Chapter 1: Exploring the Network - elktech.org · Exploring the Network Introduction to Networks....
Transcript of Chapter 1: Exploring the Network - elktech.org · Exploring the Network Introduction to Networks....
Intro to Networks v5
Chapter 1:Exploring the Network
Introduction to Networks
Intro to Networks v5 2
Networks in Our Past and Daily Lives
Intro to Networks v5 3
Clients and Servers
The advantages of Client/Server networks:
• Can provide services simultaneously to one or many clients.
• Can run multiple types of software and services
• Add security
The disadvantages of Client/Server networks:
• More Devices
• More complex
• Single point of failure
Intro to Networks v5 4
Peer-to-Peer
Intro to Networks v5 5
Components of a Network
There are three categories of network components:
Devices
Media
Services
Intro to Networks v5 6
Components of a Network End Devices
Some examples of end devices are:
• Computers (work stations, laptops, file servers, web servers)
• Network printers
• VoIP phones
• TelePresence endpoint
• Security cameras
• Mobile handheld devices (such as smartphones, tablets, PDAs, and wireless debit / credit card readers and barcode scanners)
Intro to Networks v5 7
Network Infrastructure Devices
Examples of intermediary network devices are:
• Network Access Devices (switches, and wireless access points)
• Internetworking Devices (routers)
• Security Devices (firewalls)
Functions of intermediary devices on a network:
• They direct data along alternate pathways when there is a link failure
• They filter the flow of data, based on security settings
Intro to Networks v5 8
Network Media
Criteria used to help select network media:
•The distance the media can successfully carry a signal
•The environment where the media is to be installed
Intro to Networks v5 9
Topology Diagrams
Logical Topologies
Naming scheme
IP addressing
Physical Topologies
Physical locations
Layout of devices and hosts
Length of cables
Intro to Networks v5 10
Types of Networks
The two most common types of network infrastructures are:
•Local Area Network (LAN)
•Wide Area Network (WAN).
Other types of networks include:
•Metropolitan Area Network (MAN)
•Wireless LAN (WLAN)
•Storage Area Network (SAN)
•Network Area Storage (NOS)
Intro to Networks v5 11
Local Area Networks (LAN)
A LAN is considered a small geographical area.
Servers a home, building, or campus.
Intro to Networks v5 12
Wide Area Networks (WAN)
A WAN is considered a large geographic area.
WANs connect LANs at slower speed bandwidth than LANs connect their internal end devices.
WANs are typically operated through multiple ISPs, but LANs are typically operated by single organizations or individuals.
Intro to Networks v5 13
The Internet, Extranet, and Intranet
The Internet is used to access the world, like surfing the web, online shopping, or watching a video (WAN).
The Extranet is used from the Internet to access resources inside a private company.
The Intranet is used to access private resources from inside a company (LAN).
Intro to Networks v5 14
Internet Access Technologies
Instant messaging – real-time communication between two or more people.
Social media – interactive website there people create and share user-generated content with friends and family.
Wiki – web pages that groups people can edit and use together.
Podcast – an audio basedmedium that allows peopleto deliver their recordingto a wide audience.
Weblog (blog) - a discussion or informational site published on the web and consisting of discrete entries called posts.
Intro to Networks v5 15
Connecting to the Internet
Require physical cables to be run to the building:
• DSL – splits the access into three signals (always-on, high-bandwidth connection)
• Cable – coaxial (always-on, high-bandwidth connection)
• Dialup (very low bandwidth)
• Dedicated leased line
Do NOT require physical cables:
• Cellular
• Satellite (must have line-of-sight)
Intro to Networks v5 16
Converged Networks
A converged network is a single network channel capable of delivering multiple communication forms.
Multiple services running on multiple networks.
Intro to Networks v5 17
Reliable Network
Supporting Network Architecture
As networks evolve, we are discovering that there are four basic characteristics that the underlying architectures need to address in order to meet user expectations:
•Fault Tolerance
•Scalability
•Quality of Service (QoS)
•Security
Intro to Networks v5 18
Circuit-Switched Networks
A characteristic of circuit-switched networks is that If all circuits are busy, a new call cannot be placed.
There is a finite number of circuits. During peak periods, some calls may be denied.
The circuits stays active, even if no one is speaking.
No fault tolerance.
Intro to Networks v5 19
Packet-Switched Networks
The term congestion defines a state where the demand on the network resources exceeds the available capacity.
During peak periods, communications may be delayed, but not denied.
Intro to Networks v5 20
Scalable Networks
Tier 1 – Can reach every other network on the Internet without buying anything
Tier 2 – buys from Tier 1 – but can resell. Can do that with some networks, but still buys to go some places on the Internet
Tier 3 - Probably also buy from Tier 3’s, but more on the retail market, and for a specific area. Much lower in price.
Tier-3 ISPs are the local providers of services directly to end users.
Tier-3 ISPs are usually connected to Tier-2 ISPs and pay Tier-2 providers for internet access.
Intro to Networks v5 21
Quality of Service (QoS)
Examples of priority decisions for an organization might include:
• Time-sensitive communication - increase priority for services like telephony or video distribution.
• Non time-sensitive communication - decrease priority for web page retrieval or email.
• High importance to organization - increase priority for production control or business transaction data.
• Undesirable communication - decrease priority or block unwanted activity, like peer-to-peer file sharing or live entertainment
The network provides predictable levels of service to different types of traffic.
Intro to Networks v5 22
Network Security
Requiring strong, complex passwords is a practice that ensures data confidentiality. Only the intended recipients can access and read the data.
Maintaining integrity ensures that the information has not been altered during transmission.
Ensuring availability provides the assurance of timely and reliable access to data.
These tools provide the minimum required security protection for home users:
• Antivirus software
• Antispyware software
• A firewall
Intro to Networks v5 23
Security Threats
The most common external threats to networks include:
• Viruses, worms, and Trojan horses
• Spyware and adware
• Zero-day attacks, also called zero-hour attacks
• Hacker attacks
• Denial of service attacks
• Data interception and theft
• Identity theft
Intro to Networks v5 24
Security Solutions
Network security components often include:
•Antivirus and antispyware
•Firewall filtering
•Dedicated firewall systems
•Access control lists (ACL)
• Intrusion prevention systems (IPS)
•Virtual Private Networks (VPNs)
Intro to Networks v5 25
Network Trends
Some of the top trends include:
•Bring Your Own Device (BYOD)
•Online collaboration
•Video
•Cloud computing
Intro to Networks v5 26
Bring Your Own Device (BYOD)
The acronym BYOD refers to the trend of end users being able to use their personal devices to access business/campus networks and resources.
Many wireless LANs are having to be redesign as a direct result of many students bringing their own tablets and smartphones to school to access school resources.
Intro to Networks v5 27
Online Collaboration
TelePresence provides real-time video and audio communication over the Internet so that businesses can conduct corporate meetings with participants from several remote locations.
Intro to Networks v5 28
Video Communication
Intro to Networks v5 29
Cloud Computing
Cloud computing provides applications accessed over the Internet through a subscription.
There are four primary types of clouds:
•Public clouds
•Private clouds
•Custom clouds
•Hybrid clouds
Intro to Networks v5 30
Data Centers
A data center is a facility used to house computer systems and associated components including:
• Redundant data communications connections
• High-speed virtual servers (sometimes referred to as server farms or server clusters)
• Redundant storage systems (typically uses SAN technology)
• Redundant or backup power supplies
• Environmental controls (e.g., air conditioning, fire suppression)
• Security devices
Intro to Networks v5 31