INSY 3303 Final - Scott Johnson - FALL 2023

Access Point

is a radio receiver that acts as a switch or a hub in Ethetnet LAN

How you connect a wireless device to a wired network.

Application Architecture

The way in which the functions of application layer software are spread among clients and servers in a network.

1. Presentation logic

2. Application logic

3. Data access logic

4. Data Storage

Attenuation

Loss of power in a signal as it travels from the sending device to the receiving device

Fix by using repeater

Backbone ( BN )

a larger, central network connecting several LANs, other BNs, MANs, and WANs. Routes and forwards messages and passes content

Distribution layer in a building. (Building Network)

Most common topology: Star Topology

Baselining

a process of trying to gain information about your current network.

when designers must review the list of applications that will use the network and identify the location of each, and the information is added to the emerging network documentation

Building Network (Distribution Layer)

Distributes network traffic to and from the LANs

Switched BN

Second network architecture component

Campus Network

(Core layer)

Connects all the buildings on one campus.

Routed BN

Third network architecture component

Usually faster than the backbones we use inside buildings because they typically carry more traffic than they do.

Circuit Loading

the amount of data transmitted on a circuit

build for the peak, 3x the peak

Content Caching

Storing other people's Web data that is closer to your users

You install a content engine (also called a cache engine) close to your Internet connection and install special content management software on the router

-It can save your content to other people's stuff

Content Delivery

special type of Internet service that works in the opposite direction.

Rather than storing other people's Web files closer to their own internal users

CPE ( Customer Premises Equipment )

the equipment that is installed at the customer location.

device resides at the customer site (connects w/ MPLS service provider)

Data Flow

The movement of data among processes, stores, sources, and destinations

Simplex: one-way transmission, radios and TV

Half Duplex: two-way transmission, but only in one direction at a time

Full Duplex: transmit in both directions

Dedicated Circuit

A circuit that runs from a breaker box to specific outlets.

ESP ( Encapsulating Security Payload )

encrypts IP packet and encapsulates it when the VPN software receives the Packet.

The contents of the ESP packet (the IP packet, the TCP segment, and the HTTP packet) are encrypted so that no one except the VPN gateway at the office can read them.

Forwarding Table

a table that lists the Ethernet address of the computer connected to each port on the switch.

Switch uses these to find out which circuit is connected to what computer.

FTTH ( Fiber To The Home)

Running fiber optic cables into your home

Intermodulation noise

Special type of cross-talk. The signals from two circuits combine to form a new signal that falls into a frequency band reserved for another signal.

IXP ( Internet Exchange Points )

ISPs exchange data at Internet exchange points (IXPs)

how tier pass information

ISP Tiers

is a company that provides Internet access. The most common ISP is the provider who delivers Internet to your home or business for a fee.

Tier 1 - the backbone of the Internet; interconnect with other ISPs with IXPs

Tier 2 - a service provider that utilizes a combination of paid transits with Tier 1 and Tier 3 ISPs for customers

Tier 3 - strictly purchases internet transit

Load Balancer

(also called a virtual server) a device that acts as a traffic manager at the front of a new server farm

Local loop

wired connection from a telephone company's central office in a locality to its customers' telephones at homes and businesses.

MIME ( Multipurpose Internet Mail Extension )

A standard for encoding and attaching binary files, images, video, and non-ASCII character sets within an e-mail message.

Modem/Codec

Communications hardware device that translates the digital data produced by computers into the analog signals for transmission in today's voice communication circuits

Modem: -allows devices to connect to the internet

Codec - Device that translates analog voice data into digital form

Modulation

the modification of a carrier wave's fundamental characteristics in order to encode information

MTTR ( Mean Time to Repair )

Describes how long it will take to recover a failed system.

MTTR(repair) - mTTR(responds+MTTD(Diagnose)+MTTF(fix)

Multiplexing

A form of transmission that allows multiple signals to travel simultaneously over one medium.

To divide a high-speed circuit into several slower (logical) circuits.

NAT ( Network Address Translation )

Process of converting b/w

one set of public IP addresses that are viewable from the Internet

second set of private IP addresses that are hidden from people outside of the organization.

NCO (Network Cost of Ownership)

Method that only examines the direct costs of operating computers

Networks

LAN - Local Area Network, group of computers located in the same area

BN - Backbone Network, larger central network connecting LANs, BNs, and WANs

WAN - Wide Area Network, connects BNs and MANs

Network OS

is the software that controls the network.

one that runs the network server

one that runs the network client

T Carrier

-A T-Carrier is like a highway system for data, commonly used in North America, where each lane represents a dedicated circuit for transmitting information.

T1 Circuit - provides a data rate of 1.544 Mbps, often are used to transmit both data and voice

T3 Circuit - allows transmission at a rate of 44.736 Mbps, becoming popular as the transmission medium for corporate MANs and WANs

Fractional T1 - offers portions of a 1.544-Mbps for a fraction of its full cost

Network Circuits

Wired & Wireless LANs

Wired LANs: Most LANs are built with unshielded twisted-pair (UTP) cable, shielded twisted-pair (STP) cable, or fiber-optic cable.

Wireless LANs: Use radio transmissions to send data between the NIC and the access point (AP).

