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Hierarchical Network Design

Upon completion of this chapter

What are the structured engineering principles of network design?

How do the modules of the Cisco Enterprise
Architecture model differ?

How do you apply the three hierarchical network layers in network design?

What are some trends that are challenging
enterprise network architectures?

What are the four basic modules in an enterprise campus network architecture that interconnect via the core?

How do the Borderless Network,
Collaboration Network, and Data Center/
Virtualization Network architectures address
the network challenges?

Key Terms
This chapter uses the following key terms. You can find the definitions in the glossary.
small network

page 3

medium-size network
large network

enterprise campus module
page 3

page 3

enterprise edge module
SP edge module

page 15

page 17

page 18

access layer page 6

enterprise branch module

distribution layer

enterprise teleworker module

page 22

enterprise data center module

page 22

core layer

page 7

page 9

three-tier hierarchical design page 10
two-tier hierarchical design page 10
collapsed core

page 10

modular network design page 11

page 21

Cisco Borderless Network Architecture
page 24
Cisco Collaboration Architecture

page 25

Cisco Data Center/Virtualization
Architecture page 26

Cisco Enterprise Architecture model
page 14

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Connecting Networks Companion Guide

Introduction (
Networks must meet the current needs of organizations and be able to support
emerging technologies as new technologies are adopted. Network design principles
and models can help a network engineer design and build a network that is flexible,
resilient, and manageable.
This chapter introduces network design concepts, principles, models, and architectures. It covers the benefits that are obtained by using a systematic design approach.
Emerging technology trends that will affect network evolution are also discussed.
Class Activity Design Hierarchy

A network administrator is tasked with designing an expanded network for the
After speaking with network administrators in other branches of the company, it was
decided to use the Cisco three-layer hierarchical network design model to influence the
expansion. This model was chosen for its simple influence upon network planning.
The three layers of the expanded network design include




Hierarchical Network Design Overview (1.1)
The Cisco hierarchical (three-layer) internetworking model is an industry wide adopted model for designing a reliable, scalable, and cost-efficient internetwork. In this
section, you will learn about the access, distribution, and core layers and their role in
the hierarchical network model.

Enterprise Network Campus Design (1.1.1)
An understanding of network scale and knowledge of good structured engineering
principles is recommended when discussing network campus design.

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Chapter 1: Hierarchical Network Design


Network Requirements (
When discussing network design, it is useful to categorize networks based on the
number of devices serviced:

Small network: Provides services for up to 200 devices.

Medium-size network: Provides services for 200 to 1,000 devices.

Large network: Provides services for 1,000+ devices.

Network designs vary depending on the size and requirements of the organizations.
For example, the networking infrastructure needs of a small organization with fewer
devices will be less complex than the infrastructure of a large organization with a significant number of devices and connections.
There are many variables to consider when designing a network. For instance, consider
the example in Figure 1-1. The sample high-level topology diagram is for a large enterprise
network that consists of a main campus site connecting small, medium, and large sites.

Figure 1-1 Large Enterprise Network Design

Network design is an expanding area and requires a great deal of knowledge and
experience. The intent of this section is to introduce commonly accepted network
design concepts.
The Cisco Certified Design Associate (CCDA®) is an industry-recognized certification for
network design engineers, technicians, and support engineers who demonstrate the skills
required to design basic campus, data center, security, voice, and wireless networks.

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as well as scheduled events such as maintenance windows. services block.1. A better network design approach was needed. 02_9781587133329_ch01.2) This topic discusses the three functional layers of the hierarchical network model: the access.1) Early networks were deployed in a flat topology as shown in Figure 1-2. denial-of-service (DoS) events. distribution.1. and Internet edge.2) Regardless of network size or requirements. For this reason. ■ Flexibility: The ability to modify portions of the network. or increase capacity without going through a major forklift upgrade (i. Normal conditions include normal or expected traffic flows and traffic patterns. Network Hierarchy (1. a network must be built on a hierarchical network architecture that allows for both flexibility and growth. To meet these fundamental design goals. Hierarchical Network Design (1. response times degraded. extreme traffic loads. the network is easier to design. These principles include ■ Hierarchy: A hierarchical network model is a useful high-level tool for designing a reliable network infrastructure. add new services.1.indd 4 3/13/14 2:43 AM . a critical factor for the successful implementation of any network design is to follow good structured engineering principles. Cisco has identified several modules.2. ■ Resiliency: The network must remain available for use under both normal and abnormal conditions. data center.. It breaks the complex problem of network design into smaller and more manageable areas. replacing major hardware devices).e. ■ Modularity: By separating the various functions that exist on a network into modules. As more devices and applications were added to a flat network. Hubs and switches were added as more devices needed to be connected. unusual traffic patterns. and core layers. A flat network design provided little opportunity to control broadcasts or to filter undesirable traffic.4 Connecting Networks Companion Guide Structured Engineering Principles (1. Abnormal conditions include hardware or software failures. and other unplanned events. making the network unusable. organizations now use a hierarchical network design as shown in Figure 1-3. whether intentional or unintentional. including the enterprise campus.1.

