Skills Networking Fundamentals Flashcards
What is a Network?
A network refers to two or more connected computers that can share resources such as data, a printer, an Internet connection, applications, or a combination of these resources.
Types of Networks
-Local Area Network (LAN)
-Metropolitan Area Network (MAN)
-Wide Area Network (WAN)
WAN Technologies
-Leased Line
-Circuit-switched
-Frame-relay
-Broadband Access
The OSI Model- Why a Layered Network Model?
-Reduces complexity
-Standardizes interfaces
-Facilitates modular engineering
-Ensures interoperable technology
-Accelerates evolution
-Simplifies teaching and learning
The Seven Layers of the OSI Model: Application, Presentation, & Session
Application Layers (Upper Layers):
-Network Processes to Applications
-Data Representation
-InterHost Communication
The Seven Layers of the OSI Model: Transport
End to End Connections:
-Handles transportation issues between hosts
-Ensures data transport reliability
-Establishes, maintains, and terminates virtual circuits
-Provides reliability through fault detection and recovery
-Information flow control
The Seven Layers of the OSI Model: Network
Data Delivery:
-Provides connectivity and path selection between two host systems
-Routes data packets
-Selects best path to deliver data
-The Network layer prioritizes data known as Quality of Service (QoS)
The Seven Layers of the OSI Model: Data Link
Access to Media:
-Defines how data is formatted for transmission and how access to the network is controlled
The Seven Layers of the OSI Model: Physical
Binary Transmission:
-Defines the electrical, mechanical, procedural, and functional specifications for activating, maintaining, and deactivating the physical link
Physical Media Types
-Twisted-Pair
-Coaxial
-Fiber Optics
-Wireless
Hub or Repeater
A hub (concentrator) is a device that repeats signals it receives on one port to all other ports. It is a central connection point for several network devices.
Data Link Layer
Data Link Layer protocols create, transmit, and receive packets. This layer is also responsible for logical MAC addressing and LLC processing, creating logical topologies, and controlling media access.
MAC Address
The network interface card address, called the hardware address, is protocol-independent and is usually assigned at the factory. This address is technically called the media access control address (MAC) because it is found on the MAC sub layer of the Data Link layer.
Data Link Devices
The Data Link layer is manipulated by two: bridges and switches. These are more complex and more expensive than their Physical layer counterparts, but they do have advantages
Switch
When a switch receives data the switch examines the data link header for the MAC address of the destination station and forwards it to the correct port. This opens a path between ports that can use the full bandwidth of the topology.
Network Layer
-The network layer provides connectivity and path selection between two host systems that may be located on geographically separated networks
-IP is a standard that defines the manner in which the network layers of two hosts interact. IP addresses are 32 bit long, hierarchical addressing scheme
Network Layer Devices
The devices that operate at the Network layer are routers and Layer 3 Switches
Routers
Routers facilitate communication within this internet work. It decides how to send packets within the network so that they arrive at their destination
Layer 3 Switches
The Layer 3 switch functions at the Network layer and performs the multiport, virtual LAN, data pipelining functions of a standard Layer 2 switch. It can also preform basic routing functions between virtual LANs.
Multilayer Switching: Transport, Network, and Data Link
Combines functionality of:
-Layer 2 switching
-Layer 3 switching
-Layer 4 switching
High-speed scalability
Low latency compared to routers
Transport Layer Implementations
The Transport layer is charge of the reliable/unreliable transport of data. It can be implemented as TCP or UDP.
Gateway
A gateway is a combination of hardware and software that connects dissimilar network environments. It performs translations at multiple layers of the open system interconnection (OSI) model.
Firewalls
A firewall is a system or group of systems that manages access between two or more networks
