Computer Science 336: Network Forensics

An example of a device that could be part of the Internet of Things (IoT) would be:

ALL answers are correct Factory robot Transponder tag on a shark Home alarm system

The presentation layer of the OSI model is responsible for integrating all data formats into what type of form?

Acceptable and compatible

When the receiving system lets the sender know the data was received at its destination it is called ____.

Acknowledgement

Which statement is correct about a broadcast network?

All network nodes receive a transmission.

Why are IoT devices starting to gain some newfound attention from the networking industry?

All of these answers are correct. - all processes are automated - always connected - information is given in real time and is always available

Which of the following are possible through network protocols?

All of these answers are correct. - visiting www.google.com - connecting your tablet to a wireless network - sending a text message to your friend

What type of connections does a NIC control?

Both wired and wireless connections A network interface card controls all types of network connections, including both wired and wireless connections.

In which part of the OSI Model is the physical layer?

Bottom Layer

In some situations, the presentation layer of the OSI model may have two sub-layers associated with its operation. Which option below lists both of these sublayers?

CASE and SASE

The internet is an example of a _____ _____ Network.

Wide Area A Wide Area Network or the WAN occupies a very large area, such as an entire country or the entire world such as the internet.

Which computer network, built by a business, is used to interconnect its various company sites in order to share computer resources?

EPN An EPN (Enterprise Private Network) is a computer network that is entirely controlled by one organization, and it is used to connect multiple locations. For example telecommunications companies, like AT&T, operate their own network.

IPsec (Internet Protocol Security) works by:

Encrypting and authenticating each packet

The transport layer performs data packet creation and what other types of services?

Error checking

What does layer five of the OSI model do?

Establishes, manages and terminates communicative sessions.

Which Network Protocol has nothing to do with email?

FTP

Which of the following devices can be used to interface computer networks that use different communication protocols?

Gateway A gateway is a network device to interface computer networks that use different communication protocols. This is similar to a router, but a router only connects network segments that use the same communication protocol.

Session Layer Functions / Protocols

Goal is to coordinate active applications on various hosts using assigned protocols - Network File System NFS - Structured Query Language SQL - Remote Procedure Call RPC - X Window System - AppleTalk Session Protocol ASP - DEC Sessions Control Protocol SCP - ensure the data format and structure is acceptable by the presentation layer (6) and the transport layer (4).

All of the following are protocols of the Data Link Layer except ____.

HTTP (HyperText Transfer Protocol) High-Level Data Link Control HDLC Unrestricted Simplex Protocol Collision-Free Protocols

Standard vs. Proprietary Network Protocols

Standard Protocol: - vetted by internet society 'to promote the open development, evolution, and use of the internet for the benefit of all people throughout the world.' - freely usable by people who make gadgets that communicate on a network Proprietary Protocols: - private network protocols - owned by a company or individual and becomes the intellectual property of the creator - if you want to use on you need to obtain permission and pay a royalty

Which of the following contains a large number of ports to connect network segments and sends the data it receives only to specific ports?

Switch A switch contains a large number of ports to connect network segments - just like a hub. However, a switch sends the data it receives only to specific ports.

Which of these is not one of TCP/IP's five protocol layers?

Transmission

What is it called when a standalone device does not need to rely on external computer hardware to operate?

Ubiquitous computing

In the OSI model, the hyperlink uses a(n) _____ to name the pages on the web.

Uniform Resource Locator

_____ uses encrypted data before it is sent over a public network

VPN VPN stands for Virtual Private Network and is a network in which some parts of the network use the Internet. The data is encrypted with a high level of security for traffic.

Network Node Types

a device attached to a network and it can create, send, receive and store data - unique hardware identifier - Media Access Control MAC Address - allows other devices to find it on the network Point-to-point - two devices connected to each other (pc and printer) multi-homed - connected to more than one network and has two different network addresses - redundancy: two internet circuits in case one goes down - load balancing: two internet circuits, each for a different kind of traffic Hybrid network - blends two different types of network connectivity - wired and wireless network

What is a backbone network?

a high capacity connectivity infrastructure that forms the main link to the different sub networks connected to it

One required characteristic of a network node is that it has a/an _____.

address Just like your house has an address so people can find you, a network node must have a unique address so it can be located.

