The Ideal Quiz On CCENT/CCNA Icnd1 Chapters 4 + 5

The main function of OSI Layer 1 protocols is to deliver bits from one device to another. This layer is responsible for the physical transmission of data over the network, including the electrical, mechanical, and procedural aspects of the communication. It ensures that the bits are properly encoded, transmitted, and received between devices.

Each Class C network has a total of 256 IP addresses. However, out of these 256 addresses, one address is reserved for network identification and another address is reserved for broadcast, leaving 254 addresses that can be assigned to hosts. Therefore, the correct answer is 254.

CSU/DSU, which stands for Channel Service Unit/Data Service Unit, typically connects to a four-wire line provided by a telco. CSU/DSU is a device used in telecommunications to convert digital data from a router into a format that can be transmitted over a telecommunications line, and vice versa. It provides the interface between the router and the telco's line, allowing for the transmission of data over the network. Therefore, CSU/DSU is the correct answer for this question.

DHCP (Dynamic Host Configuration Protocol) allows a client PC to request assignment of an IP address as well as learn its default gateway. DHCP is a network protocol that enables a server to automatically assign IP addresses and other network configuration parameters to devices on a network. When a client PC connects to a network, it can send a DHCP request to the DHCP server, which will then assign it an IP address and provide information about the default gateway, DNS servers, and other network settings.

DNS (Domain Name System) is the correct answer because it is the protocol that allows a client PC to discover the IP address of another computer based on that other computer's name. DNS works by translating domain names (e.g., www.example.com) into IP addresses (e.g., 192.168.1.1) that can be understood by computers. This translation process is essential for establishing connections and communication between devices on a network. ARP (Address Resolution Protocol) and RARP (Reverse Address Resolution Protocol) are used for mapping IP addresses to MAC addresses, while DHCP (Dynamic Host Configuration Protocol) is used for automatically assigning IP addresses to devices on a network.

Each Class B network has a total of 65,534 IP addresses that can be assigned to hosts. This is because Class B networks have a subnet mask of 16 bits, which allows for 2^16 (65,536) possible IP addresses. However, the first and last IP addresses in each network are reserved for network identification and broadcast respectively, leaving 65,534 addresses available for hosts.

A router normally uses the destination IP address when making a decision about routing TCP/IP packets. The destination IP address identifies the intended recipient of the packet, allowing the router to determine the appropriate next hop or outgoing interface for forwarding the packet towards its destination. The source MAC address and source IP address are used for addressing and identification purposes, but they are not typically used by the router to make routing decisions. The destination MAC address is used at the data link layer for local network communication, but it is not relevant for routing packets between different networks.

OSI Layer 3 protocols are responsible for logical addressing and path selection. Logical addressing involves assigning unique addresses to devices on a network, allowing them to communicate with each other. Path selection refers to the process of determining the best route for data packets to travel from the source to the destination. These functions are essential for efficient and reliable communication within a network. Physical addressing, arbitration, and error recovery are not specific functions of Layer 3 protocols, making them incorrect choices.

When cabling a leased line, the CSU/DSU (Channel Service Unit/Data Service Unit) typically connects to a V.35 or RS-232 end of a cable. The CSU/DSU is a device used to connect a customer's equipment to a digital line provided by a telecommunications carrier. It provides signal conversion, line conditioning, and error detection functions. The CSU/DSU is responsible for converting the data from the customer's equipment into a format that can be transmitted over the leased line and vice versa.

The given IP address, 200.1.1.1, falls within the range of Class C IP addresses. In Class C, the first octet ranges from 192 to 223, indicating that this IP address is valid for assignment to hosts.

Class A IP networks have a first octet range of 1 to 126. This range allows for a total of 126 possible values for the first octet, with the value 0 reserved as a default network address and 127 reserved for loopback testing. The range of 1 to 126 is used to designate the network address, while the remaining three octets are used to identify specific hosts within the network.

Multiple VCs can share the same access link in Frame Relay. This means that multiple virtual circuits can be established and operate over a single physical connection. This allows for more efficient use of network resources and reduces the need for separate physical links for each VC. Each VC is identified by a unique Data Link Connection Identifier (DLCI), but they can all be transmitted over the same access link.

In a point-to-point WAN link using a leased line, routers are considered to be the DTE (Data Terminal Equipment) devices. DTE devices are the end devices that originate and terminate the data transmission. In this scenario, the routers located at each end of the link serve as the DTE devices as they receive and send data across the leased line. The other options listed, such as CSU/DSU (Channel Service Unit/Data Service Unit) and central office equipment, are not DTE devices but rather components that facilitate the connection and transmission of data between the DTE devices.

A LAN-connected TCP/IP host will send packets to its default gateway if the destination IP address is in a different class of IP network than the host. This is because different classes of IP networks have different network addresses, and the default gateway is responsible for routing packets between different networks. Additionally, the host will also send packets to its default gateway if the destination IP address is in a different subnet than the host. Subnets are smaller divisions of a network, and the default gateway is needed to route packets between different subnets within the same network.

The correct answer is Data-link connection identifier. In Frame Relay, the Data-link connection identifier (DLCI) is used to identify the virtual circuits. The DLCI is a unique identifier assigned to each virtual circuit and is used by the Frame Relay devices to determine the destination of the incoming frames.

In this scenario, Router1 acts as a bridge between the Ethernet network and the HDLC serial link. When PC1 sends data to PC2, Router1 receives the frame from PC1 and removes the Ethernet header and trailer. Since the frame is being sent over the HDLC serial link, the Ethernet header and trailer are not needed and are discarded by Router1. Router1 then encapsulates the remaining data (payload) in an HDLC header and sends it to Router2. Router2 will then extract the Ethernet frame from the HDLC header and forward it to PC2. Therefore, the statement "Router1 strips the Ethernet header and trailer off the frame received from PC1, never to be used again" is correct.

The function of identifying the type of protocol that is inside the frame is specified by the protocol standard for PPP, but Cisco uses a proprietary header field for HDLC to implement this function. This means that while PPP follows the standard protocol for identifying the protocol type, Cisco's HDLC uses its own header field for the same purpose.

PC1's IP address is 10.1.1.1, which means it is on a network with a subnet mask of 255.0.0.0. This means that any IP address that starts with 10.x.x.x can be on the same network as PC1. Therefore, 10.1.1.2 is a valid address for PC2. However, 10.2.2.2 and 10.200.200.1 are on different networks and cannot be used for PC2. Similarly, 9.1.1.1 and 1.1.1.1 are on different networks and cannot be used for PC2.

The correct answer is None of these answers are correct because HDLC addressing does not use specific addresses like 1, 2, and 3, or any specific range between 1 and 1023, or between 16 and 1000. HDLC addressing uses the HDLC address field to identify the specific destination router, but there is no requirement for the addresses to be sequential or within a specific range. Therefore, none of the given options are correct.

When PC1 needs to send data to PC2, the data is divided into smaller units called packets. These packets are then sent over the network and are responsible for carrying the actual data from PC1 to PC2. Therefore, the largest entities that make it from PC1 to PC2 are the packets. Additionally, the L3 PDU (Protocol Data Unit) also plays a role in this process as it encapsulates the packets and adds necessary routing information.

A routing protocol is responsible for advertising known routes to neighboring routers, allowing them to learn about the available network paths. It also learns routes for subnets directly connected to the router and adds those routes to the routing table. Additionally, it learns routes from neighboring routers and adds them to the routing table, enabling the router to forward IP packets based on their destination IP addresses.