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CHAPTER 1

Hierarchical Network Design

Objectives
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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2

Connecting Networks Companion Guide

Introduction (1.0.1.1)
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 1.0.1.2: Design Hierarchy

A network administrator is tasked with designing an expanded network for the
company.
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

Access

Distribution

Core

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

3

Network Requirements (1.1.1.1)
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.
Note
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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2) Regardless of network size or requirements.1) Early networks were deployed in a flat topology as shown in Figure 1-2.1. For this reason. add new services. and Internet edge. To meet these fundamental design goals.2) This topic discusses the three functional layers of the hierarchical network model: the access. A flat network design provided little opportunity to control broadcasts or to filter undesirable traffic. As more devices and applications were added to a flat network. a critical factor for the successful implementation of any network design is to follow good structured engineering principles. data center. Hubs and switches were added as more devices needed to be connected.4 Connecting Networks Companion Guide Structured Engineering Principles (1.1.2.. organizations now use a hierarchical network design as shown in Figure 1-3.1. or increase capacity without going through a major forklift upgrade (i. unusual traffic patterns. ■ Modularity: By separating the various functions that exist on a network into modules. whether intentional or unintentional. response times degraded. ■ Flexibility: The ability to modify portions of the network. Abnormal conditions include hardware or software failures. extreme traffic loads. the network is easier to design. including the enterprise campus. as well as scheduled events such as maintenance windows. a network must be built on a hierarchical network architecture that allows for both flexibility and growth. It breaks the complex problem of network design into smaller and more manageable areas. 02_9781587133329_ch01. and other unplanned events. denial-of-service (DoS) events. Cisco has identified several modules. replacing major hardware devices). A better network design approach was needed. Network Hierarchy (1. These principles include ■ Hierarchy: A hierarchical network model is a useful high-level tool for designing a reliable network infrastructure. and core layers. making the network unusable.1. services block. distribution.indd 4 3/13/14 2:43 AM .e. ■ Resiliency: The network must remain available for use under both normal and abnormal conditions. Normal conditions include normal or expected traffic flows and traffic patterns. Hierarchical Network Design (1.

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

2) In a LAN environment. 02_9781587133329_ch01. it may provide teleworkers or remote sites access to the corporate network across WAN connections. While it is true that many campus networks are constructed using three physical tiers of switches. In a smaller campus.1. the access layer highlighted grants end devices access to the network. Figure 1-4 Multi Building Enterprise Network Design Note There are no absolute rules for the way a campus network is physically built. this is not a strict requirement.indd 6 3/13/14 2:43 AM . and core layers. the network might have two tiers of switches in which the core and distribution elements are combined in one physical switch.2. Notice that each building is using the same hierarchical network model that includes the access. In the WAN environment.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 (1. distribution. This is referred to as a collapsed core design.

Chapter 1: Hierarchical Network Design 7 As shown in Figure 1-5.indd 7 3/13/14 2:43 AM . In Figure 1-6.1. the access layer for a small business network generally incorporates Layer 2 switches and access points providing connectivity between workstations and servers. Figure 1-5 Access Layer The access layer serves a number of functions. 02_9781587133329_ch01.3) 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. the distribution layer is the boundary between the Layer 2 domains and the Layer 3 routed network.2. 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.

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

. The core layer consists of high-speed network devices such as the Cisco Catalyst 6500 or 6800.1.e.4) The core layer is also referred to as the network backbone.indd 9 ■ Providing high-speed switching (i. equipment ■ Avoiding CPU-intensive packet manipulation caused by security. and the WAN edge. service modules. or other processes 3/13/14 2:43 AM . quality of service (QoS) classification. such as distribution modules. Considerations at the core layer include 02_9781587133329_ch01.2. The core aggregates the traffic from all the distribution layer devices. Figure 1-7 Core Layer The core should be highly available and redundant. so it must be capable of forwarding large amounts of data quickly. fast transport) ■ Providing reliability and fault tolerance ■ Scaling by using faster. the core layer is critical for interconnectivity between distribution layer devices (for example. As shown in Figure 1-7. the data center. and not more. inspection. These are designed to switch packets as fast as possible and interconnect multiple campus components. interconnecting the distribution block to the WAN and Internet edge).Chapter 1: Hierarchical Network Design 9 The Core Layer (1.

Therefore.2. while maintaining most of the benefits of the three-tier hierarchical model.6: Identify Hierarchical Network Characteristics Go to the course online to perform this practice activity.1.5) The three-tier hierarchical design maximizes performance.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. a two-tier hierarchical design where the core and distribution layers are collapsed into one layer is often more practical. However. network availability.2. This section identifies enterprise architecture modules that are commonly found in medium-to-large organizations. 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. The primary motivation for the collapsed core design is reducing network cost. and the ability to scale the network design. 02_9781587133329_ch01. A “collapsed core” is when the distribution layer and core layer functions are implemented by a single device. Cisco Enterprise Architecture (1.1. Interactive Graphic Activity 1.indd 10 3/13/14 2:43 AM .

