Cisco 800-150 Practice Test - Questions Answers

Backing up the configuration of a network device before replacement is a critical step to ensure business continuity and minimize downtime. The primary purpose of this backup is to restore the existing settings onto the new device, ensuring that it operates identically to the one being replaced.

This process includes preserving interface configurations, routing protocols, access control lists, and other essential parameters. By restoring the backed-up configuration to the new device, network administrators can quickly reintegrate it into the network infrastructure without the need for manual reconfiguration, thereby reducing the risk of errors and service disruptions.

Options A, B, and C do not align with the primary objective of configuration backups in the context of device replacement.

In a local area network (LAN), the primary function of a switch is to operate at Layer 2 (Data Link Layer) of the OSI model. Switches use MAC addresses to forward frames to the appropriate destination ports. This targeted forwarding mechanism divides the network into separate collision domains for each switch port. By isolating collision domains, switches significantly reduce the chance of collisions, enhancing the performance and efficiency of the network.

Unlike hubs, which forward all traffic to all ports (thus creating a single collision domain), switches intelligently forward only the necessary traffic to the correct port. This capability allows multiple simultaneous conversations on different switch ports without interference.

Routers, which operate at Layer 3 (Network Layer), are used to route packets between different networks, not within the same LAN. Wireless connectivity is provided by wireless access points (WAPs), not switches. Encryption is typically handled by security protocols or devices such as firewalls and not by switches directly.

In an enterprise network, Virtual Local Area Networks (VLANs) are the key Layer 2 technology used to logically segment a network into multiple broadcast domains. VLANs allow network administrators to assign individual switch ports to specific VLANs, enabling effective network segmentation and traffic management.

This configuration extends to access layer devices, such as switches where end-user devices connect. By isolating traffic into VLANs, administrators can improve network performance, enhance security by separating sensitive departments (such as finance and HR), and simplify network management.

Unlike routing protocols such as BGP and OSPF, which operate at Layer 3, or MPLS, which is a Layer 2.5 forwarding technology used primarily in service provider networks, VLANs are explicitly designed for Layer 2 segmentation within LAN environments.

A speed mismatch occurs when two connected Ethernet devices are configured to operate at different speeds. In scenario A, one device is manually set to 1 Gbps, while the other is set to 100 Mbps. Since both ends are hard-coded to different speeds, they cannot successfully negotiate a common speed, leading to a mismatch and resulting in a failed or unstable link.

In contrast, scenario B, where both ends are manually set to the same speed, ensures compatibility and stable communication. Scenario C can lead to a duplex mismatch rather than a speed mismatch; the auto-negotiating end may default to half-duplex if it cannot determine the duplex setting of the manually configured end. Scenario D is less common; if auto-negotiation fails, devices may revert to their lowest common speed, but this typically results in reduced performance rather than a complete mismatch.

===========

The Data Link Layer (Layer 2) of the OSI model is responsible for node-to-node data transfer and plays a crucial role in error detection and media access control. It ensures that data frames are transmitted to the correct device on a local network segment.

This layer is divided into two sublayers:

Logical Link Control (LLC): Manages frame synchronization, flow control, and error checking.

Media Access Control (MAC): Controls how devices on the network gain access to the medium and permission to transmit data.

Together, these sublayers ensure reliable data transmission by detecting and possibly correcting errors that may occur in the Physical Layer. They also manage how devices share the transmission medium, preventing collisions and ensuring orderly communication.

In the context of Wide Area Networks (WANs), the key objective is to connect geographically separated networks using service provider infrastructure. The FLDTEC course emphasizes that WAN environments typically involve devices that can handle different physical transmission mediums and protocols.

Modems:

Modulate and demodulate analog signals to digital signals.

Used in WAN environments to connect over analog lines like DSL or leased lines.

Essential for interfacing between digital routers and analog telephone networks.

Optical Fiber Converters:

Also known as media converters, they are used to convert electrical signals to optical signals (and vice versa) for fiber transmission.

Common in WAN scenarios where long-distance high-speed transmission over fiber is required.

Incorrect Options:

A . Hubs: Obsolete Layer 1 devices used in LANs, not suitable for WANs.

D . Network Interface Cards (NICs): Used in end devices for LAN connectivity.

E . Wireless Access Points: Typically used in WLANs within local premises, not WAN infrastructure.

This aligns with Cisco's WAN architecture fundamentals as highlighted in FLDTEC under ''Cisco Equipment and Related Hardware.''