or tier. Each layer. in Figure 1-3 the flat network has now been divided into three separate broadcast domains. software. 02_9781587133329_ch01. Only traffic that is destined for other networks is moved to a higher layer. For example. more manageable blocks is that local traffic remains local. in the hierarchy provides specific functions that define its role within the overall network. This helps the network designer and architect to optimize and select the right network hardware. and features to perform specific roles for that network layer.indd 5 3/13/14 2:43 AM . Hierarchical models apply to both LAN and WAN design.Chapter 1: Hierarchical Network Design 5 Figure 1-2 Flat Switched Network Figure 1-3 Hierarchical Network A hierarchical network design involves dividing the network into discrete layers. The benefit of dividing a flat network into smaller.

In a smaller campus. 02_9781587133329_ch01. the network might have two tiers of switches in which the core and distribution elements are combined in one physical switch.6 Connecting Networks Companion Guide A typical enterprise hierarchical LAN campus network design includes the following three layers: ■ Access layer: Provides workgroup/user access to the network ■ Distribution layer: Provides policy-based connectivity and controls the boundary between the access and core layers ■ Core layer: Provides fast transport between distribution switches within the enterprise campus Another sample three-layer hierarchical network design is displayed in Figure 1-4. the access layer highlighted grants end devices access to the network.2) In a LAN environment. this is not a strict requirement. it may provide teleworkers or remote sites access to the corporate network across WAN connections. This is referred to as a collapsed core design. While it is true that many campus networks are constructed using three physical tiers of switches. The Access Layer (1.2. In the WAN environment.1. Notice that each building is using the same hierarchical network model that includes the access. distribution.indd 6 3/13/14 2:43 AM . Figure 1-4 Multi Building Enterprise Network Design Note There are no absolute rules for the way a campus network is physically built. and core layers.

the access layer for a small business network generally incorporates Layer 2 switches and access points providing connectivity between workstations and servers.1. 02_9781587133329_ch01.Chapter 1: Hierarchical Network Design 7 As shown in Figure 1-5. including ■ Layer 2 switching ■ High availability ■ Port security ■ QoS classification and marking and trust boundaries ■ Address Resolution Protocol (ARP) inspection ■ Virtual access control lists (VACLs) ■ Spanning tree ■ Power over Ethernet (PoE) and auxiliary VLANs for VoIP The Distribution Layer (1.indd 7 3/13/14 2:43 AM . Figure 1-5 Access Layer The access layer serves a number of functions.2. the distribution layer is the boundary between the Layer 2 domains and the Layer 3 routed network.3) The distribution layer aggregates the data received from the access layer switches before it is transmitted to the core layer for routing to its final destination. In Figure 1-6.

The device acts as the demarcation point between broadcast domains. The distribution layer can provide 02_9781587133329_ch01. ■ Redundancy and load balancing. because routers or multilayer switches do not forward broadcasts. ■ Policy-based security in the form of access control lists (ACLs) and filtering. Either a router or a multilayer switch is used to segment workgroups and isolate network problems in a campus environment.. 3/13/14 2:43 AM . ■ Broadcast domain control.indd 8 ■ Aggregation of LAN or WAN links. ■ A boundary for route aggregation and summarization configured on interfaces toward the core layer. EIGRP to OSPF). A distribution layer switch may provide upstream services for many access layer switches. ■ Routing services between LANs and VLANs and between routing domains (e.8 Connecting Networks Companion Guide Figure 1-6 Distribution Layer The distribution layer device is the focal point in the wiring closets.g.

the core layer is critical for interconnectivity between distribution layer devices (for example. and not more.4) The core layer is also referred to as the network backbone. The core aggregates the traffic from all the distribution layer devices. so it must be capable of forwarding large amounts of data quickly. As shown in Figure 1-7. fast transport) ■ Providing reliability and fault tolerance ■ Scaling by using faster. Considerations at the core layer include 02_9781587133329_ch01.indd 9 ■ Providing high-speed switching (i. equipment ■ Avoiding CPU-intensive packet manipulation caused by security. inspection. The core layer consists of high-speed network devices such as the Cisco Catalyst 6500 or 6800. and the WAN edge..e.1. the data center.Chapter 1: Hierarchical Network Design 9 The Core Layer (1. quality of service (QoS) classification. Figure 1-7 Core Layer The core should be highly available and redundant.2. such as distribution modules. service modules. These are designed to switch packets as fast as possible and interconnect multiple campus components. or other processes 3/13/14 2:43 AM . interconnecting the distribution block to the WAN and Internet edge).