Network Node

any device on a network

Internet Of Things IoT

any object that can connect to the internet and operate without human interaction ex. washing machines, door locks, kitchen appliances, and vehicles BENEFITS - always connected - information is always available - cost effective CHALLENGES - consumer adoption rate wireless standards must advance first - security concerns - privacy concerns

Parallel backbone networks differ from collapsed backbone networks in that parallel backbone components are implemented with _____.

duplicate concurrent connections to the high level backbone routers

_____ is a widely used type of broadcast network found in many homes and offices.

ethernet

When making a network connected gadget , standard network protocols can be used _____.

for free and without permission of the creator.

A network that mixes two different types of connectivity is known as a _____.

hybrid

Network Layer

layer 3 Functions: - helps transmit data between hosts - responsible for determining the shortest path for a packet of data (packet routing) - performs logical addressing - identifies devices on a network with a unique address: the network layer places this ID (IP address) in the packet header - keeping track for billing information (accounting) - can employ defenses like port knocking, secure IP (IPsec), and secure ICMP - IPsec (internet protocol security) works by encrypting and authenticating each packet (with special keys known only to the two parties)

Feedback-based flow control ____.

makes sure a message is sent back to the sender when it is ready to accept more data

The term modem is short for _____.

modulator-demodulator A modem is used to modulate an analog signal so that it carries digital information, and then demodulates the signal to obtain the transmitted information. Modem is short for modulator-demodulator.

When you attach a PC to a network, it becomes a _____.

network node

What defines the rules and specifications for how communication happens in a network?

network protocols

The set of rules or procedures for handling data or information transfer is called _____.

protocols

Broadcast Network

transmissions go to everyone and are ignored by nodes that aren't the intended recipient Ethernet - widely used type of broadcast network - PROCESS: carrier sense multiple access with collision detection (CSMA/CD) to keep nodes from talking over each other

Which protocol provides error recovery and flow control services for the transport layer?

TCP

Which of the following identifies the protocol or protocols available to the session layer for standardizing communications on a network?

TCP/IP

Four types of backbone networks are _____.

Serial, Distributed, Collapsed and Parallel networks

_____ was the company that was responsible for popularizing the VoIP platform in the early 2000s.

Skype

You can access a website by typing in a name like google.com because of _____.

DNS

Video over IP

2005 ability to initiate a one-to-one or group video call example - Facebook messenger BENEFITS - reach any audience - group calls - easy to use - widely available service - cost effective CHALLENGES - potential call quality issues - strong network required - bandwidth is much higher

Which layer is the network layer in the OSI 7 layer model?

3

IPv4 requires that every system with connectivity to the Internet have a unique _____ internet address.

32-bit

An IPv4 address contains _____ digits in _____ sets separated by a _____.

3; 4; period

Which of the following is true about half-duplex mode?

Data is transmitted in both directions but not at the same time.

Ubiquitous Computing

"persuasive computing" the act of embedding computers, typically microprocessors, into everyday objects to give them a constant means of connectivity with one another - always connected, allowing information to pass between them at all times - Reduces overall computing strain by allowing the devices to perform more straightforward and specific daily tasks instead - higher range and flexibility - reduce processing power needed to complete a particular goal - standalone mobile units that never need to rely on an external computer to carry out operations BENEFITS - high level efficiency - always connected - real time information - increased productivity - cost effective CHALLENGES - privacy concerns - security concerns - consumer adoption rate

(Open System Interconnect) OSI Model

7) Application Layer - Provides access to available resources 6) presentation layer - translates, encrypts and compresses data - establishes and maintains reliable, efficient, and effective data exchanges between network components, like gateways 5) session layer - establishes, manages and terminates communicative sessions 4) transport layer - provides reliable process-to-process message delivery and error recovery 3) network layer - moves packets from source to destination by providing inter-networking capabilities 2) data link layer - organizes bits into frames, providing node-to-node delivery 1) physical layer - transmits bits over a medium, establishing mechanical and electrical specifications

Which of these statements is NOT true about a NIC?

A NIC only allows for either a wired or wireless connection, not both. A NIC can allow for both wired connections through Ethernet and wireless connections through WiFi.

What type of hardware device is a WiFi card?

