CCNA – Semester 3 Chapter 1: LAN Design CCNA Exploration 4.0 2 Objectives • Describe how a hierarchical network supports the voice, and data needs of a small- or medium-sized business. • Describe the functions of each of the three levels of the hierarchical network design model, the principles of hierarchical network design (aggregate connectivity, network diameter, and redundancy), and the concept of a converged network. • Provide examples of how voice and video over IP affect network design. • Select appropriate devices to operate at each level of the hierarchy, including voice and video components. • Match the appropriate Cisco switch to each layer in the hierarchical network design model. 3 Switched LAN Architecture The Hierarchical Network Model • Access Layer: interfaces with end devices, to provide a means of connecting devices to the network and controlling which devices are allowed to communicate on the network. – Include routers, switches, bridges, hubs, and wireless access points. 4 The Hierarchical Network Model • Distribution Layer: aggregates the data; controls the flow of network traffic. – Distribution layer switches are typically high-performance devices that have high availability and redundancy to ensure reliability. 5 The Hierarchical Network Model • Core layer: the high-speed backbone of the internetwork. The core layer is critical for interconnectivity between distribution layer devices, so it is important for the core to be highly available and redundant. The core aggregates the traffic from all the distribution layer devices, so it must be capable of forwarding large amounts of data quickly. 6 The Hierarchical Network Model • The logical representation makes it easy to see which switches perform which function. It is much harder to see these hierarchical layers when the network is installed in a business. 7 7 Benefits of a Hierarchical Network • Scalability – Hierarchical networks can be expanded easily • Redundancy – Redundancy at the core and distribution level ensure path availability • Performance – Link aggregation between levels and high-performance core and distribution level switches allow for near wire-throughout the network • Security – Port security at the access level and policies at the distribution level make the network more secure • Manageability – Consistency between switches at each level makes management more simple • Maintainability – The modularity of hierarchical design allows the network to scale without becoming overly complicated 8 Hierarchical Network Design Principles • Network Diameter: – Measure the number of devices that a packet has to cross before it reaches its destination. Keeping the network diameter low ensures low and predictable latency between devices. 9 Hierarchical Network Design Principles • Bandwidth Aggregation: – Bandwidth aggregation is the practice of considering the specific bandwidth requirements of each part of the hierarchy. – Link aggregation allows multiple switch port links to be combined so as to achieve higher throughput between switches. Cisco has a proprietary link aggregation technology called EtherChannel, which allows multiple Ethernet links to be consolidated. 10 [...]... network design 35 Summary • • • • • • • • • VLANs separate broadcast domains on switches VLANs improve network performance, management, and security VLAN can be used for data, voice, network protocol and network management traffic There are 3 different membership modes: Static, Dynamic, and Voice VLAN mode Routers or Layer 3 switches are required for inter-VLAN communication Trunks allow multiple VLANs...Hierarchical Network Design Principles • Redundancy: – Is one part of creating a highly available network Redundancy can be provided in a number of ways For example, you can double up the network connections between devices, or you can double the devices themselves 11 Hierarchical Network Design Principles Start at the Access Layer • Design a new network: Design requirements, such as the... Design requirements, such as the level of • performance or redundancy necessary, are determined by the business goals of the organization Once the design requirements are documented, the designer can begin selecting the equipment and infrastructure to implement the design When you start the equipment selection at the access layer, you can ensure that you accommodate all network devices needing access to... inter-VLAN communication Trunks allow multiple VLANs to traverse a single link to simplify intraVLAN communication across multiple switches IEEE 802.1Q is the standard trunking protocol 802.1Q uses a process of frame tagging to keep VLAN traffic separate as it traverse the trunk link 802.1Q does not tag native VLAN traffic, which can result in problems when trunking is misconfigured 36 ... Separate Voice, Video and Data Networks Activity: 1.1.3.3 17 Matching Switches to Specific LAN Functions 18 Considerations for Hierarchical Network Switches • • Traffic Flow Analysis – The process to measure the bandwidth usage on a network and analyze the data for the purpose of performance tuning, capacity planning, and making hardware improvement decisions – Done using traffic flow analysis software... for SMB 30 Switches for SMB 31 Switches for SMB 32 Switches for SMB 33 Switches for SMB • • Activity 1.2.4.2 Activity 1.2.4.3 34 Summary • • • • • The hierarchical design model improves upon the limitation of flat, partial mesh, and mesh design models by improving the performance, scalability, availability, manageability, and maintainability of the network Hierarchical network topologies facilitate... and IP phones because you can install them anywhere you can run an Ethernet cable Layer 3 Functions: – Layer 3 switches offer advanced functionality that will be discussed in greater detail in the later chapters of this course Layer 3 switches are also known as multilayer switches 25 Switch Features Layer 3 Functions Power over Ethernet 26 Switch Features in a Hierarchical Network • Access Layer Switch . CCNA – Semester 3 Chapter 1: LAN Design CCNA Exploration 4.0 2 Objectives • Describe how a hierarchical network supports. can double the devices themselves. 11 Hierarchical Network Design Principles Start at the Access Layer • Design a new network: Design requirements, such as the level of performance or redundancy. goals of the organization. Once the design requirements are documented, the designer can begin selecting the equipment and infrastructure to implement the design. • When you start the equipment