10. Network Design

Describe how a hierarchical network model is used to design networks. Explain the structured engineering principles for network design: Hierarchy, Modularity, Resiliency, Flexibility. Describe the three layers of a hierarchical network and how they are used in network design. Identify the benefits of a hierarchical design. Describe the Cisco Enterprise Architecture model. Describe the three new business network architectures: borderless network architecture, collaboration network architecture, and the data center or virtualization network architecture.

Chapter 10: Network Design Introduction to Networking Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential Chapter 10 10.0 Introduction 10.1 Hierarchical Network Design  Overview 10.2 Cisco Enterprise Architecture 10.3 Evolving Network Architectures 10.4 Summary Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential Chapter 10: Objectives  Describe how a hierarchical network model is used to design networks  Explain the structured engineering principles for network design: Hierarchy, Modularity, Resiliency, Flexibility  Describe the three layers of a hierarchical network and how they are used in network design  Identify the benefits of a hierarchical design  Describe the Cisco Enterprise Architecture model  Describe the three new business network architectures: borderless network architecture, collaboration network architecture, and the data center or virtualization network architecture Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential Devices in a Small Network Small Network Topologies  Presentation_ID Typical Small Network Topology © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 10.1 Hierarchical Network Design  Overview   Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential Enterprise Network Campus Design Network Requirements  Small network – Provides services for to 200 devices  Medium-sized network – Provides services for 200 to 1,000 devices  Large network – Provides services for 1,000+ devices Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential Enterprise Network Campus Design Structured Engineering Principles Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential Hierarchical Network Design Network Hierarchy  Access layer – Provides workgroup or user access to the network  Distribution layer – Provides policy-based connectivity  Core layer – Provides fast transport between distribution switches Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential Hierarchical Network Design Access Layer  Layer 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 Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential Hierarchical Network Design Distribution Layer  Aggregation of LAN or WAN links  Policy-based security in the form of access control lists (ACLs) and filtering  Routing services between LANs and VLANs and between routing domains (e.g., EIGRP to OSPF)  Redundancy and load balancing  A boundary for route aggregation and summarization configured on interfaces toward the core layer Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 10 Emerging Network Architectures Data Center and Virtualization The data center architecture consists of three components:  Cisco Unified Management Solutions – Simplifies and automates the process of deploying IT infrastructure and services with speed and enterprise reliability.   Unified Fabric Solutions – Delivers network services to servers, storage, and applications, providing transparent convergence, and scalability  Unified Computing Solutions – Cisco’s next-generation data center system unites computing, network, storage access, and virtualization into a cohesive system designed to reduce total cost of ownership (TCO) Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 28 Devices in a Small Network Device Selection for a Small Network  Presentation_ID Factors to be considered when selecting intermediate devices © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 29 Devices in a Small Network Addressing for a Small Network   IP addressing scheme should be planned, documented and maintained based on the type of devices receiving the address  Examples of devices that will be part of the IP design: End devices for users Servers and peripherals Hosts that are accessible from the Internet Intermediary devices  Planned IP schemes help the administrator: Track devices and troubleshoot Control access to resources Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 30 Devices in a Small Network Redundancy in a Small Network Presentation_ID  Redundancy helps to eliminate single points of failure  Improves the reliability of the network © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 31 Devices in a Small Network Design Considerations for a Small Network  The following should be included in the network design: Secure file and mail servers in a centralized location Protect the location by physical and logical security measures Create redundancy in the server farm Configure redundant paths to the servers Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 32 Protocols in a Small Network Common Applications in a Small Network  Network-Aware Applications - software programs used to communicate over the network.   Application Layer Services -  programs that interface with the network and prepare the data for transfer Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 33 Protocols in a Small Network Common Protocols in a Small Network  Network Protocols Define: Processes on either end of a communication session Types of messages Syntax of the messages Meaning of informational fields How messages are sent and the expected response Interaction with the next lower layer Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 34 Protocols in a Small Network Real-Time Applications for a Small Network  Infrastructure - needs to be evaluated to ensure it will support proposed real time applications  VoIP is implemented in organizations that still use traditional telephones  IP telephony - the IP phone itself performs voice-to-IP conversion  Real-time Video Protocols   - Use Time Transport Protocol (RTP) and Real-Time Transport Control Protocol (RTCP) Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 35 Growing to Larger Networks Scaling a Small Network Important considerations when growing to a larger network:  Documentation – physical and logical topology  Device inventory – list of devices that use or comprise the network  Budget – itemized IT budget, including fiscal year equipment purchasing budget  Traffic Analysis – protocols, applications, and services and their respective traffic requirements should be documented Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 36 Growing to Larger Networks Protocol Analysis of a Small Network Information gathered by protocol analysis can be used to make decisions on how to manage traffic more efficiently.  Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 37 Growing to Larger Networks Evolving Protocol Requirements  Network administrator can obtain IT “snapshots” of employee application utilization   Snapshots track network utilization and traffic flow requirements  Snapshots help inform network modifications needed Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 38 Summary Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 39 Chapter 10: Summary This chapter:  Introduced the structured engineering principles of good network design that include hierarchy, modularity, resiliency, and flexibility  Explained that the typical enterprise hierarchical LAN campus network design incorporates the access layer, distribution layer, and the core layer    Identified that smaller enterprise networks may use a “collapsed core” hierarchy, whereas the distribution and core layer functions are implemented in a single device  Presentation_ID Described the benefits of a hierarchical network as scalability, redundancy, performance, and ease of maintenance © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 40 Chapter 10: Summary  Good network design incorporates reliability, scalability, and availability  Networks must be secured from viruses, Trojan horses, worms and network attacks  Document Basic Network Performance  Home networks and small business often use integrated routers, which provide the functions of a switch, router and wireless access point Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 41 Presentation_ID © 2008 Cisco Systems, Inc All rights reserved Cisco Confidential 42 ... Modular Network Design Modular Design  As the complexity of networks increased, a modular network design has been implemented  Modular design separates the network into various functional network. ..Chapter 10 10.0 Introduction 10.1 Hierarchical Network Design Overview 10.2 Cisco Enterprise Architecture 10.3 Evolving Network Architectures 10.4 Summary Presentation_ID ©... Enterprise Network Campus Design Network Requirements  Small network – Provides services for to 200 devices  Medium-sized network – Provides services for 200 to 1,000 devices  Large network –