OSI Network Layer Network Fundamentals – Chapter 5 Version 4.0 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 1 What Did We Discover Last Class? Transport Layer Serial interfaces “flapping” TCP/IP vs UDP Configuring serial interfaces Connection oriented Hardware failures Connectionless Cabling problems Header overhead Well known Port numbers © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 2 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. © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 3 Network Layer Protocols and Internet Protocol (IP) © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 4 Network Layer Protocols and Internet Protocol (IP) © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 5 Network Layer Protocols and Internet Protocol (IP) © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 6 Network Layer Protocols and Internet Protocol (IP) © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 7 Network Layer Protocols and Internet Protocol (IP) © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 8 Network Layer Protocols and Internet Protocol (IP) © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 9 Network Layer Protocols and Internet Protocol (IP) © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 10 Grouping Devices into Networks and Hierarchical Addressing © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 11 Grouping Devices into Networks and Hierarchical Addressing © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 12 Grouping Devices into Networks and Hierarchical Addressing © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 13 Grouping Devices into Networks and Hierarchical Addressing Communication problems that emerge when very large numbers of devices are included in one large network © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 14 Grouping Devices into Networks and Hierarchical Addressing Describe how hierarchical addressing solves the problem of devices communicating across networks of networks © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 15 Grouping Devices into Networks and Hierarchical Addressing The purpose of further subdividing networks into smaller networks © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 16 Fundamentals of Routes, Next Hop Addresses and Packet Forwarding © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 17 Fundamentals of Routes, Next Hop Addresses and Packet Forwarding Tracert / traceroute © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 18 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 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 19 Fundamentals of Routes, Next Hop Addresses and Packet Forwarding © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 20 Fundamentals of Routes, Next Hop Addresses and Packet Forwarding © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 21 Fundamentals of Routes, Next Hop Addresses and Packet Forwarding © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 22 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 © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 23 Fundamentals of Routes, Next Hop Addresses and Packet Forwarding © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 24 Fundamentals of Routes, Next Hop Addresses and Packet Forwarding © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 25 Fundamentals of Routes, Next Hop Addresses and Packet Forwarding Explain the role of routing protocols in building the routing table © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 26 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. © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 27 OSI Network Layer Next Addressing the Network © 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 28