Network Theory 1 Flashcards
List four network components
Device
Physical media
Network adapter
Network operating systems
A group of computers connected together to communicate and share resources is
A computer network
Types of network devices
Computers Printers Servers Fax machines Switches Routers
Describe network physical media
Media that connects devices to a network and transmits data between devices. Such as Ethernet cable, fiber optic cable, coaxial cables, copper cable.
What is a network adapter
Hardware that translate data between the network and a device
Ex. NIC
What is a network operating system
Software that controls network traffic and access to common network resources.
Another name for a node
Workstation or client
What is a node
Any device that can connect to a network and generate, process or transfer data. Communicates with other devices through its address.
Two types of nodes
End points. Nodes that function as a source or destination for data transfer.
Redistribution points. Nodes that transfer data. Like switches or routers.
A very high speed transmission path that carries the majority of network data.
A network backbone
Back bone cabling connects these two devices on a network
Switches and routers connect.
Network back bones can connect either ______ or
______
Small networks into a larger structure or server nodes to a network.
Name the types of network backbones
Serial
Parallel
Collapsed
Distributed / Hierarchical
Consists of multiple switches connected by one backbone cable. Not scaled for enterprise wide use
Serial network backbone
Consists of multiple switches connected serially to hubs or router. Easily expanded without significant cost impact.
Distributed / hierarchical network backbone
Uses a router or switch as the nexus for several subnetworks. router or switch must have multi processors to bear frequently high level of network traffic.
Collapsed network backbone
Uses a central router or switch. Suits enterprise wide applications
Parallel network backbone
What is a server
A network computer that shares resources with and responds to requests from other devices on the network.
What do servers provide
Provide centralized access and storage for resources
A network computer they utilizes the resources of other network computers
A client
What does a client computer comprise of
Has its own processor, memory storage, and can maintain its own resources and perform its own processing
T/F any computer on the network can function as a client
True
Ocular and widely deployed operating system on client computers
Microsoft Windows 7
A self sufficient computer they acts as both a server and a client to other computers on a network
Peer computer
Peer computing most often used in….?
Most often used in smaller networks with no dedicated central server.
A powerful centralized computer system that performs data storage and processing tasks on behalf of clients and other network devices
A host computer
A specialized device in a host based network they transmits data entered by a user to a host for processing and displays the results
A terminal
What is a dumb terminal
Terminals with no processor or memory of their own just keyboard and monitor only
Names of network categories and coverage areas
LAN local area network WAN wide area network MAN metropolis area network CAN campus area network PAN personal area network
self contained network that spans a small area. All nodes are directly connected with cables or short range wireless devices.
LAN local area network
List LAN technologies
Ethernet. Most common
Token ring
Token bus
FDDI Fiber Distributed Data Interface
Networks that span a large area. Often across multiple geographical locations
WAN
Two types of WANs
Private. Built by corporations
Public. The Internet
Network that connects two or three computers with cables and is most often seen in a SOHO
PAN
A variation of Personal Area Network that connects wireless devices but not through a WAP (wireless access point). Infrared and Bluetooth used to connect devices
WPAN
Wireless PAN
Widely used for sending email, transferring files and carrying out online commercial transactions. Is the
Largest global WAN
The Internet
ICANN stand for what and coordinates what in the Internet
Internet Corporation for Assigned Names & Numbers.
Coordinates the assignments of unique identification in the Internet.
ISOC Stands for and oversees what
Internet Society coordinates and oversees standards and practices for the Internet
Private network that uses Internet protocols and services to share a company’s information with its employees. Contains information that is segregated from the Internet for confidentiality and security reasons.
The intranet
What is an extranet
A private network that grants controlled access to users such as vendors, suppliers and clients outside of the network to access resources on the network.
An enterprise network includes
Elements of both local and wide area networks
Application layer
Enables applications to access a network and its resources
Packets called data
Presentation layer
Translates data so it can be moved on the network
Session layers
Establishes, maintains, and terminates connections between network devices.
Transport layer
Ensures reliable data transmission by decreasing the packet size. Data referred to as segments
Network layer
Addresses and delivers packets called datagrams across a network
Internet layer
Datalink layer
Ensures reliable data transmission by error detection. Divides the data received from the network layer into frames that are capable of being transmitted by the physical layer
Physical layer
Moves bits of data on and off the cabling media.
Network model description
A design specification for how the nodes on a network are to interact and communicate.
The three primary network models
Centralized / Hierarchical
Client / Server
Peer to peer
What is a segment
A physical subdivision of a network that links devices or serves as a connection between two nodes
A segment is bounded by
Switches and routers giving all nodes attached common access to that part of the network
What is a centralized network
A computer network where a central host computer controls all network communication and performs data processing and storage on behalf of clients
How do users on a centralized networks connect
Users connect to the host via dedicated terminals or terminal emulators
A client / server network
A network in which servers provide resources to clients
A peer to peer network
A network in which resource sharing, processing, and communications control are completely decentralized. Each individual workstation authenticates its users
Commonly referred to as a workgroup
Describe a mixed mode network
A network that incorporates more than one of the three standard network models
Examples of mixed mode networks
A client server network combined with a centralized mainframe or a workgroup created to share local resources within a client/server network
Name the physical network topologies
Physical bus, physical star, physical ring, physical tree, physical mesh, and hybrid
What is a topology
A network specification that determines the overall layout, signaling, and data flow patterns
Topologies can be either of two things
Physical. The physical wiring layout or shape
Logical. The paths through which data moves.
