Module 3: Planning and Troubleshooting Routing

and Switching

Overview

Selecting Intermediate Devices

Planning an Internet Connectivity Strategy

Planning Routing Communications

Troubleshooting TCP/IP Routing

Lesson: Selecting Intermediate Devices

Types of Devices

Multimedia: The Role of Routing in a Network Infrastructure

When to Use Routing

Types of Networking Domains

What Are the Features of Switches?

Virtual LANs

Full-Duplex Transmission in Switched Environments

Guidelines for Selecting an Appropriate Intermediate Device

Types of Devices

Device OSI layer Definition

HubPhysical (layer 1)

Extends the network by retransmitting the signalDoes not process the dataIs invisible to the nodes

SwitchData-link (layer 2)

Forwards frames according to the destination address

Uses temporary or virtual connections to connect source and destination ports

RouterNetwork (layer 3)

Used to link WANs and dissimilar LANsOperates at the packet levelSends packets based on packet addressing

Layer 3 switch

Network (layers 2 and 3)

Is a limited-purpose hardware-based IP router with bridging capabilities Also performs layer 2 switching

Multimedia: The Role of Routing in a Network Infrastructure

The objective of this presentation is to explain the role of routing in a network infrastructure

You will learn how to:

Describe how routing fits into the network infrastructure

Explain the difference between local and remote routing

Describe how the Routing and Remote Access service fits into the network infrastructure

When to Use Routing

Use routing to:Use routing to:

Isolate networks from each other

Provide a start for a secure network implementation

Isolate networks from each other

Provide a start for a secure network implementation

Traditional uses of routersTraditional uses of routers

Connecting WANs

Segmenting LANs

Connecting WANs

Segmenting LANs

SwitchSwitch

Segment BSegment B

HubHub

Segment ASegment A

Broadcast DomainBroadcast Domain

Collision Domain BCollision Domain BCollision Domain ACollision Domain A

HubHub

Types of Networking Domains

What Are the Features of Switches?

Switch feature Benefits

Layer 3Routes packets at layer 3Forwards frames at layer 2

CostSubstantially cheaper than similar performance routers

Hardware routingFast performance (near wire speed)Minimal latency

Virtual LANs

Layer 3 SwitchLayer 3 Switch

HubHubHubHubHubHub

VLAN 1VLAN 1 VLAN 2VLAN 2

VLAN ABE – Broadcast DomainVLAN ABE – Broadcast Domain VLAN CDFG – Broadcast DomainVLAN CDFG – Broadcast Domain

A B C D E F G

Full-Duplex Transmission in Switched Environments

SwitchSwitch

Full-duplex communicationFull-duplex communication

Switched EnvironmentSwitched Environment

Frame BFrame BFrame AFrame A Frame DFrame DFrame CFrame C

Guidelines for Selecting an Appropriate Intermediate Device

Ease of implementationEase of implementation

SpeedSpeed

FunctionalityFunctionality

ProgrammabilityProgrammability

CostCost

Layer 1 supportLayer 1 support

Protocol supportProtocol support

Administration and troubleshooting sophisticationAdministration and troubleshooting sophistication

Practice: Selecting Intermediate Devices

In this practice, you will learn how to:

Select an appropriate intermediate device

Identify the required features of the intermediate device

Lesson: Planning an Internet Connectivity Strategy

Multimedia: Strategies for Network Connectivity to the Internet

Requirements for an Internet Connectivity Solution

NAT as a Solution for Internet Connectivity

ISA as a Solution for Internet Connectivity

Multimedia: Selecting a NAT/Basic Firewall or ISA Server Solution

Guidelines for Planning an Internet Connectivity Strategy

Multimedia: Strategies for Network Connectivity to the Internet

The objective of this presentation is to examine some best practices for connecting a corporate network to the Internet

You will learn how to: Explain how to enable a connection from

your corporate network to the Internet Explain the functionality of NAT, ICS, and

ISA servers Identify some best practices for planning

a secure network connection to the Internet

Requirements for an Internet Connectivity Solution

Internet connectivity requirementsInternet connectivity requirements

Scalability and fault tolerance

Filtering

User access

Authentication

Bandwidth control

Time-of-day access

Extensibility and flexibility

Application connectivity

Scalability and fault tolerance

Filtering

User access

Authentication

Bandwidth control

Time-of-day access

Extensibility and flexibility

Application connectivity

131.107.0.9

NAT as a Solution for Internet Connectivity

131.107.0.9

10.10.10.710.10.10.7

Why NAT is a good solution

Same security requirements for all users

Non-routed private network

Required private addressing

NAT TableNAT Table

10.10.10.0 maps to 131.107.0.910.10.10.0 maps to 131.107.0.9

10.10.10.610.10.10.6

10.10.10.1010.10.10.10

131.107.0.9

Why ISA is a good solution

Secure Internet and private network access

Routed or non-routed network

ISA as a Solution for Internet Connectivity

IntranetIntranet

10.10.10.810.10.10.8

ISA ServerISA Server

10.10.10.0 maps to 131.107.0.910.10.10.0 maps to 131.107.0.9

10.10.10.710.10.10.7

10.10.10.910.10.10.9

10.10.10.1010.10.10.10

10.10.10.810.10.10.8

131.107.0.9

Multimedia: Selecting a NAT/Basic Firewall or ISA Server Solution

The objective of this presentation is to explain how to choose between a NAT/basic firewall or ISA Server solution

You will learn how to: Identify when to use a NAT/basic firewall

solution Identify when to use an ISA server

solution Identify the criteria for selecting the most

appropriate firewall solution Apply the appropriate firewall solution for

your organization

Guidelines for Planning an Internet Connectivity Strategy

Define the existing network structureDefine the existing network structure

Identify connectivity requirementsIdentify connectivity requirements

Select an appropriate solutionSelect an appropriate solution

Define security requirementsDefine security requirements

Practice: Planning an Internet Connectivity Strategy

In this practice, you will learn how to plan an Internet connectivity strategy

Lesson: Planning Routing Communications

Determining the Appropriate Connection Method

Selecting a Routing Protocol

Using IP Packet Filters

Multimedia: Configuring a Router to Filter Protocols

When Are VPN Tunnels Used?

