Coursera Notes

NAT stands for ______.

Network Address Translation

Which layer is responsible for getting data from one node to another?

Network Layer

What is another name for the Data Link Layer?

Network interface/Network access layer

Although TCP/IP is a commonly used term/phrase, are TCP and IP the same

No they serve different purposes.

Is a VLAN header always present in an ethernet frame?

No, not always present, but if it is, EtherType Field will immediately follow on the Ethernet Frame.

Do IP address belong to individual devices?

No, they belong to networks. MAC address belong to individual devices.

What is another way to reference each group of numbers in a MAC address?

Octet- In computer networking, any number that can be represented by 8 bits

Define OUI

Organizationally Unique identifier. These are assigned to individual hardware manufacturers by the IEEE

What is the 6th part of an ethernet Frame?

Payload- In networking terms, is the actual data being transported, which is everything that isnt a header.

Define Internetwork

A collection of networks connected together through routers, the most famous of these being the internet.

What is a patch panel

A device containing many network ports, but serves no other purpose. Cables then run from patch panel to switches or routers to provide network access.

Define Ethernet Frame

A highly structured collection of information presented in a specific order.

In a WAN, the area between a demarcation point and the ISP's core network is known as

A local Link

What is a hub and what made it obsolete?

A physical layer devices that allows for connections from many computers at once. Hubs caused collision domains which made it obsolete

What is Modulation?

A way of varying the voltage of this charge moving across the cable.

What is a Hexadecimal?

A way to represent numbers using 16 digits.

How is Hexadecimal able to represent 16 digits if only 0-9 are capable of being used?

ABCDEF are represented for the numbers 10,11,12,13,14,15

What is Line coding?

Allows devices on either end of a link to understand that an electrical charge in a certain state is a zero, and in another state is a one.

What is a data Packet

An all encompassing term that represents any single set of binary data being sent across a network link.

Define Broadcast

An ethernet broadcast is sent to every single device on a LAN

What does it mean if a VLAN tag is present?

Any frame with a VLAN tag will only be delivered out of a switch interface configured to relay that specific tag.

A technique that's used to route traffic to different destinations, depending on factors like location, congestion, or link health, is known as ____

Anycast

At the very lowest level, what data does a computer understand?

Binary Numbers

The final step of the DHCP Discovery process is known as ______.

DHCPREQUEST

Why is twisted pairs of internal wire in these cables important?

Depending on how they are arrange can drastically effect how data is sent across these wires and how resistant these signals are to outside interference?

What is the 2nd part of an Ethernet Frame

Destination MAC address. 6 bytes long, 48 bits long.

Define DHCP

Dynamic Host Configuration Protocol- A new device can connect to any network and will automatically be assigned an IP address.

A video conferencing application isn't working due to a Domain Name System (DNS) port error. Which record requires modification to fix the issue?

Service Record (SRV)

What is a network switch

Similar to a hub since you can connect many devices to it so they can communicate

A point-to-point VPN is also known as a

Site-to-site VPN

What is the 3rd part of an ethernet frame

Source MAC address 6 bytes long. The originating MAC address where information is coming from.

Define SFD

Start Frame Delimiter. Signals to a receiving device that the preamble is over and that the actual frame contents will now follow.

A new Domain Name System (DNS) server is being configured. Which record type is used to declare a new zone?

Start of Authority(SOA)

Difference between TCP and UDP?

TCP provides mechanism to ensure that data is reliably delivered while UDP does not

What is the commonly used protocol used at the transport layer

TCP-Transmission control Protocol

What is Cyclical Redundancy Check and what is its purpose?

The reason its included in the ethernet frame is so that the receiving network interface can infer if its received uncorrupted data.

T1 is short for?

Transmission System 1

Which layer sorts out which client and server programs are supposed to get data?

Transport Layer

VPNs are known as_________protocol?

Tunneling protocol

Define Unicast

Unicast is a transmission, which is always meant for just one receiving address. Info will be sent to all devices but only actually received and processed by the intended destination.

What is the 4th part of an Ethernet Frame

VLAN Header- a technique that lets you have multiple logical LANs operating on the same physical equipment.

Crosstalk

When an electrical pulse on one wire is accidentally detected on another wire.

WAN stands for_______?

Wide Area Network.

How is a MAC address split?

1.) First three octets are known as the OUI 2.) Last three octets, can be assigned in any way but can only given out once.

The "www" portion of a domain is known by which of the given options? Check all that apply

1.) Host Name 2.) Subdomain

What are the two parts of a Preamble?

1.) first seven bytes are a series of alternating ones and zeros. These act partially as a buffer between frames and can also be used by the network interfaces. 2.) SFD- start Frame Delimiter. Signals to a receiving device that the preamble is over and that the actual frame contents will now follow

How fast is a T1 Line?