while maintaining most of the benefits of the three-tier hierarchical model. network availability. A “collapsed core” is when the distribution layer and core layer functions are implemented by a single device. Therefore.6: Identify Hierarchical Network Characteristics Go to the course online to perform this practice activity.2.indd 10 3/13/14 2:43 AM . 02_9781587133329_ch01.1. and the ability to scale the network design. However.5) The three-tier hierarchical design maximizes performance.2. This section identifies enterprise architecture modules that are commonly found in medium-to-large organizations. Interactive Graphic Activity 1. many small enterprise networks do not grow significantly larger over time. Figure 1-8 Two-Tier Hierarchical Design The hierarchical network model provides a modular framework that allows flexibility in network design and facilitates ease of implementation and troubleshooting.1.2) The Cisco Enterprise Architecture is a modular approach to network design.10 Connecting Networks Companion Guide Two-Tier Collapsed Core Design (1. The example in Figure 1-8 has collapsed the distribution layer and core layer functionality into multilayer switch devices. The primary motivation for the collapsed core design is reducing network cost. Cisco Enterprise Architecture (1. a two-tier hierarchical design where the core and distribution layers are collapsed into one layer is often more practical.

The modules represent areas that have different physical or logical connectivity. Large organizations may also require dedicated connections to offsite data centers. upgrades. each targeting a specific place or purpose in the network. it became necessary to adjust the network design to one that uses a more modular approach. or the introduction of new services can be made in a controlled and staged fashion.Chapter 1: Hierarchical Network Design 11 Modular Design (1. providing for simpler problem detection and higher overall system availability. Figure 1-9 Expanding Beyond the Campus Infrastructure As the complexity of the network increased to meet these demands. ■ Network changes. As shown in Figure 1-9. A modular network design separates the network into various functional network modules. networks have become more sophisticated and complex. including 02_9781587133329_ch01. allowing greater flexibility in the maintenance and operation of the campus network.2.indd 11 ■ Failures that occur within a module can be isolated from the remainder of the network. The central campus site now requires connections to branch sites and support for teleworking employees working from home offices or other remote locations. Using a modular approach has several benefits.1. They designate where different functions occur in the network. 3/13/14 2:43 AM . networks have expanded beyond these borders.1) While the hierarchical network design works well within the campus infrastructure.

and more (see Figure 1-11). Basic network modules include ■ Access-distribution: Also called the distribution block. The use of modules in network design enables flexibility and facilitates implementation and troubleshooting. unified communications services. it can be updated or replaced by another module that has the same structural role in the overall hierarchical design. 3/13/14 2:43 AM .12 Connecting Networks Companion Guide ■ When a specific module no longer has sufficient capacity or is missing a new function or service.1. Modules in the Enterprise Architecture (1. These basic modules are connected together via the core of the network.2) A modular approach to network design further divides the three-layer hierarchical design by pulling out specific blocks or modular areas. ■ Security can be implemented on a modular basis allowing for more granular security control. this is the most familiar element and fundamental component of a campus design (see Figure 1-10).2.indd 12 Services: This is a generic block used to identify services such as centralized Lightweight Access Point Protocol (LWAPP) wireless controllers. policy gateways. Figure 1-10 Access-Distribution Module ■ 02_9781587133329_ch01.

Employees. and customers rely on data and resources in the data center to effectively create.indd 13 3/13/14 2:43 AM . collaborate. partners.Chapter 1: Hierarchical Network Design 13 Figure 1-11 Services Module ■ Data center: Originally called the server farm. This block is responsible for managing and maintaining many data systems that are vital to modern business operations. Figure 1-12 Data Center Module 02_9781587133329_ch01. and interact (see Figure 1-12).

indd 14 3/13/14 2:43 AM . video.2) The Cisco Enterprise Architecture is a modular approach to network design. Cisco Enterprise Architecture Model (1. This model provides all the benefits of the hierarchical network design on the campus infrastructure. 02_9781587133329_ch01.3: Identify Modules in a Network Design Go to the course online to perform this practice activity. The Cisco Enterprise Architecture model separates the enterprise network into functional areas that are referred to as modules.2.2. and facilitates the design of larger. more scalable networks.14 Connecting Networks Companion Guide ■ Enterprise edge: Consists of the Internet edge and the WAN edge.2.1) To accommodate the need for modularity in network design. These blocks offer connectivity to voice. Cisco developed the Cisco Enterprise Architecture model. This topic discusses the enterprise campus module. Figure 1-13 Enterprise Edge Module Interactive Graphic Activity 1.1. Cisco Enterprise Architecture Model (1. The modularity that is built in to the architecture allows flexibility in network design and facilitates implementation and troubleshooting. and data services outside the enterprise (see Figure 1-13). and the service provider edge module. enterprise edge module.2.

