Mạng máy tính - Chapter 1: Analyzing the cisco enterprise campus architecture

Chapter 1: Analyzing The Cisco Enterprise Campus ArchitectureCCNP SWITCH: Implementing IP SwitchingChapter 1 ObjectivesDescribe common campus design options and how design choices affect implementation and support of a campus LAN.Describe the access, distribution, and core layers.Describe small, medium, and large campus network designs.Describe the prepare, plan, design, implement, operate, optimize (PPDIOO) methodology.Describe the network lifecycle approach to campus design.Enterprise NetworkCore (Backbone)CampusData CenterBranchWANInternet EdgeCampus DesignsModular - easily supports growth and change. Scaling the network is eased by adding new modules in lieu of complete redesigns. Resilient - proper high-availability (HA) characteristics result in near-100% uptime. Flexible - change in business is a guarantee for any enterprise. These changes drive campus network requirements to adapt quickly.Multilayer Switches in Campus NetworksHardware-based routing using Application-Specific Integrated Circuits (ASICs)RIP, OSPF, and EIGRP are supportedLayer 3 switching speeds approximate that of Layer 2 switchesLayer 4 and Layer 7 switching supported on some switchesFuture: Pure Layer 3 environment leveraging inexpensive L3 access layer switchesCisco SwitchesCatalyst 6500 Family – used in campus, data center, and core as well as WAN and branchUp to 13 slots and 16 10-Gigabit Ethernet interfacesRedundant power supplies, fans, and supervisor enginesRuns Cisco IOSCatalyst 4500 Family – used in distribution layer and in collapsed core environmentsUp to 10 slots and several 10-Gigabit Ethernet interfacesRuns Cisco IOSCatalyst 3560 and 3750 Families – used in fixed-port scenarios at the access and distribution layersNexus 2000, 5000, and 7000 Families – NX-OS based modular data center switchesMultilayer Switching MiscellanyASIC-based (hardware) switching is supported even with QoS and ACLs, depending on the platform; 6500 switches support hardware-based switching with much larger ACLs than 3560 switches.ASICs on Catalyst switches work in tandem with ternary content addressable memory (TCAM) and packet-matching algorithms for high-speed switching.Catalyst 6500 switches with a Supervisor Engine 720 and a Multilayer Switch Feature Card (MSFC3) must software-switch all packets requiring Network Address Translation.Unlike CPUs, ASICs scale in switching architectures. ASICs integrate onto individual line modules of Catalyst switches to hardware-switch packets in a distributed manner.Traffic TypesNetwork Management – BPDU, CDP, SNMP, RMON, SSH traffic (for example); low bandwidthIP Telephony – Signaling traffic and encapsulated voice traffic; low bandwidthIP Multicast – IP/TV and market data applications; intensive configuration requirements; very high bandwidthNormal Data – File and print services, email, Internet browsing, database access, shared network applications; low to medium bandwidthScavenger Class – All traffic with protocols or patterns that exceed normal data flows; less than best-effort traffic, such as peer-to-peer traffic (instant messaging, file sharing, IP phone calls, video conferencing); medium to high bandwidthClient-Server ApplicationsMail serversFile serversDatabase serversAccess to applications is fast, reliable, and secureClient-Enterprise Edge ApplicationsServers on the enterprise edge, exchanging data between an organization and its public serversExamples: external mail servers, e-commerce servers, and public web serversSecurity and high availability are paramountService-Oriented Network Architecture (SONA)Application Layer – business and collaboration applications; meet business requirements leveraging interactive services layer.Interactive Services Layer – enable efficient allocation of resources to applications and business processes through the networked infrastructure.Networked Infrastructure Layer – where all IT resources interconnect.Enterprise Campus DesignBuilding Access, Building Distribution, and Building Core LayersBuilding Core Layer: high-speed campus backbone designed to switch packets as fast as possible; provides high availability and adapts quickly to changes.Building Distribution Layer: aggregate wiring closets and use switches to segment workgroups and isolate network problems.Building Access Layer: grant user access to network devices.Core LayerAggregates distribution layer switches.Implements scalable protocols and technologies and load balancing.High-speed layer 3 switching using 10-Gigabit Ethernet.Uses redundant L3 links.Distribution LayerHigh availability, fast path recovery, load balancing, QoS, and securityRoute summarization and packet manipulationRedistribution point between routing domainsPacket filtering and policy routing to implement policy-based connectivityTerminate VLANsFirst Hop Redundancy ProtocolAccess LayerHigh availability – supported by many hardware and software features, such as redundant power supplies and First Hop Redundancy Protocols (FHRP). Convergence – provides inline Power over Ethernet (PoE) to support IP telephony and wireless access points.Security – includes port security, DHCP snooping, Dynamic ARP inspection, IP source guard.Small Campus Network2000 end usersStricter adherence to core, distribution, access delineationCatalyst 6500 switches in core and distribution layersNexus 7000 switches in data centersDivision of labor amongst network engineersData Center InfrastructureCore layer – high-speed packet switching backplaneAggregation layer – service module integration, default gateway redundancy, security, load balancing, content switching, firewall, SSL offload, intrusion detection, network analysisAccess layer – connects servers to networkPPDIOO Lifecycle Approach to Network Design and ImplementationPPDIOO PhasesPrepare – establish organizational requirements.Plan – identify initial network requirements.Design – comprehensive, based on planning outcomes.Implement – build network according to design.Operate – maintain network health.Optimize – proactive management of network.Lifecycle ApproachLowering the total cost of network ownership Increasing network availability Improving business agility Speeding access to applications and services Identifying and validating technology requirements Planning for infrastructure changes and resource requirements Developing a sound network design aligned with technical requirements and business goals Accelerating successful implementation Improving the efficiency of your network and of the staff supporting it Reducing operating expenses by improving the efficiency of operational processes and tools Planning a Network ImplementationImplementation Components:Description of the stepReference to design documentsDetailed implementation guidelinesDetailed roll-back guidelines in case of failureEstimated time needed for implementationSummary Implementation Plan – overview of implementation planDetailed Implementation Plan – describes exact steps necessary to complete the implementation phase, including steps to verify and check the work of the network engineers implementing the planResourceswww.cisco.com/en/US/products