Fundamentals of Communication & Networking Flashcards
What is a symbol in communication?
A symbol is a particular pattern of bits represented by a signal.
What is baud rate?
Baud rate is the number of signal changes in the medium per second.
How is bit rate defined?
Bit rate refers to the number of bits transmitted over the medium per second.
What is the relationship between bit rate and baud rate?
Bit rate is equal to baud rate multiplied by the number of bits per signal.
Bit rate = Baud rate × № of bits per signal
What is bandwidth in communication?
Bandwidth refers to the range of frequencies that a communication medium can transmit.
What is latency in communication?
Latency is the difference in time between an action being initiated and its effect being noticed.
What is a protocol in communication?
A protocol is a set of rules relating to communication between devices.
What is the difference between serial and parallel data transmission?
Serial data transmission sends data one bit at a time over one communication line, while parallel data transmission uses multiple parallel lines to send multiple bits simultaneously.
What is skew in parallel data transmission?
Skew refers to the difference in time taken for one bit to be transferred among the parallel communication lines.
Why is serial data transmission more reliable over long distances?
Serial data transmission doesn’t suffer from skew or crosstalk, making it more reliable over long distances.
What is synchronous data transmission?
Synchronous data transmission uses a shared clock signal to time when signals are sent.
What is asynchronous data transmission?
Asynchronous transmission uses start and stop bits to indicate the duration of a transmission and does not require a shared clock signal.
What is physical network topology?
Physical network topology refers to the actual architecture or structure of a network.
What are the two types of physical network topology mentioned?
The two types are star and bus.
What is a physical star network topology?
In a physical star network, each client has its own direct connection to a central hub.
What are the advantages of a physical star network topology?
Advantages include direct communication between clients, easy addition/removal of clients, and elimination of collisions.
What are the disadvantages of a physical star network topology?
Disadvantages include network failure if the central hub fails and higher installation cost due to cable requirements.
What is a physical bus network topology?
A physical bus network connects clients to a single cable called a backbone.
What are the advantages of a physical bus network topology?
Advantages include lower cost of installation and shared backbone for communication
What are the disadvantages of a physical bus network topology?
Disadvantages include the risk of collisions and network failure if the backbone fails.
What is logical network topology?
Logical network topology refers to the flow of data packets within a network.
What is the difference between a logical bus network and a logical star network?
In a logical bus network, packets are delivered to all clients, while in a logical star network, packets are delivered only to their recipients.
Can a physical star network behave as a logical bus network?
Yes, by running a bus protocol on the hub, a physical star network can distribute packets to all connected clients, behaving like a bus network.
What is client-server networking?
In client-server networking, central servers provide services to clients on the network.
Which type of networks often use client-server networking?
Most schools, colleges, and businesses use client-server networks for central management of clients.
What is peer-to-peer networking?
In peer-to-peer networking, services are provided by the clients themselves, and every client has equal status.
What is the primary disadvantage of peer-to-peer networking?
All clients providing services must be running for the network to be fully operational. If a client responsible for managing storage is turned off or faulty, other clients cannot access their files.
How does peer-to-peer networking compare to client-server networking in terms of cost and setup?
Peer-to-peer networking is more cost-effective and easier to set up and maintain than client-server networking.
What are some examples of networks that use peer-to-peer networking?
Large file-sharing networks and multimedia providers often use peer-to-peer networking for high-performance services without the need for a server.
What is wireless networking?
Wireless networking allows clients to communicate within a network without being physically connected to it.
What is a wireless access point?
A wireless access point is a device that connects to a wired network and allows wireless devices to connect to the network
What is WiFi?
WiFi refers to a wireless local area network based on international standards, allowing devices to connect seamlessly to wireless networks worldwide.
How are wireless networks secured?
Wireless networks are secured by encrypting transmitted data using WPA or WPA2 and by methods such as disabling SSID broadcast and setting up MAC address filters.
What is Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)?
Protocol used in wireless networks to avoid data collisions caused by multiple devices communicating simultaneously.
Stands for Carrier Sense Multiple Access with Collision Avoidance.
How does CSMA/CA work?
When a device is ready to transmit, it listens to its communication channel to check if it is idle. If it is idle, the device transmits the data. If the channel is busy, the device waits for a random period of time before checking the channel again.
