The Bits and Bytes of Computer Networking - Week 1
What's a router? - A physical layer device that prevents crosstalk - A device that knows how to forward data between independent networks - A more advanced version of a switch - A network device used specifically for fiber cables
- A device that knows how to forward data between independent networks.
What is the type of modulation used by twisted pair cable computer networks known as? - Line crimping - Simplex communication - Line coding - RJ45
- Line coding
What does LAN stand for? - Local area network - Little area network - Locally available network Large area network
- Local area network
What are the major functions of a data link layer protocol?
- Media access control - Error control - Message delineation
What's the difference between a client and a server?
A client requests data, and a server responds to that request.
What's the difference between a client and a server? 1) Clients and servers are different names for the same thing. 2) A server requests data, and a client responds to that request. 3) A client requests data, and a server responds to that request. 4) Clients operate on the data link layer, and servers operate on the network layer.
A client requests data, and a server responds to that request.
What is a cyclical redundancy check?
A mathematical calculation used to ensure that all data arrived intact.; A cyclical redundancy check ensures that there was no data corruption.
Select the device that will have the most network ports. Desktop Laptop Server Switch
A switch will have the most network ports, because its purpose is to connect many devices.
What is the Ethernet?
Beyond specifying physical layer attributes, the Ethernet standards also define a protocol responsible for getting data to nodes on the same network or link.
A device that connects lots of devices and remembers which ones are connected to each interface is known as a _____.
By remembering which devices are connected to each interface, a switch reduces collision domains.
What is used to determine when the communications channels are clear and when a device is free to transmit data?
Carrier Sense Multiple Access with Collision Detection (CSMA/CD) is used to determine when the communications channels are clear and when a device is free to transmit data.
What is registered jack 45 (RJ45)?
aka RJ45; one of many cable plugs specifications but by far, the most common in Computer Networking;
The number system that has 16 numerals is known as _____. binary octal hexadecimal decimal
hexadecimal
Any information required
https://www.omnisecu.com/index.php Free Networking, System Administration and Security Tutorials
MAC address stands for ____ address.
media access control
A defined set of standards that computers must follow in order to communicate properly is known as a _____. switch/ collision domain/ modulation/ protocol
not a collision domain.
What is Activity LED?
will flash when data is actively transmitted across the cable
What is the function of the software in the lower layers of the OSI Model?
The software in the lower layers of the OSI Model is to provide more primitive network-specific functions like routing, addressing, and flow controls
What comprises the lower layers of the OSI Model?
The transport, network, data link, and physical layers comprise the lower layers of the OSI Model.
What is Media Access Control (MAC)?
- Controls which device transmits and when - Multipoint (shared) circuits - Half-duplex point-to-point circuits
Which of the following is an example of a network layer (layer 3) protocol? - UDP - IP Ethernet - TCP
- IP or Internet Protocol, is the most common network layer protocol.
How many octets are there in a MAC address?
6; A MAC address is a 48-bit number consisting of 6 octets.
A user is operating Client A and sends a message to Client B. What is used to identify the mode the transmission is meant for?
A MAC address is a globally unique identifier attached to an individual network interface. A MAC is used to identify which mode the transmission is meant for.
The technique that allows you to have multiple logical LANs operating on the same physical equipment is known as a ___________.
A VLAN is a way to use a single set of physical equipment in more than one way.
Which of the following statements accurately describe the differences between a hub and a switch? Check all that apply.
A hub causes larger collision domains/ a hub is a physical layer device, and a switch is a data link layer device/ a switch remembers which devices are connected on each interface, while a hub does not.
You have installed a device at the physical layer. All of the systems you connect to this device will talk to each other at the same time. What have you installed?
A hub is a physical layer device that allows for connections from many computers at once.
What is modulation?
A way of varying the voltage of this charge moving across the cable
What are Cables?
Cables are what connect different devices to each other, allowing data to be transmitted over them.
The Ethernet protocol functions at which layer of the Transmission Control Protocol/Internet Protocol (TCP/IP) model?
Data link; A lot of protocols exist at the data link layer, but the most common is Ethernet.
Where is the Start Frame Delimiter (SFD) found in an ethernet frame?
The SFD is found in the last byte of the preamble, and signals to a receiving device that the preamble is over, and that the actual frame contents will now follow.
A system has defined specifications that describe how signals are sent over connections. Which layer of the Transmission Control Protocol/Internet Protocol (TCP/IP) model provides this function?
Transport Layer protocols. The transport layer is represented by two protocols: TCP and UDP.
What is half-duplex?
While communication is possible in each direction, only one device can be communicating at a time
What's a router?
a device that knows how to forward data between independent networks.
What is network port?
generally directly attached to the devices that make up a computer network
Which of the following statements accurately describe the differences between a hub and a switch? Check all that apply. - A hub causes larger collision domains. - A switch remembers which devices are connected on each interface, while a hub does not. - Hubs are more sophisticated versions of switches. - A hub is a physical layer device, and a switch is a data link layer device.
- A hub causes larger collision domains. - A switch remembers which devices are connected on each interface, while a hub does not. - A hub is a physical layer device, and a switch is a data link layer device.
