CCNA Chapter 5 Quiz

When a device is sending data to another device on a remote network, the Ethernet frame is sent to the MAC address of the default gateway. This is because the default gateway acts as the intermediary between the local network and the remote network. The device sends the data to the default gateway's MAC address, which then forwards the data to the appropriate destination on the remote network.

The destination address used in an ARP request frame is FFFF.FFFF.FFFF. This address is the broadcast address, which means that the request is sent to all devices on the network. By using this address, the sender is able to reach all devices and ask for the MAC address associated with a specific IP address.

A collision fragment, also known as a RUNT frame, is a frame of fewer than 64 bytes in length. This term is commonly used in computer networking to refer to a data packet that is too small to be processed correctly. These fragments are typically the result of collisions on the network, where two or more devices transmit data simultaneously and the packets collide, causing errors. RUNT frames are usually discarded by network devices as they do not contain enough data to be useful.

The ARP table in a switch maps Layer 3 addresses to Layer 2 addresses. This mapping allows the switch to know the Layer 2 MAC address of a device based on its Layer 3 IP address. This information is crucial for the switch to forward network traffic efficiently within the local network. By maintaining the ARP table, the switch can quickly determine the appropriate destination MAC address for each IP address it encounters.

When host A wants to send an IP packet to host D, it sends out a broadcast of FF:FF:FF:FF:FF:FF. This broadcast is received by every other host connected to the switch, including host D. Host D then responds to the broadcast with its MAC address. This allows host A to determine the MAC address of host D and send the IP packet directly to it.

Auto-MDIX is a feature that automatically detects the type of Ethernet cable being used and adjusts the connection accordingly. This feature eliminates the need for crossover cables, as it can automatically detect and configure the connection for both straight-through and crossover cables. Auto-MDIX simplifies network setup and makes it easier to connect devices without worrying about the cable type.

Runt frames are Ethernet frames that are smaller than the minimum frame size allowed by the Ethernet standard. When a Cisco Ethernet switch receives a runt frame, it drops the frame. This is because runt frames are usually considered to be errors or invalid frames that cannot be processed properly. Dropping the runt frame helps to maintain the integrity and efficiency of the network by not forwarding or processing faulty or incomplete frames.

The minimum size of an Ethernet frame is 64 bytes, while the maximum size is 1518 bytes. Ethernet frames are used to transmit data over Ethernet networks, and they consist of various components such as the preamble, destination and source addresses, payload, and checksum. The minimum size of 64 bytes ensures that the frame can carry the necessary control information, while the maximum size of 1518 bytes is determined by the maximum payload size allowed by the Ethernet standard, which is 1500 bytes, plus additional overhead for other components.

Store-and-forward is the switching method that uses the CRC (Cyclic Redundancy Check) value in a frame. In this method, the switch receives the entire frame, checks the CRC value to ensure data integrity, and then forwards the frame to the destination. This method is reliable as it verifies the correctness of the frame before forwarding, ensuring that only error-free frames are transmitted.

ARP spoofing is a technique used to send fake Address Resolution Protocol (ARP) messages to other hosts in the local area network (LAN). The purpose of ARP spoofing is to associate IP addresses with incorrect MAC addresses. This can be done to intercept network traffic, perform man-in-the-middle attacks, or gain unauthorized access to network resources. By sending fake ARP messages, the attacker can trick other hosts into sending their data to the wrong MAC address, allowing the attacker to intercept and manipulate the network traffic.

Ethernet is a widely used technology that defines the most common LAN (Local Area Network) type in the world. It is a set of standards that specifies the physical and data link layer protocols for wired networks. Ethernet allows devices to communicate and share resources within a local network, such as a home or office. It is not specifically related to internet communication or connecting multiple sites, but rather focuses on local network connectivity.

MAC addresses must be globally unique. This means that no two devices on a network should have the same MAC address. This uniqueness is important for the proper functioning of network protocols and ensuring that data is sent to the correct destination. MAC addresses are assigned by the manufacturer of the network interface card (NIC) and are typically hardcoded into the hardware.

Host A needs to communicate with host D, but it does not have the MAC address for its default gateway. In order to find the MAC address, host A will send an ARP (Address Resolution Protocol) request. This request will be broadcasted to all devices on the same network segment. Therefore, only hosts B and C, as well as the router R1, which are all connected to the same network segment as host A, will receive the ARP request. Host D will not receive the ARP request because it is not on the same network segment as host A.

The first three bytes of a MAC address are used by the vendor assigned OUI (Organizationally Unique Identifier). This OUI helps identify the manufacturer or vendor of the network interface card (NIC) or device. The OUI is assigned by the Institute of Electrical and Electronics Engineers (IEEE) and is used to ensure uniqueness and standardization in MAC addresses. The remaining three bytes in the MAC address are assigned by the manufacturer and help identify the specific device within the vendor's range.

Based on the contents of the MAC address table, the switch has learned the MAC address of PC3 on port 3. Therefore, when PC1 sends a frame addressed to PC3, the switch will forward the frame to all ports except port 4, as it knows that PC3 is connected to port 3. This ensures that the frame reaches its intended destination while minimizing unnecessary traffic on the network.

ARP (Address Resolution Protocol) requests are used to resolve IP addresses to MAC addresses on a local network. When a device needs to communicate with another device on the same network, it sends an ARP request to find the MAC address of the target device. The correct answer states that ARP requests are received and processed by every device on the local network. This is because ARP requests are broadcasted to all devices on the network, and each device checks if the request is for its own IP address. If it is, the device responds with its MAC address. Therefore, every device on the local network receives and processes ARP requests.

A switch builds its MAC address table by recording the source Layer 2 address of incoming frames. This allows the switch to associate a specific MAC address with a specific port on the switch. By keeping track of the source MAC addresses, the switch can make forwarding decisions based on the destination MAC address of incoming frames.

On a Cisco switch, "port-based" memory buffering is used to buffer frames in queues linked to specific incoming and outgoing ports. This means that each port on the switch has its own dedicated buffer to store incoming and outgoing frames, ensuring efficient and reliable data transmission. This type of buffering allows for better traffic management and prevents congestion on the switch.

When PC1 issues an ARP request, it is asking for the MAC address of PC2. PC2 will receive this request and respond with an ARP reply, providing its MAC address to PC1. This allows PC1 to correctly address the packet and send it to PC2. Therefore, the correct answer is that PC2 will send an ARP reply with its MAC address.

Multiple ARP broadcasts on large networks with low bandwidth can result in data communication delays because the network may become congested with excessive ARP traffic. Additionally, network attackers can manipulate MAC address and IP address mappings in ARP messages in order to intercept network traffic, compromising the security and integrity of the network.

The logical link control sublayer in Ethernet standards is responsible for implementing software-based functions. It interacts directly with the NIC driver software and allows the data link layer to communicate with the upper layers of the protocol suite. The LLC sublayer is not responsible for placing and retrieving frames on and off the media. Logical link control is specified in the IEEE 802.3 standard.