CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Introduction to Classless Routing

VLSM RIP Version 2

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Introduction to Classless Routing

Variable Length Subnet Masks

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Classful Routing

• IP Version 4 provides Classes A, B, C • Limited Number of unique network addresses • Complex Routing tables • No subnet information sent in routing updates by classful routing protocols e.g. RIP v1, IGRP Chapter 1 – Introduction to Classless Routing

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Problem 1a

• • FSF Ltd has been allocated a class C address • It has 3 branch offices with a requirement of 10 hosts per network connecting via point to point links to the Head Office with 25 hosts

Design a subnet mask for FSF

Chapter 1 – Introduction to Classless Routing Head Office

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Problem 1b

• FSF Ltd plans • 3 additional branch offices (10 hosts per LAN) • Head Office (25 hosts) •

Design a new subnet mask

Chapter 1 – Introduction to Classless Routing

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Problem 1b continued

Variable Length Subnet Mask

• Use 27 bit mask for head office (5 host bits = 32 hosts) • Use 28 bit mask for branch offices (4 host bits = 16 hosts) • Use 30 bit mask for router to router links (2 host bits = 4 hosts) •

Using 192.168.200.0 write out the addressing scheme for this network

Chapter 1 – Introduction to Classless Routing

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Problem 2

• Most class A & B network addresses allocated • PHS Ltd with 800 hosts wants IP addresses for its network • 4 different Class C network addresses needed • 4 routing table entries for that network Chapter 1 – Introduction to Classless Routing

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Solution 2 – Part 1

• ISP allocates 212.23.24.0 to 212.23.27.255

• Routing table entry for PHS is – 212.23.24.0 /22 OR – 212.23.24.0 255.255.252.0

• 22 bit mask in binary: – 11111111.11111111.111111

00.00000000

• This mask groups 4 class C networks into 1 network & routing table entry Chapter 1 – Introduction to Classless Routing

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Solution 2 – Part 2

– 11010100.00010111

.000110

00.00000000 (Network) – 11111111.11111111.11111100.00000000 (Mask) 24 128 0 64 0 128 0 64 0 128 0 64 0 128 0 64 0 32 0 32 0 32 0 32 0 16 1 16 1 16 1 16 1 8 1 8 1 8 1 8 1 4 0 4 0 4 0 4 0 2 1 2 1 2 0 2 0 1 0 1 1 1 0 1 1 25 26 27 Chapter 1 – Introduction to Classless Routing

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Problem 3

• PHS Ltd has 4 class C address blocks allocated • It does not want to waste the addresses it has been given • The network administrator has the following requirements based on current use & future growth needs Head Office - 500 hosts Logistics Centre – 80 hosts Factory - 50 hosts Customer support Centre – 220 hosts Question: What is the appropriate VLSM mask solution for PHS Ltd?

Chapter 1 – Introduction to Classless Routing

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Solution 3 (example)

Internet 212.23.24.0 /23 212.23.24.0 /22 212.23.27.0 /30 Head Office 212.23.27.8 /30 212.23.27.4 /30 Customer Services Factory Logistics

List the addresses

1.

2.

3.

On interfaces On each site Still available 212.23.26.0 /24 212.23.27.64 /26 212.23.27.128 /25 Chapter 1 – Introduction to Classless Routing

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Requirements for classless routing

• Classless routing protocol e.g. EIGRP, OSPF, RIP v2 • Contiguous network addresses to allow route aggregation Chapter 1 – Introduction to Classless Routing

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Introduction to Classless Routing

RIP Version 2

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

RIP Version 1 Review

• Supported by most routers • Distance Vector routing protocol • Metric – hop count • 15 hop maximum count • Periodic routing updates (30 seconds) • Routing updates broadcast to 255.255.255.255

• Uses holddown timers • Does not send subnet information in updates • Does not support authentication Chapter 1 – Introduction to Classless Routing

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

RIP v2 enhancements

• Sends subnet information in updates – supports CIDR & VLSM • Supports authentication • Updates multicast to 224.0.0.9

Chapter 1 – Introduction to Classless Routing

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

IOS RIP v2 Command

•

Enable RIP v2 Router(config)#router rip Router(config-router)#version 2 Router(config-router)#network 10.0.0.0

Chapter 1 – Introduction to Classless Routing

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Verifying Routing Protocols

•

Check the configuration of routing protocols Router#show ip protocols Router#show running-config

•

Viewing RIP updates Router#debug ip rip

Chapter 1 – Introduction to Classless Routing

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Configuring Routes

•

Static Routes Router(config)#ip route 192.168.2.0 255.255.255.0 192.168.1.1

ip route destination network gateway Default Route Router#ip route 0.0.0.0 0.0.0.0 192.168.1.1

• Defines the default gateway for all routes • Keeps routing tables small Chapter 1 – Introduction to Classless Routing

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Default Network

• 1 router on a network must have a default route on the network e.g.

Router#ip route 0.0.0.0 0.0.0.0 192.168.1.1

• Other routers can have a default network set

Router#ip default network 192.168.1.0

Traffic for destinations outside of the LAN will be sent to the router with the network address 192.168.1.0

Chapter 1 – Introduction to Classless Routing

CISCO NETWORKING ACADEMY PROGRAM

CCNA3: Switching Basics and Intermediate Routing v3.0

Labs

• 1.1.4 Calculating VLSM Subnets • 1.2.3 Review of Basic Router Configuration with RIP • 1.2.4 Converting RIP v1 to RIP v2 • 1.2.5 Verifying RIP v2 Configuration • 1.2.6 Troubleshooting RIP v2 using Debug Chapter 1 – Introduction to Classless Routing