2.6.3 Check Your Understanding – Ports and Addresses Answers

2.6.3 Check Your Understanding – Ports and Addresses Answers

The “2.6.3 Check Your Understanding – Ports and Addresses Answers” section (2.6.3) is designed to test your knowledge of network ports and addressing concepts. In this exercise, you will review key concepts related to how ports and IP addresses are used in network communication. Understanding ports and addresses is essential for configuring network services and troubleshooting connectivity issues. This section will challenge your comprehension of port numbers, protocols, and their roles in facilitating communication between devices over a network.

  1. What is the structure of an IPv4 address called?

    • Dotted-binary format
    • Dotted-decimal format
    • Dotted-hexadecimal format
      Explanation & Hint:

      The correct answer is: Dotted-decimal format

      An IPv4 address is a 32-bit numerical label that uniquely identifies a device on a network. The structure of an IPv4 address is called dotted-decimal format because it consists of four decimal numbers separated by dots (periods).

      For example:
      192.168.1.1

      Each of the four numbers (known as octets) represents 8 bits of the 32-bit address, and each octet ranges from 0 to 255. The address is stored as a binary number in the computer, but it is presented in a human-readable form using decimal numbers.

      The other options are incorrect because:

      • Dotted-binary format would imply that the IP address is displayed in binary form (e.g., 11000000.10101000.00000001.00000001).

      • Dotted-hexadecimal format would imply that the IP address is displayed in hexadecimal form (e.g., C0.A8.01.01).

      Therefore, the correct and commonly used format for IPv4 addresses is dotted-decimal format.

  2. How is an IPv4 address represented?

    • Four binary numbers between 0 and 1 separated by colons.
    • Four decimal numbers between 0 and 255 separated by periods.
    • Thirty-two hexadecimal numbers separated by colons.
    • Thirty-two hexadecimal numbers separated by periods.
    • Explanation & Hint:

      The correct answer is: Four decimal numbers between 0 and 255 separated by periods.

      An IPv4 address is represented as four decimal numbers (also called octets) separated by periods (dots). Each number can range from 0 to 255, which corresponds to an 8-bit binary number. The entire IPv4 address is a 32-bit address divided into four 8-bit segments.

      Example:

      192.168.0.1

      • Each segment (192, 168, 0, 1) is a decimal number between 0 and 255.

      • The address is human-readable, but the underlying representation in binary might be:
        11000000.10101000.00000000.00000001

      Why the other options are incorrect:

      • Four binary numbers between 0 and 1 separated by colons: IPv4 addresses use decimal numbers and periods, not binary numbers or colons.

      • Thirty-two hexadecimal numbers separated by colons: This format resembles an IPv6 address, not IPv4.

      • Thirty-two hexadecimal numbers separated by periods: IPv4 does not use hexadecimal representation; it uses decimal numbers.

      Hence, the correct representation of an IPv4 address is four decimal numbers between 0 and 255 separated by periods.

  3. What type of interface has no physical port associated with it?

    • Console
    • Ethernet
    • Serial
    • Switch virtual interface (SVI)
    • Explanation & Hint:

      The correct answer is: Switch Virtual Interface (SVI)

      A Switch Virtual Interface (SVI) is a virtual interface configured on a network switch. Unlike physical interfaces (such as Ethernet or Serial), an SVI does not have a physical port associated with it. Instead, it is a logical interface that allows for Layer 3 (IP) communication within a switch. SVIs are commonly used for inter-VLAN routing, allowing VLANs to communicate with each other.

      Why the other options are incorrect:

      • Console: This is a physical interface used for directly accessing the device’s command-line interface (CLI) through a console cable.

      • Ethernet: This is a physical network interface used for wired connections.

      • Serial: This is another physical interface typically used for WAN connections, such as connecting to a router or a modem.

      Therefore, the correct answer is Switch Virtual Interface (SVI), as it is a purely virtual interface without a physical port.

Noted:

1. IPv4 addresses are written in dotted-decimal format. For example: 192.168.1.1.
2. IPv4 addresses are written as four groups of decimal numbers separated by periods. For example: 192.168.1.1.
3. Switch virtual interfaces (SVIs) are virtual and have no physical port. Layer 2 switches use SVIs for remote management.