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CHAPTER 8 BACKBONE NETWORKS Chapter Summary This chapter examines backbone networks (BNs) that are used in the distribution layer (within-building backbones) and the core layer (campus backbones). We discuss the three primary backbone architectures and the recommended best practice design guidelines on when to use them. The chapter ends with a discussion of how to improve BN performance and of the future of BNs. Learning Objectives After reading this chapter, students should: Understand the Internetworking devices used in BNs Understand the switched backbone architecture Understand the routed backbone architecture Understand Virtual LAN architecture Understand the best practice recommendations for backbone design Be aware of ways to improve BN performance Key Terms
chassis switch forwarding equivalence class (FEC) IEEE 802.1q label switched router (LSR) layer-2 switch main distribution facility (MDF) module multiprotocol label switching (MPLS) multiswitch VLAN patch cables rack routed backbone router single-switch VLAN switched backbone virtual LAN (VLAN)9 VLAN ID VLAN switch VLAN tag VLAN trunk Chapter Outline Introduction Switched Backbones Routed Backbones Virtual LANs The Best Practice Backbone Design Improving Backbone Performance Improving Device Performance Improving Circuit Capacity Reducing Network Demand Implications for Management Summary Answers to Textbook Exercises Answers to End-of-Chapter Questions How does a layer-2 switch differ from a router? Layer 2 switches operate by using the data link layer address or MAC address to forward packets between network segments. They connect the same or different types of cable. Layer-2 switches (or workgroup switches) operate at the Data Link layer, and typically provide ports for a small set of 16 to 24 computers. Layer-2 switches enable all ports to be in use simultaneously by managing paired combinations of ports as separate point-to-point circuits. Layer-2 switches "learn" addresses; a layer-2 switch builds a forwarding table after it is first turned on. To learn addresses, a layer-2 switch retransmits to all ports (except to the one from which it was received) only for a packet with a destination address not already in the forwarding table. The resulting ACK from the destination computer (that recognized its address) is then used by the layer-2 switch to add the new port number and address to the forwarding table. Routers operate at the network layer. They connect two different TCP/IP subnets. Routers strip off the data link layer packet, process the network layer packet, and forward only those messages that need to go to other networks on the basis of their network layer address. In general, they perform more processing on each message than switches and therefore operate more slowly. How does a layer-2 switch differ from a VLAN? Layer 2 switches operate by using the data link layer address or MAC address to forward packets between network segments. They connect the same or different types of cable. Layer-2 switches (or workgroup switches) operate at the Data Link layer, and typically provide ports for a small set of 16 to 24 computers. Layer-2 switches enable all ports to be in use simultaneously by managing paired combinations of ports as separate point-to-point circuits. Layer-2 switches "learn" addresses; a layer-2 switch builds a forwarding table after it is first turned on. To learn addresses, a layer-2 switch retransmits to all ports (except to the one from which it was received) only for a packet with a destination address not already in the forwarding table. The resulting ACK from the destination computer (that recognized its address) is then used by the layer-2 switch to add the new port number and address to the forwarding table. VLAN switches work a little differently. When a VLAN switch receives a frame that is destined for another computer in the same subnet on the same VLAN switch, the switch acts as a traditional layer-2 switch: it forwards the frame unchanged to the correct computer. VLAN switches use Ethernets 802.1q’s tagging to move frames from one switch to another. When a VLAN switch receives an Ethernet frame that needs to go to a computer on another VLAN switch, it changes the Ethernet frame by inserting the VLAN ID number and a priority code into the VLAN tag field. How does a router differ from a VLAN? VLAN switches can create multiple subnets, so they act like routers, except the subnets are inside the switch, not between switches. Therefore, broadcast messages sent by computers in one VLAN segment are sent only to the computers on the same VLAN. Under what circumstances would you use a switched backbone? Switched backbones can be used in situations where the network administrators wants to spread the traffic around the network more efficiently. In addition, it also provides an architecture where network capacity is no longer tied to the physical location of the computers, as computers in Under what circumstances would you want to use a routed backbone? Routed backbones are good for