Module 7: Routing Between
Networks
Instructor Materials
Networking Essentials (NETESS v2.0)
Instructor Materials – Module 7 Planning Guide
This PowerPoint deck is divided in two parts:
•
Instructor Planning Guide
•
Information to help you become familiar with the module
•
Teaching aids
•Instructor Class Presentation
• Optional slides that you can use in the classroom
• Begins on slide # 10
Note: Remove the Planning Guide from this presentation before sharing with anyone.
For additional help and resources go to the Instructor Home Page and Course Resources for this
course. You also can visit the professional development site on netacad.com, the official Cisco
Networking Academy Facebook page, or Instructor Only FB group.
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What to Expect in this Module
To facilitate learning, the following features within the GUI may be included in this module:
Feature
Description
Animations
Expose learners to new skills and concepts.
Videos
Expose learners to new skills and concepts.
Check Your Understanding (CYU)
Per topic online quiz to help learners gauge content
understanding.
Labs
Labs designed for working with physical equipment.
Packet Tracers
Simulation and modeling activities designed to
explore, acquire, reinforce, and expand skills.
Module Quizzes
Self-assessments that integrate concepts and skills
learned throughout the series of topics presented in
the module.
Module Summary
Briefly recaps module content.
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Check Your Understanding
•
Check Your Understanding activities are designed to let students quickly determine if they
understand the content and can proceed, or if they need to review.
•
Check Your Understanding activities do not affect student grades.
•
There are no separate slides for these activities in the PPT. They are listed in the notes area of the
slide that appears before these activities.
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Module 7: Activities
Page #
Activity Type
Activity Name
Optional?
7.1.1
Video
Dividing the Local Network
recommended
7.1.3
Animation
IP Packet Encapsulated in an Ethernet Frame
required
7.1.4
Lab
IPv4 Addresses and Network Communication
recommended
7.2.1
Video
Router Packet Forwarding
recommended
7.2.2
Animation
Path Selection
recommended
7.2.3
Video
Messages Within and Between Networks Part 1
recommended
7.2.4
Video
Messages Within and Between Networks Part 2
recommended
7.2.5
Animation
Packet Forwarding
recommended
7.2.6
Video
Messages Sent to Remote Networks
recommended
7.2.9
CYU
Select the Default Gateway
recommended
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Module 7: Activities (Cont.)
Page #
Activity Type
Activity Name
Optional?
7.2.10
CYU
The Routing Table
recommended
7.3.3
Packet Tracer
Observe Data Flow in a LAN
recommended
7.3.4
Lab
Connect to a Wireless Router
recommended
7.4.2
Module Quiz
Routing Between Networks Quiz
recommended
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Module 7: Best Practices
Prior to teaching Module 7, the instructor should:
• Review the activities and assessments for this module.
• Try to include as many questions/activities as possible to keep students engaged during classroom
presentation.
Topic 7.1
• Emphasize that the whole purpose of routing is to get packets to the proper network.
• Compare routing to taking a flight and leaving from airport A and going to airport B. You may stop at
other airports along the way.
• Ask the students for other comparisons.
• Consider doing the lab in groups of 2 or 4 students per group.
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Module 7: Best Practices (Cont.)
Topic 7.2
• Bring up an app that gives traveling directions. Have a student give you a starting destination and an
ending destination. Show how there are different ways to get to the destination, but there commonly
is a best way.
• Play the animation on 7.2.5 to show how the routing table is used to select a particular path.
Emphasize how routers are used to send packets destined for remote networks.
• Search the internet for network images. Bring a picture up and ask if a packet was being transferred
from point A to point B, would a router be used. Have some traffic stay on the local network and the
answer would be no and some examples where the traffic is sent to another network and the answer
would be yes.
• A common misconfiguration is the default gateway and time should be spent in groups or teams to
practice this skill. Search the internet using keywords of network with IP addresses. Look for pictures
that show hosts and router interfaces with IP addresses. Put students in teams of 4. Ask a team to
work together to come up with the correct default gateway. Show the image to the entire class, but
only the team can answer.
• An important concept is that the network portion of the destination IP address is used to compare
with the network numbers in the routing table to determine how the router will forward the packet.
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Module 7: Best Practices (Cont.)
Topic 7.3
• Use the 7.3.3 Packet Tracer and observe the data flow in a LAN together with the class. Otherwise,
have the students do 7.3.3 individually or in groups of 2.
• Add a router to the scenario or just draw it on the board and connect the router to the same switch
that has the 3 PCs (like the topology in Packet Tracer 7.3.3). Assign the router the address of
192.168.1.254 and ask the students what is the first PC’s default gateway, the second PC’s default
gateway, and the third PC’s default gateway. Then draw another line from the router and connect it to
a second switch. Label that router interface with 192.168.2.10. Add PCs to the second switch with the
IP addresses of 192.168.2.50 and 192.168.2.51. Ask students what the default gateway would be for
these two PCs (192.168.2.10).
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Module 7: Routing
Between Networks
Networking Essentials (NETESS)
Module Objectives
Module Title: Routing Between Networks
Module Objective: Create a fully connected LAN.
Topic Title
Topic Objective
The Need for
Routing
Explain the need for routing.
The Routing Table
Explain how routers use tables.
Create a LAN
Build a fully connected network.
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7.1 The Need for Routing
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The Need for Routing
Video - Dividing the Local Network
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The Need for Routing
Criteria for Dividing the Local Network
Broadcast Containment
Routers in the distribution layer can limit
broadcasts to the local network where they
need to be heard. Although broadcasts are
necessary, too many hosts connected on the
same local network can generate excessive
broadcast traffic and slow down the network.
