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Cisco CCNA - Fundamentals of Wireless Lans - Companion Guide. Routing Protocols and Concepts CCNA Exploration Companion Guide. Cisco CCNA Exploration Course Booklet - LAN Switching and Wireless V4. ii LAN Switching and Wireless, CCNA Exploration Companion Guide Using a Networker's Journal” PDF booklet providing important insight into the value. ii CCNA Exploration Course Booklet: LAN Switching and Wireless, Version Detailed instructions are provided within the activity as well as in the PDF link .

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Lan Switching And Wireless Pdf

This book is designed to provide information about the Cisco CCNP SWITCH exam (). Activate CCNP Routing a. LAN Switching and Wireless, CCNA Exploration Companion Guide. 4 Pages · · 14 CCNA Routing and Switching Practice Questions For aracer.mobi lan switching and wireless pdf lan switching and wireless ccna exploration companion guide LAN Switching and Wi-fi CCNA. Exploration Companion Guide .

For the small- and medium-sized business, communicating digitally using data, voice, and video is critical to business survival. Consequently, a properly designed LAN is a fundamental requirement for doing business today. You must be able to recognize a well-designed LAN and select the ap- propriate devices to support the network specifications of a small- or medium-sized business. In this chapter, you will begin exploring the switched LAN architecture and some of the principles that are used to design a hierarchical network. You will learn about converged networks. You will also learn how to select the correct switch for a hierarchal network and which Cisco switches are best suited for each network layer. The activities and labs confirm and reinforce your learning. Compared to other network de- signs, a hierarchical network is easier to manage and expand, and problems are solved more quickly. Hierarchical network design involves dividing the network into discrete layers.

Maintainability Because hierarchical networks are modular in nature and scale very easily, they are easy to maintain. With other network topology designs, maintainability becomes increasingly complicated as the network grows. Also, in some network design models, there is a finite limit to how large the network can grow before it becomes too complicated and expensive to maintain. In the hierarchical design model, switch functions are defined at each layer, making the selection of the correct switch easier.

Adding switches to one layer does not necessarily mean there will not be a bottleneck or other limitation at another layer. For a full mesh network topology to achieve maximum performance, all switches need to be high-performance switches because each switch needs to be capable of performing all the functions on the network. In the hierarchical model, switch functions are different at each layer. You can save money by using less-expensive access layer switches at the lowest layer, and spend more on the distribution and core layer switches to achieve high performance on the network.

Principles of Hierarchical Network Design Just because a network seems to have a hierarchical design does not mean that the network is well designed. These simple guidelines will help you differentiate between well-designed and poorly designed hierarchical networks. This section is not intended to provide you with all the skills and knowledge you need to design a hierarchical network, but it offers you an opportunity to begin to practice your skills by transforming a flat network topology into a hierarchical network topology.

Network Diameter When designing a hierarchical network topology, the first thing to consider is network diameter, as depicted in Figure Diameter is traditionally a measure of distance, but in the case of networking, we are using the term to measure the number of devices. Network diameter is 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.

Figure Network Diameter 4 3 C1 C2. Up to six interconnected switches could be between PC1 and PC3. In this case, the network diameter is six.

Each switch in the path introduces some degree of latency. Network device latency is the time spent by a device as it processes a packet or frame.

Each switch has to determine the destination MAC address of the frame, check its MAC address table, and forward the frame out the appropriate port. Even though that entire process happens in a fraction of a second, the time adds up when the frame has to cross many switches. In the three-layer hierarchical model, Layer 2 segmentation at the distribution layer practically eliminates network diameter as an issue.

In a hierarchical network, network diameter is always going to be a predictable number of hops between the source and destination devices. Bandwidth Aggregation Each layer in the hierarchical network model is a possible candidate for bandwidth aggregation. Bandwidth aggregation is the combining of two or more connections to create a logically singular higher bandwidth connection.

After bandwidth requirements of the network are known, links between specific switches can be aggregated, which is called link aggregation. 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. A discussion of EtherChannel is beyond the scope of this book.

To learn more, visit www. In Figure , computers PC1 and PC3 require a significant amount of bandwidth because they are frequently used for streaming video. The network manager has determined that the access layer switches S1, S3, and S5 require increased bandwidth. Following up the hierarchy, these access layer switches connect to the distribution switches D1, D2, and D4.

The distribution switches connect to core layer switches C1 and C2. Notice how specific links on specific ports in each switch are aggregated. In this way, increased bandwidth is provided for in a targeted, specific part of the network. As is customary, aggregated links are indicated in this figure by two dotted lines with an oval tying them together.

Figure Bandwidth Aggregation. Redundancy 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. This chapter explores how to employ redundant network paths between switches. A discussion on doubling up network devices and employing special network protocols to ensure high availability is beyond the scope of this book. For an interesting discussion on high availability, visit www. Implementing redundant links can be expensive. Imagine if every switch in each layer of the network hierarchy had a connection to every switch at the next layer.

It is unlikely that you will be able to implement redundancy at the access layer because of the cost and limited features in the end devices, but you can build redundancy into the distribution and core layers of the network. In Figure , redundant links are shown at the distribution layer and core layer. At the distribution layer are four distribution layer switches; two distribution layer switches is the minimum required to support redundancy at this layer.

