Review of Important Networking Concepts Introductory material. This module use

Review of Important Networking Concepts Introductory material. This module use www.phwiki.com

Review of Important Networking Concepts Introductory material. This module use

Carnes, Jennifer, Managing Editor has reference to this Academic Journal, PHwiki organized this Journal Review of Important Networking Concepts Introductory material. This module uses the example from the previous module to review important networking concepts: protocol architecture, protocol layers, encapsulation, demultiplexing, network abstractions. Networking Concepts Protocol Architecture Protocol Layers Encapsulation Network Abstractions Sending a packet from Argon to Neon

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Communications Architecture The complexity of the communication task is reduced by using multiple protocol layers: Each protocol is implemented independently Each protocol is responsible as long as a specific subtask Protocols are grouped in a hierarchy A structured set of protocols is called a communications architecture or protocol suite TCP/IP Protocol Suite The TCP/IP protocol suite is the protocol architecture of the Internet The TCP/IP suite has four layers: Application, Transport, Network, in addition to Data Link Layer End systems (hosts) implement all four layers. Gateways (Routers) only have the bottom two layers. Functions of the Layers Data Link Layer: Service: Reliable transfer of frames over a link Media Access Control on a LAN Functions: Framing, media access control, error checking Network Layer: Service: Move packets from source host to destination host Functions: Routing, addressing Transport Layer: Service: Delivery of data between hosts Functions: Connection establishment/termination, error control, flow control Application Layer: Service: Application specific (delivery of email, retrieval of HTML documents, reliable transfer of file) Functions: Application specific

TCP/IP Suite in addition to OSI Reference Model The TCP/IP protocol stack does not define the lower layers of a complete protocol stack Assignment of Protocols to Layers Layered Communications An entity of a particular layer can only communicate with: 1. a peer layer entity using a common protocol (Peer Protocol) 2. adjacent layers to provide services in addition to to receive services

Service Primitives N+1 Layer Entity N+1 Layer Entity N Layer Entity N Layer Entity Communication services are invoked via function calls. The functions are called service primitives Service Primitives Recall: A layer N+1 entity sees the lower layers only as a service provider Service Provider N+1 Layer Entity N+1 Layer Entity Service Access Points A service user accesses services of the service provider at Service Access Points (SAPs) A SAP has an address that uniquely identifies where the service can be accessed

Exchange of Data Assume a layer-N entity at A wants to send data to a layer-N peer entity to B The unit of data sent between peer entities is called a Protocol Data Unit (PDU) For now, let us think of a PDU as a single packet What actually happens: Layer N passes the PDU to one of A’s SAPs at layer N-1 The layer N-1 entity (at A) then constructs its own PDU which it sends to the layer N-1 entity at B Note: PDU at layer N-1 = Header + PDU at layer N A B Exchange of Data A B Layers in the Example

Layers in the Example Layers in addition to Services Service provided by TCP to HTTP: reliable transmission of data over a logical connection Service provided by IP to TCP: unreliable transmission of IP datagrams across an IP network Service provided by Ethernet to IP: transmission of a frame across an Ethernet segment Other services: DNS: translation between domain names in addition to IP addresses ARP: Translation between IP addresses in addition to MAC addresses Encapsulation in addition to Demultiplexing As data is moving down the protocol stack, each protocol is adding layer-specific control in as long as mation

Encapsulation in addition to Demultiplexing in our Example Let us look in detail at the Ethernet frame between Argon in addition to the Router, which contains the TCP connection request to Neon. This is the frame in hexadecimal notation. 00e0 f923 a820 00a0 2471 e444 0800 4500 002c 9d08 4000 8006 8bff 808f 8990 808f 4715 065b 0050 0009 465b 0000 0000 6002 2000 598e 0000 0204 05b4 Encapsulation in addition to Demultiplexing Encapsulation in addition to Demultiplexing: Ethernet Header

Encapsulation in addition to Demultiplexing: IP Header Encapsulation in addition to Demultiplexing: IP Header Encapsulation in addition to Demultiplexing: TCP Header Option: maximum segment size

Carnes, Jennifer San Manuel Miner, The Managing Editor www.phwiki.com

Encapsulation in addition to Demultiplexing: TCP Header Encapsulation in addition to Demultiplexing: Application data Different Views of Networking Different Layers of the protocol stack have a different view of the network. This is HTTP’s in addition to TCP’s view of the network. (Application in addition to Transport layers) Argon Neon

Network View of IP Protocol Network View of Ethernet Ethernet’s view of the network

Carnes, Jennifer Managing Editor

Carnes, Jennifer is from United States and they belong to San Manuel Miner, The and they are from  San Manuel, United States got related to this Particular Journal. and Carnes, Jennifer deal with the subjects like Local News

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