ccna dis1 - chapter03 - connecting to the network [compatibility mode]

8/3/2019 CCNA Dis1 - Chapter03 - Connecting to the Network [Compatibility Mode]

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Chapter 3 Connecting to the Network

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Objectives

Explain the concept of networking and the benefits ofnetworks.

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 communicationmethods across networks.

Plan, implement, and verify a local network.

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What is a Network?

Networks provide the ability to connect people and equipment nomatter where they are in the world.




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What is a Network?

Converged networks




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Benefits of Networking




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Benefits of Networking

Here are other uses of a network and the Internet:Sharing music and video files

Research and on-line learning

Chatting with friends

Planning vacations

Purchasing gifts and supplies




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Basic Network Components Peripherals




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Basic Network Components Hosts




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Basic Network Components Network Devices




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Basic Network Components Network Media




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Computer Roles in a Network

Servers are hosts that have software installed that enable them toprovide information, like email or web pages, to other hosts on thenetwork.

Clients are computer hosts that have software installed that enablethem to request and display the information obtained from the server.




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Computer Roles in a Network

A computer with server software can provide services simultaneouslyto one or many clients.




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Peer-to-Peer Networks




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Network Topologies




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Network Topologies




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Source, Channel, and Destination




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Source, Channel, and Destination




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Rules of Communication

Among the protocols for successful human communication are: Identification of sender and receiver

Agreed-upon medium or channel (face-to-face, telephone, letter,photograph)

Appropriate communication mode (spoken, written, illustrated,

interactive or one-way) Common language

Grammar and sentence structure

Speed and timing of delivery




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Rules of Communication - Protocols

Protocols define the details of how the message is transmitted, anddelivered




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Message Encoding




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Message Encoding




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Message Formatting

In many cultures, a personal letter contains the following elements:




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Message Formatting

When a message is sent from source to destination, it must use aspecific format or structure. Message formats depend on the type ofmessage and the channel that is used to deliver the message.




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Message Size

These sentences are limited in size to what the receiving person canprocess at one time.




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Message Timing

People use timing to determine when to speak, how fast or slow to talk,and how long to wait for a response.

These are the rules of engagement. Access Method

Flow Control

Response Timeout




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Message Patterns




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Message Patterns




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Message Patterns




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Importance of Protocols

Computers, just like humans, use rules, or protocols, in order tocommunicate.




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Standardization of Protocols

As networks became more widespread, standards were developed that definedrules by which network equipment from different vendors operated. 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




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Standardization of Protocols




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Physical Addressing




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Ethernet Communication




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Hierarchical Design of Ethernet Networks

Access Layer - to provide connections to hosts in a local Ethernetnetwork. Distribution Layer - to interconnect the smaller local networks. Core Layer - a high-speed connection between distribution layer

devices.




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Logical Addressing

The IP address is known as a logical address because it is assignedlogically based on where the host is located. IP addresses contain two parts. One part identifies the local network.

The second part of the IP address identifies the individual host.




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Access Layers

The Access Layer is the most basic level of the network. It is the part ofthe network in which people gain access to other hosts and to sharedfiles and printers.

There are several types of networking devices that can be used toconnect hosts at the Access Layer, including Ethernet hubs andswitches.




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Function of Hubs

Hubs contain multiple ports that are used to connect hosts to thenetwork. Hubs cannot determine which host should get any particular message.

A hub simply accepts electronic signals from one port and regenerates(or repeats) the same message out all of the other ports.

A hub is referred to as a shared-bandwidth device.




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Function of Hubs




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Function of Switches

Like a hub, a switch connects multiple hosts to the network. Unlike a hub, a switch can forward a message to a specific host. A table on the switch, called a MAC address table, contains a list of all

of the active ports and the host MAC addresses that are attached tothem.

Switch allows many conversations to take place at the same time,without collisions occurring.




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How does the MAC address of a new host get into the MAC addresstable? Refer: 3.4.3.2




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When a hub is connected to a switch port, the switch associates theMAC addresses of all hosts connected to that hub with the single porton the switch.




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Broadcast Messaging

Broadcasts are useful when a host needs to find information withoutknowing exactly what other host can supply it or when a host wants toprovide information to all other hosts in the same network in a timelymanner.

The broadcast MAC address in hexadecimal notation isFFFF.FFFF.FFFF.




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Broadcast Messaging

A local network is also referred to as a broadcast domain.




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MAC and IP

Address resolution protocol (ARP) is used to discover the MACaddress of any host on the same local network.




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Address Resolution Protocol (ARP)

ARP uses a three step process to discover and store the MAC addressof a host on the local network when only the IP address of the host isknown.

Refer 3.4.7.1




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Distribution Layer

The Distribution Layer connects the independent local networks andcontrols the traffic flowing between them. The Access Layer devices are connected to each other via the

Distribution Layer device, such as routers.




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Function of Routers

A router is a networking device that connects a local network to otherlocal networks. At the Distribution Layer of the network, routers directtraffic and perform other functions critical to efficient network operation.

Refer 3.5.2.1




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Function of Routers

Each port, or interface, on a router connects to a different localnetwork. The routing table contain information about the routes, or paths, that

the router uses to reach other remote networks that are not locallyattached.

Local network broadcasts are not sent across routers to other localnetworks.

Refer 3.5.2.3




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Tables Mantained by routers




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Refer 3.5.4.2




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Local Are Network (LAN)

The term Local Area Network (LAN) refers to a local network, or agroup of interconnected local networks that are under the sameadministrative control.




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Local Are Network (LAN)




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Addressing Hosts to Local and Remote Networks




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Addressing Hosts to Local and Remote Networks




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Learn to Use Packet Tracer

Refer: 3.5.7.1




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Plan and Document an Ethernet Network




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Prototypes

Once the network requirements are documented, and the physical andlogical topology maps created, the next step in the implementationprocess is to test the network design. One of the ways to test a networkdesign is to create a working model, or prototype, of the network.

Refer: 3.6.2.2




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Multi-function Device




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Sharing Resources

It is important to consider security issues, and to assign specificpermissions to shared resources. Simple File Sharing can be disabled so that more specific security

access levels can be assigned. When this is done, the followingpermissions are available to assign to resources:

Full Control

Modify

Read & Execute

List Folder Contents

Read

Write

Refer: 3.6.5.2




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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 addressand a logical IP address.

Good network design requires a network plan.




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ccna dis1 - chapter03 - connecting to the network [compatibility mode]

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