C172 - Networking and Security UCertify Notes

Private Addresses

IP addresses set aside for use in private intranets

Hub

multiport repeater. data broadcast is seen by all devices.

Token Passing

A technique where an electrical token circulates around a network-control of the token enables the user to gain access to the network. It is based on the IEEE 802.5 Token Ring Network standard.

Local Area Network (LAN)

Connects a group of computers in close proximity, such as in an office building, school, or home

Frame Format

Format that information is exchanged in the Ethernet network

Three basic steps in isolating a network problem

Step 1: Is the connection to the machine down? (Layer 1) Step 2: Is the network down? (Layer 3) Step 3: Is a service on a specific machine down? (Layer 7)

MAC address

Unique address embedded in network connected devices.

7 Layers of the OSI Model

1. Physical Layer 2. Data Link Layer 3. Network Layer 4. Transport Layer 5. Session Layer 6. Presentation Layer 7. Application Layer

Token Ring Topology

A hub that manages the passing of the token in a Token Ring network. Often has a dual ring set up to create a redundancy in the topology. Anytime their is a single point of failure the network will fail. Thus why a dual ring is preferred.

IP Internetwork

A network that uses IP addressing for identifying devices connected to the network

IP internetwork

A network that uses IP addressing for identifying devices connected to the network

Token Ring Topology

A network topology configured in a logical ring that complements the token passing protocol. A Token Ring network is a deterministic network meaning each station connected to the network is ensured access for transmission of its messages at regular or fixed time intervals.

IP Address

A number assigned to any item that is connected to the Internet.

Protocol

A set of rules governing the exchange or transmission of data between devices.

Network Interface Card (NIC)

An expansion card that enables a computer to connect other computers or to a cable modem to facilitate a high-speed Internet connection.

CSMA/CD

Carrier Sense Multiple Access/Collision Detection

Full Mesh or Partial Mesh Topology

Devices are connected with many redundant interconnections between network nodes. Every node connects to every other node we have a full mesh topology but if every node only connects to a couple of other nodes we have a partial mesh topology. To determine the number of connections in a mesh topology it is n(n-1) / 2.

ipconfig /all

Enables the MAC address information to be displayed from the command prompt

Protocols and their Network Layers

FTP - Application HTTP - Application UDP - Transport IPX - Network TCP - Transport IP - Network

Network Troubleshooting Methodology

Identify the problem. Establish theory of probable cause. Test the Theory to determine cause. Establish plan of action to resolve the problem and identify potential effects. Implement the solution or escalate as necessary. Verify full system functionality and if applicable implement preventative measures. Document findings, actions, and outcomes.

Logical topology vs Physical Topology

Logical Topology - how the user views the communications of a network. Physical Topology - The actual physical architecture of the topology. How data is actually being transferred between users.

Star Topology

Most common topology in today's LANs. Twisted pair cables with modular plugs are used to connect computers and networking devices. All nodes connected to a central point. If the central point dies the topology fails. Sometimes an extended start is employed.

Topology

Network architecture used to interconnect teh networking equipment.

Bus Topology

Network configuration wherein all computers connect to the network via a central bus cable. Has terminators in the topology to break the connection. Single cable everyone plugged into it.

Topology vs Protocol

Protocol is a set of rules established by users to exchange data while a Topology is the network architecture.

TCP/IP (Transmission Control Protocol/Internet Protocol)

Protocole suite used for internetworks such as the internet

Organizationally Unique Identifier (OUI)

The first 24 bits of a MAC address, assigned to the NIC manufacturer by the IEEE.

Internet Assigned Numbers Authority (IANA)

The international organization responsible for allocation of IP addresses. Part of the Internet Corporation for Assigned Names and Numbers (ICANN).

Host number

The portion of the IP address that defines the location of the networking device connected to the network; also called the host address

Network Number

The portion of the IP address that defines which network the IP packet is originating from or being delivered to

Switch

Used at the center of a star network to isolate sections of the network. The use of a switched connection greatly improves the available bandwidth.

Ethernet

a network standard that specifies no central computer or device on the network (nodes) should control when data can be transmitted

Open Systems Interconnection (OSI) model

a seven-layer architecture for defining how data is transmitted from computer to computer in a network, from the physical connection to the network to the applications that users run. It also standardizes interactions between network computers exchanging information.

Intranets

internal corporate networks based on internet technology