© 2007 Cisco Systems, Inc. All rights reserved.Cisco Public ITE PC v4.0 Chapter 1 1 Connecting to the Network Networking for Home and Small Businesses – Chapter 3

ITE PC v4.0 Chapter 1 2 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Objectives  Explain the concept of networking and the benefits of networks.  Explain the concept of communication protocols.  Explain how communication occurs across a local Ethernet network.  Describe Access layer devices and communication methods on a local Ethernet network.  Describe Distribution layer devices and communication methods across networks.  Plan, implement, and verify a local network.

ITE PC v4.0 Chapter 1 3 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Networking and Its Benefits  Define the term network and identify various types of networks

ITE PC v4.0 Chapter 1 4 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Networking and Its Benefits  Small home networks connect a few computers together and to the internet  Small office/home office (SOHO) networks connect home computers to a corporate network  Medium to large networks have multiple locations and hundreds of thousands of computers  World Wide networks connect hundreds of millions of computers

ITE PC v4.0 Chapter 1 5 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Networking and Its Benefits  Define the components of an Information network Hosts Shared Peripherals Networking Devices Networking Media

ITE PC v4.0 Chapter 1 6 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Networking and Its Benefits  Describe the Roles of computers on a network  Clients and servers  Servers provide a service Web Site FTP Server (File downloads)  Clients access services Outlook, Eudora Internet Explorer, Firefox FTP Client, Filezilla

ITE PC v4.0 Chapter 1 7 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Peer-to-Peer Networks  Build computer peer-to-peer network and verify  Peer-to-peer networks are typically used for 10 or fewer clients

ITE PC v4.0 Chapter 1 8 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Network Topologies  Logical topology diagrams include naming and IP address schemes

ITE PC v4.0 Chapter 1 9 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Source, Channel, Destination  Source: person with the message  Destination: target of the message  Channel: voice

ITE PC v4.0 Chapter 1 10 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Rules of Communication  Attributes of a communication protocol:

ITE PC v4.0 Chapter 1 11 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Message Encoding  Thoughts are encoded into language  Language is transmitted to recipient  Like language computer data is converted to bits before it is sent over the wire

ITE PC v4.0 Chapter 1 12 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Message Formatting  Messages must follow a particular format—like a letter or phone call  Messages are encapsulated (addressed) before being sent to the appropriate location  On a network messages are formatted into frames

ITE PC v4.0 Chapter 1 13 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Message Size  Messages have size restrictions depending on the channel used  Messages must be of a particular size  Ethernet message sizes are limited to bytes

ITE PC v4.0 Chapter 1 14 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Message Timing  Access method Determines when a message can be sent This helps avoid collisions  Flow control Determines how much information can be sent at any given time  Response timeout Determines what action to take if there is no response in a reasonable time period

ITE PC v4.0 Chapter 1 15 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Message Patterns  Unicast: Message to a single entity  Multicast: Message to a group  Broadcast: Message to everyone

ITE PC v4.0 Chapter 1 16 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Communication Protocols  Attributes of a communication protocol: Message format Message size Timing Encapsulation Encoding Standard message pattern

ITE PC v4.0 Chapter 1 17 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Importance of Protocols  Network devices must follow the protocols to communicate with one another  The Ethernet protocol defines local network communication including message format, message size, timing, encoding, and message patterns.

ITE PC v4.0 Chapter 1 18 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Standardization of Protocols  Standards are beneficial to networking in many ways: Facilitate design Simplify product development Promote competition Provide consistent interconnections Facilitate training Provide more vendor choices for customers

ITE PC v4.0 Chapter 1 19 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Standardization of Protocols  Example: BASE-T represents the 100 Megabit Ethernet using twisted pair cable standards 100 is the speed in Mbps BASE stands for baseband transmission T stands for the type of cable, in this case, twisted pair

ITE PC v4.0 Chapter 1 20 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Physical Addressing  Physical addressing identifies Source, Destination and Channel on an Ethernet Network

ITE PC v4.0 Chapter 1 21 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Ethernet Communication  Describe some of the basic characteristics of Ethernet for communicating across the channel

ITE PC v4.0 Chapter 1 22 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Hierarchical Design of Ethernet Networks  Access Layer - to provide connections to hosts in a local Ethernet network.  Distribution Layer - to interconnect the smaller local networks.  Core Layer - a high- speed connection between distribution layer devices.

