Unit 4: Computer Networks 2 (Complete Unit)

Define: Bridge

A bridge is slightly more sophisticated, only forwarding messages addressed to a computer on the other side.

Define: Firewall

A firewall monitors network traffic and blocks traffic that triggers its safety rules, providing a barrier between a trusted private network and an untrusted network like the internet.

What is Packet Sniffing?

A form of attack, also referred to as a man-in-the-middle (MITM) attack, where the attacker intercepts the data as it is traveling to or from the victim's device, including authentication credentials.

What are some characteristics of Tier 3 ISPs?

(access ISPs) are typically independent internets, sometimes called intranets, operated by a single organization that supplies internet access to homes and businesses.

Define: Modem

A modem bridges between the customer network and the ISP, converting the incoming analog data into digital, and the outgoing digital data into analog. It provides the access point to the internet.

Define: Switch

A network switch extends the network by using packet switching to forward data to the intended hard-wired devices.

What is an open network (public domain)

A network that uses standard protocols (TCP/IP)

What are some characteristics of Tier 1 ISPs?

Least common type of ISPs Backbone of the internet. consist of high-speed, high-capacity, international WANs that are typically operated by large communication companies

What is spyware?

Spyware resides on a computer, collecting information about the computer's activities and reporting back to the spyware's instigator. Passwords or credit card numbers can be exposed via spyware.

What is a Star Network?

Star networks have a single machine serving as a central point to which all others are connected.

How are networks classified?

Networks are commonly classified based on the physical distance between components (geographic scope).

Optical Wire Cable

Optical wire cable uses the concept of reflection of light through a core made up of glass or plastic. The core is surrounded by a less dense glass or plastic covering called the cladding. Optical wire cables are able to transmit large volumes of data. Their bandwidth can provide up to 26,000 times the bandwidth of the twisted pair wires, at the time of this writing.

What is the tool used to encode a document while focusing on appearance known as?

HTML Hypertext markup language (HTML) is used to encode documents and focuses on the document's appearance.

What are the four common topologies? (BSMR)

Bus Star Mesh Ring

What is the minimum grade of network cable required to transmit 1 Gpbs?

CAT5e

What is cloud computing?

Cloud computing provides large pools of shared computers that can be allocated to clients as needed. Services such as Amazon's Elastic Compute Cloud allow clients to rent virtual computers by the hour no matter where the associated computer hardware is located. provides reasonable guarantees for reliability and scalability while raising concerns about security and privacy.

What are the types of distribution systems?

Cluster Grid Cloud

What is a ring network topology?

Ring topologies connect directly to each other as a peer.

What is cluster computing?

Cluster computing uses many independent computers to provide computation or services comparable to those of a larger machine. Lower cost then a higher priced supercomputer with the same performance provides high availability as it is likely that at least one computer in the cluster will be able to answer a request even when others in the cluster are unavailable or broken down. can balance loads by automatically shifting requests among the cluster members.

Which type of transmission media can broadcast in baseband mode?

Coax cable can broadcast in both baseband and broadband modes.

Define: Router

Routers are special-purpose computers that forward messages to and from the machines on their network. They use their forwarding table to match up the private IP address with the internet IP address and send the message to the correct machine.

What is proprietary software?

Software that legally remains the intellectual property of a specific company - The source code is not freely available, and the software isn't free

What is a dictionary attack?

Dictionary attacks are performed by the attacker by using an application and a large dictionary text file with just words. When the attacker runs the application it tries identifying the password by trying hundreds or thousands of words per minute from that dictionary file.

What are Distributed systems? What are some examples?

Distributed systems execute software as processes on more than one computer. Examples: global information retrieval systems computer games

What does the internet use as unique identifiers?

IP (internet protocol)

ISPs are classified in ____ depending on the role they play in the overall internet structure.

ISPs are classified in tiers depending on the role they play in the overall internet structure.

What is a BUS Network?

In a bus network, the machines are connected to a common communication line called a bus.

What is a mesh network topology?

Mesh connects every device in a network to every other device; mesh networks enable redundancy while also introducing significantly more network traffic.

What network topology best handles downed links without losing connectivity between devices?

Mesh. The mesh network's redundancy from multiple links allows connectivity even when a link is out of service.

What is a LAN network?

LANs consist of a collection of computers in a single building or building complex. For example, the computers in a manufacturing building may be connected via a LAN.

What is the basic role of a client/server model used for interprocess communication?

The basic roles played by the processes are categorized as either a client, making requests, or a server, satisfying client requests.

What does the URL include?

The protocol domain all subdomains resource path ID name of the document collectively indicates the location of the document on the server URL: http://subdomain.domain.high-level_domain/directory-path/document_name.html

What is a brute force attack?

This is where the attacker uses all possible combinations of characters to learn a user's password. There are multiple variations of the brute force attack, such as rainbow table attack and dictionary attack.

What Is An IP Address?

This number is an exclusive number assigned to each network connect device such as printers and routers. Furthermore, the assigned IP address identifies each device. Therefore, it allows these connected devices the ability to communicate with each other over a computer network. Therefore, no device can be connected to a network without an IP address.

