Networking Fundamentals Test 1

If an ISP assigned you a /28 IPv4 address block, how many computers could be assigned an address from the block?

32-28 = 4. 2^4 = 16, 16 - 2 = 14.

What is a communication protocol? Conceptually, what two aspects of communication does a protocol specify?

A communication protocol specifies how information will be represented and communicated. It specifies how data is represented and how it is transmitted.

What is a computer network?

A computer network is a group of computer systems and other computing devices that are connected by a physical communication medium such as a wire, radio wave, or light beam.

What is an internetwork or internet?

An interwork or internet consists of two or more networks connected to one another by using a computer device called a router.

How do you connect a computer to a wired LAN

By using a Network Interface Card (NIC)

How do you connect a computer to a wireless LAN?

By using a Wireless Network Interface Card

How are computers identified on a computer that uses the TCP/IP protocol stack?

By using their IP address

Give three examples of an Internet application?

Email, web browsing, file upload and download, audio and voice telephone calls, distributed database, and video teleconferencing.

What is the family of networking technologies commonly used in wired LAN?

Ethernet

What is a Berkeley broadcast address?

First BSD (Berkeley Software Distribution) implementation of UNIX used all 0s for broadcast instead of all 1s.

What are the two types of IP addresses?

IPv4 and IPv6

Suppose you are an ISP that owns a /22 IPv4 address block. Show the CIDR allocation you would use to allocate address blocks to four customers who need addresses for 60 computers each.

In order to accommodate four customers, the prefix must be extended by at least 2 bits for a total of at least 24 bits. So, the suffix should be at most 8 bits 60 < 64 - 2 ==> 60 < 26 - 2 ==> each customer has a /26 IP address block

What is the MAC address of a computer?

It is the 48-bit address that is assigned to the NIC of that computer.

List the layers in the TCP/IP model, and give a brief explanation of each.

Layer 1: Physical Protocols in the physical layer specify details about the underlying transmission medium and the associated hardware. Layer 2: Network Interface Layer This layer is also referred to as Link layer or MAC (Media Access Control) layer. Protocols in this layer specify the details about communication between two computers on the same packet switch network (or link) and the interface between the network hardware and layer 3. Layer 3: Network The internet layer has the responsibility of sending packets known as datagrams from one host to another across potentially multiple networks. Layer 4: Transport Protocols in this layer take care of the communication from an application program on one computer to an application program on another computer. Layer 5: Session Protocols in this layer specify how a pair of applications (potentially from two different networks) interacts when they communicate.

What are the three major categories of networks and what are their characteristics?

Local Area Network (LAN): is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building. Metropolitan Area Network (MAN): spans a major city. Wide Area Network (WAN): covers a larger geographic distance, and also generally involves leased telecommunication circuits or internet links.

How are messages from different sending hosts transmitted over a packet switching network?

Messages are subdivided into small blocks called packets that include the identity of the receiving host. These packets are sent one after another on the same communication medium and the system allows other senders to send their own packets before the first sender can transmit the next packet.

Suppose you are an ISP with a /24 IPv4 address block. Explain whether you can accommodate a request from a customer who needs addresses for 255 computers. (Hint: consider the special addresses.)

No because 2^8 is 256, 256 - 2 is 254 which is less than 255 computer addresses needed.

Does IPv6 use broadcast addresses? Explain *(Not his explanation)*

No, IPv6 does not implement traditional IP broadcast, the transmission of a packet to all hosts on the attached link using a special broadcast address, and therefore does not define broadcast addresses.

What is the network protocol stack used on most internets?

TCP/IP

Is the CIDR prefix 1.2.3.4/29 valid? Why or why not?

The CIDR prefix 1.2.3.4/29 is invalid since its suffix is 100 which is not all 0's.

List major standardization organizations that create standards for data communications and computer networking.

The Institute for Electrical and Electronics Engineers (IEEE). The International Organization for Standardization (ISO).

What are the two parts of a MAC address?

The left-most group of 3 bytes (in hex) is assigned by IEEE and is used to identify the manufacturer of the NIC. This is referred to as the Organizationally Unique Identifier (OUI). The right-most group of 3 byte (in hex) is assigned by the manufacturer to identify a particular NIC.

What is the purpose of a computer network?

The purpose of a computer network is to facilitate communication and resource sharing among a wide range of computing devices.

How many IPv4 addresses are assigned to a router that connects to N networks? Explain.

There are N interfaces since each router that connects to a network has a unique IP address.

What is the technology used for wireless LAN?

Wi-Fi

In the original IPv4 classful address scheme, was it possible to determine the class of an address from the address itself? Explain.

Yes. By looking at the first few bits of the address: Class A: 0; class B: 10; class C: 110; class D: 1110; class E: 1111

Suppose you are an ISP that owns a /22 IPv4 address block. Can you accommodate requests from six customers who need addresses for 9,15, 20, 41, 128, and 260 computers, respectively? If so, how? If not, explain why.

Yes. Create two subnets A & B: A is identified with prefix 0 and B with prefix 1

Can a host have more than one IPv4 address? Explain.

Yes. If it is connected to more than one network.