2) A campus network is a building or group of buildings connected into one enterprise network that consists of many LANs.2. including ■ Enterprise branch ■ Enterprise teleworker ■ Enterprise data center Cisco Enterprise Campus (1. 02_9781587133329_ch01. The enterprise campus module describes the recommended methods to create a scalable network while addressing the needs of campus-style business operations. A campus is generally limited to a fixed geographic area. but it can span several neighboring buildings (for example. Regional offices.Chapter 1: Hierarchical Network Design 15 As shown in Figure 1-14. and mobile workers may need to connect to the central campus for data and information. an industrial complex or business park environment). the following are the primary Cisco Enterprise Architecture modules: ■ Enterprise campus ■ Enterprise edge ■ Service provider edge Figure 1-14 Cisco Enterprise Architecture Modules Connected to the service provider edge are the remote modules.2. SOHOs.indd 15 3/13/14 2:43 AM .

even at the switch port level. viruses. and other attacks on the network. VLANs. and advanced security ■ Utilize multicast traffic and QoS to optimize network traffic ■ Provide increased security and flexibility using access management. and IPsec VPNs The enterprise campus module architecture provides the enterprise with high availability through a resilient multilayer design.indd 16 3/13/14 2:43 AM .16 Connecting Networks Companion Guide The architecture is modular and can easily expand to include additional campus buildings or floors as the enterprise grows. the enterprise campus module consists of the following submodules: ■ Building access ■ Building distribution ■ Campus core ■ Data center Figure 1-15 Enterprise Campus Module Together these submodules ■ Provide high availability through a resilient hierarchical network design ■ Integrate IP communications. As shown in Figure 1-15. redundant hardware and software features. mobility. 02_9781587133329_ch01. Integrated security protects against and mitigates the impact of worms. and automatic procedures for reconfiguring network paths when failures occur.

and other common management features from end to end. This module often functions as a liaison between the enterprise campus module and the other modules. Cisco Enterprise Edge (1.3) The enterprise edge module provides connectivity for voice.2. troubleshooting.2. and data services outside the enterprise.indd 17 3/13/14 2:43 AM . The data center submodule typically contains internal email and corporate servers that provide application. logging. the enterprise edge module consists of submodules providing ■ E-commerce services ■ Internet connectivity ■ Remote access and VPN access ■ WAN site-to-site VPN access Figure 1-16 Enterprise Edge Submodules 02_9781587133329_ch01. email. print. As shown in Figure 1-16. video. centralized data center module can provide internal server resources to users.Chapter 1: Hierarchical Network Design 17 A high-capacity. file. The data center module typically also supports network management services for the enterprise. including monitoring. and Domain Name System (DNS) services to internal users.

indd 18 ■ Internet service providers (ISPs) ■ WAN services such as Frame Relay. ■ WAN: The WAN submodule uses various WAN technologies for routing traffic between remote sites and the central site. Connectivity to one or several Internet service providers (ISPs) is also provided. Devices located in the e-commerce submodule include web. application. PPP. Service Provider Edge (1. As shown in Figure 1-17. and network intrusion prevention system (IPS) appliances. Components of this submodule include firewalls. SMTP relay servers. and MAN ■ Public switched telephone network (PSTN) services 3/13/14 2:43 AM . digital subscriber line (DSL). Internet edge routers. dial-in access concentrators. Metro Ethernet.18 Connecting Networks Companion Guide Specifically. ATM.4) Enterprises use service providers (SPs) to link to other sites. cable. Components of this submodule include firewall and firewall routers. and DNS servers. and network intrusion prevention systems (IPS). Synchronous Optical Network (SONET) and Synchronous Digital Hierarchy (SDH). Enterprise WAN links include technologies such as Multiprotocol Label Switching (MPLS). Frame Relay. leased lines. ■ Internet connectivity and demilitarized zone (DMZ) : The Internet submodule of the enterprise edge provides internal users with secure connectivity to Internet services such as public servers.2.2. ATM. email. ■ Remote access and VPN: The VPN/remote access submodule of the enterprise edge provides remote-access termination services. and database servers. the SP edge module can include 02_9781587133329_ch01. Cisco Adaptive Security Appliances (ASA). including authentication for remote users and sites. FTP and HTTP servers. these submodules consist of: ■ E-commerce networks and servers: The e-commerce submodule enables enterprises to support e-commerce applications through the Internet. and wireless. firewall and firewall routers. and DNS. It uses the high-availability designs of the data center module.