A network interface card to establish a wireless connection A WiFi card is a type of network interface card to establish a wireless connection.

How does the use of a router differ from a bridge in telecommunication?

A router is a communication device that is used to connect two different networks, while a bridge is networking device that divides the network into different segments to manage the amount of traffic. Routers are communication devices used to connect two different networks. A router sorts incoming data and distributes it to the correct destination. For example, if you have a network within a single office building, many different devices from within the network may access resources outside the network. Bridges are networking devices that divide up the network into different segments to manage the amount of traffic. This prevents unnecessary traffic from entering other parts of the network and reduces congestion.

What is Ethernet?

A standard for computer networking technologies Ethernet is a standard for computer networking technologies. This standard makes it possible for various computer systems to connect to each other.

What is WiFi?

A type of wireless network connection WiFi is a type of wireless network connection that uses radio signals to transmit data.

Functions in Presentation Layer

Character-Code Translation: translates from ASCII to the extended binary code decimal interchange code (EBCDIC) Data Conversion: performs bit order reversal functions, converts CR (byte code for a carriage return) to CR/LF(byte code for a carriage return with a line feed) and converts integer numbers to floating point numbers Data compression: reduces the number of bits requiring transmission, which improves the data throughput Data encryption and Decryption: encryption is needed for security purposes when sending data across networks Data Translation: Networks provide the capability of connecting different types of computers, servers, and mainframes on the same network and may employ different character sets - responsible for fixing any irregularities while making translations transparent between networked systems other protocols in presentation layer: - Musical instrument digital interface MIDI - Moving Picture experts group MPEG - Tabbed document interface TDI - Transport Layer Security TLS - External Data representation XDR Sub Layers: CASE & SASE common service element CASE - provides application layer services and makes service requests of the session layer Specific application service element SASE - provides application services or protocols

An NIC is used for which of the following?

Connecting a computer to a network.

List of common protocols

HTTP/HTTPS - hypertext transfer protocol/secure - delivers webpages to your devices, HTTPS delivers web pages securely using encryption POP3 - transport layer security/secure socket layer - allows people to access their email IMAP - internet message access protocol - modern protocol for people to access their email SMTP - Simple Message Transport Protocol - transfers email between email servers - email delivery service - also be used to access email DNS - domain name system - assigns common easy to remember names to internet addresses ie. - www.google.com instead of 216.58.219.100 WiFi - provides wireless internet access TCP - transmission control protocol - guarantees that what you send gets to the other side UDP - user diagram protocol - doesn't guarantee delivery - useful for internet video IP - internet protocol - one of the base protocols that run the internet - used to transmit most types of data packets on the internet

Which of these is not a design issue for the network layer?

Handling session information

Design Issues of the OSI Model

How to handle store-and-forward packet switching - how to break up the message into smaller pieces so the whole thing will reassemble at the destination in one meaningful piece What services are going to provide for the transport layer just above - lets the layer above know what the network layer can be expected to do How you're going to implement a connection-based service - wired connections need to be handled on this layer How you're going to implement a connection-less service - Wireless connections also need to be handled here. Whether you are going to use virtual circuits or datagrams

In the OSI model, all of the following are protocols of the application layer except:

ICANN

Which internet protocol is responsible for moving data packets along the Internet network?

IP

If a device is going to be connected to the Internet, it will need to be supplied what kind of address?

IP address If a device is going to be connected to the Internet, it will need to be supplied with an Internet Protocol (IP) address, which will be tied to the MAC address so the device can be found by other Internet devices.

Washing machines, kitchen appliances, and vehicles all have the potential of being connected to the internet at all times. What would these devices be classified as if they were given that functionality?

