Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Networks > Network > Flashcards

Network Flashcards

1
Q

What is a Computer Network?

A

A network is a group of devices that are able to communicate with one another and share data, files, programs, and operations.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Hardware

A

Is what physically connects the computers in the network together.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Software

A

The software is what enables us to use the hardware for communication and exchanging information.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Interoperable

A

This means that different types of computers, using different operating systems, can be connected, communicate with each other, and share information - as long as they follow the network protocols

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is a network?

A

. A network is a group of two or more devices
. Connected though an infrastructure
. A computer network is a system that connects two or more computing devices for transmitting and sharing information.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Star topology

A

Star topology is a network topology in which each network component is physically connected to a central node such as a router, hub or switch. In a star topology, the central hub acts like a server and the connecting nodes act like clients.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Bus topology

A

Bus topology is a type of network topology used in computer networking where all devices are connected to a single central cable or bus. In a bus topology, data is transmitted along the bus, and all devices on the network can see the data, but only the device for which the data is intended will process and respond to it.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Token Ring topology

A

Token Ring Topology is a network configuration where devices are physically connected in a circular or ring-like arrangement. In this topology, data is transmitted sequentially from one device to the next in a unidirectional or bidirectional manner, and network access is controlled by a token. Only the device in possession of the token is allowed to transmit data on the network, ensuring orderly and collision-free communication.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Mesh topology

A

Mesh topology is a type of network topology used in computer networking, where every device is interconnected with every other device in the network. This interconnectivity creates multiple redundant paths for data transmission, increasing network reliability and fault tolerance.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Partial mesh topology

A

Partial Mesh Topology is a type of network topology in which some, but not all, devices are interconnected with one another. In a partial mesh topology, not every node has a direct connection to every other node, as is the case in a full mesh topology. Instead, specific nodes are strategically connected to one another, typically for reasons of cost, efficiency, or practicality.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Star topology adv

A

Advantages of Star Topology
. It is very reliable – if one cable or device fails then all the others will still work
. It is high-performing as no data collisions can occur
. Less expensive because each device only need one I/O port and wishes to be connected with hub with one link.
. Easier to put in
. Robust in nature
. Easy fault detection because the link are often easily identified.
. No disruptions to the network when connecting or removing devices.
. Each device requires just one port i.e. to attach to the hub.
. If N devices are connected to every other in star, then the amount of cables required to attach them is N. So, it’s easy to line up.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Star topology dis

A

Disadvantages of Star Topology
. Requires more cable than a linear bus .
. If the connecting network device (network switch) fails, nodes attached are disabled and can’t participate in network communication.
. More expensive than linear bus topology due to the value of the connecting devices (network switches)
. If hub goes down everything goes down, none of the devices can work without hub.
. Hub requires more resources and regular maintenance because it’s the central system of star .
. Extra hardware is required (hubs or switches) which adds to cost
. Performance is predicated on the one concentrator i.e. hub.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Bus topology adv

A

Advantages:
. Allows relatively good rate of data transmission
. Simple to implement
. Very easy to connect a node to the backbone.
. Potentially requires less cable length than a Star topologyresulting in lower costs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Bus topology dis

A

Disadvantage:
. Does not cope with heavy traffic rates (coaxial cable)
. Prone to collisions when two nodes are transmitting at the same time.
. Difficult to administer/troubleshoot. E.G. a cable brake can disable the entire network; no redundancy.
. Limited cable length, number of stations limited by the length of the cable (backbone).
. Performance degrade as additional computers are added
. No longer a popular method for designing a network as the range is limited.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Token Ring topology adv

A

Advantage:
. All nodes on the network have an chance of transmitting data.
. It has good Quality of Service (Token)
. There are no collisions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Token Ring topology dis

A

Disadvantage:
. If one of the nodes/cables goes down then the whole network may go down.
. Tokens may get lost (corrupted (software)).
. Difficult to add and remove nodes to /from the ring
. No longer a popular method for designing a network as the design is limited in range.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Mesh topology adv