As shown in Figure 1-18.indd 19 ■ Single-homed: A single connection to an ISP ■ Dual-homed: Two or more connections to a single ISP 3/13/14 2:43 AM . redundant connections to a single ISP can include 02_9781587133329_ch01. and enterprise teleworker modules. Redundant Internet connections vary depending if the enterprise is connecting to a single ISP or multiple ISPs. video. redundancy or failover should be considered.Chapter 1: Hierarchical Network Design 19 Figure 1-17 Service Provider Edge Module The SP edge provides connectivity between the enterprise campus module to the remote enterprise data center. enterprise branch. and data services over a single IP communications network ■ Supports QoS and service level agreements ■ Supports security using VPNs (IPsec / MPLS) over Layer 2 and Layer 3 WANs When acquiring Internet services from an ISP. The SP edge module ■ Spans across large geographic areas in a cost effective manner ■ Converges voice.

Options for connecting to multiple ISPs include ■ Multihomed: Connections to two or more ISPs ■ Dual-multihomed: Multiple connections to two or more ISPs Figure 1-19 Connecting to Multiple ISPs 02_9781587133329_ch01.indd 20 3/13/14 2:43 AM . as shown in Figure 1-19. it is possible to set up redundancy using multiple ISPs.20 Connecting Networks Companion Guide Figure 1-18 Connecting to a Single ISP Alternatively.

to the remote branches.2. such as security. In Figure 1-20. The enterprise branch module allows enterprises to extend head-office applications and services. 02_9781587133329_ch01. and mobility options to employees. the enterprise branch module connects to the enterprise campus site primarily using a WAN link. as well as general connectivity into the campus network and the different components located inside the enterprise campus.2. These locations are typically responsible for providing security.5) The remote functional area is responsible for remote connectivity options and includes the following modules. while smaller sites may use an ISR G2 router. Large remote sites may use high-end Cisco Catalyst switches. These remote sites rely on the SP edge to provide services and applications from the main site. However.Chapter 1: Hierarchical Network Design 21 Remote Functional Area (1. as shown in Figure 1-20. Cisco Unified Communications. it also has an Internet link as a backup.indd 21 3/13/14 2:43 AM . telephony. The edge device connecting the remote site to the central site varies depending on the needs and size of the site. The Internet link uses site-to-site IPsec VPN technology to encrypt corporate data. Figure 1-20 Remote Connectivity Areas Enterprise Branch The enterprise branch module includes remote branches that allow employees to work at noncampus locations. and advanced application performance.

or customer/client sites. Redundant data centers provide backup using synchronous and asynchronous data and application replication. but exists at a remote location. Enterprise Data Center The enterprise data center module is a data center with all of the same functional options as a campus data center. Additionally.2. The network had distinct borders and access requirements. Users could only access network resources with company-owned computers.indd 22 3/13/14 2:43 AM .22 Connecting Networks Companion Guide Enterprise Teleworker The enterprise teleworker module is responsible for providing connectivity for workers who operate out of different geographically dispersed locations. Traditionally.3.2. Maintaining 02_9781587133329_ch01. Integrated security. This provides an added layer of security as the offsite data center can provide disaster recovery and business continuance services for the enterprise. such as cable modem or DSL. Interactive Graphic Activity 1. High-end switches such as the Cisco Nexus series switch use fast WAN services such as Metro Ethernet (MetroE) to connect the enterprise campus to the remote enterprise data center.1) As businesses have grown more dependent on networks for success. Staff can securely log in to the network over the VPN and gain access to authorized applications and services from a single cost-effective platform. The teleworker module recommends that mobile users connect to the Internet using the services of a local ISP. This section discusses new networking architecture trends. the network and devices offer server and application load balancing to maximize performance. VPN services can then be used to secure communications between the mobile worker and central campus.6: Identify Modules of the Cisco Enterprise Architecture Go to the course online to perform this practice activity.3) New technologies are constantly challenging network administrators. including home offices.and identitybased networking services enable the enterprise to extend campus security policies to the teleworker. This solution allows the enterprise to scale without major changes to the infrastructure. data. IT Challenges (1. hotels. network architectures have evolved over the years.1. and applications were housed on premise. Evolving Network Architectures (1. users.