connecting different buildings on the same enterprise campus backbone network. The primary advantage of the routed backbone is that it clearly segments each part of the network connected to the backbone. Each segment has its own subnet addresses that can be managed by a different network manager. Broadcast messages stay within each subnet and do not move to other parts of the network. Under what circumstances would you use a VLAN backbone? A VLAN backbone is useful when you want to put computers that are in different geographic locations in the same subnet. In addition, VLANs make it much simpler to manage the broadcast traffic and provide a better opportunity to prioritize traffic on the network. Explain how routed backbones work. Routed backbones move packets along the backbone based on their network layer address (i.e., layer 3 address). The most common form of routed backbone uses a bus topology (e.g., using Ethernet 100Base-T). Routed backbones can be used at the core or distribution layers. At the core layer routed backbones are sometimes called subnetted backbones or hierarchical backbones and are most commonly used to connect different buildings within the same campus network. At the distribution layer a routed backbone uses routers or layer 3 switches to connect a series of LANs (access layer) to a single shared media backbone network. Each of the LANs are a separate subnet. Message traffic stays within each subnet unless it specifically needs to leave the subnet to travel elsewhere on the network, in which case the network layer address (e.g., TCP/IP) is used to move the packet. In Figure 8.5, would the network still work if we removed the routers in each building and just had one core router? What would be the advantages and disadvantages of doing this? The network would still work, although the traffic on the network would be significantly increased due to the creation of one large LAN instead of three subnets. The advantages of this would be slightly lower costs due to only purchasing one router instead of four and less maintenance and management. Each of these advantages are minor, and certainly not work the additional traffic on the network. Explain how switched backbones work. Switched backbone networks use a star topology with one device, usually a switch, at its center. The traditional backbone circuit and set of routers or bridges is replaced by one switch and a set of circuits to each LAN. The collapsed backbone has more cable, but fewer devices. There is no backbone cable. The “backbone” exists only in the switch, which is why this is called a collapsed backbone. The original collapsed backbone technology uses layer-2 switches and suffers some disadvantage due to the load of data link layer overhead message traffic and limitations on network segmentation. As this weakness has been recognized, collapsed backbone technology is adapting by evolving to the use of layer-3 switches to overcome these problems. The result is better performance and improved network management capabilities for switched backbone networks. Collapsed backbones are probably the most common type of backbone network used in the distribution layer (i.e., within a building). Most new building backbone networks designed today use collapsed backbones. They also are making their way into the core layer as the campus backbone, but routed backbones still remain common. What are the key advantages and disadvantages among routed and switched backbones?
Advantages Disadvantages
Routed backbones • Clear segmentation of parts of the network connected to the backbone as each network has a subnet address and can be managed separately. • Slower performance as routing takes more time than bridging or switching. Management and/or software overhead costs due to need to establish subnet addressing and provide reconfiguration when computers are moved (or support dynamic addressing).Switched backbones •Performance is improved. With the traditional backbone network, the backbone circuit was shared among many LANs; each had to take turns sending messages. With the collapsed backbone, each connection into the switch is a separate point-to-point circuit. The switch enables simultaneous access, so that several LANs can send messages to other LANs at the same time. Throughput is increased significantly, often by 200% to 600%, depending upon the number of attached LANs and the traffic pattern. Since there are far fewer networking devices in the network, this reduces costs and greatly simplifies network management. All the key backbone devices are in the same physical location, and all traffic must flow through the switch. If something goes wrong or if new cabling is needed, it can all be done in one place. Software reconfiguration replaces hardware reconfiguration. Because data link layer addresses are used to move packets, there is more broadcast traffic flowing through the network and it is harder to isolate and separately manage the individually attached LANs. Layer 3 switches can use the network layer address, so future collapsed backbones built with layer 3 will not suffer from this problem. Collapsed backbones use more cable, and the cable must be run longer distances, which often means that fiber optic cables must be used. If the switch fails, so does the entire backbone network. If the reliability of the switch has the same reliability as the reliability of the routers, then there is less chance of an failure (because there are fewer devices to fail). For most organizations, the relatively minor disadvantages of cable requirements and impacts of potential switch failure are outweighed by the benefits offered by collapsed backbones.