A

Advantage:
. Provides redundant paths between devices
. The network can be expanded without disruption to current users.
. If a node/cable fails traffic can be rerouted easily

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Mesh topology dis

A

Disadvantage:
. Requires more cable than the other LAN topologies.
. Complicated implementation.
. Large amounts of redundancy throughout the network

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Partial mesh topology adv

A

. Advantages over the full mesh topology
. Reduces the complexity by having less connections.
. All nodes are connected to more than one other but NOT all others nodes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Connection-oriented protocol

A

Connection establishment
Exchange information
Disconnect

TCP is an example of a connection-oriented protocol
Virtual circuits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Connectionless protocol

A

Less assurance of delivery
No connection established therefore no disconnection

IP is an example of a connectionless protocol
Datagrams

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Trade-offs between VC’s and Datagram’s

A

No call establishment or clearing is involved with datagram’s, though they are required for virtual circuits.
Datagram’s require complete addressing information to be sent with each packets; virtual circuits require only a “circuit ID”
Datagram’s are discarded if congestion occurs; virtual circuits must take more elaborate precautions

23
Q

TCP/IP

A

TCP/IP is a suite, or family, of protocols that govern the way data is transmitted across networks.
TCP/IP protocols work together to break the data into small pieces that can be efficiently handled by the network,
It communicates the destination of the data to the network,
Verifies/acknowledges the receipt of the data on the receiving end of the transmission,
Reconstructs the data in its original form.
Check that the data is not corrupt

24
Q

IP

A

Envelopes and addresses the dataEnables the network to read the envelope and forward the data to its destinationDefines how much data can fit in a single “envelope” (a packet)
It also contains the source address

25
Q

Quality of Service(QoS)

A

High Quality of Service
Low fixed delay
Limited packet loss
—————————————
Variable delay
Lost packets
Sequencing Problems

26
Q

Data Packet

A

A packet is a single unit, or “package”, of data that is sent across a network.
Data is broken into packets before it is sent across the Internet.
Examples of types of data that are sent across the Internet using packets include:
E-mail messages (SMPT, POP3)
Files, via File Transfer Protocol (FTP)
Web pages, via the hypertext transfer protocol (HTTP)

27
Q

TCP

A

Breaks data up into packets that the network can handle efficiently. Verifies that all the packets arrive at their destination “reassembles” the data in sequence

28
Q

Network Interface Cards

A

. Transmission is via a Network Interface Card (NIC) will reach every other NIC

. Each NIC will have a unique LAN address

29
Q

NIC unique address

A

Originally MAC-48 (802.X only) but now EUI-48 (broader remit)

48-bit globallyuniqueidentifier called a MAC Address (Media Access Control Address)

Written in Hexadecimal e.g. 00:60:8C:00:54:99

This is burned into its ROM chip.

The manufacturer assigns the MAC address

30
Q

Access and distribution rules for shared media LANs

A

Access rules for Ethernet hubs:
Listen before sending
Stop if multiple users start at the same time

Distribution rules for Ethernet hubs:
All traffic goes everywhere
one packet at a time

31
Q

Access and distribution rules for switched Ethernet LANs

A

Access rules for switched Ethernet:
Send whenever you want to
No Collisions

Distributed rules for switched Ethernet:
Traffic only goes where it needs to go
Multiple Ethernet frames can be flowing

32
Q

Switched Ethernet Characteristics

A

Automatically learns source address
Forwards selectively to the destination
Supports many ports per switch
Supports full duplex on dedicated ports

33
Q

Unicast (single Destination) addressing)

A

Specifies a single node on a network to transmit too

34
Q

Multicast (Multiple but not all destinations) addressing

A

Transmits packets to all nodes in a target group. Not all destinations

35
Q

Broadcast (All destinations) addressing

A

Transmits packets to ALL nodes on a network
Example: A client PC is sending a broadcast frame that it wants to send to all devices

