Network Components - Servers

• Vandana G. Bandhoesingh is the instructor and holds a BSc and MBA.
• The course will include student introductions covering name, age, work experience, and technical interests are covered.
• The course topics include networking components, TCP/UDP/IP network protocols, subnetting, and basic network troubleshooting.
• The course assesment consists of 25 multiple-choice questions (70%) and a class practical assignment (30%) with the language of assesment in english

Network Components - Servers

• A server is software running on robust hardware with enough capacity to coordinate multiple client requests.
• Servers have bandwidth capacity and storage and can be physical or virtual.
• A web server hosts websites.
• Email servers facilitate sending/receiving emails through IMAP, POP, or SMTP servers.
• FTP servers are for file transfer protocols, such share files through intranet on a LAN.
• Identity servers (AAA, TACACS) are for authentication, authorization, and accounting purposes.
• Security measures are required to secure servers.

Network Components - Router

• A router connects several network components to each other.
• Routers route traffic from one network to another and learn about neighbors.
• Routers create access lists, including whitelists and blacklists.
• Each port on a router operates in a separate broadcast domain.

Network Components - Switch

• A switch connects devices from one specific network to each other.
• Switches send traffic to specific devices connected to that port or interface.
• Bandwidth of each port is limited to 100Mbps.
• Traffic can be defined through VLANs.
• Spanning tree protocol allows switches to create redundant networks.

Network Components - Switch - Spanning Tree

• Spanning tree decides the best path (shortest path and less delay) for data transmission.
• Spanning tree prevents loops in a network while maintaining backup connections.

Switching

• Switches learn MAC addresses (unique physical addresses of devices) and map them to IP addresses.
• Switches keep track of an ARP table per port.

Network Components - Hub

• A hub is a basic switch that transmits traffic to everyone within the network.
• Hub bandwidth capacity of 100Mbps is distributed to all connections.
• Hubs forward all incoming packets to everyone within the network, without discernment.
• Hubs create unnecessary traffic and load on the network.

Network Components - Access Points

• Access points are wireless routers that connect several hosts.

Network Components - Firewall

• A firewall establishes a barrier between a trusted internal network and an untrusted external network, like the Internet.
• Firewalls function as routers, connecting external networks with internal ones.
• Firewalls create access rules and monitor incoming and outgoing traffic based on security rules.

Client–Server vs. Peer-to-Peer

• A client–server network centrally connects to one server, while a peer-to-peer network connects to multiple hosts.

OSI Model Layers

• The Application Layer (Layer 7) serves as the interface for users and applications.
• The Presentation Layer (Layer 6) manages data format, encryption, and decryption.
• The Session Layer (Layer 5) establishes, maintains, and terminates connections between applications.
• The Transport Layer (Layer 4) ensures reliable data transfer, managing error-free, sequenced delivery without losses or duplications.
• The Network Layer (Layer 3) controls subnet operations.
• The Data Link Layer (Layer 2) enable error-free transfer data frames.
• The Physical Layer (Layer 1) transmits and receives raw bit streams over the physical medium.

Encapsulation and De-encapsulation

• Data from the Application layer (Layer 5) gains an HTTP header. The packets are called DATA.
• Data then reaches the Transport layer (Layer 4), where a TCP header is added (encapsulated). These packets become known as SEGMENTS. UDP packets are called DATAGRAMS.
• At the Network layer (Layer 3), an IP header is added, and the packets are called PACKETS.
• Packets arrive at the Data Link layer (Layer 2), where they are called FRAMES, and gain a data link header and trailer used by ethernet, frame-relay, or ATM.
• Finally, frames reach the Physical layer (Layer 1) and are converted into BITS for transmission.

Connectionless (UDP)

• Data is sent without establishing or tearing down a connection.

Connection-Oriented (TCP)

• A connection is established and maintained before data transfer, and the connection is close down once complete.
• Virtual circuits include TCP on the internet and packets are generally routed.

Bandwidth, Data Rate, and Throughput

• Data rate: The speed at which data is transmitted (kbps or Mbps).
• Throughput is the actual data volume consumed (e.g., mobile data plan usage).

Physical Layer Specifications

Wired Networks

• Copper Cat 5e or Cat 6 and fiber optic cables are included.

Wireless Networks

• Outdoor cellular technologies include GSM, MicrowaveWiMAX, LTE, and Satellite.
• Indoor wireless technologies include Wireless LAN (WiFi) and Bluetooth.

Types of Networks

• There are varying networks such as WWAN, WMAN, WLAN and WPAN

Physical Layer- Wired Vs Wireless

Wired Networks

• wired networks have a higher operation speed
• wired networks have high system bandwith
• wired networks have cables that are not expsensive
• wired networks that are limited based on connected systems

Wireless Networks

• have a lower operation speed of transmission
• require subscriber stations, wireless routers and wireless access points that are expensive
• have an unlimted transmission range

Wired Vs Wireless

• Interference is less in wired as there is 1 connection, not an effect on others
• Wireless interferenceis higher due to conditions between signal and receiver
• QOS is better in wired
• Wired has more realibility comparitively.

Data Link Layer - Switchports

• Ethernet ports can be half-duplex, full-duplex, 10 Mbps half/full duplex, 100 Mbps fast ethernet, or 1000 Mbps (1Gb).
• Half-duplex transmits data in only one way at a time.
• Full-duplex transmits data in both ways at the same time.

Data Link Layer - VLans

• Virtual LANs split networks on a logical or software basis, but physically connect to one node or wire.
• IEEE 802.1Q protocol is typically used for packet-tagging in VLANs.