1.544 Mb/sec

A company with a large number of hosts creates three subdomains under a main domain. For easier management of the host records, how many zones should be used?

4

The total number of IPv4 addresses is approximately:

4 billion

How long is a MAC address?

48-bit number normally represented by 6 groupings of two hexadecimal numbers

How many Layers does the TCP/IP Model have?

5 Layers 1.) Physical Layer 2.) Data Link Layer 3.) Network Layer 4.) Transport Layer 5.) Application Layer

What port on a name server is used for User Datagram Protocol (UDP) name request packets?

53

Define BGP-

Border Gateway Protocol. Routers share data with each other via this protocol, which lets them learn about the most optimal paths to forward traffic.

A DNS record that's used to redirect traffic from one domain name to another is known as a _______ record.

CNAME

Ethernet protocol solved the problem of collision domain by using a technique known as what?

CSMA/CD- Carrier Sense Multiple Access with Collision Detection

What is CSMA/CD and what is it used for?

Carrier Sense Multiple Access with Collision Detection. Used to determine when the communications channels are clear, and when a device is free to transmit Data.

Can a Cat6 or Cat5e send data over longer distances without losing data?

Cat 6

What makes Cat6 different than your standard Cat5e cables in regards to how they send data?

Cat6 cables send pulses of light to send data. Versus Cat5e cables send voltages to deliver data.

Network Software is usually divided into what two categories

Client and Server

A proxy is something that____________?

Communicates on behalf of something else.

What is the 5th part of an ethernet frame?

EtherType Field- 16 bits long and used to describe the protocol of the contents of the frame.

What is another term of a data packet?

Ethernet Frame

What is the most popular protocol used at the data Link Layer?

Ethernet Protocol

what is the 7th part of the ethernet frame?

FCS- Frame Check Sequence - 4 bytes or 32-bit number that represents a checksum value

What is the IP address of a broadcast

FF:FF:FF:FF:FF:FF

An IT systems engineer creates a new Domain Name System (DNS) zone that contains pointer (PTR) resource records. Which zone type has been created?

FQDN

Along with an IP address, a subnet mask, and a name server, the other thing required for a computer to operate on a network is a _______.

Gateway router

What is the Network Layer primarily responsible for?

Getting data delivered across a collection of networks,

What the difference between hubs and switches in terms of which layer they belong to?

Hubs operate at layer 1, switches at layer 2(data Link layer)

What is the most common protocol used at the Network Layer

IP-Internet Protocol

Define Simplex communication

Information can flow in only one direction. Ex. Baby monitor

What happens if the Checksum from the receiving party doesnt match that of the original generated by the sending party? and what does it mean if the numbers dont match up?

Information is either discarded or re-transmitted. This means some amount of data must have been lost or corrupted during transmission.

What is another term for Modulation in computer networking?

Line Coding

Which of the following is NOT configured by a Dynamic Host Protocol (DHCP) server?

MAC address

What does MAC stand for

Media Access Control

What is the importance of using DNS?

Name Resolution

What is the importance of using DNS?

Name resolution, translates a domain name into an IP address

What technique allows for inbound traffic through a NAT?

Port Preservation

An internal system behind a firewall needs to be configured for remote access. How should Network Address Translation be configured?

Port forwarding

What is the first part of an ethernet frame?

Preamble- 8 bytes(64 bits) long and can itslef be split into two sections

Which technique is used with Network Address Translation (NAT) where a source port chosen by a client is the same port used by a router?

Preservation

Advantages of Data Compressions

Reduction in storage hardware, data transmission time, and communication bandwith.

A service that might appear to be a single server to external clients, but actually represents many servers living behind it, is known as a _______.

Reverse Proxy

During the name resolution process, which server does a local recursive server contact first?

Root name server

An IT engineer is planning a website upgrade with load balancing features. What technology is used?

Round Robin

Which layer do routers operate at?

Router operate at layer 3, network layer

what makes in home routers and ISP routers different

Router store internal tables containing information about how to route traffic between lots of different networks all over the world. Where as in home routers are far more simple, they do not contain complex tables such as ISP routers.

When a client computer sends a request to a Domain Name System (DNS) server, what type of packet is sent?

SYN

Define Duplex Communication

The concept that information can flow in both directions across the cable

How is duplex communication made possible?

The way networking cables ensure that duplex communication is possible is by reserving one or two pair for communicating in one direction. Leave the other pair(s) for flow of data in the other direction.

Two-factor Authentication is_______?

a method where you need more than a username and a password

NAT addresses concerns over the dwindling IPv4 address space by

allowing computers using non-routable address space to communicate with the Internet.

The Dynamic Configuration Host Protocol (DHCP) operates at which Open Systems Interconnection (OSI) model layer?

application layer

What separates switches from hub in terms of how they operate

switches eliminate collision domains as it inspects the contents of the data being transmitted and only sends data to the intended device.