Internet of Things

Physical Layer

Layer 1 the basic hardware components used in the OSI physical layer include the network interface cards (NICs), connectors and interfaces, and cables that facilitate the transmission of data from source to destination Physical Layer Cable Types: Shielded Twisted Pair - foil shielding around pairs of twisted wires to prevent electromagnetic interference Unshielded Twisted Pair: same way as a shielded twisted pair but without the extra foil shielding around the wires Coaxial Cable - a wire covered by alternative conducting and insulating shields; more reliable when connecting different networks Cable Connections: RJ-45 - 8-wire connectors used specifically for connecting LAN or Ethernet cables Fiber ST, SC - Fiber ST, SC: These are fiber cable connectors that are always used in pairs. One wire is for transmitting data, and the other is for receiving it. ST and SC are fiber connector standards in the USA and UK respectively. Fiber LC - used for fiber optic cables and transmission of optical signals Transmission Media Simplex - Data is transmitted in a single direction Half-Duplex - Data can be transmitted in both directions, but not at the same time Full-Duplex - Data transmission can occur in both directions at the same time

Data Link Layer

Layer 2 - ensures that all packets of information are passed on free of errors - makes sure the appropriate physical protocol is assigned to the data Main functions: - deal with transmission errors - regulate the flow of data - provide a well-defined interface to the network layer Protocols: (protect information transfer) Unrestricted Simplex Protocol - allows data to travel in one direction - only the frame's arrival is the possible successful outcome Simplex Stop-and-Wait Protocol - takes into account that the receiver may not be as fast as the sender - sender sends data and waits for the receiver to send a message back called an acknowledgment - acknowledgment that the data has been received or that it is ready for more frames Data Flow to the Network Layer - feedback-based flow control: makes sure a message is sent back to the sender when it is ready to accept more data - rate-based flow control: limits the rate at which senders may transmit data without using feedback from the receiver

A _____ is a computer network that connects computers within a school.

Local Area Network A Local Area Network or LAN is a computer network that connects computers within a limited area, such as an office building or school.

The network layer converts:

Logical addresses into physical addresses

Your device's unique hardware identifier is known as your _____.

MAC address Your device's unique hardware identifier is known as your MAC (Media Access Control) address and is built into your device.

The API that allows applications on separate computers to communicate over a LAN is:

NetBIOS

Hubs, routers and switches (which can also be nodes) are examples of what type of gear?

Network infrastructure Hubs, routers and switches (which can also be network nodes) are examples of network infrastructure, which provides connectivity.

What does NIC stand for?

Network interface card or controller NIC stands for network interface card or controller. The term refers to a separate card with the electronic circuitry and physical connectors on it. In most new computers, the NIC is built into the motherboard, and no separate card is used.

Which network covers the smallest geographic area?

Personal Area Network A Personal Area Network is a computer network organized around a single individual person within a single building. It typically contains one or several computers and several other devices, such as a printer, cell phone, digital camera, etc.

Which option contains the name of the layer responsible for translating, encrypting and compressing data within the OSI model?

Presentation

The session layer provides communicative support to which two OSI layers?

Presentation and transport

Among others, what are the two primary networking features managed by the presentation layer of the OSI model?

Protocols and architecture

Which connector is NOT used in a network cable?

RJ-11

The presentation layer of the OSI model translates data into an acceptable format usable by which layer?

The application layer

At the 'sending' computer, the transport layer provides input to which OSI layer?

The network layer

Which of these statements is FALSE?

The network layer controls the conversations between different computers.

In the OSI model, what does the application layer do?

This layer actively interacts with the operating system or application when the user decides to transfer files, read messages, or perform network-related activities.

Backbone Networks

backbone network: a network containing a high capacity connectivity infrastructure that forms the main link, or backbone, to the different parts of the network. - covers a local area within a building or vicinity or may have global outreach that spans geographical area - cabling, switches, bridges, routers, gateways in varying segments Serial backbone: consists of two or more connected devices or nodes linked to each other via a single cable in series that connects to an extension to the network - small network setups - highly susceptibility to faults and system downtime - if one network gets disrupted the whole network is down Distributed Backbone: a hierarchical formation of devices that are adaptable to multiple connectivity. - spans a larger network with multiple sub networks connected - suited for enterprise wide connectivity - Expanding and troubleshooting the network is simple, as layers of the network are easily added and managed. Collapsed backbone: a single, high specification router that serves as the central connection supporting the rest of the network - characterized by high computational power to handle traffic from various networks - dependent on a single router, makes the network vulnerable - if the router goes down the entire network does too - applicable in situations where two different types of sub networks need to be connected and managed effectively Parallel Backbone: employs a system of replicated connections to the backbone infrastructure - nodes and switches are implemented with duplicate concurrent connections to the high-level backbone routers - this setup ensures high network speeds, robustness, and high fault tolerance - expensive with the increased cabling - variation of the collapsed backbone infrastructure used to connect and managed different types of sub networks effectively - offers higher fault tolerance capabilities