The access layer switches, S1, S3, S4, and S6, are cross-connected to the distribution layer switches. The bolder dotted lines here indicate the secondary redundant uplinks. This protects your network if one of the distribution switches fails. In case of a failure, the access layer switch adjusts its transmission path and forwards the traffic through the other distribution switch. Figure Redundancy C1 C2.

Some network failure scenarios can never be prevented—for example, if the power goes out in the entire city, or the entire building is demolished because of an earthquake. Redundancy does not attempt to address these types of disasters. To learn more about how a business can continue to work and recover from a disaster, visit www. Imagine that a new network design is required. Design requirements, such as the level of performance or redundancy necessary, are determined by the business goals of the organization.

After 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 the network. After you have all end devices accounted for, you have a better idea of how many access layer switches you need. The number of access layer switches, and the estimated traffic that each generates, helps you to determine how many distribution layer switches are required to achieve the performance and redundancy needed for the network.

After you have determined the number of distribution layer switches, you can identify how many core switches are required to maintain the performance of the network. A thorough discussion on how to determine which switch to select based on traffic flow analysis and how many core switches are required to maintain performance is beyond the scope of this book.

For a good introduction to network design, an excellent reference is Top-Down Network Design, by Priscilla Oppenheimer, available at ciscopress. What Is a Converged Network? Small- and medium-sized businesses are embracing the idea of running voice and video services on their data networks. Legacy Equipment Convergence is the process of combining voice and video communications on a data network.

Converged networks have existed for a while now, but were feasible only in large enterprise organizations because of the network infrastructure requirements and complex management that was involved to make them work seamlessly. High network costs were associated with convergence because more expensive switch hardware was required to support the additional bandwidth requirements. Converged networks also required extensive management in relation to quality of service QoS , because voice and video data traffic needed to be classified and prioritized on the network.

Few individuals had the expertise in voice, video, and data networks to make convergence feasible and functional. In addition, legacy equipment hinders the process. Figure shows legacy telephone company switches and a legacy wiring closet. Also, many offices still use analog phones, so they still have.

Because analog phones have not yet been replaced, you will see equipment that has to support both legacy private branch exchange PBX telephone systems and IP-based phones. This sort of equipment will slowly be migrated to modern IP-based phone switches.

Figure Legacy Equipment. Advanced Technology Converging voice, video, and data networks has become more popular recently in the smallto medium-sized business market because of advancements in technology. Convergence is now easier to implement and manage, and less expensive to download. Figure shows a high-end IP phone and switch combination suitable for a medium-sized business of to employees. The figure also shows a Cisco Catalyst Express switch and a Cisco G phone suitable for small- to medium-sized businesses.

This VoIP technology used to be affordable only to enterprises and governments. Moving to a converged network can be a difficult decision if the business already invested in separate voice, video, and data networks. It is difficult to abandon an investment that still works, but there are several advantages to converging voice, video, and data on a single network infrastructure.

One benefit of a converged network is that there is just one network to manage.

With separate voice, video, and data networks, changes to the network have to be coordinated across networks. Also, additional costs result from using three sets of network cabling. Using a single network means you have to manage just one wired infrastructure. Other benefits are lower implementation and management costs. It is less expensive to implement a single network infrastructure than three distinct network infrastructures.

Managing a single network is also less expensive. Traditionally, if a business has a separate voice and data network, it has one group of people managing the voice network and another group managing the data network.

With a converged network, you have one group managing both the voice and data networks. New Options Converged networks give you options that had not existed previously.

There is no need for an expensive handset phone or videoconferencing equipment. You can accomplish the same function using special software integrated with a personal computer. The person in the top left of Figure is using a softphone on the computer. When software is used in place of a physical phone, a business can quickly convert to converged networks because there is no capital expense in downloading IP phones and the switches needed to power the phones.

With the addition of inexpensive webcams, videoconferencing can be added to a softphone. These are just a few examples provided by a broader communications solution portfolio that redefine business processes today.

Separate Voice, Video, and Data Networks The new options for software and hardware for the purpose of integrating voice, video, and data, force the issue of redesigning existing networks to support these devices. It is no longer feasible to separate out the voice, video, and data networks.

When a new phone is added, a new line has to be run back to the PBX. The PBX switch is typically located in a Telco wiring closet, separate from the data and video wiring closets.

The wiring closets are usually separated because different support personnel require access to each system. However, using a properly designed hierarchical network and implementing QoS policies that prioritize the audio data, voice data can be converged onto an existing data network with little to no impact on audio quality.

Videoconferencing data can consume significant bandwidth on a network. Now that properly designed hierarchical networks can accommodate the bandwidth requirements of voice. As a result. Data networks can consume significant data bandwidth. Figure Video Network The data network. Using a properly designed hierarchical network and implementing QoS policies that prioritize the video data. When selecting switch hardware.

Your plan should take into account future bandwidth requirements. All network data contributes to the traffic. Some companies are replacing their existing telephone systems with converged VoIP phone systems.

Accompanying the new devices is an increase in network traffic. download the appropriate Cisco switch hardware to accommodate both current needs as well as future needs.

A business may start with a few PCs interconnected so that they can share data. Traffic Flow Analysis Traffic flow analysis is the process of measuring the bandwidth usage on a network and analyzing the data for the purpose of performance tuning. Considerations for Hierarchical Network Switches Companies need a network that can meet evolving requirements. To help you more accurately choose appropriate switches.

