Networking Basics

Internetworking Elements

• A typical network consists of devices, media, and services that are interconnected through rules to facilitate message exchange
• The term "messages" includes web pages, emails, instant messages, telephone calls, and other forms of communication online

Network Elements

• There are four crucial parts to a network: rules, medium, messages and devices

Internetworking

• Internetworking is graphically represented and uses icons for networking devices

Common Internetworking Symbols

• Switch: The most common device for interconnecting local area networks
• Firewall: Secures networks
• Router: Directs messages across a network
• Wireless Router: A specific type of router found in home networks
• Cloud: Summarizes a group of networking devices
• Serial Link: A type of WAN interconnection, depicted as a lightning bolt

Hardware

• Network Interface Card (NIC): Also known as a LAN adapter is the hardware providing a network connection to a PC or other host device.
• Physical Port: This is a connector or outlet on internetworking devices where a device connects to a host for networking services
• Interface: It is typically a specialized port on an internetworking device that connects to individual networks, routers use network interfaces for interconnection.

Network Services

• To support computer applications, humans require services like WWW, email, instant messaging and IP Telephony, these services need to be provided by the network
• Rules or protocols must govern devices interconnected by a medium providing services. These protocols enable networked devices to communicate while TCP/IP is the industry standard
• TCP/IP specifies formatting, addressing, and routing, ensuring messages reach the intended recipient

Transmitting Messages

• Before an instant message is transmitted, it is converted to a transmittable format
• All types of messages are converted to binary coded digital signals before being sent for delivery

Devices

• A wide range of devices, including computers, telephones, cameras, music systems, printers, and game consoles, can participate in network services
• Routers are essential components in networks of any size, connecting two or more networks and ensuring efficient message delivery

Mediums

• Computers need to connect to a wired or wireless local network to send a message to it's destination
• Wireless networking is available in public hotspots
• Ethernet is the primary wired technology, using cables to connect devices, best for high-speed, large-data transfers like multimedia

Services

• Network services like instant messaging must be accessible to both sender and recipient
• Programs supporting the human network include email, bulletin boards, chat rooms, and instant messaging

Messaging Rules

• Rules or protocols specify how messages are directed through the network and interpreted at the destination
• Protocols such as XMPP, TCP, and IP are critical for enabling communication with Jabber instant messaging

Network Architecture Basics

• Refers to the supporting technologies, programmed services, and protocols that move messages across an infrastructure
• Four key aspects of network architecture include fault tolerance, scalability, Quality of Service (QoS), and security

Fault Tolerance

• Fault-tolerant networks minimize hardware or software failure impact and allow quick recovery using redundant links or paths between source and destination

Scalability

• Scalable networks can quickly expand to accommodate new users and applications without impacting service performance

Quality of Service

• Converged internetworking is changing network architectures to accomodate the quality of service expectations

Security

• Network security requirements have evolved as the Internet has become a widely accessible means for business and personal communications