1
|
- Networking Standards
- and the OSI Model
|
2
|
- Identify organizations that set standards for networking
- Explain the layers of OSI Model
- Describe specific networking services within each layer of OSI Model
|
3
|
- Explain how two systems communicate through OSI Model
- Discuss the structure and purpose of data frames
- Describe the two types of addressing contained in OSI Model
|
4
|
- Documented agreements containing technical specifications or other
precise criteria that stipulate how a particular product or service
should be designed or performed
- Many different industries use standards to ensure that products,
processes, and services suit their purpose
|
5
|
- American National Standards Institute (ANSI)
- Comprised of industry and government representatives
- Determine standards for electronics industry in addition to other
fields
- Electronic Industries Alliance (EIA)
- Trade organization composed of representatives from electronics
manufacturing firms across United States
- Sets standards for members, helps write ANSI standards, and lobbies for
legislation favorable to the industry
|
6
|
- Institute of Electrical and Electronic Engineers (IEEE)
- International society of engineering professionals
- Promotes development and education in electrical engineering and
computer science fields
- International Organization for Standardization (ISO)
- Collection of standards organizations
- Goal is to establish international technological standards to
facilitate global exchange of information and barrier-free trade
|
7
|
- International Telecommunication Union (ITU)
- Formerly called Consultative Committee on International Telegraph and
Telephony (CCITT)
- United Nations agency that regulates international telecommunications
- Assists developing countries
|
8
|
- Open Systems Interconnection (OSI) Model
- Model for understanding and developing computer-to-computer
communication
- Developed in the 1980s by ISO
- Divides network architecture into seven layers
- Network architect
- Professional involved in network design
|
9
|
|
10
|
- Physical layer
- First layer of OSI Model
- Contains physical networking media
- Data Link layer
- Second layer of OSI Model
- Primary function is to divide data it receives from Network layer into
distinct frames that can be transmitted by Physical layer
|
11
|
- Structured package for moving data
- Includes raw data (or payload) along with sender’s and receiver’s:
- Network addresses
- Error-checking and control information
|
12
|
- Third layer of OSI Model
- Translates network addresses into their physical counterparts
- Decides how to route data from sender to receiver
|
13
|
- Because Network layer handles routing, routers belong in Network layer
- To route means to direct data based on addressing, usage patterns, and
availability
- Network layer protocols also accomplish:
|
14
|
- Fourth layer of OSI Model
- Ensures that data are transferred between points reliably and without
errors
- Handles flow control
- Method of gauging appropriate rate of data transmission
|
15
|
- Sequencing
- Process of assigning a placeholder to each piece of a data block to
allowing receiving node’s Transport layer to reassemble data in correct
order
- Acknowledgement (ACK)
- Response generated in Transport layer
- Confirms to sender that its frame was received
|
16
|
- Fifth layer of OSI Model
- Establishes and maintains communication between two nodes on the network
- Session
- Refers to a connection for data exchange between two parties
- Term session is most often used in context of terminal and mainframe
communications
|
17
|
- Presentation layer
- Sixth layer of OSI Model
- Translates between application and network
- Application layer
- Seventh, or top, layer of OSI Model
- Provides interface to software enabling programs to use network devices
|
18
|
- Routine that allows a program to interact with the operating system
- Belongs to Application layer of OSI Model
- Microsoft Message Queueing (MSMQ)
- API used in network environment
- Stores messages sent between nodes in queues
- Forwards these messages to their destination
|
19
|
|
20
|
- Token
- Special control frame indicating to rest of network that a particular
node has right to transmit data
- Frame Check Sequence (FCS)
- Field in a frame responsible for ensuring that data carried by frame
arrives intact
|
21
|
|
22
|
|
23
|
- Ethernet
- Networking technology originally developed in 1970s by Xerox
- Four types of Ethernet technology are used on LANs today
- Each type is governed by a set of IEEE standards
|
24
|
- Token Ring
- Networking technology developed by IBM in the 1980s
- Relies upon direct links between nodes and a ring topology, using
tokens to allow nodes to transmit data
|
25
|
- 802.3 standard
- IEEE standard for Ethernet networking devices and data handling
|
26
|
- Preamble
- Marks beginning of entire frame
- Start of Frame Delimiter (SFD)
- Indicates beginning of addressing frame
- Destination Address
- Contains destination node address
|
27
|
- Source Address
- Contains address of originating node
- Length (LEN)
- Indicates length of packet
- Data
- Contains data, or segmented part of data, transmitted from originating
node
|
28
|
- Pad
- Used to increase size of the frame to its minimum size requirement of
46 bytes
- Frame Check Sequence (FCS)
- Provides an algorithm to determine whether data were correctly received
- Most commonly used algorithm is Cyclic Redundancy Check (CRC)
|
29
|
- 802.5 Standard
- IEEE standard for Token Ring networking devices and data handling
|
30
|
- Start Delimiter (SD)
- Signifies beginning of packet
- Access Control (AC)
- Contains information about priority of the frame
- Frame Control (FC)
|
31
|
- Destination Address
- Contains destination node address
- Source Address
- Contains address of originating node
- Data
- Contains data transmitted from originating node
|
32
|
- Frame Check Sequence (FCS)
- Used to check integrity of the frame
- End Delimiter (ED)
- Indicates end of the frame
- Frame Status (FS)
- Indicates whether destination node recognized and correctly copied the
frame
|
33
|
- Data Link layer address
- Also called MAC address, after Media Access Control (MAC) sublayer
- Number uniquely defining a network node
- Composed of Block ID and Device ID
- Manufacturer-hard codes the address on the NIC
|
34
|
- Network layer address
- Resides at Network level of OSI Model
- Follows hierarchical addressing scheme
- Can be assigned through operating system software
|
35
|
|
36
|
- To accommodate shared access for multiple network nodes, IEEE expanded
OSI Model by separating Data Link layer into two sublayers:
- Logical Link Control (LLC) sublayer
- Media Access Control (MAC) sublayer
|
37
|
- LLC
- Upper sublayer
- Provides common interface
- Supplies reliability and flow control services
- MAC
- Lower sublayer
- Appends physical address of destination computer onto the frame
|
38
|
|
39
|
- Standards are documented agreements containing technical specifications
or other precise criteria used as guidelines to ensure materials,
products, processes, and services suit their purpose
- Prominent standards organization include:
|
40
|
- OSI Model divides networking architecture into seven layers:
- Physical layer
- Data Link layer
- Network layer
- Transport layer
- Session layer
- Presentation layer
- Application layer
|
41
|
- A data request from a software program is received by Application layer
services and is transferred down through layers of OSI Model until it
reaches the Physical layer
- Data frames are small blocks of data with control, addressing, and
handling information attached to them
- Each node on a network can be identified by two types of addresses:
- Network layer address
- Data Link layer address
|
42
|
- In addition to frame types, IEEE networking specifications apply to
connectivity, networking media, error checking algorithms, encryption,
emerging technologies, and more
- ISO expanded OSI Model by separating the Data Link layer into sublayers:
|