© 2007 Cisco Systems, Inc. All rights reserved.Cisco Public 1 Version 4.0 OSI Network Layer Network Fundamentals – Chapter 5

2 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public What Did We Discover Last Class?  Transport Layer  TCP/IP vs UDP  Connection oriented  Connectionless  Header overhead  Serial interfaces “flapping”  Configuring serial interfaces  Hardware failures  Cabling problems  Well known Port numbers

3 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public What I will Learn  The role of the Network Layer, as it describes communication from one end device to another end device.  Examine Internet Protocol (IP), and its features for providing connectionless, best-effort service.  Understand the principles used to guide the grouping of devices into networks.  Hierarchical addressing of devices and how this allows communication between networks.  The fundamentals of routes, next hop addresses and packet forwarding to a destination network.

4 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Layer Protocols and Internet Protocol (IP)

5 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Layer Protocols and Internet Protocol (IP)

6 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Layer Protocols and Internet Protocol (IP)

7 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Layer Protocols and Internet Protocol (IP)

8 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Layer Protocols and Internet Protocol (IP)

9 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Layer Protocols and Internet Protocol (IP)

10 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Layer Protocols and Internet Protocol (IP)

11 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Grouping Devices into Networks and Hierarchical Addressing

12 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Grouping Devices into Networks and Hierarchical Addressing

13 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Grouping Devices into Networks and Hierarchical Addressing

14 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Grouping Devices into Networks and Hierarchical Addressing Communication problems that emerge when very large numbers of devices are included in one large network

15 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Grouping Devices into Networks and Hierarchical Addressing Describe how hierarchical addressing solves the problem of devices communicating across networks of networks

16 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Grouping Devices into Networks and Hierarchical Addressing  The purpose of further subdividing networks into smaller networks

17 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Fundamentals of Routes, Next Hop Addresses and Packet Forwarding

18 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Fundamentals of Routes, Next Hop Addresses and Packet Forwarding Tracert / traceroute

19 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Fundamentals of Routes, Next Hop Addresses and Packet Forwarding The role of a gateway and the use of a simple route table in directing packets toward their ultimate destinations

20 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Fundamentals of Routes, Next Hop Addresses and Packet Forwarding

21 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Fundamentals of Routes, Next Hop Addresses and Packet Forwarding

22 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Fundamentals of Routes, Next Hop Addresses and Packet Forwarding

23 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Fundamentals of Routes, Next Hop Addresses and Packet Forwarding  Trace the steps of IP packets as they are routed through gateways from devices on one network to devices on other networks

24 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Fundamentals of Routes, Next Hop Addresses and Packet Forwarding

25 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Fundamentals of Routes, Next Hop Addresses and Packet Forwarding

26 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Fundamentals of Routes, Next Hop Addresses and Packet Forwarding Explain the role of routing protocols in building the routing table

27 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public What I will Learn  The role of the Network Layer, as it describes communication from one end device to another end device.  Examine Internet Protocol (IP), and its features for providing connectionless, best-effort service.  Understand the principles used to guide the grouping of devices into networks.  Hierarchical addressing of devices and how this allows communication between networks.  The fundamentals of routes, next hop addresses and packet forwarding to a destination network.

28 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public OSI Network Layer Next Addressing the Network