CCNA Lan Chapter #1

The core layer of the hierarchical network design model is referred to as the high-speed backbone of the internetwork, where high availability and redundancy are critical. This layer is responsible for providing fast and reliable connectivity between different parts of the network. It ensures that data can be efficiently transmitted across the network and that there are backup paths in case of failures. The core layer is designed to handle large amounts of traffic and to provide a stable and resilient foundation for the network.

Having SW3 connected to both SW1 and SW2 exhibits the characteristic of redundancy in hierarchical network designs. Redundancy refers to the practice of having multiple paths or connections between network devices to ensure that if one path fails or becomes unavailable, there is an alternative path available for data transmission. In this case, by connecting SW3 to both SW1 and SW2, there are redundant paths for data to flow, increasing network reliability and minimizing the risk of network downtime.

Quality of service (QoS) should be enabled at all three layers of the hierarchical network for organizations implementing a voice over IP solution. QoS ensures that voice traffic is given priority over other types of traffic, such as data, to maintain a high level of call quality and minimize latency and packet loss. By enabling QoS at all three layers, including the access layer, distribution layer, and core layer, organizations can prioritize voice traffic throughout the network and ensure a smooth and reliable voice over IP experience for their users.

Redundancy is the recommended hierarchical design characteristic at both the core and distribution layers to protect the network in the case of a route failure. Redundancy refers to the duplication of critical network components or connections to provide backup options in case of failure. By implementing redundancy at both layers, the network can ensure that there are alternative routes available in case of a failure, minimizing downtime and maintaining network connectivity. This helps to enhance network reliability and resilience.

Link aggregation is a feature that supports higher throughput in switched networks by combining multiple switch ports. It allows multiple physical links to be bundled together to form a single logical link, increasing the overall bandwidth and providing redundancy. This enables the network to handle more traffic and improves performance by distributing the load across multiple links. By aggregating the bandwidth of multiple ports, link aggregation enhances the network's capacity and allows for faster data transfer.

The access layer of the hierarchical design model provides a means of connecting devices to the network and controlling which devices are allowed to communicate on the network. This layer is responsible for connecting end-user devices, such as computers and phones, to the network infrastructure. It also enforces security policies and controls access to the network.

An access layer LAN 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 reliable transfer of data between adjacent network nodes. It operates at the level of individual frames and uses MAC addresses to determine the destination of each frame. The access layer switch uses this information to forward the frames to the appropriate destination within the local area network.

The distribution layer in the hierarchical design model controls the flow of network traffic using policies and performs routing functions between virtual LANs (VLANs). It helps to delineate broadcast domains by separating them into different VLANs. The distribution layer is responsible for filtering and forwarding traffic between different networks and ensuring efficient and secure communication throughout the network.

Configuring communication between devices on different VLANs requires the use of Layer 3 of the OSI model. Layer 3, also known as the network layer, is responsible for routing and forwarding data packets across different networks. It handles IP addressing, subnetting, and routing protocols, which are essential for devices on different VLANs to communicate with each other. Layer 1 is the physical layer, Layer 2 is the data link layer, Layer 4 is the transport layer, and Layer 5 is the session layer, none of which are directly involved in VLAN communication.

The correct answer is to configure port security options on S1 and use Layer 3 access control features on D1 and D2 to limit access to the HR servers to just the HR subnet. This adheres to the hierarchical network model design principles by implementing security measures at different layers of the network. Port security on S1 ensures that only authorized devices can connect to the network, while Layer 3 access control on D1 and D2 restricts access to the HR servers based on their IP subnet. This approach helps in reducing network traffic load and ensuring secure access to the HR servers.

Switches are normally not required to process all ports at wire speed at the access layer. The access layer is responsible for connecting end devices such as computers, printers, and IP phones to the network. Since the access layer is the closest to the end devices, the traffic volume is typically lower compared to the core or distribution layers. Therefore, switches at the access layer do not need to process all ports at wire speed, as the traffic demands are lower in this layer.

Enterprise level switches are designed to handle large amounts of network traffic in a high-performance environment. High forwarding rate is a characteristic associated with enterprise level switches as they are capable of processing and forwarding data packets at a fast rate, ensuring efficient and smooth network operation. Support for link aggregation is another characteristic as enterprise level switches often have the capability to combine multiple physical links into a single logical link, providing increased bandwidth and redundancy for critical network connections.

Moving a conventional company architecture to a completely converged network creates a shared infrastructure, resulting in a single network to manage. This means that all the different components of the network, such as voice, data, and video, are combined into one network, eliminating the need for separate networks and reducing complexity. With a single network to manage, it becomes easier to monitor and maintain the network, leading to improved efficiency and cost-effectiveness.

Link aggregation should be implemented at the access, distribution, and core layers of the hierarchical network. Link aggregation, also known as link bundling or port trunking, is a technique used to combine multiple physical links into a single logical link. This helps to increase bandwidth, improve network performance, and provide redundancy. By implementing link aggregation at all three layers of the hierarchical network, organizations can ensure that the benefits of link aggregation are realized throughout the network, from the access layer where end devices connect, to the distribution layer where traffic is routed, and finally to the core layer where high-speed backbone connections are established.

A modular switch is best described by its flexible characteristics. This means that it can be easily customized and expanded based on the specific needs of a network. It allows for the addition or removal of modules, such as interface cards or power supplies, to adapt to changing requirements. This flexibility enables the switch to support various network configurations and technologies, making it a versatile and adaptable solution.

StackWise technology allows up to nine switches to be interconnected via the use of a fully redundant backplane. This means that multiple switches can be connected together to form a single logical unit, increasing the overall capacity and performance of the network. The use of a fully redundant backplane ensures high availability and fault tolerance, as if one switch fails, the others in the stack can continue to operate seamlessly. This technology provides scalability and flexibility for expanding the network infrastructure.

At all three levels of the Cisco three-layer hierarchical model, Quality of Service (QoS) and link aggregation are supported. QoS ensures that certain network traffic receives priority over others, allowing for better performance and efficient resource allocation. Link aggregation combines multiple physical links into a single logical link, increasing bandwidth and providing redundancy. Both of these features are essential for optimizing network performance and ensuring high availability in the hierarchical model.

In order to determine the necessary port density for new switches, the network technician would need information on traffic flow analysis and expected future growth. Traffic flow analysis would provide insights into the current network usage patterns, allowing the technician to identify areas of high traffic and allocate sufficient ports to handle the load. Expected future growth would help in estimating the number of additional devices that will be connected to the network, enabling the technician to plan for future expansion and avoid potential bottlenecks.

At the distribution layer of the Cisco hierarchical network model, three commonly supported features are security policies, quality of service, and Layer 3 functionality. Security policies ensure that the network is protected against unauthorized access and potential threats. Quality of service allows for the prioritization and management of network traffic to ensure optimal performance for different types of applications. Layer 3 functionality enables routing and connectivity between different networks, allowing for efficient communication across the network infrastructure.

The switch that operates at the network core needs to support 10 Gigabit Ethernet to ensure high-speed data transmission. Quality of service (QoS) is also important to prioritize network traffic and ensure efficient utilization of network resources. Additionally, hot-swappable hardware is necessary for easy replacement of faulty components without causing network downtime. Port security and security policies are not mentioned as essential features for optimum network performance and reliability in this scenario.