Power over Ethernet. Although there is no precise definition of network traffic flow. Layer 3 functionality. We continue our discussion of switched LAN design with an analysis of topology diagrams. Traffic flow analysis is done using traffic flow analysis software. As the business adds more employees. Figure Traffic Flow Analysis. When you are making your decisions about which hardware to download.

You can manually monitor individual switch ports to get the bandwidth utilization over time. Analysis Tools Many traffic flow analysis tools that automatically record traffic flow data to a database and perform a trend analysis are available. Traffic flow data can be used to help determine just how long you can continue using existing network hardware before it makes sense to upgrade to accommodate additional bandwidth requirements.

This is much easier than having to interpret the numbers in a column of traffic flow data. You can monitor traffic flow on a network in many ways. Port density is the number of ports per switch. When analyzing the traffic flow data. In large networks. Analyzing the various traffic sources and their impact on the network allows you to more accurately tune and upgrade the network to achieve the best possible performance.

Manual recording of traffic data is a tedious process that requires a lot of time and diligence. Using the included charts. Figure displays sample output from Solarwinds Orion 8. In a typical office building. That translates to 20 switch ports needed to connect the workstations to the network.

Consider what will happen if the HR department grows by five employees. You may find the Human Resource HR department located on one floor of an office building. By measuring the network traffic generated for all applications in use by different user communities.

Each department has a different number of users and application needs and requires access to different data resources available through the network. Some user communities use applications that generate a lot of network traffic. But this plan does not account for future growth. User Community Analysis User community analysis is the process of identifying various groupings of users and their impact on network performance. As well as looking at the number of devices on a given switch in a network.

The way users are grouped affects issues related to port density and traffic flow. LAN Design 17 For a list of some commercial traffic flow collection and analysis tools. If you were to select an appropriate access layer switch to accommodate the HR department. With that in mind. A solid network plan includes the rate of personnel growth over the past five years to be able to anticipate the future growth.

As shown in Figure For a list of some freeware traffic flow collection and analysis tools. Cannot accommodate the addition of five more computers! A workgroup-sized user community in a small business is supported by a couple of switches and is typically connected to the same switch as the server.

If the Finance users are using a network-intensive application that exchanges data with a specific server on the network. By locating users close to their servers and data stores. Note that spanning-tree protocol STP.

One complication of analyzing application usage by user communities is that usage is not always bound by department or physical location. The resources that medium-sized business or enterprise user communities need could be located in geographically separate areas. In medium-sized businesses or enterprises. You may have to analyze the impact of the application across many network switches to determine its overall impact.

Data stores can be servers. When considering the traffic for data stores and servers. As you can see in Figure Bandwidth aggregation and switch forwarding rates are important factors to consider when attempting to eliminate bottlenecks for this type of traffic. A topology diagram graphically displays any redundant paths or. To improve the performance. Topology Diagrams A topology diagram is a graphical representation of a network infrastructure.

Some server applications generate very high volumes of traffic between data stores and other servers. By examining the data paths for various applications used by different user communities. Servers and data stores are typically located in data centers within a business.

A device can be physically located in the data center but represented in quite a different location in the logical topology. A data center is a secured area of the building where servers. A topology diagram shows how all switches are interconnected.

Notice how many switches are present in the network. Figure displays a simple network topology diagram. The topology diagram also displays where different user communities are located on the network and the location of the servers and data stores. The topology diagram identifies each switch port used for interswitch communications and redundant paths between access layer switches and distribution layer switches.

It shows where and how many switches are in use on your network. Topology diagrams can also contain information about device densities and user communities. Constructing a topology diagram from the physical layout of the network becomes a tedious and time-consuming exercise. Network cables in the wiring closets disappear into the floors and ceilings. Having a topology diagram allows you to visually identify potential bottlenecks in network traffic so that you can focus your traffic analysis data collection on areas where improvements can have the most impact on performance.

And because devices are spread throughout the building. LAN Design 21 aggregated ports between switches that provide for resiliency and performance.

In this section. Fixed Configuration Switches Fixed configuration switches are just as you might expect. What that means is that you cannot add features or options to the switch beyond those that. Networking equipment in a hierarchical design is placed into central locations. When you look up the specifications for a switch. Another consideration is the thickness of the switch expressed in number of rack units. The physical size of the switches can be an important consideration when selecting switches to be deployed.

Switch Form Factors When you are selecting a switch. The stacked switches effectively operate as a single larger switch. The particular model you download determines the features and options available. Stackable switches use a special port for interconnections and do not use line ports for interswitch connections.

If you bought a modular switch with a port line card. Stackable switches are desirable where fault tolerance and bandwidth availability are critical and a modular switch is too costly to implement. The line cards contain the ports. The line card fits into the switch chassis like expansion cards fit into a PC.

StackWise allows you to interconnect up to nine switches using fully redundant backplane connections. The larger the chassis. Cisco introduced StackWise technology in one of its switch product lines. Stackable Switches Stackable switches can be interconnected using a special backplane cable that provides high-bandwidth throughput between the switches. LAN Design 23 originally came with the switch. The speeds are also typically faster than using line ports for connection switches.

Modular switches come with different sized chassis that allow for the installation of different numbers of modular line cards.