Point to point connections
A direct connection between two nodes on a network
An example of point to point connections
Connecting one hosts NIC directly to another hosts NIC with a cat 5 crossover cable is an example of what
Explain multi point connections
Connections between multiple nodes. Each connection had more than two end points. Signal transmission is not private. All devices that share the medium can detect the signal but do not receive it unless they are the recipient.
Example of multi point connections
The most common way to physically connect s network. Physical bus & star networks are examples
What are radiated connections and give an example
Also called a broadcast connection. Is a wireless point to point or multi point connection between devices. Ex. Wireless LAN, Infrared & wifi networks.
Explain wi-if
Wireless radio communications following IEEE 892.11. Most common choice for ordinary wireless LAN connectivity. Doesn’t need line of sight to the access point.
What is a physical bus topology
A network topology where the nodes are arranged in a linear format. Must install terminators at the ends of the cables to prevent signal loss from reflection
What are some disadvantages of Bus topology
Unreliable. A break in the network cable cause the entire bus to fail
Cannot support multiple pairs of terminators at the same time
Transmits data slower because only two nodes vs. communicate at any time
Explain the physical star topology
A network topology that uses a central connectivity device such as a switch to connect each node
Each node sends data to the switch and then forwards data to the appropriate destination node or passes it through to all attached nodes like a hub
Advantages and disadvantages of star topologies
Reliable and easy to maintain
Single failed node does not bring down the whole network
If the central connectivity device (switch) fails the entire network fails
Examples of star topologies
Common in client/server networks
A host based computing system are classic examples of
Describe physical ring topologies
A network topology where each node is connected to the two nearest nodes. The upstream and downstream neighbors flow of data is unidirectional to avoid collisions
No central connecting device to control network traffic
Nodes in the network connect to form a circle
Each node handles all data packets that pass through it
Advantages and disadvantages of physical ring topologies
Data moves in one direction through each node that scans data packets, accepts packets destined for it and forwards packets destined for another node.
Each node acts as a repeater and boosts the signal when it transmits the data packet. Potentially unreliable as the failure of a single node can bring down the entire network
A variant of the ring topology is the dual ring topology which
Allows the use of two rings with each ring carrying data in opposite directions. Is faster as data can be sent through the shortest path between a sender and receiver. More reliable be excuse if breakage in ring it auto reconfigured to a single ring data flow. Reduces down time on the network
Explain physical mesh topology
A network topology where each node is directly connected to every other node. Allows each node to communicate with multiple nodes at same time. No congestion and data travels very fast
Advantages and disadvantages of mesh topology
No node can be isolated from the network making it extremely reliable.
Difficult to implement and maintain because of the number of connections increase exponentially with the number of nodes. Provides reliable communication between independent networks
Explain the partial mesh topology
A variation on the mesh topology. Only a few nodes have direct links with other nodes
Commonly used in subnetworks of large networks where the number of users is low
Advantages and disadvantages of partial mesh topology
Less complex
Less expensive and contains less redundancy then full mesh
Describe the physical tree topology
A network topology where a central or root node is hierarchically connected to one or more second level nodes one level lower in the hierarchy. The root node has a point to point link with each d the second level nodes while each of the second level nodes is connected to one or more throw level nodes
What is a hybrid topology
Any topology that exhibits the characteristics of more than one standard topology. Complex to maintain because of the wide range of technologies
List three common hybrid topologies
Star-bus. Connects several star networks to a network backbone in a buss layout. Links central nodes of the star networks using a common bus
Star of stars. Connects the central nodes of two or more star networks with a new common node. Data transfer routed through the common node
Star-ring. Connects the central node of multiple star networks in a ring. The data flow between different subnetworks is through this ring
Logical network topologies provide what information
Provides data transmission path between a sender and receiver and the different places in which this path converges or diverges
Describe the logical bus topology
A network topology In which nodes receive the data transmitted all at the same time regardless Of the physical wiring layout of the network
In a logical bus with a physical star topology
Nodes connect to a central switch and resemble a star. Data flows in a single continuous stream from sending node to all other nodes through the shared switch. Only one node can transmit data at a time
The logical ring topology is
A network topology where each node receives data only from its upstream neighbor and retransmits data only to its downstream neighbors regardless of the physical layout of the network
A logical ring must be used with a physical ring topology like a star-ring
The logical star topology
Less common than logical ring or bus. All nodes wired onto the same bus cable, a central device polls each node to check if it needs to transmit data. Central device also controls now long a node has access to the cable. A multiplexer or mux manages individual signals and enables them to share the media.