In the OSI physical layer, data is transmitted in the form of _____.

both optical and electromagnetic signals

Media Access Control AMC Address

built into the wired or wireless network card inside your device. Think of it as your unique hardware identifier. IP/TCP Internet Protocol (IP) Address: assigned to the device when it connects to the internet - used for communicating devices on the internet - MAC address is fixed and the IP address can change based upon where the devise is when it connects to the internet Internet of Things IoT - some devices can connect and be part of a network without any human intervention - since so many things are connected to the internet now, its called IoT Network Infrastructure - hubs, routers, and switches can be network nodes as can firewalls and network servers - like office phones

Voice over IP (VoIP)

connect to the internet and use a network to place voice calls without the need for physical phone line - early 2000s Skype was introduced BENEFITS - Widely available service - easy to use - cost-effective - group calls CHALLENGES - potential call quality issues - strong network required - possible security concerns

Transport Layer

provides communication services between computers on a network - performs error checking to ensure that the transmission is free of errors Services: - identify the application and the client's identity - ensure that the complete message arrives - Segment the data for transportation from the network layer - detect errors in transmission - put any segmented data in the right order - share multiple sessions Functions: Process-Level Addressing - addressing at the transport layer enables differentiation between software programs, allowing their use on different network layer protocols simultaneously. Multiplexing and Demultiplexing - Multiplexing is accomplished on the sending computer, where data received from multiple application programs are prepared for transport. Demultiplexing occurs at the receiving computer, after which the data packets are forwarded to the appropriate application process Segmentation, Packaging and Reassembly - Larger amounts of data are divided and separated into small packets, which are then transmitted from the sending computer to the receiving computer. At the receiving computer, the transport layer reassembles the data for transmission to the session layer. Connection Establishment, Management and Termination - The transport layer establishes a reliable communicative connection, maintaining the connection as data is transmitted. When the data has been sent and communication is no longer necessary, the transport layer terminates the connection. Acknowledgments and Re-transmissions - Most protocols start a timer on each occurrence of data transmission. When the data is successfully received, an acknowledgment message is forwarded to the sending computer verifying receipt. If the sending computer does not receive an acknowledgment, the data is assumed lost and re-transmitted. Flow Control - Based on the amount of activity, the transport layer may institute a slow-down between nodes, thus preventing bottlenecks or network delays. Protocols Transmission Control Protocol TCP User Diagram Protocol UDP - aid to transport layer in managing communications between multiple computer resources - TCP provides error recovery and flow control in support of user application protocols li

If you set up a multi-homed network with two Internet circuits from different providers, you have built _____ into your Internet connectivity.

redundancy

Session Layer

responsible for setting up and managing communicative sessions - enables the sending and receiving of data for an undetermined length of time - " application programming interfaces (APIs)" - Network basic input/output system NETBIOS; allows applications on separate computers to communicate and establish sessions to access shared resources over a LAN - TCP/IP; standardizes communications across networks

The Data Link layer is the

second layer in the OSI Model

Multiplexing is facilitated by the _____ computer and demultiplexing is facilitated by the _____ computer.

sending; receiving

A _____ network cannot be applied at enterprise level due to its high susceptibility to faults.

serial backbone

At the 'receiving' computer, the transport layer provides input to which OSI layer?

session layer

Which option below best completes this sentence: Among other communicative tasks, the session layer also terminates:

sessions between software processes

Which of the following challenges does not fit into Voice over IP?

slow adoption rate

All of the following are functions of the Data Link Layer except

stop all bad files from passing to the Physical Layer Provide a well defined interface to the Network Layer Regulate the flow of data Deal with transmission errors

One of the main disadvantages of the collapsed backbone is the _____.

susceptibility to complete system failure if the backbone router fails

Network Protocols

the rules and specifications for how communication happens on the information super-highway - cars = data packets Basic Layers: 1) electrical signaling - 1's and 0's machine language 2) internet layer - transparent to regular uses 3) pc layer - transparent to regular uses 4) Lasy layer - people interaction

In the OSI model, the application layer is:

the seventh layer