Lan switching and wireless ccna exploration companion guide pdf

Using cross-connected connections. This approach can consume many power outlets and a lot of closet space. Without using a highdensity modular switch. High port densities allow for better use of space and power when both are in limited supply. Large enterprise networks that support many thousands of network devices require high density.

Port Density Port density is the number of ports available on a single switch. If you have two switches that each contain 24 ports. Fixed configuration switches typically support up to 48 ports on a single device. On the other hand.

With a single modular switch. Due to the contention for bandwidth. If the switch forwarding rate is too low. If the switch is connected to the rest of the network by a single network cable. LAN Design 25 You must also address the issue of uplink bottlenecks. This allows you to use less expensive. Switch product lines are classified by forwarding rates. Link aggregation helps to reduce these bottlenecks of traffic by allowing up to eight switch ports to be bound together for data communications.

If you have a port switch. If the switch supports a forwarding rate of only 32 Gbps. Forwarding rates are important to consider when selecting a switch. Forwarding Rates As illustrated in Figure Entry-layer switches have lower forwarding rates than enterpriselayer switches. A series of fixed configuration switches may consume many additional ports for bandwidth aggregation between switches for the purpose of achieving target performance.

Wire speed is the data rate that each port on the switch is capable of attaining—either Mbps Fast Ethernet or Mbps Gigabit Ethernet.

Wire speed describes the theoretical maximum data transmission rate of a connection. IP phone. Cisco uses the term EtherChannel when describing aggregated switch ports. PoE allows you more flexibility when installing wireless access points and IP phones because you can install them anywhere you can run an Ethernet cable.

Check the model of the networking device to determine whether the port supports PoE. Power over Ethernet Power over Ethernet PoE allows the switch to deliver power to a device over the existing Ethernet cabling.

LAN Switching and Wireless: CCNA Exploration Companion Guide - PDF Free Download - Fox eBook

Keep in mind that EtherChannel reduces the number of available ports to connect network devices. You do not need to consider how to run ordinary power to the device. EtherChannel technology allows a group of physical Ethernet links to create one logical Ethernet link for the purpose of providing fault tolerance and highspeed links between switches.

With the addition of multiple 10 Gigabit Ethernet uplinks on some enterprise-layer switches. In this example. PoE ports on a switch.

You should select a switch that supports PoE only if you are actually going to take advantage of the feature because it adds considerable cost to the switch.

Wireless Access Point receives power through the Ethernet cable. Layer 3 switches offer advanced functionality that will be discussed in greater detail in the later chapters of this book. Figure illustrates some functions of Layer 3 switches. Layer 3 switches are also known as multilayer switches. You will then be able to match the switch specification with its capability to function as an access.

Voice traffic is typically given a separate VLAN. Port security allows the switch to decide how many or what specific devices are allowed to connect to the switch. Fast Ethernet allows up to Mbps of traffic per switch port. Access Layer Switch Features Access layer switches facilitate the connection of end node devices to the network. Port security is applied at the access.

Fast Ethernet is adequate for IP telephony and data traffic on most business. D1 D2 Layer 3 routing performed by the switch to route traffic to server subnet. Depending on the performance requirements for your network.

All Cisco switches support port layer security. Access layer switches allow you to set the VLANs for the end node devices on your network. For this reason.

In this way. S1 S2 S3 Port speed is also a characteristic you need to consider for your access layer switches. You will learn about port security in Chapter 2. Most modern devices. Link aggregation allows the switch to operate multiple links simultaneously as a logically singular high bandwidth link.

LAN Design 29 networks. Access layer switches take advantage of link aggregation when aggregating bandwidth up to distribution layer switches.

Cisco IP phones are types of equipment that are found at the access layer. Bottlenecks present a much more significant quality of service issue for voice and video data than they do for data. Link aggregation is another feature that is common to most access layer switches. The uplink from the distribution layer to the core presents a much more significant bottleneck to the entire network because distribution layer switches collect the traffic of multiple network segments.

PoE dramatically increases the overall price of the switch across all Cisco Catalyst switch product lines. QoS needs to be enabled on access layer switches so that voice traffic from the IP phone has priority over.

In a converged network supporting voice. Gigabit Ethernet does have a drawback—switches supporting Gigabit Ethernet are more expensive. This allows for much more efficient data transfers. When a Cisco IP phone is plugged into an access layer switch port configured to support voice traffic.

Gigabit Ethernet allows up to Mbps of traffic per switch port. Although the uplink connection between the access layer and distribution layer switches can become a bottleneck.

As you will learn later in this book. ACLs also allow you to control which network devices can communicate on the network. Access lists are used to control how traffic flows through the network.

This routing typically takes place at the distribution layer because distribution layer switches have higher processing capabilities than the access layer switches.

An access control list ACL allows the switch to prevent certain types of traffic and permit others. The distribution layer switches are under high demand on the network because of the functions that they provide.

Features of distribution layer switches are illustrated in Figure Using ACLs is processingintensive because the switch needs to inspect every packet to see if it matches one of the ACL rules defined on the switch. Another reason why Layer 3 functionality is required for distribution layer switches is because of the advanced security policies that can be applied to network traffic.

It is important that distribution switches support redundancy for adequate. Distribution layer switches alleviate the core switches from needing to perform that task. This inspection is performed at the distribution layer because the switches at this layer typically have the processing capability to handle the additional load. Because inter-VLAN routing is performed at the distribution layer.