36
Q

The LAN Networking Model

A

LANs operate at the data link layer of the reference model (more about this is a future lecture)
IEEE divided the data link layer into two sub-layers:
. Logical link control (LLC)
. Media Access Control (MAC)

37
Q

Power over Ethernet (PoE)

A

Power over Ethernet utilizes the Ethernet cabling to deliver power to some Ethernet-attached devices, such as:
Ethernet telephones
Wireless Access Points
PoE defined in 802.3af

Advantages:
Power outlets may not be near
Backup power may not be available in everyone’s office

38
Q

IP Address Fields

A

The IP address has 3 key address fields:

A unique 32 bit address assigned to a node (computer) on a network IPv4.
A unique 128 bit address assigned to a node (computer) on a network IPv6

Subnet Mask field
32 bit pattern used to determine the network and host addresses.

Default gateway field
Optional identifies the address of the router to access another network beyond your own over the internet

39
Q

Header Fields

A

Each packet contains a header as well as the actual data.
The header is constructed on the sending computer
The header contains information that is used by the protocols and layers
A header has several distinct units of information known as fields.

40
Q

The “What if” conditions

A

Network protocols control the “what if” conditions

41
Q

Trade-offs between VC’s and Datagram’s

A

No call establishment or clearing is involved with datagram’s, though they are required for virtual circuits.

Datagram’s require complete addressing information to be sent with each packets; virtual circuits require only a “circuit ID”

Datagram’s are discarded if congestion occurs; virtual circuits must take more elaborate precautions

42
Q

CSMA/CD

A

CSMA/CD stands for Carrier Sense Multiple Access with Collision Detection. It is a network protocol used in Ethernet networks to manage access to the communication medium (typically a shared cable). The purpose of CSMA/CD is to regulate how network devices, such as computers, share the communication channel to avoid data collisions.

Here’s how CSMA/CD works:

Carrier Sense: Before transmitting data, a device using CSMA/CD first checks the communication channel to determine if it is idle or busy. If the channel is busy, the device waits for it to become idle.

Multiple Access: Multiple devices share the same communication channel. They have the right to attempt to transmit data when the channel is sensed to be idle.

Collision Detection: While a device is transmitting data, it continues to listen to the channel. If a collision is detected (i.e., another device has also attempted to transmit at the same time), both devices stop transmitting and initiate a backoff period before attempting to transmit again.

Backoff Period: When a collision occurs, the involved devices enter a random backoff period during which they wait before attempting to transmit again. This randomness helps minimize the chances of repeated collisions.

43
Q

What Is the OSI Model?

A

The OSI (Open Systems Interconnection) model is a conceptual framework with seven layers that standardizes the functions of telecommunication and computing systems. Each layer serves a specific purpose, facilitating communication and interoperability between different devices. The layers, from bottom to top, are Physical, Data Link, Network, Transport, Session, Presentation, and Application. They handle tasks such as physical connection, error detection, routing, end-to-end communication, and application support. The model provides a structured approach to understanding and implementing networking protocols, although real-world protocols may not strictly adhere to its divisions.

44
Q

What topology does CSMA/CD run on?

A

CSMA/CD (Carrier Sense Multiple Access with Collision Detection) was typically associated with Ethernet networks that used a bus or linear bus topology. In a bus topology, all devices on the network are connected to a single communication channel, often a coaxial cable. This shared communication medium is accessible to all devices on the network

45
Q

what is UDP?

A

UDP, or User Datagram Protocol, is a connectionless and lightweight transport protocol within the Internet Protocol (IP) suite. It operates at the transport layer of the OSI model and is characterized by its lack of connection setup, unreliability (no error recovery or retransmission), low overhead, and suitability for real-time applications. UDP is commonly used in scenarios where low latency is crucial, such as online gaming, video streaming, voice over IP (VoIP), and other applications where a slight loss of data is acceptable. Unlike TCP, UDP does not guarantee the delivery of packets or implement flow control, making it faster but less reliable.