What device forwards data and operates at layer three of the Transmission Control Protocol/Internet Protocol (TCP/IP) model?
A router is a device that knows how to forward data between independent networks and operates at layer three.
Which layer in the Transmission Control Protocol/Internet Protocol (TCP/IP) model is responsible for delivering data between two nodes? Datalink, Network, Transport, Application
Not Transport
Something that requests data from a server is known as a ____.
client; A client requests data, and a server responds to that request.
When an electrical pulse on one wire is accidentally detected on another nearby wire, this is known as _____.
cross talk; Crosstalk is reduced by the way that wires are twisted inside of a cable.
What section in an ethernet frame will you find a Virtual Local Area Network (VLAN) header?
EtherType field, You may find a VLAN header in the EtherType field. This will indicate that the frame is called a VLAN frame.
What address is used for Ethernet broadcasts?
FF::FF:FF::FF::FF:FF
Which of the following is an example of a network layer (layer 3) protocol? IP, TCP, UDP, Ethernet
IP, or Internet Protocol, is the most common network layer protocol.
What is the type of modulation used by twisted pair cable computer networks known as?
Line coding
What is a patch panel?
a device containing many network ports. But it does no other work. It's just a container for the endpoints of many runs of cable
What are two approaches to control?
1. Contention Access (allow collisions) 2. Controlled access (prevent collisions)
What three concepts are central to the OSI model?
1. Services 2. Interfaces 3. Protocols
Which of the following are examples of layers of our five-layer network model? Check all that apply. The transport layer The application layer The physical layer The presentation layer
-The transport layer -The application layer -The physical layer
How are the seven OSI layers defined?
7. Application: Provides different services to the application 6. Presentation: Converts the information 5. Session: Handles problems which are not communication issues 4. Transport: Provides end to end communication control 3. Network: Routes the information in the network 2. Data Link: Provides error control 1. Physical: Connects the entity to the transmission media (An acronym used to help remember the model from bottom to top is "Please Do Not Throw Sausage Pizza Away." From top-down the "All People Seem To Need Data Processing" acronym can be utilized.)
How many wires are in a standard Category 6 cable?
8; A standard Cat6 cable has 8 wires that consist of four twisted pairs inside of a single jacket.
What is an Internetwork?
A collection of networks connected together through routers is an internetwork, the most famous of these being the Internet.
You get in your car after work and turn on the radio. What type of communication does the radio use?
A radio provides one way communication, or unidirectional. This is simplex communication.
What are the five layers in the Internet protocol stack?
Application layer Transport layer Network layer Data link layer Physical layer.
What is the Application Layer (Layer 5)?
Application layer is the top-most layer of five layered TCP/IP network model. While the lower layers of TCP/IP protocol suite are primarily concerned with formatting, encapsulating and transmitting data across the network to the destination computer, the top-most layer (Application layer) provides an interface between the network applications and other layers of TCP/IP protocol stack and ultimately the network.
What are the principal responsibilities of each layer?
Application layer: HTTP, SMTP, and FTP protocols are used in the application layer, it is used to send data over multiple end systems. Transport layer: Transfers the content between two endpoints mainly. TCP and UDP protocols are used in the transport layer. Network layer: Move the packets between any two hosts in the network. IP protocol is used in the network layer. Datalink layer: Move the packets from one node to the next to another node. Point-to-point protocol (PPP) used in the data link layer. Physical layer: Transfer the individual bits from one node to the next node within the frame.
Multiple systems try to send data at the same time. The electrical pulses sent across the cable interfere with each other. What type of network segment is being used?
Collision Domain; A collision domain is a network segment where only one device can communicate at a time.
A network segment where only one device can communicate at a time is known as a _____. - cross talk - protocol - collision domain - modulation
Collision domain - A collision domain is the term used to describe a network segment where collisions may occur -- that is, a network segment where only one device can successfully communicate at a time.
What is a Computer networking?
Computer networking is the name we've given to the full scope of how computers communicate with each other.
What is the TCP/IP model?
Five layers Application Layer (Layer 5) Transport Layer (Layer 4) Network Layer (Layer 3) Datalink Layer (Layer 2) Physical Layer (Layer 1)
What's the difference between full and half duplex?
Full duplex allows communications in two directions at the same time; half duplex means that only one side can communicate at a time.
What's the difference between full and half duplex? -Full duplex is slower than half duplex - Full duplex allows communications in two directions at the same time; half duplex means that only one side can communicate at a time. -Full duplex is a form of simpler communication - Half duple occurs when hubs are in use, full duplex occurs when switches are in use
Full duplex allows communications in two directions at the same time; half duplex means that only one side can communicate at a time.
What are functions of the Transport Layer?
Functions of Transport Layer are: 1 - Transport Layer provides an interface for network applications to access the network. 2 - Transport Layer provides interface for accepting data from different applications on the source computer and sending that data to the recipient applications on different destination computers (Multiplexing). Similarly on the destination computer, the incoming data from different remote computers need to be directed to the correct applications for that data was meant for (De-multiplexing). 3 - Transport layer treats each packet independently for final delivery, because each packet for final delivery belongs to different Applications on different destination computers. 4 - Transport layer has protocol/mechanisms for loss-free delivery of data to destination applications. 5 - Transport layer provides mechanisms for error checking, flow control, and re-transmission of lost data. Two major protocols at the Transport layer, Transmission Control Protocol (TCP) and User Datagram Protocol (UDP), work differently to achieve these goals.