Instead of using ACLs for every access layer switch in the network. This allows you to repair the failed component without impacting the functionality of the network.

It is also recommended that distribution layer switches support multiple. This results in poor performance and quality for audio and video communications. LAN Design 31 availability. Priority policies ensure that audio and video communications are guaranteed adequate bandwidth to maintain an acceptable quality of service. Core layer switch features are illustrated in Figure To maintain the priority of the voice data throughout the network.

Loss of a distribution layer switch could have a significant impact on the rest of the network because all access layer traffic passes through the distribution layer switches. Newer distribution layer switches support aggregated 10 Gigabit Ethernet 10GbE uplinks to the core layer switches. Having more than one power supply allows the switch to continue operating even if one of the power supplies failed during operation.

Having hot-swappable power supplies allows you to change a failed power supply while the switch is still running. Because distribution layer switches accept incoming traffic from multiple access layer switches.

Distribution layer switches are typically implemented in pairs to ensure availability. QoS is an important part of the services provided by core layer switches.

The core layer also needs to support link aggregation to ensure adequate bandwidth coming into the core from the distribution layer switches. Based on your results. At the core and network edge. With hot-swappable hardware. In a more realistic situation. To perform a hardware replacement. Layer 2 redundancy is examined in Chapter 5 when we discuss the spanning-tree protocol.

If you choose an inadequate switch to run in the core of the network. Convergence in this context refers to the time it takes for the network to adapt to a change. Layer 3 redundancy typically has faster convergence than Layer 2 redundancy in the event of hardware failure. A complete discussion on the implications of Layer 3 redundancy is beyond the scope of this book.

The availability of the core layer is also critical. CCNA Exploration Companion Guide The core layer of a hierarchical topology is the high-speed backbone of the network and requires switches that can handle very high forwarding rates.

The required forwarding rate is largely dependent on the number of devices participating in the network. You determine the necessary forwarding rate by conducting and examining various traffic flow reports and user community analyses. This allows corresponding distribution layer switches to deliver traffic as efficiently as possible to the core.

Because QoS provides a. It remains an open question about the need for Layer 2 redundancy in this context. Because high-speed WAN access is often prohibitively expensive. Many true core-layercapable switches have the capability to swap cooling fans without having to turn the switch off.

Take care to evaluate your needs for the present and near future. Core layer switches should have support for aggregated 10 Gigabit Ethernet connections.

Because of the high workload carried by core layer switches. Each product line offers different characteristics and features. LAN Design 33 software-based solution to prioritize traffic. A small business with 12 employees might be integrated into the network of a large multinational enterprise and require all the advanced LAN services available at the corporate head office. The classification presented reflects how you might see the range of Cisco switches if you were a multinational enterprise.

The Catalyst Express offers the following: The Cisco switch product lines are as follows: The following classification of Cisco switches within the hierarchical network model represents a starting point for your deliberations on which switch is best for a given application. Cisco currently has seven switch product lines. If you think of the needs of a medium-sized business. The Cisco Catalyst Express series switches are scaled for small business environments ranging from 20 to employees.

To learn more about the Cisco Express series of switches. Figure Catalyst Catalyst The Catalyst series switches enable entry-layer enterprise. They are managed using a built-in web management interface.

The Catalyst Express does not support console access. The Catalyst Express series switches are available in different fixed configurations: The Catalyst series switches. To learn more about the Catalyst series of switches. Catalyst The Cisco Catalyst series is a line of enterprise-class switches that include support for PoE.

LAN Switching and Wireless, CCNA Exploration Companion Guide

The Catalyst series switches are available in different fixed configurations: These switches. This switch series supports console and auxiliary access to the switch. Catalyst The Catalyst Catalyst The Cisco Catalyst series of switches. Figure Catalyst The Catalyst series switches are available in different stackable fixed configurations: The Catalyst series supports Cisco StackWise technology.

This series offers forwarding rates from 32 Gbps to Gbps Catalyst E switch series. StackWise technology allows you to interconnect up to nine physical Catalyst switches into one logical switch using a highperformance 32 Gbps.

The Catalyst series offers multilayer QoS and sophisticated routing functions. This allows the switches to achieve higher availability. This switch series supports dual. The Catalyst series switches are available in different modular configurations: The modular capability of the Catalyst series allows for very high port densities through the addition of switch port line cards to its modular chassis.

Catalyst The Catalyst series switches. The Cisco Catalyst is not a typical access layer switch. It is a specialty access layer switch designed for data center deployments where many servers may exist in close proximity. The Catalyst is ideal for very large network environments found in enterprises.

Figure Catalyst The Catalyst series switches are available in different modular configurations: Catalyst series switches do not support the StackWise feature of the Catalyst series.

The Catalyst series is the highest-performing Cisco switch. Catalyst The Catalyst series modular switch. The Catalyst is capable of managing traffic at the distribution and core layers. Use file e You will add all the necessary devices and connect them with the correct cabling. Comparing Switches The following tool can help identify the correct switch for an implementation: Build a Hierarchical Topology 1.

An array of Cisco Catalyst switch product lines are available to support any application or business size. The traffic flow. Lab Review of Concepts from Exploration 1—Challenge 1.

The configuration contains design and configuration errors that conflict with stated requirements and prevent end-to-end communication. You examine the given design and identify and correct any design errors. Troubleshooting a Small Network 1. Review of Concepts from Exploration 1 1.