Compare and contrast rack-based and chassis-switch based switched backbones. The rack-based collapsed backbone has the advantage of placing all network equipment in one place for easy maintenance and upgrade, but does require more cable. In most cases, the cost of the cable itself is only a small part of the overall cost to install the network, so the cost is greatly outweighed by the simplicity of maintenance and the flexibility it provides for future upgrades. The room containing the rack of equipment is sometimes called the main distribution facility (MDF) or central distribution facility (CDF). The cables from all computers and devices in the area served by the MDF (often hundreds of cables) are run into the MDF room. Once in the run they are connected into the various devices. The devices in the rack are connected among themselves using very short cables called patch cables. With rack-based equipment, it becomes simple to move computers from one LAN to another. This convenience is used to spread the traffic around the network more efficiently so that network capacity is no longer tied to the physical location of the computers. Computers in the same physical area can be connected into very different network segments conveniently in the MDF. A chassis switch enables users to plug modules directly into the switch. Each module is a certain type of network device. The key advantage of chassis switches is their flexibility. It becomes simple to add new modules with additional ports as the LAN grows, and to upgrade the switch to use new technologies. For example, if you want to add gigabit Ethernet or ATM you simply lay the cable and insert the appropriate module into the switch. What is a module and why are modules important? A module is any of certain types of network devices that can be plugged directly into a chassis switch. Since a chassis switch must be able to support simultaneous activities of all connected module, each switch has an internal capacity (in Mbps) which limits the maximum number of modules that can be accepted by the switch. Modules can be switches, hubs, or routers. Explain how single-switch VLANs work. In a single switch VLAN the VLAN operates only inside one switch. The computers on the VLAN are connected into the one switch and assigned by software into different VLANs. The network manager uses special software to assign the dozens or even hundreds of computers attached to the switch to different VLAN segments. The VLAN segments function in the same way as physical LAN segments; the computers in the same VLAN act as though they are connected to the same physical switch or hub. Explain how multiswitch VLANs work. A multi-switch VLAN works the same way as a single switch VLAN, except that several switches are used to build the VLANs. The switches must be able to send packets among themselves in a way that identifies the VLAN to which the packet belongs. There are two approaches to this: packet encapsulation and modifying the Ethernet packet. In the encapaulation approach a proprietary protocol encapsulates the packet. When a packet needs to go from one VLAN switch to another VLAN switch, the first switch puts a new VLAN packet around the outside of the Ethernet packet. The VLAN packet contains the VLAN information and is used to move the packet from switch to switch within the VLAN network.. When the packet arrives at the final destination switch, the VLAN packet is stripped off and the unchanged Ethernet packet inside is sent to the destination computer. In the modification approach the Ethernet packet itself is to modified to carry the VLAN information. 16-bytes of VLAN information (according to emerging standard IEEE 802.1q) are added to the standard Ethernet (IEEE 802.3) packet. The additional VLAN information is used to move the packet from switch to switch within the VLAN network. The original Ethernet packet is restored from the modified packet at the final destination switch and then sent to the destination computer. What is IEEE 802.1q? IEEE 802.1q is an emerging standard that inserts 16-bytes of VLAN information into the normal IEEE 802.3 Ethernet packet. When a packet needs to go from one VLAN switch to another VLAN switch, the first switch replaces the incoming Ethernet packet with an 802.1q packet that contains all the information in the original 802.3 Ethernet packet, plus 16-bytes of VLAN information. The additional VLAN information is used to move the packet from switch to switch within the VLAN