Chapter 1 Flashcards
(30 cards)
Peer-to-Peer Networks
The Advantages:
*Easy to set up
*Less complexity
*Lower cost since network devices and dedicated servers may not be required.
*Can be used for simple tasks such as transferring files and sharing printers.
The Disadvantages:
*No centralized administration
*Not as secure
*Not scalable
*All devices may act as both clients and servers which can slow their performance.
What are the three categories of network components?
*Devices
*Media
*Services
Host/end Devices
Every computer on a network is called a host or end device:
*Computers (work stations, laptops, file servers, web servers)
*Network printers
*VoIP phones
*TelePresence endpoint
*Security cameras
*Mobile handheld devices (such as smart phones, tablets, PDAs, and wireless debit / credit card readers and barcode scanners)
Intermediary network devices
Examples of intermediary network devices are:
*Network Access Devices (hubs, switches, and wireless access points)
*Internetworking Devices (routers)
*Security Devices (firewalls)
Role of the intermediary device
*Regenerate and retransmit data signals
*Hold information about available pathways
*Notify other devices of errors
*Direct data along alternate pathways when there is a link failure
*Classify and direct messages according to priorities
*Permit or deny the flow of data, based on security settings
Hub
*Limited intelligence. Traffic received is sent out all ports of the hub
*All ports are on the one collision domain. Allow a lot of collisions on the network segment and are often not a good solution
*Also acts as a repeater
Switches
*Network devices connect to the switch
*The switch has many ports and refers to a table of MAC addresses to determine which port to use to forward the frame.
*Switches create a different collision domain per switch port
Routers
Routers are devices that connect different networks to each other.
-Use IP addresses to forward packets to other networks.
-Each interface is on a different network or subnet
-The router determines the path the data takes through the network
Also known as a default gateway
Network Media
Consists of Wireless Media, LAN Media and WAN Media.
Copper- Electrical pulses eg. twisted pair coax.
Fiber Optic - Light pulses
Wireless - Electromagnetic
waves.
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)
*Personal Area Network (PAN)
Wide Area Networks (WAN)
Intranet and Extrantranet
Connecting Remote Users to the Internet
Connecting Remote Users to the Internet:
DSL = Digital Subscriber Line
DSL – Digital Subscriber Line, Broadband connection, splits data channel into 3 signals - voice, data upload and data download
Cable – Cable supplier supplies internet access through coax cable
Cellular – used by phones/tablets
Satellite – used in rural areas, although not if wooded as signal could be blocked
Dial up – hardly used, too slow
Connecting to the InternetConnecting Businesses to the Internet
Metro Ethernet- Metro Ethernet is typically available from a provider to the customer premises over a dedicated copper or fiber connection
The Converging Network
What are the four basic characteristics that underlying architectures need to address in order to meet user expectations?
*Fault Tolerance
*Scalability
*Quality of Service (QoS)
*Security
Providing QoS
Examples of priority decisions might include:
*Increase priority for services like telephony or video distribution.
*Increase priority for production control or business transaction data.
*Decrease priority for web page retrieval or email.
*Decrease priority or block unwanted activity, like peer-to-peer file sharing or live entertainment.
When the network is busy or congested, QoS priorities can reduce the likelihood of delay on time sensitive traffic.
Questions
*What term is used to describe prioritising of network traffic?
*What name is given to a network that incorporates voice, video and data?
*What term is used to describe the capability built into a network that allows users to continue working even if some network components fail?
*What term is used to describe a networks capability to grow and react to future changes?
Answers:
1 Quality of Service (QoS)
2 Converged
3. Fault tolerance
4. Scalability
Circuit Switched Networks
*Temporary path/circuit is created but is dedicated for the time of the call
*Any failure, have to start again with whole new path, no fault tolerance
*Example of circuit switched is a leased line
*Major advantage – dedicated bandwidth
Packet-Switched Networks
*Data broken into packets
*Data sent down different paths
*More efficient use of bandwidth
*Can adapt if there is a failure
1) Which type of switching breaks messages in to multiple blocks?
2) What advantage does circuit switched have over packet switched?
3) Is a leased line packet or circuit switched?
4) Which type of switching will result in denied access if all lines are already being accessed?
Answers:
1.Packet switched
2.Dedicated bandwidth
3.Circuit switched
4.Circuit switched
Cloud Computing
Businesses:
-Gives organizations flexibility
-Agility and rapid deployment
-Reduced cost of infrastructure
-Refocus of IT resources
-Users can subscribe withproviders to access applications and data in the cloud. Data may be synced across many devices
Cloud Computing and Data Centres
A data centre is a facility used to house computer systems and associated components including:
-Redundant connections
-High-speed virtual servers
-Redundant storage systems
-Redundant power supplies
-Environmental controls (e.g., air conditioning, fire suppression)
-Security devices
Four types of Clouds
Public Clouds
Available to the general public through a pay-per-use model or for free.
Private Clouds
Intended for a specific organization or entity such as the government.
Hybrid Clouds
Made up of two or more Cloud types – for example, part custom and part public.
Each part remains a distinctive object but both are connected using the same architecture.
Custom Clouds
Built to meet the needs of a specific industry, such as healthcare or media.
Can be private or public.