02_9781587133329_ch01.1. To meet this need. Networks are transforming from a data-only transportation system of connected LAN devices to a system that enables the connections of people. and information in a media-rich.Chapter 1: Hierarchical Network Design 23 security. devices. Some of the top trends include ■ Bring your own device (BYOD) ■ Online collaboration ■ Video communication ■ Cloud computing These trends.2) The speed of change in market and business environments is requiring IT to be more strategic than ever before. as well as the overlaying policies and technologies that allow organizations to support emerging trends in a safe and manageable way. These architectures must account for the network design principles established in the Cisco Enterprise Architecture.3. the network border has shifted. There are several new networking trends that continue to effect organizations and consumers. The intent of this section is to provide an introduction and overview of emerging architecture trends. while allowing for more advanced services than ever before. businesses and consumers must continue to adjust to this ever-changing environment. Today. As new technologies and end-user devices come to market. new business network architectures are necessary. and services was simpler. Emerging Enterprise Architectures (1.indd 23 3/13/14 2:43 AM . Cisco has introduced the following three network architectures: ■ Cisco Borderless Network Architecture ■ Collaboration Architecture ■ Data Center/Virtualization Architecture Note Network architectures continually evolve. converged network environment. creating new challenges for IT departments. also introduce new security risks that IT must address. productivity. Evolving business models are creating complex technology challenges that IT must address. To address these emerging network trends.

It is based on wired. and seamlessly to the corporate network in a BYOD environment. as shown in Figure 1-21. Specifically.indd 24 ■ Borderless end-point/user services: As highlighted in Figure 1-21.3. borderless network services unify the approach to securely deliver applications to users in a highly distributed environment. policy-based connection for a seamless user experience. Devices that can connect to the borderless network can range from PCs to tablets and smartphones. the Collaboration Architecture. but an evolving solution to help IT evolve its infrastructure to deliver secure. providing unified access to wired and wireless devices. security. End-point/user services define the user experience and enable the attributes of secure. The crucial element to scaling secure access is a policy-based architecture that allows IT to implement centralized access controls. it provides secure.3. For example. Cisco Borderless Networks (1. It enables an IT department to architect and deploy its systems and policies efficiently to all end user devices that require connection to the network. They consistently adopt existing networks and develop new network architectures. reliable. reliable. borderless end-point/user services connect the various devices to provide access to network services. It securely connects internal users and remote users and provides access to network resources. and application optimization devices working in harmony to help IT balance demanding business challenges and changing business models. and the Data Center and Virtualization Architecture. It is not a static solution. from multiple devices. and seamless user experiences in a world with many new and shifting borders.24 Connecting Networks Companion Guide Emerging Network Architectures (1. the Cisco Borderless Network Architecture delivers two primary sets of services: 02_9781587133329_ch01. and seamless access to resources from multiple locations. 3/13/14 2:43 AM . It removes the location and device borders. In doing this. and seamless performance on a broad range of devices and environments.1) The Cisco Borderless Network Architecture is a network solution that allows organizations and individuals to connect securely. persistent. This topic introduces the Cisco Borderless Network Architecture. It enables the device to establish a secure. switching.2. reliably. reliable. ■ Borderless network services: As highlighted in Figure 1-22. most smartphones and tablets can download and use the Cisco AnyConnect software. routing.2) Cisco has been at the forefront of network design for decades. and to applications that can be located anywhere. wireless.

and APIs. The Cisco Collaboration Architecture comprises a portfolio of products. Collaboration Architecture (1. including BYOD. applications. and to innovate.2) Working in a collaborative environment helps increase productivity.2. 02_9781587133329_ch01.Chapter 1: Hierarchical Network Design 25 Figure 1-21 Borderless Network Architecture Figure 1-22 Services Supported in Borderless Networks The borderless network architecture supports a highly secure. high-performing network that is accessible to a wide range of devices. software development kits (SDKs). Collaboration and other types of groupware are used to bring people together for one reason or another: such as to socialize.indd 25 3/13/14 2:43 AM . The individual components work together to provide a comprehensive solution.3. to work together. mobility and cloud computing and must be able to support the growing requirements for online voice and video. to cooperate and contribute to the production of something. It needs to be flexible enough to scale in its support for future growth in terms of business expansion.