You then cable the network. Hierarchical network topologies facilitate network convergence by enhancing the performance necessary for voice and video data to be combined onto the existing data network. You are given only the set of objectives to complete. This requires creating and assigning two subnetwork blocks. You will use common commands to test and document the network.

Implementing this model improves the performance. The bottlenecks can then be addressed to improve the performance of the network and accurately determine appropriate hardware requirements to satisfy the desired performance of the network.

We surveyed the different switch features. Implementation of a core-distribution-access design model for all sites in an enterprise C. LAN Design 41 onto the router. Which three options correctly associate a layer of the hierarchical design model with its function?

Choose three. When all errors have been corrected. Distribution—high-speed backbone E. Combining conventional data with voice and video on a common network.

Check Your Understanding Complete all the review questions listed here to test your understanding of the topics and concepts in this chapter. Answers are listed in the appendix. Implementation of standard equipment sets for LAN design B.

Access—interface for end devices D. Distribution—traffic control and security policies C. Access—implementation of security policies 2. Core—interface for end devices B. Core—high-speed backbone F. With respect to network design. Lower quality of service configuration requirements 4. What factor may complicate user community analysis? Intensity of use of a department application server D. Server-to-server traffic may skew user port usage data.

Combines voice and data network staffs C. Anticipated department port growth F. Data backed up to tape G. Different organization applications may share data stores. Simplified data network configuration B. What would be the port capacity of a single port on a port Gigabit Ethernet switch? Simplified network changes F. Simpler maintenance than hierarchical networks E. Forwarding rates—processing capabilities of a switch by quantifying performance of the switch by how much data it can process per second C.

Which four options describe data store and data server analysis actions? Choose four. Application usage is not always bound by department or physical location. Workstation ports required for a department B.

Network attached storage 5. Which three options are potential benefits of a converged network? Application changes may radically affect predicted data growth.

Amount of traffic for a SAN E. Port density—capability to use multiple switch ports concurrently for higher throughput data communication B. Wire speed—data rate that each port on the switch is capable of attaining 7. Amount of server-to-server traffic C. Link aggregation—number of ports available on a single switch D.

Combines voice. Which two of the following pairings are accurate? Choose two. LAN Design 43 8. Controls access of end devices to network E. Layer 1 B. Low bandwidth for interswitch communications E. Rapid forwarding of traffic. What is a feature offered by all stackable switches? PoE PoE D.

Routing C. Layer 2 C. Predetermined number of ports B. Redundant components D. Layer 3 support C. VLANs E. Layer 3 D.

Fully redundant backplane C. Providing PoE D. Redundant paths B. Support for Gigabit connectivity D. What function is performed by a Cisco Catalyst access layer switch? Link aggregation Port security B. High-level policy enforcement C. Which three features are associated with the core layer of the hierarchical design model? PoE capability Which two characteristics describe the core layer of the hierarchical network model?

Layer 4 9. Ports cannot be added to the device. Capable of interconnection via a special backplane cable. Match the terms with the correct descriptions. Capability to recover connectivity after a network failure. Ratio of number of ports to number of switches. Allows for the installation of line cards or modules.

List and describe the three layers of the hierarchical network model. Binding together of distinct links for enhanced throughput. Prioritization of network traffic.

Ratio of quantity of data to time.

You can find the answers in the appendix. Capability of a device to power another device using Ethernet. How do you configure basic security on a switch that operates within a network designed to support voice. What are the functions that enable a switch to forward Ethernet frames in a LAN? Every device that is transmitting continues to transmit to ensure that all devices on the network detect the collision.

Although the messages are corrupted. You also learn about some key malicious threats to switches and learn to enable a switch with a secure initial configuration. The messages propagate across the media until they encounter each other. Network Fundamentals. At that point. When a device is in listening mode. When a collision occurs. If a device detects a signal from another device. You explore how Ethernet communications function and how switches play a role in the communication process.

When there is no traffic detected. Networking Fundamentals. It is much harder to see these hierar- chical layers when the network is installed in a business. Click the Physical Layout button in the figure. The figure shows two floors of a building. The user computers and network devices that need net- work access are on one floor.

The resources, such as e-mail servers and database servers, are lo- cated on another floor. To ensure that each floor has access to the network, access layer and distribution switches are installed in the wiring closets of each floor and connected to each of the devices needing network access. The figure shows a small rack of switches.

The access layer switch and distribution layer switch are stacked one on top of each other in the wiring closet. Although the core and other distribution layer switches are not shown, you can see how the physi- cal layout of a network differs from the logical layout of a network. Benefits of a Hierarchical Network There are many benefits associated with hierarchical network designs. Scalability Hierarchical networks scale very well.

The modularity of the design allows you to replicate design elements as the network grows. Because each instance of the module is consistent, expansion is easy to plan and implement.

For example, if your design model consists of two distribution layer switches for every 10 access layer switches, you can continue to add access layer switches until you have 10 access layer switches cross-connected to the two distribution layer switches before you need to add additional distribution layer switches to the network topology.

Also, as you add more distribution layer switches to accommodate the load from the access layer switches, you can add additional core layer switches to handle the additional load on the core. Redundancy As a network grows, availability becomes more important. You can dramatically increase availabil- ity through easy redundant implementations with hierarchical networks. Access layer switches are connected to two different distribution layer switches to ensure path redundancy.

