Google IT Bits and bytes of networking (Course 2)

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

binary

How many bits are reserved for the Transmission Control Protocol (TCP) flags?

10

How many octets are there in a MAC address?

A MAC address is a 48-bit number consisting of 6 octets.

Transport layer protocols, like TCP and UDP, introduce the concept of a port. How many bits is a port field?

A TCP or UDP port is a 16-bit numbe

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?

A network layer is a combination of the data line and defined in the article of OSI reference model. This layer defines how the data should be sent physically through the network. This layer is responsible for the transmission of the data between two devices on the same network.

A typical routing table may contain which of the following?

A routing table entry needs to know how many hops away a destination network is and A routing table entry has to be tied to a specific destination network.

How many octets does a subnet mask have?

A subnet mask is the same length as an IP address.

Which of the following statements accurately describe the differences between a hub and a switch?

A switch remembers which devices are connected on each interface, while a hub does not. casues large collisions

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

Application

What's a router?

Awesome work! A router connects independent networks by forwarding data between them.

What type of transmission will have a zero in a special bit in the destination Media Access Control (MAC) address?

Awesome! A unicast transmission uses the Ethernet level to look at a special bit in the destination MAC address. If the least significant bit in the first octet of a destination address is set to zero, it means that the ethernet frame is intended for only the destination address

The Domain Name System (DNS) network service uses which transport layer protocol?

Awesome! DNS uses the UDP protocol for queries and resolution. It is a connectionless protocol.

The entirety of a packet at one layer becoming the payload section at another layer is known as

Awesome! Encapsulation occurs at each layer of our network stack, except for the physical layer.

Application layer data lives in the _____ section of the transport layer protocol.

Awesome! The payload section of one layer contains the content of the layer above it.

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

Awesome! The requesting client initiates a query with a DNS server by sending a Synchronize (SYN) packet as a first step in the three-way handshake.

A proxy is something that _______________________.

Awesome! While proxies are many things, they primarily communicate on behalf of something else.

What's the standard number for a TTL field?

Awesome! While this value can be set to anything from 0 to 255, 64 is the recommended standard

What does CIDR stand for?

CIDR stands for Classless Inter-Domain Routing.

Which of the following allows computers on a network to automatically receive address assignment information?

DHCP

The process by which a client configured to use DHCP attempts to get network configuration information is known as

DHCP Discovery is how a client determines configuration information.

How many Transmission Control Protocol (TCP) control flags are there?

How many Transmission Control Protocol (TCP) control flags are there?

What address is used for Ethernet broadcasts?

Excellent! The address FF:FF:FF:FF:FF:FF is used for Ethernet broadcast traffic.

When using Fixed Allocation DHCP, what's used to determine a computer's IP?

Great job! Fixed Allocation DHCP ensures that computers receive an IP address reserved for it via its MAC address.

How many bits are used to direct traffic to specific services running on a networked computer?

Great work! A port is a 16-bit number that's used to direct traffic to specific services running on a networked computer.

The Domain Name System (DNS) provides an easy way to remember addresses. Without DNS, how many octets for an Internet Protocol (IP) address would have to be memorized

Great work! An IP address is presented with 4 octets separated by decimals, like 192.168.1.1.

A device that connects lots of devices and remembers which ones are connected to each interface is known as a?

Great work! By remembering which devices are connected to each interface, a switch reduces collision domains.

What is the process of taking a single IP datagram and splitting it up into several smaller datagrams called?

Great work! Fragmentation is the process of taking a single IP datagram and splitting it up into several smaller datagrams.

What is the most common example of a connection-oriented protocol?

Great work! Other examples of connection-oriented protocols exist, but TCP is, by far, the most common.

How many bits are in the checksum field in a Transmission Control Protocol (TCP) header?

Great work! The checksum field is a 16-bit field and is used to make sure no data was lost or corrupted during transmission.

What ordering of TCP flags makes up the Three-way Handshake?

Great work! The computer that wants to establish a connection sends a packet with the SYN flag set. Then, the server responds with a packet with both the SYN and ACK flags set. Finally, the original computer sends a packet with just the ACK flag set.

A device receives a Transmission Control Protocol (TCP) packet. The device understands where the actual data payload begins. Which portion of the TCP header provides this information

Great work! The data offset field communicates how long the TCP header for a segment is. This causes the receiving network device to understand where the actual data payload begin

A router is performing basic routing functions. What will be the third step in the transmission of a packet?