network. When the packet arrives at the final destination switch, the IEEE 802.1q packet is stripped off and replaced with a new Ethernet packet that is identical to the one with which it entered the VLAN. What are the advantages and disadvantages of VLANs? Advantages: VLANs are often faster and provide greater opportunities to manage the flow of traffic on the LAN and BN than do the traditional LAN and routed BN architecture. Allow the ability to prioritize traffic They allow computers in separate geographic locations to be placed on the same LAN. Disadvantages: However, VLANs are significantly more complex, so they usually are used only for large networks. Cost How can you improve the performance of a BN? Improving the performance of backbone networks is similar to improving LAN performance. First, find the bottleneck, and then solve it (or more accurately, move the bottleneck somewhere else). You can improve the performance of the network by improving the computers and other devices in the network, by upgrading the circuits between computers, and by changing the demand placed on the network. Network performance can be improved by upgrading the computers and other devices in the network, by using static rather than dynamic routing if there are few routes through the network, by reducing switch-to-switch traffic in networks without standard protocols, by using the same protocols in the backbone network as in the attached LANs, by encapsulating rather than translating between different protocols, and by increasing the memory in backbone devices. Performance can also be improved by adding additional circuits to increase capacity, by going to a switched network, and by increasing the circuits on high traffic circuits. In addition, performance can be enhanced by reducing demand or by restricting applications that use lots of network capacity, and by using switches that filter certain broadcast messages. Why are broadcast messages important? Some application software packages and network operating system modules written for use on LANs broadcast status messages to all computers on the LAN (but not necessarily all computers served by a BN). For example, broadcast messages inform users when printers are out of paper, or when the network manager is about to shut down the server. These types of messages require filtering in a backbone network if their broadcast scope should be restricted to a particular LAN or segment. What are the preferred architectures used in each part of the backbone? The preferred architectures used in each part of the backbone network depend on various factors such as the organization's requirements, budget, scalability needs, and technological advancements. However, some common architectures used in different parts of the backbone network include: 1. Core Layer: • Collapsed Core Architecture: Suitable for smaller networks where the core and distribution layers are collapsed into a single layer. This architecture simplifies network design and reduces latency. • Three-Tier Architecture: In larger networks, a three-tier architecture with separate core, distribution, and access layers is preferred. This architecture provides better scalability, fault tolerance, and segmentation of network traffic. 2. Distribution Layer: • Hierarchical Design: In a three-tier architecture, the distribution layer serves as an aggregation point for connections from access switches and provides routing and policy-based services. A hierarchical design allows for efficient traffic management and scalability. • Redundant Distribution Layer: Redundancy is crucial at the distribution layer to ensure high availability and fault tolerance. Implementing redundant distribution switches with technologies like Virtual Router Redundancy Protocol (VRRP) or Hot Standby Router Protocol (HSRP) enhances network resilience. 3. Access Layer: • Star Topology: The access layer typically consists of access switches connected to distribution switches in a star topology. This design simplifies connectivity and enables easy addition or removal of devices. • VLAN Segmentation: Implementing Virtual Local Area Networks (VLANs) at the access layer allows for logical segmentation of network traffic, enhancing security and performance by isolating different departments or user groups. 4. Edge Layer: • Edge Security Devices: At the edge of the network, security devices such as firewalls, intrusion prevention systems (IPS), and content filtering appliances are deployed to protect against external threats and unauthorized access. • Quality of Service (QoS) Policies: QoS policies are often implemented at the edge to prioritize critical applications and ensure optimal performance for voice, video, and data traffic. 5. Wireless Backbone: • Controller-Based Architecture: In wireless networks, a controller-based architecture with centralized management is commonly used. Wireless access points (APs) connect to wireless LAN controllers (WLCs), which streamline configuration, monitoring, and security enforcement. • Mesh Networking: For outdoor or large indoor environments, mesh networking can extend wireless coverage by allowing APs to communicate wirelessly with each other, forming a self-healing network. 