100 Gigabit Ethernet

100 Gigabit Ethernet (or 100GbE) and 40 Gigabit Ethernet (or 40GbE) are high-speed computer network standards developed by the Institute of Electrical and Electronics Engineers (IEEE). They support sending Ethernet frames at 40 and 100 gigabits per second over multiple 10 Gbit/s or 25 Gbit/s lanes. Previously, the fastest published Ethernet standard was 10 Gigabit Ethernet. They were first studied in November 2007, proposed as IEEE 802.3ba in 2008, and ratified in June 2010. Another variant was added in March 2011.

PPPoE

PPPoE (Point-to-Point Protocol over Ethernet) is a specification for connecting multiple computer users on an Ethernet local area network to a remote site through common customer premises equipment, which is the telephone company's term for a modem and similar devices. PPPoE can be used to have an office or building-full of users share a common Digital Subscriber Line (DSL), cable modem, or wireless connection to the Internet. PPPoE combines the Point-to-Point Protocol (PPP), commonly used in dialup connections, with the Ethernet protocol, which supports multiple users in a local area network. The PPP protocol information is encapsulated within an Ethernet frame.

Gigabit Ethernet

Gigabit Ethernet, a transmission technology based on the Ethernet frame format and protocol used in local area networks (LANs), provides a data rate of 1 billion bits per second (one gigabit). Gigabit Ethernet is defined in the IEEE 802.3 standard and is currently being used as the backbone in many enterprise networks.

Gigabit Ethernet is carried primarily on optical fiber (with very short distances possible on copper media). Existing Ethernet LANs with 10 and 100 Mbps cards can feed into a Gigabit Ethernet backbone. An alternative technology that competes with Gigabit Ethernet is ATM. A newer standard, 10-Gigabit Ethernet, is also becoming available.

Advanced networking

Simple switched Ethernet networks, while a great improvement over repeater-based Ethernet, suffer from single points of failure, attacks that trick switches or hosts into sending data to a machine even if it is not intended for it, scalability and security issues with regard to broadcast radiation and multicast traffic, and bandwidth choke points where a lot of traffic is forced down a single link.

Bridging and switching

What Are Bridges and Switches?

Bridges and switches are data communications devices that operate principally at Layer 2 of the OSI reference model. As such, they are widely referred to as data link layer devices.
Bridges became commercially available in the early 1980s. At the time of their introduction, bridges connected and enabled packet forwarding between homogeneous networks. More recently, bridging between different networks has also been defined and standardized.

Ethernet frame

A data packet on an Ethernet link is called an Ethernet frame. A frame begins with preamble and start frame delimiter. Following which, each Ethernet frame continues with an Ethernet header featuring destination and source MAC addresses. The middle section of the frame is payload data including any headers for other protocols "Internet Protocol" carried in the frame. The frame ends with a 32-bit cyclic redundancy check which is used to detect any corruption of data in transit. A data packet on the wire is called a frame and consists of binary data. Data on Ethernet is transmitted most-significant byte first, within each byte, however, the least-significant bit is transmitted first.

Ethernet on OSI model

The OSI model is the foundation of modern networking There are 7 layers. Each layer has unique responsibilities among them passing information to the layers above and below it.  The seven layers are: Physical, Data-link, Network, Transport, Session, Presentation and Application.