Great work! The router looks up the destination network of the IP address in its routing table in the third step.

What transport layer protocol does DNS normally use?

IP is not a transport layer protocol. DNS usually operates over the UDP protocol.

When NAT hides the source IP of an originating device, this is known as ________.

IP masqueradin

Administration and definition of TLDs are handled by a non-profit organization known as _______.

Icann

Why do entries in a local Address Resolution Protocol (ARP) table expire after a short amount of time?

It ill fill up the cache

NAT addresses concerns over the dwindling IPv4 address space by ___________________.

NAT allows networks to use non-routable address space for their internal devices.

What are the four things that all computers need configured in order to operate on a modern network?

Name server - default gateway - IP address - subnet mask

What's the difference between full and half duplex?

Nice job! A half duplex connection allows communication in both directions, but only one side can communicate at a time.

How many bits long is a Autonomous System Number (ASN)?

Nice job! ASNs are numbers assigned to individual autonomous systems. Just like IP addresses, ASNs are 32-bit numbers. But, unlike IP addresses, they're normally referred to as just a single decimal number instead of being split out into readable bits.

You open a web page and log into your email. The traffic travels over many routers. What protocol will the routers use to determine the most optimal path to forward the traffic?

Nice job! Border Gateway Protocol (BGP) lets routers learn about the most optimal paths to forward traffic.

Which of the following is an example of a network layer (layer 3) protocol?

Nice job! IP, or Internet Protocol, is the most common network layer protocol. - level 3

What is the process of taking a large network and splitting it up into many individual and smaller subnetworks called?

Nice job! Subnetting is the process of taking a large network and splitting it up into many individual and smaller subnetworks, or subnets.

VPNs are known as a _____ protocol.

Nice job! VPNs are tunneling protocols.

Another term for POTS, or the Plain Old Telephone System, is _______________.

Nice work! POTS and PSTN refer to the same thing.

A _______ record is responsible for resolving an IP to a domain name.

PTR record (pointer

What technique allows for inbound traffic through a NAT?

Port forwarding is a technique that allows for inbound traffic through a router configured to NAT.

Which of the following allows computers on a network to automatically receive address assignment information?

Right on! DHCP is used to automatically assign IP addresses to devices on a network.

What is the purpose of an ARP response?

Right on! The node that wants to send data sends a broadcast ARP message to the MAC broadcast address which is all F's. When the network interface receives this ARP broadcast, it sends back what's known as an ARP response. This response message will contain the MAC address for the network interface in question.

HTTP is an example of which layer protocol?

Right on! There are lots of application layer protocols, but HTTP is one of the most common ones.

UDP stands for ?

Right on! User Datagram Protocol is one of the more common transport layer protocols.

How many possible host IDs do you always lose per network?

Right on! You always lose two host IDs per network. So, if a /24 network has 2^8 or 256 potential hosts, you really only have 256 - 2 = 254 available IPs to assign.

A concept that involves iterating over a list of items one by one in an orderly fashion is known as

Round robin ensures a fairly equal distribution across its members.

Select examples of routing protocols?

Routing info protocol and Border Gateway Protocol

You get in your car after work and turn on the radio. What type of communication does the radio use?

Simplex is the simplest method of communication technology. Your car radio is a good example, as it only receives a signal, it cannot transmit.

A DNS TTL determines what?

TTL stands for Time to Live and determines how long a DNS entry can be cached.

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

That's right! A DHCPACK is the final step in the DHCP Discovery process.

RFC stands for

That's right! RFCs have long been used to help establish agreed-upon standards and protocols.

Which layer abstracts away the need for any other layers to care about what hardware is in use?

The Data link layer

What address is used for Ethernet broadcasts?

The address FF:FF:FF:FF:FF:FF is used for Ethernet broadcast traffic.

Unlike our five-layer model, the OSI network model adds two more layers on top of the Application Layer. What are they?

The session and presentation layer

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?

Well done! Preservation helps a router determine which traffic belongs to which host when using NAT.

A communication sent through Transmission Control Protocol (TCP) arrives out of order. What allows the data to be put back together in the correct order?

Well done! Sequence numbers allow the data to be put back together in the correct order.