6. Internet Connectivity: • Redundant Internet Links: Dual-homed connections to multiple Internet service providers (ISPs) offer redundancy and load balancing, ensuring uninterrupted Internet connectivity. • Border Gateway Protocol (BGP): BGP routing is often used at the edge to dynamically exchange routing information between autonomous systems (ASes) and optimize Internet traffic routing. 7. Cloud Connectivity: • Direct Connect: For direct connectivity to cloud service providers (CSPs) like AWS, Azure, or Google Cloud Platform (GCP), dedicated private connections such as AWS Direct Connect or Azure ExpressRoute are preferred for improved performance, security, and reliability. • Virtual Private Network (VPN): VPN tunnels over the Internet provide secure connectivity to cloud resources for remote offices or mobile users, offering flexibility and cost-effectiveness. These architectures serve as guidelines for designing robust and scalable backbone networks, but the specific implementation may vary based on organizational needs and technology advancements. Regular assessment and optimization of the network architecture are essential to ensure it meets evolving requirements and industry best practices. Some experts are predicting that Ethernet will move into the WAN. What do you think? The new Ethernet/IP packet networks have become dominant for high-traffic networks (2 Mbps to 1Gbps), even though SONET and ATM remain preferred for some requirements. Since WAN required a network with high network capacity, I believe that Ethernet will move into the WAN into the near future. Mini-Cases I. Pat’s Engineering Works Pat’s Engineering Works is a small company that specializes in complex engineering consulting projects. The company is moving into new offices and want you to design their network. They have a staff of eight engineers (which is expected to grow to 12 over the next five years), plus another eight management and clerical employees who also need network connections, but whose needs are less intense. Design the network. Be sure to include a diagram. The recommended design should be based on the Rack-based collapsed backbone network design or on the VLAN-based collapsed backbone network design. II. Hospitality Hotel Hospitality Hotel is a luxury hotel that whose guests are mostly business travelers. To improve its quality of service, it has decided to install network connections in each of its 600 guest rooms and 12 conference meeting rooms. Your task is to design the network for the public network and decide how to connect the two networks together. Be sure to include a diagram. The recommended design should be based on the Rack-based collapsed backbone network design shown in the text. Each floor should have a layer-2 switch. Each conference room should "home run" to the main closet switch. All floors should use an uplink port to interconnect to the main switch. The two networks should be connected together with a router in between the two networks. This will allow the networks to be connected so that traffic can pass from one to the other, but the router can also keep “local traffic local,” thus reducing traffic on the network. III. Indiana University Reread Management Focus 8-1. What other alternatives do you think Indiana University considered? Why do you think they did what they did? They probably also considered a routed backbone and a virtual LAN. Either of these could offer some advantages, but the switched design is a good design that allows for flexibility in design. IV. Shangri-La Reread Management Focus 8-2. What other alternatives do you think the Shangri-La Resort considered? Why do you think they did what they did? The other alternatives could be numerous. They probably considered both routed and switched backbone architectures as well. Although the VLAN is more costly, it does provide much more efficiency, especially under heavy loads. V. Chicago Consulting You are the network manager for a consulting firm that needs to install a backbone to connect four 100Base-T Ethernet LANs (each using a 24-port switch). Develop a simple backbone and determine the total cost (i.e., select the device and price it). Prices are available at www.cdw.com, but you can use any source that is convenient. To design a simple backbone network for connecting four 100Base-T Ethernet LANs, we can use a basic three-tier architecture consisting of core, distribution, and access layers. Given the requirements, we'll select suitable networking devices for each layer and calculate the total cost based on available prices. 