LAN and WAN Design:Putting It All Together

Chapter 11

Learning ObjectivesDiscuss general LAN and WAN design issues that include using structured wiring and structured networking

Describe and implement LAN design principles

Explain and implement WAN design principles

General LAN and WAN Design Issues

Factors that affect design

Analyzing existing topology and resources

Network management

Cable installation and replacement

Structured wiring

Vertical wiring and structured networking

Full-duplex communications

Bridge, router, and hub design issues

Factors That Affect a LAN or WAN Design

Anticipated network traffic

Redundancy requirements

User movement

Accommodating for future growth

Security considerations

WAN connectivity

LAN and WAN costs

Designing for Redundancy

Analyzing Existing Topology and Resources

Inspect cable plant

Compile bandwidth utilization baseline data

Audit resources

Review traffic

Perform network capacity management

Network ManagementDirectly related to network design and topology; some topologies are easier to manage than others

Cable Installation and Replacement

Limitations of Thinnet/Thicknet Cable Plants

Cannot meet high bandwidth requirements

Expensive to maintain and troubleshoot

Difficult to expand

Cable Replacement FactorsReplacement of legacy cable

Cable and connector costs

Installation costs

Environmental requirements

Extra cable requirements

Creation or redesign of wiring closet locations

Guidelines for Installing CableUse structured wiring and structured networking principlesMeet or exceed maximum bandwidth requiredInstall Category 5 or better UTP cable horizontally to desktopInstall multimode fiber-optic riser cable between floorsFollow IEEE specs for cable run distances

Single-mode fiber-optic cable for long runs

continued…

Guidelines for Installing CableInstall 802.11 wireless options where appropriateInstall star-based cable plantsInstall only high-quality cableFollow all building codesDo not exceed 25 pounds of force when pulling twisted-pair cableFollow rules for cable bend radius

continued…

Guidelines for Installing CableLeave extra cable at endpoints

Use a qualified contractor, if desired

Adhere to IEEE specs for cable and installation

Label cable following EIA/TIA-606 standard

Ground cable plants

Structured WiringCable fans out in horizontal star fashion from centralized chassis switch(es) or hub(s) located in telecommunications rooms or wiring closets

Structured Wiring Requirements

Flexible cabling, eg, twisted-pairWiring nodes into physical starAdherence to EIA/TIA-568-A / EIA/TIA-568-B standards for horizontal wiringCentralized cable plant in chassis hubs or switchesBuilt-in intelligence for chassis hubs or switches

continued…

Structured Wiring Requirements

Ability to isolate hosts/servers on own cable segment

Ability to provide high-speed links to network devices

Vertical WiringCabling and network equipment used between floors

Physically links telecommunications room(s) on one floor to adjoining floors

Ties horizontal cable on each floor into logical backbone

Principles of Vertical WiringDeploy extended star topology between devices

Use high-speed cable to reduce congestion and because it is not susceptible to EMI and RFI

Follow EIA/TIA-568-A / EIA/TIA-568-B standards for vertical or backbone cabling

Use riser rated cable for cable runs through cable ports or vertical shafts

Install fire-stop material

Structured NetworkingUse of solid horizontal and vertical wiring design that enables centralizing a network at strategic points

Administrative Capabilities of Structured Networks

Centralize or distribute network management

Incorporate vertical and horizontal network design using high-speed communications on the backbone (fat pipes)

Reconfigure network physically and logically

continued…

Administrative Capabilities of Structured Networks

Segment network according to workgroup patterns, using VLANs

Add redundancy

Quickly expand network and introduce new high-speed network options

Proactively monitor and diagnose problems for quick resolution

Using Full-Duplex Communications

Ability to send and receive simultaneouslyUse in areas of network with high-speed linksEliminates collisionsIncreases network throughput and reduces number of lost framesMost switches employ one of two types of flow control

JammingBuffering

Bridge, Router, and Hub Design Issues

Bridges and routers Design flexibilityHigh-speed networking optionsRedundancy

HubsCentralize network management and troubleshootingReproduce network traffic on all segments

Advantages of RFIs and RFPsHelp organizations clearly define needs

Provide vendors with understanding of the organization

Enable vendors to show how they would address those needs

Provide basis for contract negotiation

Supply guidelines for installation process

LAN Design PrinciplesReplace legacy hubs with switchesReplace older switches that do not offer SNMP compatibility with newer ones that have itConnect high-speed workstations to switchesConnect servers to high-speed switched portsConnect integrated or workgroup area switches to high-speed switchesConnect major department segments or high-speed switches to routers

Walking Through a Design

Locating Hosts and ServersIn centralized host or server farms

Saves money

High traffic

In different locations throughout the networkReduces network traffic

Provides securityFlexibility if disaster destroys one location

Can have redundant hosts at different locations

Connecting Hosts and Servers

Building in Redundancy

Interspersed Hosts and Servers

Designing for Multimedia Applications

Often include increased bandwidth

Often include implementation of Internet Group Management Protocol

Wireless LAN Network Designs

Peer-to-peer

Multiple-cell

Peer-to-Peer Design

Maintenance andSupport Issues

Constant process

To reduce maintenance, develop schemes to replace aging devices before they become a maintenance problem

WAN Design PrinciplesDevices required at local site to accomplish WAN connectivity

Routers

Access servers

Modems

Specialized adapters

Multiplexers

Wireless, microwave, and satellite devices

ATM WAN access switches

Configuring LAN Topology for WAN Connectivity

WAN Connectivity Using a Router

Wireless MANs and WANsWireless MAN options

Wireless bridgeProprietary infrared designProprietary radio wave optionsTerrestrial microwave

Wireless WAN optionsGeosynchronous satellitesLEO satellites

WAN Provider TopologiesEstablished by WAN service provider

Selection depends on:Bandwidth required

Budget

Speed and type of interfaces on the LAN

Price StructureRanges from unlimited usage to limited usage billed per minuteCost-related elements

Monthly service chargesLAN connectivity equipmentUser training and supportNetwork staff trainingNetwork support and troubleshootingLost work time when a connection is downPeriodic equipment upgrade costs

Bandwidth ConsiderationsChoice of service provider depends on:

Amount of bandwidth needed

Service level agreement (SLA) offered by provider

Vendor and Customer Equipment

Equipment varies according to size of vendor

Equipment should be at more than one location

Chapter SummaryGeneral LAN design principles

Accommodating for growth and security

Implementing the cable plant

Using structured wiring and structured networking techniques

Using full-duplex communications

Designing around switches and routers

Creating requests for information and requests for proposals

continued…

Chapter SummarySpecific LAN design principles

Where to locate hosts and servers

How to design for multimedia applications

Wireless LAN designs and maintenance and support issues

continued…

Chapter SummaryWAN design principles

Wireless MAN and WAN designs

WAN provider topologies

Price structure

Bandwidth

Equipment issues