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

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

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

enterprise edge module. 02_9781587133329_ch01. more scalable networks. and facilitates the design of larger. Cisco Enterprise Architecture Model (1.14 Connecting Networks Companion Guide ■ Enterprise edge: Consists of the Internet edge and the WAN edge.indd 14 3/13/14 2:43 AM .2.2.1) To accommodate the need for modularity in network design.2. This topic discusses the enterprise campus module. and data services outside the enterprise (see Figure 1-13). Figure 1-13 Enterprise Edge Module Interactive Graphic Activity 1. video.1. The modularity that is built in to the architecture allows flexibility in network design and facilitates implementation and troubleshooting. These blocks offer connectivity to voice. Cisco developed the Cisco Enterprise Architecture model.2. Cisco Enterprise Architecture Model (1.3: Identify Modules in a Network Design Go to the course online to perform this practice activity. and the service provider edge module. This model provides all the benefits of the hierarchical network design on the campus infrastructure.2) The Cisco Enterprise Architecture is a modular approach to network design. The Cisco Enterprise Architecture model separates the enterprise network into functional areas that are referred to as modules.

but it can span several neighboring buildings (for example. The enterprise campus module describes the recommended methods to create a scalable network while addressing the needs of campus-style business operations. Regional offices. SOHOs.2) A campus network is a building or group of buildings connected into one enterprise network that consists of many LANs. an industrial complex or business park environment).Chapter 1: Hierarchical Network Design 15 As shown in Figure 1-14.2. 02_9781587133329_ch01. and mobile workers may need to connect to the central campus for data and information. including ■ Enterprise branch ■ Enterprise teleworker ■ Enterprise data center Cisco Enterprise Campus (1. A campus is generally limited to a fixed geographic area.indd 15 3/13/14 2:43 AM . 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.

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

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

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

Redundant Internet connections vary depending if the enterprise is connecting to a single ISP or multiple ISPs. and enterprise teleworker modules. The SP edge module ■ Spans across large geographic areas in a cost effective manner ■ Converges voice. As shown in Figure 1-18. 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.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 .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. redundant connections to a single ISP can include 02_9781587133329_ch01. redundancy or failover should be considered. video. enterprise branch.

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_ch01.20 Connecting Networks Companion Guide Figure 1-18 Connecting to a Single ISP Alternatively. as shown in Figure 1-19.indd 20 3/13/14 2:43 AM . it is possible to set up redundancy using multiple ISPs.

while smaller sites may use an ISR G2 router.5) The remote functional area is responsible for remote connectivity options and includes the following modules. and mobility options to employees.Chapter 1: Hierarchical Network Design 21 Remote Functional Area (1.indd 21 3/13/14 2:43 AM . to the remote branches. 02_9781587133329_ch01. The Internet link uses site-to-site IPsec VPN technology to encrypt corporate data. These locations are typically responsible for providing security. The edge device connecting the remote site to the central site varies depending on the needs and size of the site.2. telephony. Large remote sites may use high-end Cisco Catalyst switches. the enterprise branch module connects to the enterprise campus site primarily using a WAN link. These remote sites rely on the SP edge to provide services and applications from the main site. However. and advanced application performance. Figure 1-20 Remote Connectivity Areas Enterprise Branch The enterprise branch module includes remote branches that allow employees to work at noncampus locations. such as security. as shown in Figure 1-20.2. In Figure 1-20. as well as general connectivity into the campus network and the different components located inside the enterprise campus. Cisco Unified Communications. it also has an Internet link as a backup. The enterprise branch module allows enterprises to extend head-office applications and services.

3. Enterprise Data Center The enterprise data center module is a data center with all of the same functional options as a campus data center. This section discusses new networking architecture trends. Additionally.1) As businesses have grown more dependent on networks for success. Integrated security. Traditionally. IT Challenges (1. but exists at a remote location. The network had distinct borders and access requirements.3) New technologies are constantly challenging network administrators.2. Evolving Network Architectures (1.6: Identify Modules of the Cisco Enterprise Architecture Go to the course online to perform this practice activity. Users could only access network resources with company-owned computers. and applications were housed on premise.2. This solution allows the enterprise to scale without major changes to the infrastructure. users. the network and devices offer server and application load balancing to maximize performance. Redundant data centers provide backup using synchronous and asynchronous data and application replication. Maintaining 02_9781587133329_ch01. The teleworker module recommends that mobile users connect to the Internet using the services of a local ISP. including home offices.indd 22 3/13/14 2:43 AM .1. such as cable modem or DSL. 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. VPN services can then be used to secure communications between the mobile worker and central campus. Interactive Graphic Activity 1.22 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. This provides an added layer of security as the offsite data center can provide disaster recovery and business continuance services for the enterprise.and identitybased networking services enable the enterprise to extend campus security policies to the teleworker. data. or customer/client sites. network architectures have evolved over the years. hotels. 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.