2. as shown in Figure 1-24: ■ 02_9781587133329_ch01. storage.0. The Data Center Architecture consists of three components. session management. tagging. web conferencing. computing. The applications within this layer help users stay connected and productive. and virtualization platforms together. location. It includes virtual machines. messaging. the network. ■ Network and Computer Infrastructure: This layer is responsible for allowing collaboration anytime. mobile applications. WebEx Social. Cisco Jabber. from anywhere.3. and policy and security management.3) The Cisco Data Center/Virtualization Architecture is built upon Cisco Data Center 3.indd 26 Cisco Unified Management Solutions: Management solutions simplify and automate the process of deploying IT infrastructure and services with speed and enterprise reliability. 3/13/14 2:43 AM . These applications include voice. and enterprise social software. client frameworks.26 Connecting Networks Companion Guide As shown in Figure 1-23. Cisco’s collaboration architecture is composed of three layers: ■ Application and Devices: This layer contains unified communications and conference applications such as Cisco WebEx Meetings. Figure 1-23 Cisco Collaboration Architecture Data Center and Virtualization (1. contact management. ■ Collaboration Services: This layer supports collaboration applications including the following services: presence. on any device. video. and TelePresence. Solutions operate transparently across physical and virtual resources in cloud environments. It comprises a comprehensive set of virtualization technologies and services that bring the network. and storage.

2.2. scalability. Components of the architecture come together to build network systems that span an organization from network access to the cloud.indd 27 3/13/14 2:43 AM . ■ Unified Computing Solutions: Cisco’s next-generation data center system unites computing. and virtual interface cards (VICs). adding features and functionality in an integrated solution. 02_9781587133329_ch01. storage. Building off the basic network infrastructure. organizations can use these network architectures to grow their network over time. storage access. network. Solutions include Cisco Nexus switches.3.3. Cisco Fabric Manager. rack-mount servers.Chapter 1: Hierarchical Network Design 27 ■ Unified Fabric Solutions: Flexible network solutions deliver network services to servers. fabric interconnects. and Cisco NX-OS software. and provide organizations with the services they need.3: Cisco Unified Fabric Video Go to the course to see a short video on the Cisco Unified Fabric. and virtualization into a cohesive system designed to reduce total cost of ownership (TCO) and increase business agility. providing transparent convergence. and applications.4) These three architectures are built on an infrastructure of scalable and resilient hardware and software. Figure 1-24 Components of the Data Center Architecture Video 1. The Cisco Unified Computing System (Cisco UCS) is built with blade servers. Catalyst switches. Expanding the Network (1. and sophisticated intelligence.

indd 28 Video 1. 3/13/14 2:43 AM . Interactive Graphic Interactive Graphic 02_9781587133329_ch01.3.4: Evolution of a Corporate WAN Go to the course to see a short video on the evolution of a network to a WAN infrastructure.5: Identify Evolving Network Architecture Terminology Go to the course online to perform this practice activity. Connecting Networks Companion Guide One of the first steps in growing the network is expanding from the campus infrastructure to a network that connects remote sites through the Internet and through the WAN. Activity 1.

You are tasked with completing the upgrades to the enterprise network.4. Packet Tracer Activity Packet Tracer Activity 1. Therefore. which includes dual-stacked IPv4 and IPv6 as well as a variety of addressing and routing technologies. The structured engineering principles of good network design include hierarchy.4. Half of the enterprise network uses IPv4 medium-size business.1.4) Class Activity 1.Everywhere You are the network administrator for your small. and flexibility. Borderless network services interest you as you plan your network’s future. The requirements also include a variety of routing and switching technologies.3: Skills Integration Challenge . you realize that your wired and wireless networks need manageability and deployment design.Chapter 1: Hierarchical Network Design 29 Summary (1.indd 29 3/13/14 2:43 AM . and the other half uses IPv6 addressing.2: Skills Integration Challenge This Packet Tracer Activity provides an opportunity to review skills from previous coursework. resiliency. modularity. You are tasked with completing upgrades to the network infrastructure that has two locations.EIGRP You are a network technician new to a company that has lost its last technician in the middle of a system upgrade.1. 02_9781587133329_ch01. Your business has just expanded into a different town and needs to expand its presence across the Internet. this leads you to consider the following Cisco borderless services as possible options for your business: Packet Tracer Activity ■ Security: TrustSec ■ Mobility: Motion ■ Application performance: App Velocity ■ Multimedia performance: Medianet ■ Energy management: EnergyWise Packet Tracer Activity 1.1: Borderless Innovations .1. While planning for network policies and services.4.

