Intro to Computer Networking: Week 2

An ARP broadcast is sent to the special MAC address ________.

*FF:FF:FF:FF:FF:FF* 00:00:00:00:00:00 255.255.255.255 192.168.0.1 *ARP broadcasts are used to ask all devices on a local area network if they're associated with a specific IP address.*

Select examples of routing protocols. Check all that apply.

*Routing Information Protocol* Transmission Control Protocol User Datagram Protocol *Border Gateway Protocol*

How many bits long is an IP address?

*32 bits* 64 bits 8 bits 256 bits *IP addresses are 32-bit-long numbers made up of four octets, and each octet is normally described in decimal numbers.*

What does CIDR stand for?

*Classless Inter-Domain Routing* Classfull Inter-Destination Routing Classfull Identification Routing Classless Internet Destination Routing

QoS services are protocols that allow routers to make decisions about which IP datagram may be more important than others. Which IP header field would QoS details be found?

*Service type field* Total length field Identification field Fragmentation offset field *These 8 bits can be used to specify details about quality of service, or QoS, technologies. The important take away about QoS is that they're services that allow routers to make decisions about which IP datagram may be more important than others.*

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

*Subnetting* Clustering Cloud computing Dynamic Host Configuration Protocol (DHCP) *Subnetting is the process of taking a large network and splitting it up into many individual and smaller subnetworks, or subnets.*

Which octet of the subnet mask 255.255.255.0 will tell the router the corresponding host ID?

*The last octet* The middle two octets The first and last octet The first octet *The size of a subnet is entirely defined by its subnet mask. So for example, with a subnet mask of 255.255.255.0, we know that only the last octet is available for host IDs, regardless of what the size the network and subnet IDs are.*

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

/64 */24* /8 /16 *255.255.255.0 is one of the more common subnet masks.*

A single octet in an IP address represents what range of decimal numbers?

0-155 *0-255* 0-250 1-255 *Eight bits of data, or a single octet, can represent all decimal numbers from 0-255.*

How many octets does a subnet mask have?

1 2 3 *4* *A subnet mask is the same length as an IP address.*

Computer A wants to send some data to computer B. Computer A knows that Computer B is not on its local network, so it sends the packet to the router between Network A and Network B. Based on how many network hops have happened, how much will the TTL field be decremented by?

1 8 6 *2* *The router decrements the TTL field by one for each network hop and calculates a new header checksum.*

Which number cannot be represented by eight bits of data?

12 *436* 232 128 *Eight bits of data, or a single octet, can represent all decimal numbers from 0-255. 436 is beyond this limit.*

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

12 4 *2* 8 *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.*

Which is a valid IP address?

126.396.659.100 598.36.789 *128.42.64.78* A8:97:4F:6D:H6:0F *128.42.64.78 has the correct notation and does not containany numbers that can't be represented by a single octet.*

Which of the following is a correct form of CIDR notation?

192.168.1.0\24 *192.168.1.0/24* 192.168.1.0 + 255.255.255.0 192.168.1.0:24 *CIDR notation uses a forward slash and then lists the numbers of bits in the subnet mask.*

There are ____ octets in an IP address.

2 *4* 8 16 *An octet represents eight bits, or one byte.*

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

256 *65536* 16 1600 *If you have a 16-bit number, you can just perform the math 2^16 which would be 65536 numbers.*

Please select all of the valid IP addresses. Check all that apply.

257.70.312.49 *8.8.8.8* *192.168.1.1* 123.456.123.456

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

Clustering *Fragmentation* Load balancing NAT firewall *Fragmentation is the process of taking a single IP datagram and splitting it up into several smaller datagrams.*

What type of network address space allows for nodes on a network to communicate with each other, but prevents any gateway router from forwarding traffic there, and are reserved for internal networks?

IP address MAC address *Non-routable address space* Subnet mask *Non-routable address space allows for nodes on such a network to communicate with each other, but no gateway router will attempt to forward traffic to this type of network.*

What protocol communicates data between routers representing the edges of autonomous systems?

Interior gateway Link state Distance-vector *Exterior gateway* *Exterior gateway protocols are used to communicate data between routers representing the edges of autonomous systems.*

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

It will use too much memory. To keep space in the table. It only needs to be used one time. *To account for network changes.*

What is the term for the place one network ends and another begins?

NAT firewall Subnet DMZ *Demarcation point* *To demarcate something means to set something off. When discussing computer networking you'll often hear the term demarcation point to describe where one network or system ends and another one begins.*

What is eight bits of data called?

Octoploid *Octet* Figure eight Octuplet

Which are a type of interior gateway protocol? (Check all that apply)

RDP (Remote Desktop Protocol) TFTP (Trivial File Transfer Protocol) *Link state routing protocols* *Distance-vector protocols* *A router using a distance vector protocol basically just takes its routing table, which is a list of every network known to it and how far away these networks are in terms of hops. Then the router sends this list to every neighboring router, which is basically every router directly connected to it.*

RFC stands for ______.

Routing Frequency Control *Request For Comments* Realtime Frame Check Redundant Frame Controller *RFCs have long been used to help establish agreed-upon standards and protocols.*

What protocol is used to discover the hardware address of a node with a certain IP address?

SQL database CIDR, or Classless Inter-Domain Routing *ARP table* Subnet mask *An ARP table is just a list of IP addresses and the MAC addresses associated with them.*

What is the correct term for the list of IP addresses and the MAC addresses associated with them?

SQL database Directory service *ARP table* File transfer protocol (FTP) *ARP is a protocol used to discover the hardware address of a node with a certain IP address.*

Ranges of IP addresses that anyone can use for their internal networks are known as ______.

Subnet Masks Demarcation Points Autonomous Systems *Nonroutable Address Space*

A typical routing table may contain which of the following? Check all that apply.

TTL *Destination network* *Total hops* Destination address *A routing table entry has to be tied to a specific destination network.*

Who is permitted to use non-routable address space?

The IANA It's for testing purposes only The IETF *Anyone*

What happens to the TTL field of an IP datagram every time it reaches a router?

The TTL field is used for a cyclical redundancy check. The TTL field is incremented by one. *The TTL field is decremented by one.* The TTL field is reset to zero. *At every router hop, the TTL field is decremented by one until it reaches zero, causing the datagram to be discarded.*

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

The router forwards the packet. The router examines the destination IP. A router receives a packet of data. *The router looks up the destination network in its routing table.* *The router looks up the destination network of the IP address in its routing table in the third step.*

Using logical operators, 1 AND 0 = _____.

True *False* 1 2 *Using the AND operator, the result is only 1, or true, if both sides are also 1, or true.*

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

subnetting *encapsulation* fragmentation routing *Encapsulation occurs at each layer of our network stack, except for the physical layer.*

A network device that knows how to forward data along to other networks is known as a ______.

switch hub *router* server *A router allows devices on different networks to communicate with each other.*