gain access to the network Layers 1 & 2 define the network’s physical media and related tasks OSI
7. Application Layer ( Layer 7) Provides an entrance point for programs (e.g. web browsers, e-mail system) to gain network services Represent application programming interfaces (APIs) that developers can use to perform network functions when building applications OSI
8. Presentation (Layer 6) Translates data between computing systems on a network Performs: – data encryption – data compression – data conversion OSI
9. Session (Layer 5) Enables two application to create a persisten communication connections. Ensures that both sender and receiver are ready to communicate OSI
10. Transport (Layer 4) Ensures packets are delivered in order in which they are sent without loss or duplication. On the sending side, this layer is responsible for braking down larger messages into smaller packets for transmission On the receiving end, this layer is responsible for reassembling the packets into a single message to pass up to the upper layer OSI
11. Network (Layer 3) Determines the physical path of the data to be transmitted based on the network conditions, priority of server and other factors. The only layer that uses logical networking and can move packets between different networks. OSI
12. Data-link (Layer 2) Provides error free transfer of data frames from one computer to another over the physical layer. The Media Access Control (MAC) address of the network card exists at this layer that is added to the packet to create a frame. OSI
13. Physical Layer (Layer 1) Establishes the physical interface and mechanisms for placing a raw stream of data bits on the network cabling. OSI
15. TCP/IP Protocol Suite Is an industry standard suite of protocols that provides communication in a heterogeneous environment. Only has four layers: Application Transport Internet Network Interface OSI
19. Hubs – operate at the physical layer of the OSI model. - Can only perform tasks with the electrical signal on the network - regenerate 1s and 0s on network cabling - unable to make decisions about where the regenerated signal should be sent. - synonymous to a “Repeater” - sometimes called as a “Multiport Repeater” Network Terms
20. Bridge - is a network device that are able to control network traffic based on MAC addresses. Switches - has the same functionality of a bridge - creates a table that lists port location of each computer and direct packets to the destination computer. Network Terms
21. Routers - operate at the network layer of the OSI model. - moves packets from one logical networks to another Gateway - is a device that converts one protocol to another. - can operate at any layer of the OSI Model, depending on which protocol is being converted. (e.g. SNA gateway) Network Terms
22. HTTP – Hypertext Transfer Protocol (80) - specifies the client/server interaction processes between web browsers and servers FTP – File Transfer Protocol (21) - Performs file transfer and basic file management task on remote computers Network Terms
23. SMTP – Simple Mail Transfer Protocol (25) - carries email messages between servers and from client to servers DNS – Domain Name System (53) - Resolves internet host names to IP addresses for network communications. Network Terms
24. POP3 – Post Office Protocol Version 3 (110) - used by mail clients for reading emails SNMP – Simple Network Management Protocol (161) - enables to collect information about network devices such as hubs, routers and bridge. Network Terms
25. TCP – Transmission Control Protocol - provides connection-oriented reliable communications for applications UDP – User Datagram Protocol - provides connectionless and unreliable communication. Network Terms
26. IP – Internet Protocols - addresses and routes packets between hosts and networks. ARP – Address Resolution Protocol. - obtains hardware address of hosts located on the same physical network Network Terms
27. IGMP – Internet Group Management Protocol - manages host membership in IP multicast groups ICMP – Internet Control Message Protocol - Sends messages and reports errors regarding the delivery of a packets. Network Terms
29. Subnet Mask - defines the part of an IP address that is the network ID and the part of an IP address that is the host id. - composed of four octets, similar to an IP address Subnet Mask