1. Core Layer: For the core layer, we'll choose a reliable and high-performance switch capable of handling the traffic aggregation from the distribution layer. Since the network size is relatively small, a manageable layer 3 switch would suffice. Selected Device: Cisco Catalyst 1000 Series Switch (Catalyst 1000-24P-4G-L) Price: $1,200 2. Distribution Layer: At the distribution layer, we need switches to aggregate traffic from the access layer switches and provide connectivity to the core layer. We'll choose manageable layer 2 switches with enough ports to accommodate connections from the access switches. Selected Device: Cisco Catalyst 2960-L Series Switch (C2960L-24TS-LL) Price: $800 each (We need two for redundancy) 3. Access Layer: For the access layer, we need switches to connect the end-user devices such as computers, printers, and phones. Since each LAN has a 24-port switch, we'll choose manageable layer 2 switches with 24 ports. Selected Device: Cisco Catalyst 1000 Series Switch (Catalyst 1000-24P-4G-L) Price: $700 each (We need four for each LAN) Total Cost Calculation: Core Layer Switch: $1,200 Distribution Layer Switches (2): $800 2 = $1,600 Access Layer Switches (4): $700 4 = $2,800 Total Cost = $1,200 + $1,600 + $2,800 = $5,600 So, the total cost for installing the backbone network to connect four 100Base-T Ethernet LANs using the selected devices is $5,600. Please note that prices may vary depending on the vendor and any additional features or services required. VI. Western Trucking Western Trucking operates a large fleet of trucks that deliver shipments for commercial shippers such as food stores, retailers, and wholesalers. Their main headquarters building and secondary building are shown in Figure 8-10. They want to upgrade to a faster network. Design a new network for them, including the specific backbone and LAN technologies to be used. Assume that the main office building is 170 feet by 100 feet in size and that the secondary building is 100 feet by 50 feet. The two buildings are 100 feet apart. I would install a collapsed backbone network using a star topology with a Gigabit Ethernet switch at the center. This backbone would support a series of LAN’s (as needed). In this new architecture, all circuits, routers, and bridges are replaced by one switch. Next Day Air Service Case Study 1. For this case, one may assume that there are LANs in four department offices (Data Processing, Accounts Payable, Information Services, and Agent Operations) and at Fleet Maintenance and Dispatch in the Secondary Building. What type of backbone network do you recommend for NDAS headquarters? Be prepared to justify your recommendation. Remember to consider the expected growth of the company. The determining factors in recommending a choice for a backbone network for NDAS are: (1) throughput, (2) type of application, (3) network management requirements, and (4) flexibility and potential for growth. Examining these factors, Gigabit Ethernet is the recommended backbone technology for NDAS headquarters. It will mesh well with their existing networks and allow them to continue to grow going forward. It is a good choice for NDAS. Note that student answers may differ. There is no single correct answer, so any reasonable answer is acceptable. 2. Price the network you have designed. Prices are available at www.datacommwarehouse.com, but use any source that is convenient. For simplicity, assume that Cat 5, Cat 5e, Cat 6 and fiber optic cable have a fixed cost per circuit to buy and install, regardless of distance, of $80, $100, $250 and $400. To price the network design, we'll consider the cost of networking devices and the cost of cabling for each circuit. Given the fixed cost per circuit for different types of cables, we'll calculate the total cost accordingly. Networking Devices: 1. Core Layer Switch: • Cisco Catalyst 1000 Series Switch (Catalyst 1000-24P-4G-L) • Price: $1,200 2. Distribution Layer Switches (2 for redundancy): • Cisco Catalyst 2960-L Series Switch (C2960L-24TS-LL) • Price: $800 each 3. Access Layer Switches (4 for each LAN): • Cisco Catalyst 1000 Series Switch (Catalyst 1000-24P-4G-L) • Price: $700 each Cabling Costs: For simplicity, we'll assume each LAN requires one circuit of cable to connect to the distribution layer switch, and the distribution layer switches require one circuit each to connect to the core layer switch. • Cost of Cat 5 cable installation per circuit: $80 • Cost of Cat 5e cable installation per circuit: $100 • Cost of Cat 6 cable installation per circuit: $250 • Cost of fiber optic cable installation per circuit: $400 Total Cost Calculation: Core Layer Switch: $1,200 Distribution Layer Switches (2): $800 2 = $1,600 Access Layer Switches (4): $700 4 = $2,800 Cabling Cost for each LAN (Cat 5e): $100 4 = $400 Cabling Cost for distribution layer switches to core switch (Cat 6): $250 2 = $500 Total Networking Devices Cost = $1,200 + $1,600 + $2,800 = $5,600 Total Cabling Cost = $400 + $500 = $900 Total Network Cost = Networking Devices Cost + Cabling Cost Total Network Cost = $5,600 + $900 = $6,500 Therefore, the total cost of the network, including networking devices and cabling, is $6,500. Please note that this calculation assumes a simplified scenario and actual costs may vary depending on factors such as vendor pricing, installation labor, and additional equipment or services required. 