(Note: this explanation does not include RTS/CTS).
What is Exponential Backoff Algorithm?
Algorithm used in CSMA/CA to increase the waiting time period for a device with each check of the channel, helping to avoid collisions.
What is Hidden Nodes?
Problem in wireless networks where devices checking for an idle channel cannot “see” some parts of the network where communication may be occurring. CSMA/CA alone cannot overcome this issue.
What is Request to Send/Clear to Send (RTS/CTS)?
Protocol used to overcome the problem of hidden nodes in CSMA/CA. It adds an additional step where the transmitting device sends a “request to send” message to the server, and if the server is idle, it responds with a “clear to send” message to initiate communication.
How does RTS/CTS protocol work?
After checking for an idle channel, the transmitting device sends a “request to send” message. If the server responds with a “clear to send” message, the transmitting device can begin communication. If no response is received, the server is busy with a hidden node, and the transmitting device must wait before starting the CSMA/CA process again.
What is the structure of the Internet?
The Internet is defined as a network of interconnected computer networks that uses an end-to-end communication protocol.
What is the role of an internet service provider (ISP)?
An internet service provider is a company that provides customers with access to the Internet. They offer internet access to smaller regional and local ISPs, who then sell access to homes and businesses.
What is packet switching and how does it work?
Packet switching is a method of transmitting data over networks. Data is split into packets and sent individually to the recipient via the best possible route. Routers play a crucial role in directing packets to their destination.
What is the purpose of routers and gateways?
Routers and gateways connect different networks and allow packets to reach their destination. Routers find the fastest route for packets, while gateways modify packets to conform to different protocols when networks use different protocols.
What is a uniform resource locator (URL)?
A uniform resource locator is an address assigned to files on the Internet. It specifies the protocol, subdomains, domain, directories, file name, and file extension required to access a specific resource.
What is a domain name and how does it work?
A domain name identifies an organization or individual on the Internet. It uses alphanumeric characters and maps to an IP address. Domain names are easier for humans to remember than IP addresses.
What is the role of a firewall in internet security?
A firewall regulates the packets that pass between a device and the Internet. It can perform packet filtering and stateful inspection to control and monitor network traffic.
What is the difference between symmetric and asymmetric encryption?
Symmetric encryption uses a shared private key for both encryption and decryption. Asymmetric encryption involves a pair of mathematically related keys: a private key kept secret and a public key shared on the Internet.
How do digital signatures work in ensuring message integrity?
Digital signatures verify the sender of a message and confirm that it hasn’t been tampered with during transmission. A digest of the message is encrypted with the sender’s private key and appended to the message. The recipient can verify the signature using the sender’s public key.
What are worms, trojans, and viruses?
Worms, trojans, and viruses are types of malware. Worms self-replicate between computers, trojans disguise themselves as benign files, and viruses require a host file to reside in. They can spread through networks, the Internet, or physical media.
How can malware be prevented?
Preventing malware involves maintaining good code quality, using antivirus software, keeping software up to date, practicing good security measures, and training employees about the risks of opening suspicious email attachments.
What does TCP/IP stand for?
TCP/IP stands for Transmission Control Protocol/Internet Protocol.
How many layers form the TCP/IP stack?
The TCP/IP stack is formed from four layers: application, transport, network, and link.
What is the role of the application layer in TCP/IP?
The application layer selects and uses the correct protocol to transmit data. It interacts with the user through application software.
What is the responsibility of the network layer in TCP/IP?
The network layer provides the correct IP addresses for each packet’s source and destination. It involves routers that use IP addresses to send packets to their destinations.
What does the transport layer do in TCP/IP?
The transport layer establishes a virtual path between the sender and receiver, splits the transmission into packets, assigns sequence numbers to packets, and identifies the port number to be used.
What is the role of the link layer in TCP/IP?
The link layer controls physical connections between hardware in a network, adds MAC addresses to packets, and identifies the hardware to which a packet should be sent.
What happens to a packet when it reaches the receiving end?
When a packet reaches the receiving end, it goes through the reverse process of the TCP/IP stack. The link layer removes MAC addresses, the network layer removes IP addresses, and the transport layer uses the port number and sequence number to ensure proper positioning.