Using IPSec in Tunnel Mode

Guidelines for Planning Router Connectivity

Determining the Appropriate Connection Method

Connection method When used

Leased lines

Security is important Speed and reliability are required No budget constraints

Tunneling Security is important No modem infrastructure

Demand-dial routing Security is important

On demand Limited traffic Per-instance fee pricing structure

Demand-dial -persistent

Ample traffic Flat fee pricing structure

Selecting a Routing Protocol

Protocol Criteria

Static routes

Routing information rarely changes Small internetworks Scalability not an issue Manual updates required

RIP (dynamic)

Routing information constantly changes Automatic routing table updates required Existing routers use RIP Design includes demand-dial interface Maximum number of routers an IP packet will cross is 15

OSPF (dynamic)

Routing information constantly changes Existing routers use OSPF Design includes redundant paths between two subnets Design has more than 50 subnets

All other protocolsAll other protocols

ICMPICMP

Using IP Packet Filters

Branch OfficeBranch Office

Branch OfficeBranch Office

Interface A inbound

filter

Interface A inbound

filter

Interface B outbound

filter

Interface B outbound

filter

Interface C outbound

filter

Interface C outbound

filter

All protocolsAll protocols

All other protocolsAll other protocols

SNMPSNMP

Corporate HeadquartersCorporate Headquarters

Multimedia: Configuring a Router to Filter Protocols

The objective of this presentation is to show how to configure a router to filter specific protocols

Use the Routing and Remote Access service to add a router to the console

Configure the router to process ICMP packets

Use the ping command to identify blocked outgoing filters

When Are VPN Tunnels Used?

VPN with PPTP tunnel

Used if:Used if:

All routers support VPN tunnels

You are using MS-CHAP or EAP-TLS

Router authentication uses user-based certificates

All routers support VPN tunnels

You are using MS-CHAP or EAP-TLS

Router authentication uses user-based certificates

VPN with L2TP tunnel

Used if:Used if:

All routers support VPN tunnels

Router authentication uses computer-based certificates or user-based certificates

All routers support VPN tunnels

Router authentication uses computer-based certificates or user-based certificates

Using IPSec in Tunnel Mode

Using IPSec in tunnel mode: Enforces IPSec policies for all tunnel traffic Supports point-to-point security Specifies tunnel endpoint at both routers

Security Between NetworksSecurity Between Networks

Windows Server/RouterWindows Server/Router

Windows Server/RouterWindows Server/Router

Guidelines for Planning Router Connectivity

Identify the router connection methodIdentify the router connection method

Determine which connectivity options to useDetermine which connectivity options to use

Determine which routing protocol to useDetermine which routing protocol to use

Identify filter settingsIdentify filter settings

Practice: Planning Routing Communications

In this practice, you will plan router communications based on the provided scenario

Lesson: Troubleshooting TCP/IP Routing

How to Isolate a Routing Problem

When to Use Each of the Troubleshooting Tools

Demonstration: Using Troubleshooting Tools

Troubleshooting TCP/IP Routing

How to Isolate a Routing Problem

Inside-Out StrategyInside-Out StrategyOutside-In StrategyOutside-In Strategy

Can you ping the

remote host?

Can you tracert to

remote host?

Can you access the

failed system?

If problem still exists, check route configuration

Contact the administrator

of the failed system

Check system configuration

Fix configuration

problem

Determine where trace

fails

YesYes

No No

Yes

No

Is the IP configuration

correct?

Correct the configuration

Use tracert to identify

communication breakdown

No

Is the routing table

accurate?

Correct/delete the incorrect route entries

Contact network support engineer

Can you ping the gateway?

Can you ping interior gateways?

No

No

No

Yes

Yes

Yes

Divide-by-Half : Isolate by ½ the connection issue, then isolate by ½ againDivide-by-Half : Isolate by ½ the connection issue, then isolate by ½ again

When to Use Each of the Troubleshooting Tools

Troubleshooting area Utility to use

Local computer configuration

HostnameIpconfigNetStatNbtstatARP

Network connections NetDiag

Tracing paths

TracertPingPathping

DNS NSlookup

Demonstration: Using Troubleshooting Tools

The instructor will demonstrate the use of Netdiag for troubleshooting routing issuesThe instructor will demonstrate the use of Netdiag for troubleshooting routing issues

Troubleshooting TCP/IP Routing

TCP/IP configuration

Default client route and static route configuration

Demand-dial routing configuration

Router configuration

Practice: Troubleshooting TCP/IP Routing

In this practice, you will troubleshoot TCP/IP routing in a sample enterprise

Lab A: Planning and Troubleshooting Routing

Exercise 1: Planning a Routing Strategy

Exercise 2: Troubleshooting a Routing Problem