The LAN Switching Basic Quiz

A switch uses the MAC address to make forwarding decisions. MAC (Media Access Control) address is a unique identifier assigned to the network interface card (NIC) of a device. The switch examines the destination MAC address of incoming packets and uses this information to determine which port to forward the packet to. This allows the switch to efficiently and accurately route network traffic within a local area network (LAN).

A switch uses Layer 2 of the OSI model to make a forwarding decision. Layer 2, also known as the Data Link layer, is responsible for the physical addressing of devices on the network and the delivery of data frames between devices on the same local network. Switches examine the destination MAC address in the data frames received and use this information to determine the appropriate port to forward the frame to.

The maximum hop count for RIP is 15. Hop count refers to the number of routers a packet must traverse to reach its destination. RIP (Routing Information Protocol) is a distance-vector routing protocol that uses hop count as its metric. It means that RIP will choose the route with the fewest hops to reach a destination. In RIP, if the hop count exceeds 15, the route is considered unreachable or invalid, and the packet will be discarded. Therefore, 15 is the maximum hop count for RIP.

A straight cable is used to connect devices of different types, such as a switch to a router, a switch to a workstation, and a hub to a workstation. It is called a straight cable because the pin assignments on one end of the cable are the same as the pin assignments on the other end, allowing for direct communication between the devices.

EIGRP, which stands for Enhanced Interior Gateway Routing Protocol, is a proprietary routing protocol developed by Cisco. It is used to exchange routing information within an autonomous system (AS) in a computer network. EIGRP provides fast convergence, scalability, and support for both IPv4 and IPv6 networks. As a proprietary protocol, it is only available on Cisco devices and is not open to other vendors. Therefore, the correct answer is Cisco.

A crossover cable is the correct answer because it is used to connect devices of the same type, such as workstation to workstation, switch to switch, and router to PC. This type of cable is designed to allow the transmission of data between two devices without the need for a separate network switch. It is called a crossover cable because the transmit and receive wires are crossed over in the cable, allowing the devices to communicate directly with each other.

OSPF (Open Shortest Path First) is a link state routing protocol. It is used to determine the shortest path between routers in a network by exchanging link state information. OSPF uses a hierarchical structure and calculates routes based on the cost of the links. It is widely used in large networks due to its scalability and fast convergence. RIP (Routing Information Protocol) and IGRP (Interior Gateway Routing Protocol) are distance vector routing protocols, while EIGRP (Enhanced Interior Gateway Routing Protocol) is a hybrid routing protocol.

Link-state routing protocols, such as OSPF and IS-IS, use Dijkstra's Algorithm to calculate the shortest path between nodes in a network. Dijkstra's Algorithm is a graph search algorithm that finds the shortest path from a source node to all other nodes in a weighted graph. It operates by iteratively selecting the node with the smallest distance and updating the distances to its neighboring nodes. In the context of link-state routing protocols, Dijkstra's Algorithm is used to determine the best path for forwarding packets based on the link-state information exchanged between routers.

A prefix of /30 in networking refers to a subnet with a 30-bit network mask, which allows for 2 bits to be used for host addressing. With 2 bits, there are 4 possible combinations: 00, 01, 10, and 11. However, the first combination (00) is reserved for the network address and the last combination (11) is reserved for the broadcast address. Therefore, only 2 combinations (01 and 10) can be used for addressing hosts, allowing for 2 hosts to be addressed with a prefix of /30.

VLSM stands for Variable Length Subnet Masking. It is the ability to subnet a subnet and use different subnet masks with the same classful network. This allows for more efficient allocation of IP addresses by allowing different subnets within a network to have different sizes, depending on the number of hosts they need to accommodate. This flexibility is not possible with classful networks, which use fixed subnet masks. CIDR (Classless Inter-Domain Routing) is related to VLSM but refers to the practice of assigning IP addresses based on arbitrary boundaries rather than fixed classes. Route summarization is the process of combining multiple smaller subnets into a larger one for routing efficiency. BGP (Border Gateway Protocol) is a routing protocol used to exchange routing information between different autonomous systems on the internet.

A rollover cable is used to configure a router by connecting to the serial port of a computer. This type of cable is specifically designed for connecting a computer to the console port of a router or switch. It has a pinout that reverses the transmit and receive pins, allowing the computer and the router to communicate effectively. By using a rollover cable, network administrators can access the command-line interface of the router and configure its settings.

An autonomous system refers to a collection of networks that are under the control of a single administrative entity. It is a network that operates independently and has its own routing policies. This allows for efficient management and control of the networks within the system. Unlike other options such as segment, area, or WAN, an autonomous system specifically emphasizes the concept of a unified network infrastructure under a common administration.

The DUAL (Diffusing Update Algorithm) Algorithm is the distance vector algorithm used by EIGRP (Enhanced Interior Gateway Routing Protocol). It is responsible for calculating the best path to a destination network by considering various factors such as bandwidth, delay, reliability, and load. The DUAL Algorithm helps in maintaining loop-free and efficient routing within the network by exchanging routing information with neighboring routers and making dynamic routing decisions based on the information received.

The feasible distance in EIGRP refers to the lowest cost of a route. It is the metric used to determine the best path for routing packets. The feasible distance is calculated based on the bandwidth, delay, reliability, and other factors of the route. It helps EIGRP determine the most optimal path for packet transmission within the network.

Switches create multiple collision domains. A collision domain is a network segment where collisions can occur when two or more devices transmit data at the same time. Switches use a technique called micro-segmentation to create separate collision domains for each of its ports, thereby reducing the likelihood of collisions and improving network performance.

The "Show ip protocols" command will verify RIP configurations. This command displays the current routing protocol configurations on a router, including RIP. It provides information such as the routing protocol timers, network advertisements, and interfaces on which RIP is enabled. By using this command, network administrators can verify if RIP is correctly configured and functioning as expected.

IGRP is a classful routing protocol because it does not support variable length subnet masking (VLSM). Classful routing protocols divide the IP address space into fixed-sized network classes, such as class A, B, or C, and do not allow for the use of subnet masks to create smaller subnets within these classes. IGRP uses a fixed-length subnet mask and does not support the use of VLSM, making it a classful routing protocol.

The purpose of LSA's (Link State Advertisements) is to construct a topological database. LSA's are used in link-state routing protocols, such as OSPF (Open Shortest Path First), to exchange information about network links and routers. By exchanging LSA's, routers can build a detailed map of the network's topology, including information about link costs, network addresses, and neighboring routers. This topological database is then used to calculate the best path to a destination and make routing decisions within the network.

Cut-Through frame transmission mode reads the destination address of a frame only before forwarding it. In this mode, the switch starts forwarding the frame as soon as it reads the destination address, without waiting for the entire frame to be received. This mode offers low latency but does not perform error checking or discard frames with errors.

OSPF routes packets within a single Autonomous System (AS). An AS is a collection of networks that are under a common administration and share a common routing policy. OSPF is an interior gateway protocol (IGP) designed to support large networks and is used to exchange routing information within an AS. By routing packets within a single AS, OSPF helps ensure efficient and reliable communication between networks within that AS.