If one of the dis- tribution layer switches fails, the access layer switch can switch to the other distribution layer switch. Additionally, distribution layer switches are connected to two or more core layer switches to ensure path availability if a core switch fails. Typically, end node devices, such as PCs, printers, and IP phones, do not have the ability to connect to multiple access layer switches for redundancy. If an access layer switch fails, just the devices connected to that one switch would be affected by the outage.

The rest of the net- work would continue to function unaffected. Performance Communication performance is enhanced by avoiding the transmission of data through low-per- forming, intermediary switches. Data is sent through aggregated switch port links from the access layer to the distribution layer at near wire speed in most cases. The distribution layer then uses its high performance switching capabilities to forward the traffic up to the core, where it is routed to its final destination.

Because the core and distribution layers perform their operations at very high speeds, there is less contention for network bandwidth. As a result, properly designed hierarchical networks can achieve near wire speed between all devices. Security Security is improved and easier to manage.

Access layer switches can be configured with various port security options that provide control over which devices are allowed to connect to the net- work.

You also have the flexibility to use more advanced security policies at the distribution layer. You may apply access control policies that define which communication protocols are deployed on your network and where they are permitted to go. For example, if you want to limit the use of HTTP to a specific user community connected at the access layer, you could apply a policy that blocks HTTP traffic at the distribution layer. Restricting traffic based on higher layer protocols, such as IP and HTTP, requires that your switches are able to process policies at that layer.

Some access layer switches support Layer 3 functionality, but it is usually the job of the distribution layer switches to process Layer 3 data, because they can process it much more efficiently. Manageability Manageability is relatively simple on a hierarchical network. Each layer of the hierarchical design performs specific functions that are consistent throughout that layer. Therefore, if you need to change the functionality of an access layer switch, you could repeat that change across all access layer switches in the network because they presumably perform the same functions at their layer.

Deployment of new switches is also simplified because switch configurations can be copied be- tween devices with very few modifications. Consistency between the switches at each layer allows for rapid recovery and simplified troubleshooting.

In some special situations, there could be con- figuration inconsistencies between devices, so you should ensure that configurations are well doc- umented so that you can compare them before deployment. Maintainability Because hierarchical networks are modular in nature and scale very easily, they are easy to main- tain. With other network topology designs, manageability becomes increasingly complicated as the network grows. Also, in some network design models, there is a finite limit to how large the net- work can grow before it becomes too complicated and expensive to maintain.

In the hierarchical design model, switch functions are defined at each layer, making the selection of the correct switch easier.

Adding switches to one layer does not necessarily mean there will not be a bottle- neck or other limitation at another layer. For a full mesh network topology to achieve maximum performance, all switches need to be high-performance switches, because each switch needs to be capable of performing all the functions on the network.

In the hierarchical model, switch functions are different at each layer. You can save money by using less expensive access layer switches at the lowest layer, and spend more on the distribution and core layer switches to achieve high perform- ance on the network. These simple guidelines will help you differentiate between well-designed and poorly designed hierarchical networks. This section is not intended to provide you with all the skills and knowledge you need to design a hierarchical network, but it offers you an opportunity to begin to practice your skills by transforming a flat network topology into a hierarchical network topology.

Network Diameter When designing a hierarchical network topology, the first thing to consider is network diameter. Diameter is usually a measure of distance, but in this case, we are using the term to measure the number of devices.

Network diameter is 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 be- tween devices. Roll over the Network Diameter button in the figure. In the figure, PC1 communicates with PC3. There could be up to six interconnected switches be- tween PC1 and PC3. In this case, the network diameter is 6. Each switch in the path introduces some degree of latency.

Network device latency is the time spent by a device as it processes a packet or frame. Each switch has to determine the destination MAC address of the frame, check its MAC address table, and forward the frame out the appropriate port. Even though that entire process happens in a fraction of a second, the time adds up when the frame has to cross many switches.

In the three-layer hierarchical model, Layer 2 segmentation at the distribution layer practically eliminates network diameter as an issue. In a hierarchical network, network diameter is always going to be a predictable number of hops between the source and destination devices.

Bandwidth Aggregation Each layer in the hierarchical network model is a possible candidate for bandwidth aggregation. Bandwidth aggregation is the practice of considering the specific bandwidth requirements of each part of the hierarchy. After bandwidth requirements of the network are known, links between spe- cific switches can be aggregated, which is called link aggregation.

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. A discussion of EtherChannel is beyond the scope of this course. Roll over the Bandwidth Aggregation button in the figure.

In the figure, computers PC1 and PC3 require a significant amount of bandwidth because they are used for developing weather simulations.

The network manager has determined that the access layer switches S1, S3, and S5 require increased bandwidth. Following up the hierarchy, these ac- cess layer switches connect to the distribution switches D1, D2, and D4. The distribution switches connect to core layer switches C1 and C2. Notice how specific links on specific ports in each switch are aggregated. In this way, increased bandwidth is provided for in a targeted, specific part of the network. Note that in this figure, aggregated links are indicated by two dotted lines with an oval tying them together.

In other figures, aggregated links are represented by a single, dotted line with an oval. 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.