4. scalable networks. and maintainability. and enterprise teleworker.indd 30 3/13/14 2:43 AM . The Cisco Enterprise Architecture modules are used to facilitate the design of large. the services block. performance. enterprise branch.2: Design Hierarchy Class Activity 1. distribution layer.1: Borderless Innovations . and the enterprise edge.1.OSPF Packet Tracer Activity 1.EIGRP 02_9781587133329_ch01. service provider edge.3: Skills Integration Challenge . and the core layer.0. Class Activities Class Activity 1. Practice The following activities provide practice with the topics introduced in this chapter.2: Skills Integration Challenge . The basic module blocks that are connected by the core include the access distribution block.1.1.30 Connecting Networks Companion Guide A typical enterprise hierarchical LAN campus network design includes the access layer. A modular design that separates the functions of a network enables flexibility and facilitates implementation and management.4. redundancy. a “collapsed core” hierarchy. The Labs and Class Activities are available in the companion Connecting Networks Lab Manual (978-1-58713-331-2). enterprise data center.1. The benefits of a hierarchical network include scalability.Everywhere Packet Tracer Activity Packet Tracer Activities Packet Tracer Activity 1.4. In smaller enterprise networks. The primary modules include the enterprise campus. The Packet Tracer Activity PKA files are found in the online course. can be more practical. where the distribution layer and core layer functions are implemented in a single device. enterprise edge. the data center.

Cisco Enterprise Data Center Architecture E. quality of service (QoS). WAN F. 1. Access B. modularity. and security F. hierarchy. quality of service (QoS). Modularity. and security B. flexibility. Workgroup 3. Hierarchy. Flexibility. Which layer of the hierarchical network design model is often called the backbone? A. Distribution D. resiliency. Flexibility. and security G. Which network architecture combines individual components to provide a com- prehensive solution allowing people to cooperate and contribute to the production of something? A.Chapter 1: Hierarchical Network Design 31 Check Your Understanding Questions Complete all the review questions listed here to test your understanding of the topics and concepts in this chapter. and security 2. What are the four structured design principles? A. resiliency. hierarchy. The appendix.” lists the answers. Availability. quality of service (QoS) C. Cisco Enterprise Campus Architecture C. resiliency. modularity. “Answers to the ‘Check Your Understanding’ Questions. Cisco Enterprise Branch Architecture D. resiliency D. modularity. and security E. Cisco Borderless Network Architecture F. Hierarchy. Core C.indd 31 3/13/14 2:43 AM . Cisco Enterprise Teleworker module 02_9781587133329_ch01. modularity. Cisco Collaboration Architecture B. resiliency. Availability. modularity. Network E.

Consists of the access layer and distribution layer in one device D. persistent.32 Connecting Networks Companion Guide 4. Firewall appliance B. Wireless access point 7.) A. Network 5.indd 32 3/13/14 2:43 AM . It is used to establish a secure. Consists of the distribution and core layer in one device 02_9781587133329_ch01. C. Modular multilayer switch E. It is part of the borderless end-point/user services. Layer 2 switch C. Which two statements regarding the Cisco AnyConnect software are true? (Choose two. Also called a three-tier hierarchical network design C. It is part of the borderless network services. Which two statements correctly describe a collapsed core network design? (Choose two. F. It is used to connect any device to the network. Distribution E. Application C. Layer 3 switch D. Access B. D. B.) A. Also called a two-tier hierarchical network design B. At which layer of the hierarchical network model do users connect to the net- work? A. It is used to connect from anywhere. policy-based connection. It is used to connect without an Internet connection. VoIP phones F. 6. Core D. Consists of the access layer and core layer in one device E.) A. Which three devices are found in the access layer of the hierarchical network model? (Choose three. E.

It satisfies telephony requirements for users who are located at medium to large enterprise sites. and more? A. 02_9781587133329_ch01. and TelePresence to help users stay connected and productive. To reduce remote security threats. Which network architecture functions through a combination of technologies that include wired. it forces users who are located at main sites to log on to resources. security. Which goal can be accomplished by implementing the Cisco enterprise telework- er module? A. It supports collaboration applications with presence. Cisco Jabber. Type of applications 10. Cisco Enterprise Teleworker 11.indd 33 3/13/14 2:43 AM . C. 9. B.Chapter 1: Hierarchical Network Design 33 8. It is responsible for allowing collaboration anytime. B. It allows the enterprise to deliver secure voice and data services to workers no matter where or when they work. contact management. wireless. Protocols required D. D. Size of the network E. location. and policy and security management. session management. Connectivity to the branch site C. from anywhere. Type of security implemented F. Cisco Enterprise Edge E. Cisco Borderless Network B. What does the application and device layer of the Cisco Collaboration Architecture do? A. tagging. It contains applications such as Cisco WebEx Meetings. client frameworks. Cisco Enterprise Branch C. Connectivity to the data center B. Cisco Enterprise Campus D. on any device. It allows the enterprise to add large branch sites that span geographic areas. C. What should be considered first when starting the network design? A.

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