ITE PC v4.0 Chapter 1 23 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Logical Addressing  IP addresses are considered logical addresses  IP addresses have a host portion and a network portion  Both IP addresses and MAC addresses are required for communication

ITE PC v4.0 Chapter 1 24 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Access and Distribution Layer Devices  Switches and hubs are access layer device that allows multiple computers to connect to the network  Routers are distribution layer devices that allow multiple networks to communicate with one another

ITE PC v4.0 Chapter 1 25 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Access Layer  The access layer allows multiple devices to connect to the network  Devices such as phones, printers, computers, servers, etc. all connect at the access layer  Hubs and switches are access layer devices

ITE PC v4.0 Chapter 1 26 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Function of Hubs  Hubs ONLY broadcast messages  Hubs are considered Layer 1 devices (OSI Model)

ITE PC v4.0 Chapter 1 27 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Functions of Switches  Switches send unicast messages to the destination  Switches learn MAC addresses by “flooding”  Switches are Layer 2 devices (OSI Model)

ITE PC v4.0 Chapter 1 28 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Broadcast Messages  Broadcast messages allow a host to send a message to all other hosts on the network while sending the message only once  The broadcast MAC address is FFFF.FFFF.FFFF  If a host sends a message to a hub it is broadcast to all hosts on the network  A local network is referred to as a broadcast domain

ITE PC v4.0 Chapter 1 29 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Switch Behavior  When a switch receives data from a host with a MAC address not listed in it’s MAC table it adds that address to the table  When a switch receives a frame with a destination MAC address not in it’s table it floods the frame to all ports  When a switch receives a frame with a destination MAC address in the table, the frame is sent as a unicast

ITE PC v4.0 Chapter 1 30 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public MAC and IP  A NIC will only accept a frame if the destination MAC is a broadcast MAC or it is the NICs MAC  Most applications rely only on the IP address  MAC is determined using address resolution protocol (ARP)

ITE PC v4.0 Chapter 1 31 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public ARP  The sender broadcasts a frame including the IP address of the destination  All network hosts receive the broadcast, but only the host with a matching IP address responds by sending it’s MAC address back to the sender  The sending host receives the message and stores the MAC address and IP address information in the ARP table.

ITE PC v4.0 Chapter 1 32 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Distribution Layer Devices and Communication Methods  Broadcast containment  Security  Locations  Logical Grouping

ITE PC v4.0 Chapter 1 33 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public  Describe the function of routers and how they are used in the network A router connects a network to other networks Routers rely on packets and logical address A packet is the encapsulated data inside a frame

ITE PC v4.0 Chapter 1 34 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Default Gateway  Default Gateways allow devices on one network to communicate with another network

ITE PC v4.0 Chapter 1 35 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Routing Tables  Routers use IP addresses to determine where traffic should be sent  Routers are considered layer 3 devices  Routers modify MAC addresses but do not change IP addresses of data passing through

ITE PC v4.0 Chapter 1 36 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Tables Maintained by Routers  ARP Tables are used to determine the MAC of the destination  Routing tables are used to send traffic out a specific interface  Routing tables can be updated dynamically or manually

ITE PC v4.0 Chapter 1 37 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Local Area Network (LAN)  A group of local computers or network devices under one administrative control

ITE PC v4.0 Chapter 1 38 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Adding Network Hosts to Local and Remote Networks  Locally: just plug in  Remotely: requires routing

ITE PC v4.0 Chapter 1 39 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Packet Tracer 5.3  Be sure to do packet tracer activities in the curriculum

ITE PC v4.0 Chapter 1 40 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Plan, Implement and Verify a Local Network  Plan and document the building of a small home or small business Ethernet network

ITE PC v4.0 Chapter 1 41 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Plan and Document an Ethernet Network  Network planning starts with information gathering: Number of hosts Applications used Sharing and Internet connectivity requirements Security and privacy considerations Reliability expectations Connectivity requirements including, wired and wireless

ITE PC v4.0 Chapter 1 42 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Plan and Document an Ethernet Network  Physical environment Temperature control and placement of power outlets  Physical configuration Location of routers and switches Device interconnections and cabling Hardware configuration  Logical configuration Location and size IP addressing Naming and sharing Permissions

ITE PC v4.0 Chapter 1 43 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Plan, Implement and Verify a Local Network  Build a virtual model of their small home or small business network

ITE PC v4.0 Chapter 1 44 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Multi-function Device  Multi-function routers include: Router Wireless access point Switch Firewall

ITE PC v4.0 Chapter 1 45 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Connecting the Linksys Router  Internet port connects to the Internet  Ethernet port connects to the Ethernet

ITE PC v4.0 Chapter 1 46 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Plan, Implement and Verify a Local Network  Perform simple workgroup tasks in order to share resources

ITE PC v4.0 Chapter 1 47 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Summary  Information networks carry data using hosts as clients, servers, or both.  All computer communication involves a source, destination, and channel.  Rules called protocols govern computer communications.  Larger networks are divided into smaller, more manageable ones using a layered hierarchical design.  Each network host needs both a physical MAC address and a logical IP address.  Good network design requires a network plan.

ITE PC v4.0 Chapter 1 48 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public