Which section in an ethernet frame contains the data from higher layers, such as Internet Protocol (IP) and the transport and application layers?

Well done! The payload contains all of the data from higher layers, such as the IP, transport, and application layers, that's actually being transmitted.

What's the difference between a client and a server?

What's the difference between a client and a server?

Using CIDR notation, the subnet mask 255.255.255.0 would be written as _______.

Wohoo! 255.255.255.0 is one of the more common subnet masks or /24.

A subnet ID is calculated via a

Wohoo! A subnet mask is also a way to determine the size of a subnet.

When data can flow across a cable in both directions, this is known as?

Wohoo! Duplex communication occurs when data flows in both directions.

What does a value of one in an ACK control flag represent?

Woohoo! A value of one in the ACK flag field means that the acknowledgement number field should be examined.

IANA has primarily been responsible with assigning address blocks to five regional internet registries (RIR). A tech needs to research address blocks assigned in the United States. Which RIR should the tech contact?

Woohoo! ARIN primarily serves the United States and Canada.

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

Woohoo! DNS uses port 53 over UDP for name resolution communications.

What is the maximum decimal number possible to represent with 16 bits?

Woohoo! If you have a 16-bit number, you can just perform the math 2^16 which would be 65536 numbers.

Which two protocols work at the transport layer and ensures that data gets to the right applications running on those nodes?

Woohoo! TCP works at the transport layer and is responsible for ensuring that data gets to the right applications. TCP provides reliable delivery.

Something that requests data from a server is known as a?

Yep! A client requests data, and a server responds to that request.

What is a cyclical redundancy check?

Yep! A cyclical redundancy check ensures that there was no data corruption.

An A Record contains what?

Yep! An A record contains an IPv4 address.

You need to identify the manufacturer of a network interface. Where will you look for this information?

You nailed it! The first three octets of a MAC address are known as the Organizationally Unique Identifier (OUI). These are assigned to individual hardware manufacturers.

Which technology uses a tunneling protocol?

You got it! A VPN uses a tunnel to maintain private and secure communications.

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?

You got it! A collision domain is a network segment where only one device can communicate at a time.

A ________ is where one network ends and another begins.

You got it! It's important to know about demarcation points so that you understand where responsibility of the operation of a network begins and ends.

Ports 1-1023 are known as which ports?

You got it! System ports are used for very well-known services.

What layer in the Transmission Control Protocol/Internet Protocol (TCP/IP) model does IP use?

You got it! The network layer is also sometimes called the internet layer. The most common protocol used at this layer is Internet Protocol (IP).

A user requests an unencrypted webpage from a web server running on a computer, listening on the Internet Protocol address 10.1.1.150. What will be the socket address?

You got it! The socket address will be 10.1.1.150:80. Unencrypted web traffic uses port 80 and ports are normally denoted with a colon after the IP address.

How many root servers are there

You got it! There are 13 root servers.

Two-factor authentication is_________________________.

You got it! Two-factor authentication requires a username/password and something extra.

MAC address stands for?

You nailed it! A MAC address is sometimes also referred to as a hardware address.

A Local Area Network (LAN) uses Category 6 cabling. An issue with a connection results in a network link degradation and only one device can communicate at a time. What is the connection operating at?

You nailed it! A full duplex connection that has a connection issue will report itself to be operating as half duplex.

A Transmission Control Protocol (TCP) connection is established and two devices ensure that they're speaking the same protocol. What has occured?

You nailed it! A three-way handshake involves segments that have SYN, SYN/ACK, and ACK which happens every time a TCP connection is established.

A fully qualified domain name can contain how many characters?

You nailed it! An FQDN is limited to a total length of 255 characters.

What is eight bits of data called?

You nailed it! Eight bits of data, or a single octet, can represent all decimal numbers from 0-255.

What port does the File Transfer Protocol (FTP) typically listen on?

You nailed it! FTP typically listens on port 21.

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?

You nailed it! Four (4) zones would include the parent and the three (3) subdomains.

What is the type of modulation used by twisted pair cable computer networks known as?

You nailed it! Line coding is the modulation of an electrical charge so that each side of a connection knows what is a one and what is a zero.

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

anycast

MX stands for _______?

mail excahnge

What is a valid DNS setup?

one domain name can point to man IPs and many domain names can point to same IP

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

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

t it! A MAC address is a hardware address assigned to a device by the manufacturer.