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Network Architecture & Standards. Unit 2, Chapter 3 & 4 Why Standards?. Objectives. Explain the importance of network architecture. Identify 802.x LAN standards as described by IEEE. - PowerPoint PPT Presentation
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Network Architecture & Network Architecture & StandardsStandards
Unit 2, Chapter 3 & 4Why Standards?
Objectives
Explain the importance of network architecture.Identify 802.x LAN standards as described by IEEE.Match the seven layers of the OSI model to network equipment and their role in cross-platform interoperabilityDescribe the function of a network access PDU.Differentiate between connectionless and connection-oriented protocols.Describe selected basic functions of a protocol.
Architectures & Standards
Networks Architecture – Principles in the design and implementation of a network– Reduction in complexity, common solution– Isolate network complexities from users– Ability to connect different types of devices– Management of the network
Communications Standards – Rules to establish compatibility among similar productsView Points– Vendor – IBM, DEC, Microsoft, Novell– Industry – IEEE, ANSI, NIST
Vendor Technologies
Systems Network Architecture (SNA)Digital Network Architecture (DNA)Burroughs Network Architecture (BNA)Novell (IPX/SPX - XNS)Banyan Virtual Integrated Network Services(Vines - XNS)
International Telecommunications Union
Most important telecommunications standards setting bodyV. Standards – Connection of digital equipment to analog PSTN linesX. Standards – Connection of digital equipment to digital linesDevelopment of the Open System Interconnect Model with International Standards Organization– Basis for interconnecting dissimilar systems
OSI Model LayersApplication Layer (7)
– Where user works with at a terminal Presentation Layer (6)
– Code conversion & data reformatting from application - networkSession Layer (5)
– Establishing the communications rules(pacing, accounting)– Turns communications on & off
Transport Layer (4)– Identifies the actual address of recipient of the message– Responsible for ensuring data is transmitted (retransmission)
Network Layer (3)– Routing message to recipient– Establishes, maintains and terminates communications
Data Link Layer (2)– Establishing link between 2 points & packing data, block transfers
Physical Layer (1)– Electrical components for the communication– http://www.reskit.net/MCTFAQS/The%20OSI%20Model%20as%20explained%20by%20Laura.htm
More OSI
X.25 standard for data transmission – Used in packet switching networks – 1st 3 OSI layers (physical, data link, network)
Encapsulation: process that surrounds the original data or requests with control characters for routing and error checking
Internet Architecture Principles
Multiplexing– Multiple Independent data streams on one physical
communication lineSurvivability– Message gets through no matter what
Service Generality– Useful for multiple purposes
Diverse Network Technologies– Accommodate previous network technologies
(Arpanet, Satellite-based networks….)
TCP/IP
Transmission Control Protocol / Internet ProtocolAdvanced Research Project Agency (ARPA)– Arpanet
TCP/IP = 4 or 5 layers of OSI Model
OSI –TCP/IP Models
OSI Model TCP/IP
L7 Application
Application
L6 Presentation
L5 Session
L5 Session
TransportL4 Transport
L3 Network
InternetL2 Data Link
L2 Data linkData link (Network
interface)
L1 Physical (Hardware)
Protocol Stack
Protocol – Set of rules used for communication between 2 points on a networkWhat does the transportation header contain? Pg 76
Protocol Functions
Encapsulation: control information (Where going? Is it right? Which protocols to use?)Fragmentation (Segmentation) & Re-assemblyError Control: using a check character to determine an error in the network access layerSynchronizationOrdered Deliver (Sequencing)AddressingMultiplexingTransmission Services
Other Protocol Functions
Connection Control – – Connection Oriented – TCP
• Established and maintained before successful transmission– Connectionless – UDP
• Communication without establishing a connection (PING)
Ordered Delivery – – Important to maintain order of packets – connection
orientedFlow Control – Control data rate sent by transmitter
Other Protocol Functions
Error Control – Error Detection & Error Correction– Check Sum, retransmit– Sequence Numbering, retransmit
Addressing – – Network, Application – Layer dependent
Transmission Services– Message priority
Protocols
Transport– Ensure messages are exchanged reliably– Arrival of all data at the destination– Presentation in the same order as sent– Virtual Circuit – Route between sender & Receiver
Data Link– Communication Startup– Character Identification– PDU identification, how to process– Error Control, what scheme to use– Termination
Review Questions
1. Communications standards define what needs to be done but not how to do it.a. Trueb. False
Review Questions
2. Which field in a header tells the destination of a message or PDU?a. addressb. flagc. byted. none of the above
Review Questions
3. It is more difficult for a machine to process a code if all of the bits are of the same duration.a. Trueb. False
Review Questions
4. The combination of the first three layers of the OSI model is the standard for the ______________.a. X.25 standard for data transmissionb. V. standardc. consolidated transmission standardd. Consolidated Transmission Protocol
Review Questions
5. When data or a request from one layer is passed down to another layer, the data are surrounded by control characters or other information. This process is called _____________.a. enclosureb. encapsulationc. isolationd. permutation
Review Questions
6. The process of reassembling a message a TCP/IP packetized stream of data that has been fragmented is called __________.a. reassemblyb. reconstitutionc. segmentationd. togetherness
Review Questions
7. It is much easier for a machine to process a code if ____________________.a. it is a true binary codeb. all of the characters have the same number of bitsc. all of the bits are the same durationd. all of the above
Review Questions
8. An example of a communications medium is ____________.a. a telephoneb. a personal computerc. a teleprinterd. a copper wire
Review Questions
9. The PSTN is an example of a _____________.a. mesh networkb. star networkc. bus networkd. ring network
Review Questions
10. The OSI layer responsible for establishing the communication rules between certain machines or applications is the ______________.a. network layerb. transport layerc. session layerd. data link layer