Network Fundamentals – Chapter 5 OSI Network Layer Network Fundamentals – Chapter 5

Objectives Identify the role of the Network Layer, as it describes communication from one end device to another end device Examine the most common Network Layer protocol, Internet Protocol (IP), and its features for providing connectionless and best-effort service Understand the principles used to guide the division or grouping of devices into networks Understand the hierarchical addressing of devices and how this allows communication between networks Understand the fundamentals of routes, next hop addresses and packet forwarding to a destination network

Network Layer Protocols and Internet Protocol (IP) Network Layer provides services to exchange the individual pieces of data over the network between identified end devices. It uses 4 processes: Addressing Encapsulation Routing Decapsulation

Network Layer Protocols Protocols implemented at the Network layer that carry user data include: Internet Protocol version 4 (IPv4) Internet Protocol version 6 (IPv6) Novell Internetwork Packet Exchange (IPX) AppleTalk Connectionless Network Service (CLNS/DECNet)

Network Layer Protocols and Internet Protocol (IP) The basic characteristics and the role of the IPv4 protocol:Connectionless, best effort, Media independent

Network Layer Protocols and Internet Protocol (IP) Connectionless Service

Network Layer Protocols and Internet Protocol (IP) Best Effort Service (unreliable protocol)

Network Layer Protocols and Internet Protocol (IP) Media independent

Network Layer Protocols and Internet Protocol (IP) Describe the role of framing in the Transport Layer and explain that segments are encapsulated as packets

Network Layer Protocols and Internet Protocol (IP) The major header fields in the IPv4 protocol: IP Source Address, IP destination Address, Time To Live (TTL), Type of Service, Protocol, Fragment Offset

Grouping Devices into Networks and Hierarchical Addressing Network can be grouped based on factors that include: Geographic location, purpose, and ownership

Grouping Devices into Networks and Hierarchical Addressing Dividing a large network can increase network performance

Grouping Devices into Networks and Hierarchical Addressing Dividing a large network can increase network security

Grouping Devices into Networks and Hierarchical Addressing Dividing network can improve Address Management

Grouping Devices into Networks and Hierarchical Addressing Describe how hierarchical addressing solves the problem of devices communicating across networks of networks

Grouping Devices into Networks and Hierarchical Addressing Describe the purpose of further subdividing networks into smaller networks

Fundamentals of Routes, Next Hop Addresses and Packet Forwarding An intermediary gateway device is allowing devices to communicate across sub-divided networks

Fundamentals of Routes, Next Hop Addresses and Packet Forwarding Trace the steps of an IP packet as it traverses unchanged via routers from sub network to sub-network

Fundamentals of Routes, Next Hop Addresses and Packet Forwarding The gateway, also known as the default gateway, is needed to send a packet out of the local network. If the network portion of the destination address of the packet is different from the network of the originating host, the packet has to be routed outside the original network. To do this, the packet is sent to the gateway

Fundamentals of Routes, Next Hop Addresses and Packet Forwarding Define a route and its three key parts

Fundamentals of Routes, Next Hop Addresses and Packet Forwarding Describe the purpose and use of the destination network in a route

Fundamentals of Routes, Next Hop Addresses and Packet Forwarding Describe the purpose and use of the next hop in a route

Fundamentals of Routes, Next Hop Addresses and Packet Forwarding Trace the steps of several IP packets as they are routed through several gateways from devices on one sub network to devices on other sub networks

Fundamentals of Routes, Next Hop Addresses and Packet Forwarding Describe the purpose of routing protocols and the need for both static and dynamic routes

Fundamentals of Routes, Next Hop Addresses and Packet Forwarding Explain how routes are manually configured to build routing table

Fundamentals of Routes, Next Hop Addresses and Packet Forwarding Explain the role of routing protocols in building the routing table

Summary