Security
Routers in the distribution layer can separate
and protect certain groups of computers
where confidential information resides.
Routers can also hide the addresses of
internal computers from the outside world to
help prevent attacks, and control who can get
into or out of the local network.
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The Need for Routing
Criteria for Dividing the Local Network (Cont.)
Locations
Routers in the distribution layer can be used
to interconnect local networks at various
locations of an organization that are
geographically separated.
Logical Grouping
Routers in the distribution layer can be used
to logically group users, such as departments
within a company, who have common needs
or for access to resources.
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The Need for Routing
Now We Need Routing
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The Need for Routing
Lab - IPv4 Addresses and Network Communication
In this lab, you will complete the following objectives:
•
•
Build a simple peer-to-peer network and verify physical connectivity.
Assign various IP addresses to hosts and observe the effects on network communication.
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7.2 The Routing Table
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The Routing Table
Video - Router Packet Forwarding
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The Routing Table
Path Selection
•
•
•
•
Each router interface connects to a different
network.
A routing table contains information for how
to reach local and remote networks.
The destination IP address is used and
compared with the networks in the routing
table to determine the interface to forward
the packet out of.
Routers do not forward broadcast
messages.
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The Routing Table
Video - Messages Within and Between Networks - Part 1
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The Routing Table
Video - Messages Within and Between Networks - Part 2
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The Routing Table
Packet Forwarding
•
•
The destination MAC address is used to forward the packet to either the router if the destination
IP address is for a different network or a specific network device on the local network.
The ARP table shows a mapping of IP address to MAC address.
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The Routing Table
Video - Messages Sent to Remote Networks
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The Routing Table
Routing Table Entries
•
•
•
•
A routing table contains network addresses
and the best path to reach a network.
Two ways routes can be added to a routing
table
• Dynamically learned from other
routers
• Manually entered by a network
administrator
A default route is the router interface used
when forwarding packets to a destination
that is not in the routing table.
If a packet is destined for a network that is
not in the routing table and no default route
exists, the packet will be dropped.
Type
Network
Port
C
10.0.0.0/8
FastEthernet0/0
C
172.16.0.0/16
FastEthernet0/0
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The Routing Table
The Default Gateway
•
•
•
When a host sends a message to a device
on the same network, it forwards the
message directly and uses ARP to
discover the MAC address.
When a host sends a message to a device
on a remote network, the hosts uses the
MAC address of the router as the
destination, but still has the IP address of
the remote host as the Layer 3 destination.
It is very important that each host has the
correct default gateway that is the IP
address of the router on the same network.
PC
IPv4 Address Subnet Mask Default
Gateway
H1
192.168.1.1
255.255.255.0 192.168.1.254
H2
192.168.1.2
255.255.255.0 192.168.1.254
H3
192.168.1.3
255.255.255.0 192.168.1.254
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7.3 Create a LAN
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Create a LAN
Local Area Networks
•
•
3 LANs
LANs are under one administrative
control.
LANs are usually either wired Ethernet
or wireless.
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Create a LAN
Local and Remote Network Segments
Advantages of a single local segment:
• Appropriate for simpler networks
• Less complexity and lower network cost
• Allows devices to be "seen" by other devices
• Faster data transfer - more direct
communication
• Ease of device access
All Hosts in One Local Segment
Disadvantages of a single local segment:
• All hosts are in one broadcast domain which
causes more traffic on the segment and may
slow network performance
• Harder to implement QoS
• Harder to implement security
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Create a LAN
Local and Remote Network Segments (Cont.)
Advantages of having hosts on a remote segment
• More appropriate for larger, more complex
networks
• Splits up broadcast domains and decreases
traffic
• Can improve performance on each segment
• Makes the machines invisible to those on other
local network segments
• Can provide increased security
• Can improve network organization
Hosts on a Remote Segment
Disadvantages of having hosts on a remote
segment
• Requires the use of routing (distribution layer)
• Router can slow traffic between segments
• More complexity and expense (requires a router)
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Create a LAN
Packet Tracer - Observe Data Flow in a LAN
In this activity, you will complete the following objectives:
•
•
•
•
Develop an understanding of the basic functions of Packet Tracer.
Create/model a simple Ethernet network using 3 hosts and a switch.
Observe traffic behavior on the network.
Observe data flow of ARP broadcasts and pings.
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Create a LAN
Lab - Connect to a Wireless Router
In this lab, you will complete the following objectives:
•
•
•
Connect a PC to a wireless router using Ethernet cable.
Configure the PC with an appropriate IP address.
Verify the PC configuration using a command prompt.
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7.4 Routing Between Networks
Summary
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Routing Between Networks Summary
What Did I Learn in this Module?
•
•
•
•
•
•
•
•
•
•
•
Routers are needed to connect multiple Layer 3 IP networks.
Switches make their forwarding decision based on the destination Layer 2 MAC address.
Routers make their forwarding decision based on the destination Layer 3 IP address.
Each router has a routing table.
A routing table contains all locally connected networks and the interfaces that connect to the networks.
A routing can contain remote networks learned dynamically from other routers or entered manually by a
network administrator.
A default route in the routing table is the router interface used when forwarding packets to a destination
that is not in the routing table.
If a packet is destined for a network that is not in the routing table and no default route exists, the
packet will be dropped.
A local area network (LAN) is under the same administrative control and typically is wired Ethernet or
wireless.
A simple network design keeps all hosts on a single local network.
If a network design has multiple local networks, a router is needed for communication between
networks.
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Routing Between Networks Summary
New Terms and Commands
•
•
•
•
•
•
•
•
•
broadcast containment
logical grouping
routing table
path selection
default gateway
default route
local area network (LAN)
local network
remote network
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