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

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

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

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

Components of the architecture come together to build network systems that span an organization from network access to the cloud.2.3. and virtual interface cards (VICs).Chapter 1: Hierarchical Network Design 27 ■ Unified Fabric Solutions: Flexible network solutions deliver network services to servers. and applications. and virtualization into a cohesive system designed to reduce total cost of ownership (TCO) and increase business agility. storage. Building off the basic network infrastructure. providing transparent convergence. scalability.3. Cisco Fabric Manager. ■ Unified Computing Solutions: Cisco’s next-generation data center system unites computing. and Cisco NX-OS software. Figure 1-24 Components of the Data Center Architecture Video 1. 02_9781587133329_ch01. Solutions include Cisco Nexus switches. organizations can use these network architectures to grow their network over time. storage access. fabric interconnects. Expanding the Network (1. and provide organizations with the services they need.indd 27 3/13/14 2:43 AM . adding features and functionality in an integrated solution. Catalyst switches. rack-mount servers. The Cisco Unified Computing System (Cisco UCS) is built with blade servers.4) These three architectures are built on an infrastructure of scalable and resilient hardware and software. network.2. and sophisticated intelligence.3: Cisco Unified Fabric Video Go to the course to see a short video on the Cisco Unified Fabric.

28 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.indd 28 Video 1. Interactive Graphic Interactive Graphic 02_9781587133329_ch01. 3/13/14 2:43 AM .3.5: Identify Evolving Network Architecture Terminology Go to the course online to perform this practice activity.2. Activity 1.3.2.4: Evolution of a Corporate WAN Go to the course to see a short video on the evolution of a network to a WAN infrastructure.

You are tasked with completing the upgrades to the enterprise network.3: Skills Integration Challenge . Packet Tracer Activity Packet Tracer Activity 1.2: Skills Integration Challenge This Packet Tracer Activity provides an opportunity to review skills from previous coursework. 02_9781587133329_ch01.to medium-size business. resiliency. The structured engineering principles of good network design include hierarchy. Your business has just expanded into a different town and needs to expand its presence across the Internet.Everywhere You are the network administrator for your small. While planning for network policies and services. modularity. Half of the enterprise network uses IPv4 addressing.4. You are tasked with completing upgrades to the network infrastructure that has two locations. Borderless network services interest you as you plan your network’s future.4) Class Activity 1.1. 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. Therefore. The requirements also include a variety of routing and switching technologies.indd 29 3/13/14 2:43 AM .1: Borderless Innovations .EIGRP You are a network technician new to a company that has lost its last technician in the middle of a system upgrade.4. and flexibility. which includes dual-stacked IPv4 and IPv6 as well as a variety of addressing and routing technologies.1. and the other half uses IPv6 addressing.1. you realize that your wired and wireless networks need manageability and deployment design.4.Chapter 1: Hierarchical Network Design 29 Summary (1.

In smaller enterprise networks.EIGRP 02_9781587133329_ch01.4.4. The primary modules include the enterprise campus.Everywhere Packet Tracer Activity Packet Tracer Activities Packet Tracer Activity 1.2: Skills Integration Challenge . The Labs and Class Activities are available in the companion Connecting Networks Lab Manual (978-1-58713-331-2). scalable networks. enterprise data center. Class Activities Class Activity 1.1. and the enterprise edge.indd 30 3/13/14 2:43 AM . can be more practical. and enterprise teleworker.3: Skills Integration Challenge . enterprise edge. the services block.30 Connecting Networks Companion Guide A typical enterprise hierarchical LAN campus network design includes the access layer. distribution layer.1: Borderless Innovations . redundancy.0. performance.1. the data center. The Packet Tracer Activity PKA files are found in the online course. service provider edge. A modular design that separates the functions of a network enables flexibility and facilitates implementation and management. where the distribution layer and core layer functions are implemented in a single device.2: Design Hierarchy Class Activity 1. The basic module blocks that are connected by the core include the access distribution block.1. The Cisco Enterprise Architecture modules are used to facilitate the design of large.1. Practice The following activities provide practice with the topics introduced in this chapter. The benefits of a hierarchical network include scalability. and maintainability. enterprise branch.4. and the core layer. a “collapsed core” hierarchy.OSPF Packet Tracer Activity 1.

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

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

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

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