What is a socket address?
A socket address is formed by combining an IP address with a port number. It identifies the application to which a packet should be sent.
What are the two types of IP addresses commonly used?
The two types of IP addresses commonly used are IPv4 and IPv6
What are the well-known ports used for FTP?
Port numbers 20 and 21.
What is the purpose of SSH?
SSH is used for remote management of computers, allowing them to be accessed and controlled remotely.
Which port is commonly used for HTTP?
Port 80
What is the difference between HTTP and HTTPS?
HTTPS performs the same function as HTTP but encrypts information during transmission, providing security and preventing tampering or modification of data.
What are the port numbers used for POP3?
Port numbers 110 and 995.
Which protocol is used for sending emails?
SMTP (Simple Mail Transfer Protocol).
How is an IP address divided?
An IP address is divided into a network identifier and a host identifier.
How can the network identifier part of an IP address be determined?
The network identifier part can be determined by applying a subnet mask.
What is the difference between IPv4 and IPv6?
IPv4 addresses are represented as dotted quad numbers, while IPv6 addresses are formed of eight blocks separated by colons and use hexadecimal characters.
What is the purpose of DHCP?
DHCP is used to assign IP addresses to devices as they join a network.
How does NAT facilitate communication between a private network and the Internet?
NAT replaces the private IP address of a device with a router’s public (routable) IP address when communicating with devices on the Internet.
When is port forwarding used?
Port forwarding is used when a client needs to communicate with a server connected to a private network.
What is the client-server model?
In the client-server model, clients send request messages to servers, and servers reply with response messages.
What is an API?
An API (Application Programming Interface) is a set of protocols that define how different applications can communicate with each other.
What is the purpose of the WebSocket protocol?
The WebSocket protocol allows for a constant stream of information between a client’s web browser and a server.
What is CRUD in the context of online databases?
CRUD stands for create, retrieve, update, delete, representing four commands used to query databases.
What are the four HTTP request methods used in REST?
The four HTTP request methods used in REST are POST, GET, PUT, and DELETE.
What are the advantages of JSON over XML
JSON is more compact, easier to read, easier to create, and faster for computers to process compared to XML.
What is the difference between thin-client and thick-client computing?
In thin-client computing, the majority of processing power belongs to servers, while in thick-client computing, clients have their own processing power and storage.
What are the advantages of thin-client networks?
- Centralized control and management of software updates and security.
- Lower hardware costs as thin clients are typically less expensive than full-fledged computers.
- Easier addition of new clients to the network.
- Reduced maintenance requirements as most tasks are handled by the server.
- Lower energy consumption due to the lower processing power of thin clients.
What are the advantages of thick-client networks?
- Higher performance as the processing power and storage are located on the client device.
- Greater offline functionality as thick clients can perform tasks independently of a server.
- Reduced dependency on network connectivity.
- Enhanced user experience with potentially more advanced graphics and features.
- Lower server infrastructure costs compared to thin-client environments.
What are the disadvantages of thin-client computing?
- Reliance on network connectivity; if the network goes down, thin clients may become unusable.
- Performance limitations as the processing power is dependent on the server’s capabilities.
- Limited offline functionality as most tasks require a connection to the server.
- Higher server infrastructure costs to handle the processing and storage demands of multiple thin clients.
What are the disadvantages of thick-client computing?
- Higher hardware costs as thick clients require more powerful and expensive components.
- Increased maintenance requirements as each client device needs individual updates and security measures.
- Difficulties in managing software compatibility across multiple client devices.
- Potential security risks if individual client devices are compromised or lost.
- Less centralized control and management compared to thin-client environments.
What does CRUD stand for?
CRUD stands for create, retrieve, update, delete.
What are the SQL equivalents for the CRUD commands?
- Create: INSERT
- Retrieve: SELECT
- Update: UPDATE
- Delete: DELETE
What does REST stand for?
REST stands for representational state transfer.
What is the purpose of REST in online database applications?
REST is a design methodology used for online database applications that are queried with a web browser.
What are the corresponding SQL commands for the four HTTP request methods in REST?
- POST: INSERT
- GET: SELECT
- PUT: UPDATE
- DELETE: DELETE
