Which Port Does Switch0 Use to Send Frames to the Host with the IPv4 Address 10.1.1.5? Detailed Answer

Introduction

In modern networking, switches play a crucial role in ensuring that data packets reach their intended destinations efficiently. Unlike hubs, which simply broadcast traffic to all connected devices, switches intelligently forward frames based on MAC addresses. This functionality enhances network performance and security, making switches an essential component in any networking environment.

A common networking question arises when determining how a switch, such as Switch0, selects the appropriate port to forward frames to a specific host with an IPv4 address, such as 10.1.1.5. Understanding this process requires a deep dive into how switches manage MAC address tables, handle frame forwarding, and interact with Address Resolution Protocol (ARP). In this article, we will explore these concepts in detail, ensuring a comprehensive understanding for IT professionals and students preparing for networking certification exams.

DumpsQueen provides high-quality study materials to help candidates master networking concepts and excel in certification exams. This guide will clarify the process of switch frame forwarding and equip readers with the knowledge required to answer related exam questions confidently.

How Does a Switch Forward Frames?

A switch operates at the Data Link Layer (Layer 2) of the OSI model and makes forwarding decisions based on MAC addresses. Unlike routers, which work with IP addresses, switches focus on MAC addresses to determine where to send frames. When a switch receives an Ethernet frame, it examines the destination MAC address and checks its MAC address table to determine the correct port for forwarding the frame.

If the MAC address is already stored in the table, the switch sends the frame directly to the corresponding port. If the address is unknown, the switch floods the frame out of all ports except the one it was received on. This process ensures that the correct device receives the data, while minimizing unnecessary traffic in the network.

Understanding MAC Address Tables

A switch maintains a MAC address table, also known as a Cisco Exam Dumps Content Addressable Memory (CAM) table, which maps MAC addresses to switch ports. Each entry in this table consists of the following information:

The MAC address of a connected device.
The corresponding switch port where the device is connected.
A timestamp indicating when the MAC address was last updated.

Switches learn MAC addresses dynamically by examining the source MAC address of incoming frames. If a switch receives a frame from a new device, it records the MAC address and associates it with the port where the frame arrived. This learning process allows the switch to build an efficient forwarding database over time.

Role of ARP in IP-to-MAC Resolution

Switches work with MAC addresses, but network communication typically occurs using IP addresses. To bridge this gap, devices use the Address Resolution Protocol (ARP) to resolve IP addresses to MAC addresses. When a device needs to communicate with another device on the same network, it sends an ARP request to determine the MAC address associated with the target IP address.

For example, if a computer wants to send data to the host with IPv4 address 10.1.1.5, it first sends an ARP request: "Who has 10.1.1.5?" The device with that IP address responds with its MAC address, allowing the sender to construct a frame with the correct Layer 2 destination address. Once the MAC address is known, the switch forwards the frame through the appropriate port.

Identifying the Correct Port for IPv4 Address 10.1.1.5

When a switch receives a frame destined for the host with IP address 10.1.1.5, it follows these steps to determine the correct port:

The switch examines the frame’s destination MAC address.
It checks the MAC address table to see if the address is associated with a specific port.
If the address is found, the switch forwards the frame to the correct port.
If the address is not found, the switch floods the frame to all ports except the incoming one, prompting the target device to respond and allowing the switch to learn its MAC address.

For example, consider the following network setup:

Host A (10.1.1.1) has a MAC address of 00:1A:2B:3C:4D:5E and is connected to FastEthernet0/1.
Host B (10.1.1.5) has a MAC address of 00:1A:2B:3C:4D:6F and is connected to FastEthernet0/2.
If Switch0 has learned the MAC address of Host B, it will forward frames destined for 10.1.1.5 through FastEthernet0/2.

Thus, in this scenario, the correct answer to the question "Which port does Switch0 use to send frames to the host with the IPv4 address 10.1.1.5?" is FastEthernet0/2.

Conclusion

Switches are fundamental components of modern networks, ensuring efficient and intelligent data transmission based on MAC addresses. When forwarding frames to a host with a specific IPv4 address, such as 10.1.1.5, Switch0 determines the correct port by consulting its MAC address table. If the MAC address is known, the switch forwards the frame directly. If not, it floods the network to locate the target device.

Understanding these concepts is crucial for networking professionals and students preparing for Cisco certification exams. By mastering switch operations, MAC address learning, and ARP processes, candidates can enhance their troubleshooting skills and optimize network performance.