In this module, we delve into the components of Ethernet architecture, its specifications, and the intricacies of connecting networks. We will also explore wireless and remote access protocols and standards, along with primary network architectures and their characteristics.
Ethernet
Understanding the characteristics and differences of various Ethernet architectures is crucial. The IEEE 802.3 standard, known as Ethernet, is a bus-based broadcast network with decentralized control, operating at speeds of 10 Mbps, 100 Mbps, or higher. Ethernet is the most common topology type in the LAN market.
Basic Elements of Ethernet
- Physical Medium: Carries Ethernet signals between machines on the network.
- Protocols: Rules determining how machines on the network access data.
- Frame: Contains a standard set of bits and carries data within the system.
Operation of Ethernet
In an Ethernet network, a node (a computer) represents a separate point on the network with its unique function. Nodes use a shared medium to transfer Ethernet signals bit by bit from sender to receiver. Before transmitting, a node ensures the medium is idle. Transmissions occur based on the order send requests are initiated. The destination address in the packet determines its final destination, while all other nodes ignore it.
Medium Access Control (MAC)
Medium Access Control ensures every computer on the Ethernet network gets a fair opportunity to transmit frames. The Ethernet frame consists of bits organized into fields, including address fields, a data field, and an error-checking field.
Advantages and Disadvantages of Ethernet
Advantages:
- High-speed LAN transmissions.
- Supports different wiring configurations.
- Suitable for large LAN or micro-to-mainframe applications.
- Easy to install.
Disadvantages:
- Potential for packet collisions, requiring retransmission.
- Limited to certain distance constraints without repeaters or switches.
Remote Access
Remote access allows obtaining access to a computer or network from a remote location. Common methods include ISDN, wireless, cable modem, and DSL technologies. Remote access protocols control connectivity, with three main types:
- Point-to-Point Protocol (PPP): Offers the best security and support.
- Serial Line Internet Protocol (SLIP): Used by older remote access servers.
- Microsoft Remote Access Protocol: Nearly obsolete, used by legacy clients.
Wireless Access Points
A wireless router, also known as a wireless access point, connects hundreds of network devices. Various standards include:
- 802.11a: 54 Mbps, 115 feet range
- 802.11b: 11 Mbps, 125 feet range
- 802.11g: 54 Mbps, 125 feet range
- 802.11n: 300 Mbps, 240 feet range
Ethernet Specifications
Fast Ethernet
Fast Ethernet transmits at 100 Mbps, an upgrade from the standard 10 Mbps Ethernet. It is used for higher-speed LAN transmissions.
Gigabit Ethernet
Gigabit Ethernet transmits at 1000 Mbps, providing even faster data transfer than Fast Ethernet. Understanding the differences between straight-through, crossover, and rollover cables is essential.
Connecting Network Devices
Straight-Through Cable
Used to connect computers to networking devices like hubs and switches. The RJ-45 connectors at each end have the same pin-out.
Crossover Cable
Connects two hubs or switches directly. One end of the cable is connected to the input of the other end.
Rollover Cable
Connects a computer terminal to a network router’s console port. It is flat and light blue, with reversed pin-outs on each end.
Network Architectures
Network Architecture Overview
Network architecture maps a computer network, allowing architects to design, build, and manage it. The internet uses TCP/IP architecture, the worldwide standard for LANs and WANs.
OSI Model
The Open Systems Interconnection (OSI) model is an open standard for communication using various equipment. It includes seven layers for inter-computing and inter-networking communications.
Network Configuration Management (NCM)
NCM involves organizing and maintaining information on all network components, with tools divided into vendor-neutral and vendor-specific categories.
Conclusion
This module introduced Ethernet architecture, cabling types, and network architectures. Understanding these concepts is vital for designing and implementing high-quality networks, enhancing your technical leadership skills in the field.