Network Controls

Developing a secure network means developing controls. Controls are software, hardware, rules, or procedures that reduce or eliminate threats to network security.

Network Demand

restrict applications that use a lot of network capacity, such as desktop videoconferencing, medical imaging, or multimedia.

NOC ( Network Operations Center )

Organization that is responsible for monitoring and fixing problems

OSI Layers

1. Physical Layer - physical connection between sender and receiver

2. Data Link Layer - Responsible for moving a message from one computer to the next

3. Network Layer - Performs routing and selects the next computer to which the message should be sent

4. Transport Layer - Responsible for linking application layer software to the network and establishing end-to-end connections between sender and receiver.

5) Session: managing and structuring all session

6) Presentation: formats the data for presentation to the user

7) Application Layer - Application software used by the network user

Groups of layers

- Hardware Layers = Physical & Data Link Layers

- Internetwork layers = Transport Layers & Network Layer

Overhead

-All the layers of information.

-Used for purposes such as error checking and marking the start and end of characters and packets.

PDU ( Protocol Data Unit )

(sometimes called a packet) a single unit of data that contains information that is needed to transmit the message through the network.

This contains layer-specific information necessary for a message to be transmitted through a network.

Peering

When separate ISPs link their networks to swap traffic on the Internet and they do not charge each other when they transmit the messages.

Performance and Failure Statistics

performance how many packets are being moved on what circuits and what the response time. Failure statistics also tell availability, the percentage of time the network is available to users.

PVC ( Permanent Virtual Circuit )

are connections b/wthe different locations in the packet network;

this makes packet-switched networks act like DCNs, that are defined for frequent and consistent use by the network.

Polling

the process of sending a signal to a client computer that gives it permission to transmit

The client stores all messages that need to be transmitted

The controlling device polls the client to see if it has data to send

RAID ( Redundant Array of Independent Disks )

Multiple disks are added together to increase performance or provide protection against faults.

RAID help prevent disk subsystems from being a single point of failure.

Reduce Network Traffic

Network monitoring tools

Analyze traffic patterns

Eliminate network bottlenecks

RFP ( Request for Proposal )

a document that specifies what equipment, software, and services are desired and ask vendors to provide their best prices.

Ring Architecture

- Connects computers in a closed loop to address the issues of the bus topology.

- It resembles a ring, with each computer linked to the next

.- It lacks strong security features and is not considered the most practical choice for modern networks.

Risk Control Strategy

the way an organization intends to address a risk. They can either accept it, Mitigate it, share it, or defer it.

RSVP ( Resource Reservation Protocol )

a general-purpose protocol that permits application layer software to request connections that have certain minimum data transfer capabilities.

RTP (Real-time Transport Protocol)

Used for delivering audio and video over an IP network.

-Sends overhead information, such as the number of packets, time stamps, etc

Security Goals

CIA:

- Confidentiality

- Integrity

- Availability

Security Protocols

- Wired Equivalent Privacy (WEP): oldest, worst security

- Wi-Fi Protected Access (WPA): little better

- 802.11i (WPA2): better

- MAC Address filtering: the problem w/ this is that you can fake an address

Security Threats

Ensuring business continuity

Preventing unauthorized access

Star Architecture

- connects all computers to one central computer that routes messages to the appropriate computer, used mainly for wireless points and P2P connection

easy to manage because the central computer receives and routes all messages in the network

Subnet

a subdivision of a network that is created either to conserve addresses or to support specific network requirements.

TCO ( Total Cost of Ownership )

A factor considered when purchasing new products and services.

It will attempts to identify the cost of a product or service over its lifetime.

TCP ( Transmission Control Protocol )

- provides reliable, ordered, and error-checked delivery of a stream of packets on the internet. TCP is tightly linked with IP and usually seen as TCP/IP in writing.

- TCP is the transport layer protocol that links the application layer to the network layer.

Throughput

Total number of information bits received per second, after taking into account the overhead bits and the need to

re-transmit frames containing errors.

Traffic Limiting

When a flood of packets are entering the network, limit incoming access regardless of source (some may be legitimate)

Turnpike Effect

Traffic increases much faster than originally forecast.

Unauthorized Access

The use of a computer or network without permission

User Authenticationterm

the process of verifying the credentials of a particular user of a computer or software system

Virtual LAN

Networks in which computers are assigned to LAN segments by software rather than by hardware

Used for large networks

Expensive and complex

IEEE 802.1q

VPN ( Virtual Private Network )

private packet-switch network over the public Internet by establishing a PVC that acts as a dedicated circuit

Wireless Media

a form of media in which the message is broadcast through the air, such as microwave or satellite

WWW ( World Wide Web )

A system of interlinked hypertext documents contained on the Internet

1. Physical Layer

( data in binary )

physical connection between sender and receiver

2. Data Link Layer

( ethernet frame )

Responsible for moving a message from one computer to the next

3. Network Layer

( IP packet )

Performs routing and selects the next computer to which the message should be sent

4. Transport Layer

( TCP segment )

Responsible for linking application layer software to the network and establishing end-to-end connections between sender and receiver.

5. Session

( HTTP packet )

managing and structuring all session

6. Presentation

( HTTP packet )

formats the data for presentation to the user

7. Application Layer

( HTTP packet )

Application software used by the network user