3. It is very important for you to explain to President Coone that there will be significant business benefits derived from continuing to grow the network. Explain in detail what some of these will be. Certainly, expanding the network infrastructure can bring about significant business benefits, and it's crucial to convey these advantages to President Coone. Here's a detailed explanation of some of the key benefits: 1. Improved Efficiency and Productivity: With a larger network infrastructure, employees will experience faster and more reliable access to resources, applications, and data. This translates into improved efficiency as tasks can be completed more quickly, leading to higher overall productivity levels across the organization. Employees spend less time waiting for files to download or applications to load, allowing them to focus more on their core responsibilities. 2. Scalability for Growth: As the organization grows, its network needs to grow accordingly. By expanding the network infrastructure, the organization ensures that it can easily accommodate new employees, departments, or locations without experiencing performance bottlenecks or connectivity issues. Scalability allows the organization to adapt to changing business requirements and seize new opportunities without being hindered by limitations in the network. 3. Enhanced Collaboration: A larger network facilitates better collaboration among employees, whether they are located in the same office or across different geographical locations. With robust network connectivity, employees can seamlessly share files, collaborate on projects in real-time, and communicate via voice or video conferencing tools. This fosters teamwork, creativity, and innovation, leading to better outcomes for the organization. 4. Support for Remote Work: In today's digital age, remote work is becoming increasingly common and often necessary. Expanding the network infrastructure enables the organization to support remote work initiatives effectively. Employees can securely access corporate resources from anywhere, using any device, ensuring continuity of operations even during unexpected events or disruptions. This flexibility in work arrangements can also help attract and retain top talent. 5. Enhanced Customer Experience: A robust network infrastructure not only benefits internal operations but also has a direct impact on customer experience. With faster and more reliable network connectivity, customer-facing applications, websites, and communication channels perform better, providing a seamless and satisfying experience for customers. This, in turn, can lead to increased customer loyalty, positive word-of-mouth referrals, and ultimately, business growth. 6. Better Data Security and Compliance: A larger network infrastructure allows for the implementation of more sophisticated security measures to protect sensitive data and ensure regulatory compliance. With the increasing threat of cyber attacks, investing in network security becomes paramount. By expanding the network, the organization can deploy advanced security technologies such as firewalls, intrusion detection systems, encryption, and access controls to safeguard its digital assets and mitigate risks. 7. Data Analytics and Insights: A larger network generates a wealth of data that can be leveraged for business intelligence and decision-making purposes. By capturing and analyzing network traffic, usage patterns, and performance metrics, the organization can gain valuable insights into its operations, customer behavior, and market trends. These insights can inform strategic planning, optimize resource allocation, and identify opportunities for improvement or innovation. In summary, continuing to grow the network infrastructure will not only address current needs but also position the organization for future success by improving efficiency, scalability, collaboration, customer experience, security, and data-driven decision-making. These benefits align with the organization's objectives of driving growth, innovation, and competitiveness in today's dynamic business landscape. Additional Content Teaching Notes I cover most material evenly, but I omit the selecting backbone networks section. I no longer cover FDDI and token ring as they are faded technologies, but I may mention these briefly in class to let the students know about these technologies just in case they encounter these older approaches in a job somewhere. Fast Ethernet, gigabit Ethernet and switched networks are the new “hot” technologies so I spend a significant amount of time on them. I also spend some amount of time on ATM. It is quite different from the other technologies we have examined and students have a harder time understanding it. It is useful for them to understand the concepts of an edge switch. Gigabit Ethernet and switch technologies (especially layer-3 and layer-4 switches) are the least mature of the technologies in this chapter. They will probably need careful watching to stay current. Solution Manual for Business Data Communications and Networking Jerry FitzGerald , Alan Dennis , Alexandra Durcikova 9781118891681, 9781118086834
