CEG3185 Tutorial 7

Routers and Routing

IP Address An Internet Protocol address (IP address)

is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication.

 An IP address serves two principal functions: host or network interface identificationlocation addressing.

IP Address IP addresses format

binary numbers,usually stored in text files and displayed

in human-readable notations, such as 172.16.254.1(IPv4)

IPv432-bit numberstill in use today.

IPv6128-bits numberdeveloped in 1995.

IPv4 Address Formats

IPv4 Address FormatsClass A

Start with binary 0,Range 1.x.x.x to 126.x.x.x7-bit Network, 24-bits Host.

Class BStart with binary 1,Range 128.x.x.x to 191.x.x.x14-bit Network, 16-bits Host.

Class CStart with binary 110,Range 192.x.x.x to

223.x.x.x21-bit Network, 8-bit Host.

IPv4 Address FormatsClass D

Start with binary 1110,Range 224.x.x.x to 239.x.x.x

MulticastClass E

Start with binary 11110,Range 240.x.x.x to 255.x.x.x

Future use

Subnet

A subnet, is a logically visible subdivision of an IP network. 

All computers that belong to a subnet are addressed with a common, identical, most-significant bit-group in their IP address.

Logical divide an IP address into two fieldsa network or routing prefix the rest field or host identifier.

Subnet MasksA subnet mask used to determine what subnet an IP

address belongs to. For a IP address 150.215.017.009

subnet mask 255.255.240.000Full address

IP Address 10010110.11010111.00010001.00001001

Subnet mask 11111111.11111111.11110000.00000000

So, the IP address 150.215.017.009 belong to the subnet 150.215.016.000(10010110.11010111.001000.000000)

Class B Network Host addressSubnet

RouterA router is a device that forwards data

packets between computer networks. Routers perform the "traffic directing" functions on the Internet. Reads the address information in the packet to

determine its ultimate destination. Using information in its routing table or

routing policy.Directs the packet to the next network on its

journey.

Routing ProtocolA routing protocol specifies how routers

communicate with each other, disseminating information that enables them to select routes between any two nodes on a computer network.

Routing algorithms determine the specific choice of route. Each router has a priori knowledge only of networks attached to it directly.

A routing protocol shares this information first among immediate neighbors, and then throughout the network. This way, routers gain knowledge of the topology of the network.

Static RoutingStatic routing is not really a routing protocol. Static routing is simply the process of

manually entering routes into a device's routing table via a configuration file that is loaded when the routing device starts up.

Since these manually configured routes don't change after they are configured (unless a human changes them) they are called 'static' routes.

Dynamic Routing AlgorithmDynamic routing protocols are supported by

software applications running on the router which dynamically learn network destinations and how to get to them and also advertise those destinations to other routers. A router using dynamic routing will 'learn' the

routes to all networks that are directly connected to the device.

Next, the router will learn routes from other routers that run the same routing protocol (RIP, RIP2, EIGRP, OSPF, IS-IS, BGP etc).

OSPF(Open Shortest Path First)OSPF is an interior gateway protocol (IGP)

that routes Internet Protocol (IP) packets solely within a single routing domain (autonomous system). It gathers link state information from available routers and constructs a topology map of the network.

OSPF detects changes in the topology, such as link failures, and converges on a new loop-free routing structure within seconds.

It computes the shortest path tree for each route using a method based on Dijkstra's algorithm, a shortest path first algorithm.

Lab 7 ScheduleThis lab will be conducted in group of 3

students. The lab sessions will be 3-hours long.

Two lab sessions per week: Tuesdays 14:30-17:30 pm Wednesdays 8:30-11:30 am

Please refer to the lab manual for concrete lab descriptions and how to write lab reports.

Each group need submit one lab report. Please sign attendance sheet and

demonstrate your work to the TA.

ObjectivesIn this lab, you will learn about the hardware

and the software component of the Cisco Router, and acquire general knowledge of networking protocols.

You need to configure the router R1, R2, R3 and build the connection between routers and computers.

In this lab, you only need to follow the lab manual to finish the Lab1, Lab2 and Lab3 in the lab manual.

Equipment List1) Cisco 2901 Routers(3) 2) Intel-Based computer with NIC card

running Windows 7 (3)3) Cross-over RJ-45 Ethernet Cable (3)4) Console Cable with an RJ-45 connector

to DB9 adapter (3)5) Serial link for connecting serial ports

together (3)6) Power supply (3)

Router ModelThe routers used in this lab are Cisco 2901.

Please check out your router series number before you begin your lab.

Generally, the top router is marked as R1, the middle one is marked as R2, the bottom router is marked as R3.

Fig. 1 Front View of Cisco 2901 Router

Cisco 2901 Router

Fig. 2 Backplane for Cisco 2901 Router

1. RJ-45 connector

2. RJ-45-to-DB-9 serial connector

Connectors

ProceduresLab1

Interconnect the devicesLab2

Configure the console port connectionConfigure the workstation for networkingConfigure the routersConfigure the interfacesConfigure Static Routing

Lab3Configure Dynamic Routing using OSPF

About the Lab ManualThe lab tasks are Lab 1, 2 and 3 in the Lab

Manual.

The Lab Manual was written based on the Cisco router 3600/2600 series. But the commands on the configuration of routers are compatible with the new routers 2901 and can be used in this lab.

Please follow the Lab Manual step by step to accomplish the lab tasks.

Note 1Since the routers are new, it is required to input

the username (cisco) and password (cisco). But it’s temporary (used only once) and you have to create new ones.

Then configure the authentication:

yourname#config

yourname(config)# username lab privilege 15 secret 0

guessme

Here “lab” is the username and “guessme” is the

password

Note 1

Note 2For router configuration:

yourname(config)#hostname R1

R1(config)#end

R1#

It enables you to make further configuration of the

routers.

You can input the “?” (e.g. Router>?) to ask for help on the use of commands.

Note 2

Note 3Cisco 2901 uses GigabitEthernet interface

instead of FastEthernet interface.

When interconnect the devices, be clear about the R1, R2 and R3 and their S0, E0, and NIC.

Note 3

Revise Figure 2.1 in the lab manual page 13.

Thank you!