This chapter explores how to employ redundant network paths between switches. A discussion on doubling up network devices and employing special net- work protocols to ensure high availability is beyond the scope of this course. Implementing redundant links can be expensive. Imagine if every switch in each layer of the net- work hierarchy had a connection to every switch at the next layer.

It is unlikely that you will be able to implement redundancy at the access layer because of the cost and limited features in the end devices, but you can build redundancy into the distribution and core layers of the network. Roll over the Redundant Links button in the figure.

In the figure, redundant links are shown at the distribution layer and core layer. At the distribution layer, there are two distribution layer switches, the minimum required to support redundancy at this layer. The access layer switches, S1, S3, S4, and S6, are cross-connected to the distribution layer switches. This protects your network if one of the distribution switches fails. In case of a fail- ure, the access layer switch adjusts its transmission path and forwards the traffic through the other distribution switch.

Some network failure scenarios can never be prevented, for example, if the power goes out in the entire city, or the entire building is demolished because of an earthquake. Redundancy does not at- tempt to address these types of disasters.

Start at the Access Layer Imagine that a new network design is required. Design requirements, such as the level of perform- ance 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 infra- structure 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 the network.

After you have all end devices accounted for, you have a better idea of how many access layer switches you need. The number of access layer switches, and the estimated traffic that each generates, helps you to determine how many distribu- tion layer switches are required to achieve the performance and redundancy needed for the net- work.

After you have determined the number of distribution layer switches, you can identify how many core switches are required to maintain the performance of the network. A thorough discussion on how to determine which switch to select based on traffic flow analysis and how many core switches are required to maintain performance is beyond the scope of this course. For a good introduction to network design, read this book that is available from Cisco- press.

Small and medium-sized businesses are embracing the idea of running voice and video services on their data networks. Legacy Equipment Convergence is the process of combining voice and video communications on a data network.

There were high network costs associated with convergence because more expensive switch hardware was required to support the additional bandwidth re- quirements. Converged networks also required extensive management in relation to Quality of Ser- vice QoS , because voice and video data traffic needed to be classified and prioritized on the network.

Few individuals had the expertise in voice, video, and data networks to make conver- gence feasible and functional. In addition, legacy equipment hinders the process. The figure shows a legacy telephone company switch. Most telephone companies today have made the transition to digital-based switches. However, there are many offices that still use analog phones, so they still have existing analog telephone wiring closets.

Because analog phones have not yet been replaced, you will also see equipment that has to support both legacy PBX telephone systems and IP-based phones. This sort of equipment will slowly be migrated to modern IP-based phone switches. Click Advanced Technology button in the figure. Advanced Technology Converging voice, video, and data networks has become more popular recently in the small to medium-sized business market because of advancements in technology.

Convergence is now easier to implement and manage, and less expensive to download. The figure shows a high-end VoIP phone and switch combination suitable for a medium-sized business of employees. The figure also shows a Cisco Catalyst Express switch and a Cisco G phone suitable for small to medium-sized businesses.

This VoIP technology used to be affordable only to enterprises and governments. Moving to a converged network can be a difficult decision if the business already invested in sepa- rate voice, video, and data networks. It is difficult to abandon an investment that still works, but there are several advantages to converging voice, video, and data on a single network infrastructure.

One benefit of a converged network is that there is just one network to manage. With separate voice, video, and data networks, changes to the network have to be coordinated across networks. There are also additional costs resulting from using three sets of network cabling. Using a single network means you just have to manage one wired infrastructure.

Another benefit is lower implementation and management costs. It is less expensive to implement a single network infrastructure than three distinct network infrastructures. Managing a single net- work is also less expensive.

Traditionally, if a business has a separate voice and data network, they have one group of people managing the voice network and another group managing the data net- work. With a converged network, you have one group managing both the voice and data networks. Click New Options button in the figure. New Options Converged networks give you options that had not existed previously.

You can now tie voice and video communications directly into an employees personal computer system, as shown in the fig- ure. There is no need for an expensive handset phone or videoconferencing equipment. You can ac- complish the same function using special software integrated with a personal computer.

Softphones, such as the Cisco IP Communicator, offer a lot of flexibility for businesses. The per- son in the top left of the figure is using a softphone on the computer. When software is used in place of a physical phone, a business can quickly convert to converged networks, because there is no capital expense in downloading IP phones and the switches needed to power the phones. With the addition of inexpensive webcams, videoconferencing can be added to a softphone.

These are just a few examples provided by a broader communications solution portfolio that redefine business processes today. When a new phone is added, a new line has to be run back to the PBX. The PBX switch is typically located in a telco wiring closet, separate from the data and video wiring closets.

The wiring closets are usually sepa- rated because different support personnel require access to each system. However, using a properly designed hierarchical network, and implementing QoS policies that prioritize the audio data, voice data can be converged onto an existing data network with little to no impact on audio quality.

Click the Video Network button in the figure to see an example of a separate video network. In this figure, videoconferencing equipment is wired separately from the voice and data networks. Videoconferencing data can consume significant bandwidth on a network.

As a result, video net- works were maintained separately to allow the videoconferencing equipment to operate at full speed without competing for bandwidth with voice and data streams.

Using a properly designed hierarchical network, and implementing QoS policies that prioritize the video data, video can be converged onto an existing data network with little to no impact on video quality. Click the Data Network button in the figure to see an example of a separate data network. The data network interconnects the workstations and servers on a network to facilitate resource sharing.

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