IP Routing – Practice Test

IP is an acronym for Internet Protocol. Internet Protocol is a set of rules and protocols that govern the way data is transmitted over the internet. It defines how data packets are addressed, routed, and delivered to their destination. IP is an essential component of the internet infrastructure and enables communication between different devices and networks.

An octet is a unit of digital information that consists of 8 bits. Each bit can be either a 0 or a 1, representing binary data. Therefore, there are 8 bits in an octet.

The default subnet mask for Class B is 255.255.0.0. This subnet mask is used to divide an IP address into network and host portions. In Class B, the first two octets are used for the network portion, while the last two octets are used for the host portion. The subnet mask 255.255.0.0 signifies that the first two octets are fixed for the network, allowing for a larger number of hosts compared to Class C.

The default subnet mask for Class C is 255.255.255.0. This subnet mask is used to divide an IP address into network and host portions. In Class C, the first three octets are reserved for the network portion, while the last octet is used for the host portion. The subnet mask 255.255.255.0 signifies that the first three octets are fixed and the last octet can vary for different hosts within the network.

The default subnet mask for Class A is 255.0.0.0. In IPv4, IP addresses are divided into classes, with Class A being used for large networks. The subnet mask determines the network and host portions of an IP address. In Class A, the first octet is used for the network portion, while the remaining three octets are used for the host portion. The default subnet mask for Class A has all the bits in the first octet set to 1, indicating that the entire first octet is used for the network portion. Therefore, the correct answer is 255.0.0.0.

The four commonly used classes of IP addresses are Class A, Class B, Class C, and Class D. Class A addresses are used for large networks, Class B addresses are used for medium-sized networks, Class C addresses are used for small networks, and Class D addresses are used for multicast addresses. Therefore, the correct answer is "All of the above" as it includes all four classes of IP addresses.

RIP (Routing Information Protocol) uses hop count as the metric to determine the best path for routing. Hop count refers to the number of routers or network devices that a packet must pass through to reach its destination. In RIP, each router increments the hop count value by one when forwarding a packet. By comparing the hop counts of different routes, RIP selects the path with the lowest hop count as the best route. Therefore, hop count is the metric used by RIP to make routing decisions.

TCP stands for Transmission Control Protocol. It is a widely used networking protocol that provides reliable and ordered delivery of data packets over an IP network. TCP ensures that data packets are transmitted accurately and in the correct order, and it also handles congestion control and flow control to optimize network performance.

The beginning range for a layer three multicast address is 224.0.0.0. This range is reserved for multicast addresses and is used for various multicast protocols and applications. Multicast addresses in this range are used for communication between multiple hosts that are interested in receiving the multicast traffic.

OSPF (Open Shortest Path First) uses the metric of "cost" to determine the best path for routing. The cost is calculated based on various factors such as bandwidth, load, delay, reliability, and MTU (Maximum Transmission Unit). By considering these factors, OSPF can select the most efficient and reliable route for data transmission. The lower the cost, the more preferred the route becomes. Therefore, the correct answer is "cost".

The given IP address is 198.176.174.202 with a 28-bit subnet mask. A 28-bit subnet mask means that the first 28 bits of the IP address are used for the network address, and the remaining 4 bits are used for host addresses within the subnet.

To determine the subnet number, we need to find the network address by setting all the host bits to 0. In this case, the network address is 198.176.174.192.

To determine the subnet broadcast address, we need to find the address where all host bits are set to 1. In this case, the subnet broadcast address is 198.176.174.207.

Therefore, the correct answer is 198.176.174.192 – 198.176.174.207.

IGRP (Interior Gateway Routing Protocol) uses multiple metrics to determine the best path for routing. These metrics include bandwidth (the capacity of a link), load (the current traffic on a link), delay (the time taken for a packet to travel from source to destination), reliability (the probability of a link being operational), and MTU (Maximum Transmission Unit, the maximum size of a packet that can be transmitted). By considering these metrics, IGRP can make more informed decisions about the optimal routes for data packets within a network.

The correct answer is "ip name-server." This command is used to define a DNS server for the router to use in order to resolve logical names. By specifying the IP address of the DNS server, the router can send DNS queries to that server and receive the corresponding IP addresses for the logical names it needs to resolve.

OSPF and IS-IS are the routing protocols that are Link State. These protocols use the Link State Database (LSDB) to store information about the network topology, including the state and cost of each link. By exchanging link state information with neighboring routers, OSPF and IS-IS are able to build a complete and accurate map of the network. This allows them to calculate the shortest path to a destination and make efficient routing decisions. IGRP, on the other hand, is a distance vector routing protocol and does not use the Link State approach.

The correct answer is "ip host." This command is used to define an alias host name on a router. It allows the router to associate a specific IP address with a hostname, making it easier to manage and access network devices. The "ip host" command is commonly used in network configurations to create static mappings between IP addresses and hostnames.

The given subnet mask, 255.255.255.242, is illegal because it does not follow the standard subnet mask format. In a valid subnet mask, the network portion consists of consecutive 1s followed by consecutive 0s in the host portion. However, in this case, the subnet mask has a 1 followed by a 0 in the host portion, which is not allowed.

A Class B address has a default subnet mask of 255.255.0.0. However, in this question, a subnet mask of 255.255.255.128 is given, which means that the network portion of the address is extended by 1 bit, allowing for more subnets.

With a mask of 255.255.255.128, the last octet of the address is divided into 2 parts: the first 7 bits represent the network portion, and the last bit represents the host portion.

In the network portion, there are 7 bits, which can have 2^7 (128) possible combinations. However, the first and last combinations are reserved, so there are 128 - 2 = 126 usable networks.

In the host portion, there is 1 bit, which can have 2^1 (2) possible combinations. However, the first combination (all 0s) represents the network address, and the last combination (all 1s) represents the broadcast address, so there are 2 - 2 = 0 usable hosts.

Therefore, the correct answer is 510 networks and 126 hosts.

RIP (Routing Information Protocol) and IGRP (Interior Gateway Routing Protocol) are both examples of distance vector routing protocols. Distance vector routing protocols determine the best path for data packets based on the distance or number of hops to a destination. These protocols exchange routing information with neighboring routers and update their routing tables accordingly. RIP and IGRP use the Bellman-Ford algorithm to calculate the best path and have limitations such as slow convergence and limited scalability. On the other hand, OSPF (Open Shortest Path First) and IS-IS (Intermediate System to Intermediate System) are examples of link-state routing protocols, which use more advanced algorithms and have better scalability and faster convergence.

PING and Traceroute are network diagnostic tools that operate at different layers of the OSI reference model. PING tests the connectivity between two devices at the network layer (Layer 3), while Traceroute determines the path taken by packets from the source to the destination, also operating at the network layer. Additionally, both PING and Traceroute rely on lower layers for their functionality, such as the physical layer (Layer 1) for transmitting the packets and the data link layer (Layer 2) for addressing and error detection. Therefore, PING and Traceroute test the Physical, DataLink, and Network layers of the OSI reference model.