46
Q

The MAC address

A

A MAC (Media Access Control) address is a unique identifier for network interfaces on a physical network. It consists of 48 bits, usually represented as twelve hexadecimal digits grouped in pairs. The first half identifies the manufacturer, known as the Organizationally Unique Identifier (OUI), and the second half is a unique identifier assigned by the manufacturer to the specific network interface. MAC addresses are crucial for data link layer communication and are typically hardcoded into network interface hardware, though they can be altered using software in a process known as “MAC spoofing.”

47
Q

IP Address Fields

A

The IP address has 3 key address fields:

A unique 32 bit address assigned to a node (computer) on a network IPv4.
A unique 128 bit address assigned to a node (computer) on a network IPv6

Subnet Mask field
. 32 bit pattern used to determine the network and host addresses.

Default gateway field
. Optional identifies the address of the router to access another network beyond your own over the internet

48
Q

Sending Data

A

Determine if the destination is on the same network or a remote network.

This is achieved by using the Address Resolution Protocol (ARP):
. It uses a broadcast to determine if the address is on the same domain at layer 3
. ARP will translate the IP address into the MAC address to aid communication at the data link layer.

If the destination is local, the node can initiate direct communication.
Otherwise the communication must be via a gateway (router).
Once the packet is prepared it is passed to the Network Access Layer.
The Network Access Layer transmits the packet to the connection media to begin its journey to its destination.

49
Q

Receiving Data

A

The packet is first received by the Network Access Layer.

The datagram is checked for corruption and the correct address.
If all is ok
. The Network Access Layer extracts the data and passes it to the designated protocol

The IP will again check for corruption
The IP addresses will be compared to ascertain that the packet was delivered to the correct address.
The instruction set is checked to determine the next action.
This could be to deliver the data to the next layer TCP or UDP.

50
Q

Header Fields

A

Each packet contains a header as well as the actual data.

The header is constructed on the sending computer

The header contains information that is used by the protocols and layers

The header contains:
. The IP address of the sending computer
. The IP address of the destination computer
. A set of instructions

As the Packet travels through the switches/routers where the header is examined and updated.

51
Q

Header Contents

A

Versions:
. IP Version in use e.g. IPv4 or IPv6

Internet Header Length (IHL):
. The length of the IP header in 32 bit words

Type of Service:
. Special routing information requirements
. Low or Normal delay
. Normal or high throughput
. Normal or high reliability

52
Q

Header Contents cont’d

A

Total Length:
. Identifies the length of packet in octets
. Length includes IP header and data.

Identification:
. An incrementing sequenced number assigned by the source IP

Flags:
. Indicates fragmentation possibilities
. DF – Don’t Fragment
. MF – More fragments, 0 indicates no more fragments or there was no fragments.

Fragment Offset:
. Numeric value assigned to each fragment
. Used to reassemble the fragments

Time to live:
. Time in seconds or router hops that the datagram can survive
. Router decrement this field by one or the number of seconds that the datagram is delayed.
. When the field reaches nought the datagram is discarded

Protocol:
. Holds the protocol address where the IP should deliver the data.

Header checksum:
. Hold a 16 bit calculated value to verify the validity of the header

Source IP address:
. Address is used by the destination IP to verify delivery.

IP data payload:
. This is the data to be delivered, It size is variable

53
Q

Host ID and Network ID

A

Every computer has a unique IP address:
. guided by the public and private addressing rules.

Every computer on a LAN has the same network ID

Within that network each computer will have a unique host ID

When these two are combined they create the IP address.

54
Q

Servers

A

Servers can have multiple ID addresses because they can have multiple NIC’s.

Each network adapter is a point of contact and therefore known as a node.

Therefore each Host ID corresponds to each individual node.

Networks (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions