NetworkingSlide2_The OSI Model.
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NetworkingSlide2_The OSI Model. - Leaderboard
NetworkingSlide2_The OSI Model. - Details
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| 🇬🇧 | 🇬🇧 |
| What is a hub? | Multi-port repeater (4,6,8...ports), connects nodes in a BUS network; 1 Collision domain, 1 Broadcast domain. |
| Encapsulation of the Network Layer. | 1.) Protocol Data Unit: Packet. 2.) Accepts Segment from Layer 4/Transport Layer. 3.) Adds Network header. 4.) Process packet to layer 2/ Data Link Layer. |
| Function of the Data Link Layer. | A.) Provides hardware addressing of devices which identifies and locates nodes on network. b.) Provides framing and error detection. (not correction). c.) Provides logical topology. |
| Encapsulation of the Data Link Layer | 1.) Protocol Data Unit: Frame. 2.) Accepts packets from Layer 3/ Network Layer. 3.) Adds the Data Link header and trailer. 4.) Passes from Layer 1/ Physical Layer. |
| Function of the Physical Layer. | A.) Provides physical topology. b.) Moves bits between devices. c.) Represents bits sing state transitions of voltage (copper), light (fibre), or audio (wireless). |
| Encapsulation of the Physical Layer. | 1.) Protocol Data Unit: Bit 2.) Accepts frame from layer 2/ Data link layer. 3.) Passes bits to transmission Media. |
| Steps of Decapsulation (BOTTOM TO TOP) | 1.) Transmission media passes bits to physical. 2.) Physical passes frame to data link. 3.) Data link passes packet to network. 4.) Network passes segment to transport. 5.) Transport passes data to session. 6.) Session passes data to presentation. 7.) Presentation passes data to application. |
| What are the devices used at the Physical Layer? | NIC(Network Adapter/LAN Adapter). Cable. Repeater. Modem. Hub. |
| What does a repeater do? | Extends networks by amplifying the signal (2 ports). |
| What does a modem do? | Modulates/Demodulates between digital and analog. |
| Functions of the Network Layer. | A.) Provides logical addressing of hosts which identifies and locates their network. b.) Provides routing which transports data between networks. c.) Routers use routing tables to perform path determination. - Accept (receive) data destined for their network. - Forward (relay) data destined for known networks. - Drop (reject) data destined for unknown networks. |
| What devices are used at the Data Link Layer? | Switch. Bridge. |
| What is a Switch? | Connects nodes into a Star Network(LAN); Uses ASICs for Forward/Filter decisions; x Collision Domains (x = # of ports) and 1 Broadcast Domain |
| What is a Bridge? | Precursor to switches (used software for Foward/Filter decisions). |
| What devices are used at the Network Layer? | Router. Gateway. |
| What is a router? | Connects networks into an internetwork (WAN); x Collision Domains; x Broadcast Domain ( x = # of ports). |
| What is a gateway? | A device used to connect two different networks, especially a connection to the internet. |
| What is a firewall? | A network security system that monitors and controls incoming and outgoing network traffic based on predetermined security rules. |
| Encapsulation process of the Application Layer. | 1.) Protocol Data Unit: Data 2.) Accepts input from application. 3.) Passes Data to layer 6/Presentation Layer. |
| Background for the OSI model... | The International Organisation of Standards(ISO), developed an architectural model/blueprint for open communication. This allows interoperability through industry standardization and multi-vendor development. |
| Characteristics of OSI model. | Layered Architecture. Modularizes and simplifies development, design, implementation and support of components. Defines who does what, when and how. A REFERENCE MODEL NOT AN IMPLEMENTATION MODEL. |
| What are the 7 layers. | Application Presentation Session Transport Network Data Link Physical |
| List the Upper Layers | Application. Presentation. Session. |
| List the Lower Layers | Transport. Network. Data Link. Physical. |
| What are the Peer Layers? | Logically Layers communicate with their corresponding layers. eg. Application to Application and so on.... |
| What are service layers? | Physically, layers communicate with their lower levels. |
| What is Encapsulation? | Senders data wrapped with Protocol Data Units(PDUs) by each lower layer at header and occasionally at trailer. |
| Functions of the Application Layer. | Provides: a). A user interface.ie. access input, displays output. b). Services. eg. file, print, message, wed, database, application. c). Communication protocols for applications. eg.... - HTTP for Edge/Firefox. - SMTP/IMAP/POP for Outlook/Thunderbird. - FTP for File Explorer/Filezilla. Uses application process/interfaces/APIs |
| Define Protocol. | System of rules allowing two or more nodes to communicate by transmitting and receiving data. |
| Functions of the Presentation Layer. | A.) Presents Data b.) Translates and formats data.eg. - encoding/decoding. - encrypting/ decrypting. - compressing/ decompressing. |
| Encapsulation process of the Presentation Layer. | 1.) Protocol Data Unit:Data 2.) Accept data from Layer 7/Application Layer 3.) Encodes, Encrypts and/or Compresses Data 4.) Passes data to layer 5/ Session Layer |
| Function of the Session Layer. | A.) Provides dialog control. b.) Keeps different application data separate. c.) Set up, manage or tear down session. d.) Organizes communication as: - Simplex (unidirectional). - Half Duplex (bidirectional asynchronous). - Full Duplex (bidirectional synchronous). |
| Encapsulation of the Session Layer. | 1.) Protocol Data Unit: Data. 2.) Accepts Data from Layers 6/ Presentation Layer. 3.) Passes Data to Layer 4/ Transport Layer. |
| Function of Transport Layers. | A.) Provides end to end connection by establishing logical connection between the hosts. b.) Segments data and delivers through data streams. c.) Provides two types of delivery: - Reliable (connection-oriented) - Unreliable (connection-less) |
| Encapsulation of Transport Layer. | 1.) Protocol Data Unit: Segment. 2.) Accepts Data from layer 5/ Session Layer. 3.) Adds Transport Header. 4.) Passes segment to layer 3/ Network Layer. |
| What is Connection-Oriented? | Sender creates a virtual circuit with receiver using a 'Three way Handshake'. (SYN, SYN/ACK, ACK). |
| When is windowing used? | To specify the number of segments after which acknowledgement is sent. |