Some Networks are commonly classified based on the physical distance between components, However there is another way, what is it?

networks considers the topology of the network or the pattern in which the machines are connected.

Define: repeater

passes signals back and forth between two buses without considering the meaning of the signals

What are the three major categories of networks?

personal area network (PAN), local area network (LAN), and wide area network (WAN).

What is a PAN network?

personal area network. normally used for short-range communications, within a few feet, such as wireless headphones to a smartphone or a wireless mouse to a PC.

What is common network media used in wireless networks?

radio waves microwaves infrared waves.

Define: Gateway or Gateway Point

the point where a network is linked to the internet

What is a denial-of-service (DoS) attack

the process of overloading a computer with messages and results in suffocating the network resources.

The suffix .edu is an example if ...

top-level domain (TLD) denoting an educational institution

Each hypertext document available through the World Wide Web is given a unique address called a...

universal resource locator (URL) or uniform resource identifier (URI).

What are the two common twisted pair cables that are used?

unshielded twisted pair (UTP) shielded twisted pair (STP)

What are the benefits of using protocols?

vendors are able to build products for network applications that are compatible with products from other vendors.

What does TCP/IP stand for?

Transmission Control Protocol (TCP) and the Internet Protocol (IP)

What are common network media used in wired networks?

Twisted pair cables copper coaxial cable optical fiber cables

What is a Wan network?

WANs link systems over a greater distance, including machines on the opposite sides of the world.

Rather then remembering an IP address how are websites referred to?

Websites are referred to by a naming convention called a domain name.

What is a virus?

a software program that infects a computer by inserting itself into programs that already reside in the machine. When the "host" program is executed, the virus is also executed, possibly performing degradations of portions of the operating system, erasing large amounts of data, or corrupting data and other programs.

What is proxy server?

a software that acts as an intermediary between a client and a server to shield the client from adverse actions of the server.

What is a closed network (proprietary)

closed loop system.

Complete The Statement: The star topology is used today in wireless networks where...

communication is carried out via radio broadcast to a central machine called the access point (AP).

What is grid computing?

distributed system that is more loosely coupled than clusters but still works together as a system to complete large tasks. typically includes specialized software to make it easier to distribute the workload and data among the machines in the grid.

IP addresses are traditionally written in _____________ notation.

dotted decimal IP addresses such as 192.168.1.1 are written in dotted decimal notation.

What are Coaxial Cables?

have an outer plastic covering containing two parallel conductors, each having a separate insulated cover. Coaxial cable transmits information in two modes: baseband mode, with dedicated cable bandwidth, and broadband mode, in which cable bandwidth is split into separate ranges. The bandwidth of coaxial cables is about 80 times the bandwidth of twisted wires. Cable modems and televisions typically use coaxial cables.

What is used to construct and and maintain individual networks comprising the internet?

internet service providers (ISPs)

What are some characteristics of Tier 2 ISPs?

more common and regional in scope. Tier 1 and Tier 2 ISPs are essentially networks of routers that collectively provide the internet's communication infrastructure.

Today we use ___________-bit addresses (IP version 6 or IPv6).

128

Define: Server

A server is a computer that provides services, such as website hosting and routing, for other devices.

What is a protocol?

A standard that specifies the format of data as well as the rules to be followed during transmission

What is phishing?

A technique used to obtain private information by simply asking for it. The perpetrator sends emails posing as a legitimate business asking for information.

What is an AP?

Access Point. A radio beacon with an ethernet plug on it.

What is a Peer-to-peer (P2P) model in interprocess communication?

In this model, processers both request and provide service to each other. Instant messaging and interactive games played by users on multiple machines are both examples of the P2P model. They also exchange files, forming a swarm. This file exchange approach is popular in distributing music recordings and motion pictures via the internet.

What Is IPv6?

Internet Protocol version 6 is the replacement for IPv4. First of all, an IPv6 address looks like this 2600:1005:b062:61e4:74d7:f292:802c:fbfd. While an IPv4 address looks like this 75.123.253.255.

Which technique allows someone to obtain sensitive information, such as usernames and passwords, by pretending to be a trustworthy person?

Phishing Phishing is the fraudulent attempt to obtain sensitive information such as usernames, passwords, and credit card details by disguising the source as a trustworthy entity.

What is a Domain Name Server (DNS)?

The DNS server is like a phone book or contact list, and it contains a list of all the IP addresses and their respective sites' names. It locates and sends the IP address back to the browser, then the browser redirects the request to the datacenter which hosts the site, and the data center responds with the corresponding information.

What is the difference between HTML and XML?

The extensible modeling language (XML), provides a standardized style for designing notational systems for representing data as text files. XML emphasizes semantics, while HTML focuses on appearance.

What does Interprocess communication allow?

allows the activities or processes on different computers within a network to coordinate actions and complete tasks.

What is a worm?

an autonomous program that forwards copies of itself to other machines in a network and could result in detriment of individual machines or the operations of the network.

What is malware?

any software intentionally designed to cause damage to a computer, server, client, or computer network (by contrast, software that causes unintentional harm due to some deficiency is typically described as a software bug).