What is the Physical Layer (Layer 1)?
It represents the physical devices that interconnect computers. The physical layer is all about cabling, connectors, and sending signals. The Physical Layer of the TCP/IP model is responsible for converting the Ethernet frame from the upper layer (Datalink Layer) into a stream of bits suitable for the transmission medium (electrical signals, light signals, or radio waves). The Physical layer manages and synchronizes signals for the actual transmission. The Physical layer places the bitstream on network media. On the destination device, the Physical layer reassembles these signals into the frame and transfers them to its upper layer (Datalink layer, Layer 2) of the TCP/IP model for further processing.
What does LAN stand for?
Local area network
What is the Network Layer (Layer 3)?
Network Layer (Layer 3) allows different networks to communicate with each other through devices known as routers. The Network Layer is the third layer of the TCP/IP protocol stack from the bottom. The TCP/IP model network layer's (layer 3) functions are similar to the network layer (layer 3) of the OSI model. The major protocols included in the Network layer (Layer 3) are Internet Protocol (IPv4 or IPv6), Internet Control Message Protocol (ICMP), Address Resolution Protocol (ARP), Reverse Address Resolution Protocol (RARP), and Internet Group Management Protocol (IGMP).
Select the device that will have the most network ports. Desktop, Server, Switch, Laptop
Switch; A switch will have the most network ports, because its purpose is to connect many devices.
How many layers does the OSI have?
The OSI model has seven layers, each of which has a different level of abstraction and performs a well-defined function. The principles that were applied to arrive at the seven layers are as follows (Feig)
What is the OSI model?
The Open Systems Interconnection model (OSI model) is a conceptual model that characterizes and standardizes the communication functions of a telecommunication or computing system without regard to its underlying internal structure and technology.
What comprises the upper layers of the OSI Model?
The application, presentation, and session layers comprise the upper layers of the OSI Model.
What is duplex communication?
The concept that information can flow in both directions across the cable (e.g. phone call)
What is the Datalink Layer (Layer 2)?
The data link layer is responsible for defining a common way of interpreting these signals, so network devices can communicate. The Datalink layer is the second layer of the TCP/IP model from the bottom. Datalink Layer is responsible for the encapsulation of outgoing IP Datagrams from the Network layer (Layer 3) into Frames. Datalink Layer inserts a layer 2 header and also a layer 2 trailer to its upper layer data (Network Layer). Finally, Frames are sent over the network as bitstream at the physical layer to the destination computer.
A defined set of standards that computers must follow in order to communicate properly is known as a _____.
The defined set of standards that computers must follow in order to communicate properly is called a protocol.
What is a protocol?
The defined set of standards that computers must follow in order to communicate properly is called a protocol.
What immediately follows the Start Frame Delimiter in an ethernet frame?
The destination MAC address immediately follows the Start Frame Delimiter.
What is the fifth layer of the Transmission Control Protocol/Internet Protocol (TCP/IP) model?
The fifth layer of the TCP/IP model is the application layer. The application layer focuses on application specific protocols.
You need to identify the manufacturer of a network interface. Where will you look for this information?
The first three octets of a MAC address are known as the Organizationally Unique Identifier (OUI). These are assigned to individual hardware manufacturers.
What is a twisted pair cable?
The most common type of cabling used for connecting computing devices; called that because it features pairs of copper wires that are twisted together; helps protect against electromagnetic interference and crosstalk from neighboring pairs
Which of the following are examples of layers of our five-layer network model? Check all that apply. The physical layer The transport layer, The presentation layer The application layer
The physical layer The transport layer, The application layer
What is the function of the software in the upper layers of the OSI Model?
The software in the upper layers perform application specific functions like data formatting, encryption, and connection management.
A user has multiple web pages open and is using email. Which layer of the Transmission Control Protocol/Internet Protocol (TCP/IP) model is responsible for sorting the data to send email and web pages to the appropriate location?
The transport layer is responsible for sorting out which client and server programs are supposed to get data.
What is the Transport Layer (Layer 4)?
While the network layer delivers data between two individual nodes, the Transport Layer (Layer 4) sorts out which client and server programs are supposed to get that data. The Transport Layer is the fourth layer of the TCP/IP protocol stack from the bottom. The TCP/IP model transport layer's (layer 4) functions are similar to the transport layer (layer 4) of the OSI model. Transport layer protocols (Transmission Control Protocol (TCP)/User Datagram Protocol (UDP)) encapsulate the data from the upper layer (Application layer) with a Transport layer header during outgoing transmission.
What is full duplex?
devices on either side of a networking link can both communicate with each other at the exact same time
What is Link LED?
will be lit when a cable is properly connected to two devices that are both powered on
What is simplex communication?
information can flow in one direction across the cable (e.g. baby monitor)
A device that knows how to forward traffic between independent networks is known as a _____.
router