Lesson 4C

10 Gigabit Ethernet (10GbE)

10 Gigabit Ethernet is currently the highest speed at which Ethernet operates. It can achieve speeds of 10 Gbps, which is 10 times faster than Gigabit Ethernet.

Broadcast MAC Address

A MAC address in which all bits are set to 1 (FF:FF:FF:FF:FF:FF). Broadcast messaging, in which one host sends messages to all other hosts at the same time, is accomplished using a broadcast MAC address composed of all Fs. Each F in the hexadecimal notation represents four ones (1s) in the binary address.

Power over Ethernet (PoE)

A wired networking standard that allows electrical power to be sent along with data over standard Ethernet cables uses the IEEE 802.3af standard for transferring both electrical power and data to remote devices over twisted-pair cable in an Ethernet network. This technology allows you to place devices such as network switches, Voice over IP (VoIP) phones, wireless access points, and cameras in locations where it would be inconvenient or impossible to run electrical power for the device. PoE provides up to 15.4 W of power and requires CAT5 or higher copper cable.

802.3

An IEEE specifications and standards for Ethernet implementations.

Functions of an Ethernet transceiver

Converting digital data to optical or vice versa

Functions of an Ethernet transceiver

Detecting collisions

MAU Media Access Unit

Ethernet transceivers are sometimes referred to as media access units (MAUs)

Fast Ethernet

Ethernet technology that can transmit data at speeds of 100 Mbps. It can use either coaxial cables or optical fibers. It is used as a backbone network to interconnect several LANs.

802.1x

IEEE standard That provides a framework to make wireless networks more secure. It makes use of existing protocols that enable the user to be authenticated by a central authority.

802.11

IEEE standard that describes Layer 1 and Layer 2 specifications for wireless LANs in the 2.4-, 3.6- , 5-, and 60-GHz frequency bands. Numerous amendments to the standards have been adopted as Wi-Fi technology has evolved.

802.3af

IEEE standard that describes Power over Ethernet (PoE) technology, which enables networks to deliver electrical power and standard data over Ethernet cabling. Up to 15.4 W of DC power can be supplied to each powered device, with 12.95 W being ensured to the powered device due to power dissipation during delivery.

802.1q

IEEE standard that is used to support Ethernet-based virtual LANs. It specifies how Ethernet frames are tagged for handling over the network

Switched Ethernet

Modern Ethernet where there are one or more direct point-to-point connections between hosts or network segments. The switch enables each device to use the full bandwidth of the medium. In switched Ethernet, switches read the destination Layer 2 (MAC) address and forward the frame only to the destination node. A 24-port switch can, in theory, handle 12 pairs of conversations simultaneously.

What mode network adapters operate in

Most network adapters can operate in full duplex or half duplex mode

OUI aka Block ID

Organizationally Unique Identifier in MAC address - the first three bytes

Source Address (SA)

Part Ethernet Frame, (6 bytes) This is the MAC address of the computer transmitting data—the SA is always a unicast address

Frame Type

Part of Ethernet Frame, (2 bytes) This is the length of the entire Ethernet frame in bytes, or the frame type ID of the frame. This field can hold a value between 0 and 65,534, but the maximum value is usually less than 1,500

Preamble PRE

Part of Ethernet frame that (7 bytes) A pattern of ones and zeros used to signal the start of the frame and provide synchronization and timing information. The preamble notifies all nodes that there is data to follow.

Start Frame Delimiter (SFD)

Part of Ethernet frame, (1 byte) The SFD identifies the beginning of the data field

Frame Check Sequence (FCS)

Part of Ethernet frame, (4 bytes) The FCS checks the frame by using a 32-bit cyclic redundancy check (CRC) value. The FCS allows the receiving device to detect errors in the Ethernet frame and reject it if it appears damaged.

Destination Address (DA)

Part of Ethernet frame, (6 bytes) This is the MAC address of the computer to which the frame is being transmitted; it can be a unicast, multicast, or broadcast address

Ethernet Data

Part of Ethernet frame, (n bytes) The payload of the frame (or the information being sent). It must be a minimum of 46 bytes long and can be a maximum of 1,500 bytes. If the length of data is less than 46 bytes, the data field must be extended by adding a filler to increase the length to a minimum of 46 bytes.

Functions of an Ethernet transceiver

Processing on the Ethernet interface

Functions of an Ethernet transceiver

Providing network access

MAC address

The first 3 bytes uniquely identify the manufacturer and are referred to as the organizationally unique identifier (OUI).

MAC address

The remaining 3 bytes identify the device itself and are known as the Universal LAN MAC address. MAC addresses can be assigned manually.

Network adapters auto negotiate feature

There is also an auto negotiation feature, where devices perform self-configuration to achieve the best possible mode of operation across a link. In many cases, the network adapter is configured to use auto negotiation by default, but there are times when this is not the optimal configuration. If a network adapter is set to auto negotiate duplex, and it is connected to a full duplex-only switch or router, the auto-negotiate port will negotiate to half duplex because the full duplex port does not send any negotiation signals. This will cause a duplex mismatch, which can severely affect performance.

Network Adapters

They can be built into the motherboard of a computer or other network device, installed in an expansion slot on the motherboard, or externally connected through a USB port.

Full duplex network adapter

While an eight-port 100-MB switch in full duplex mode can theoretically carry 1,600 MB of data, in reality only high-end switches can deliver full throughput.

Gigabit Ethernet

an Ethernet technology that can transmit data at speeds of 1,000 Mbps and primarily uses optical fibers for transmission. It can be used for distances ranging from 500 to 5,000 meters depending on the type of optical fiber used. The hardware required for Gigabit Ethernet is very expensive when compared with other types of Ethernet.

Ethernet frame

data packet that has been encoded at the Data Link layer (Layer 2) for transmission from one node to another on an Ethernet network. The basic Ethernet frame contains seven fields.

Transceiver

device that has both a transmitter and a receiver integrated into it and, as a result, can both send and receive data. On Ethernet networks, most modern transceivers are built into the network adapter, but you might find external transceivers in use. In networking, the transceiver supports the network adapter in allowing data transmission through the medium.

Network Adapter aka Network Interface Card (NIC)

device that serves as an interface between a network node and the network. To connect to a network, whether wired or wireless, a node must have a network adapter installed

Full duplex network adapter

enables a device to send and receive data simultaneously using separate channels or wire pairs for transmitting and receiving. If the network adapter is connected to a switch that is also in full duplex mode, it can transmit and receive at maximum speed. This means that a 100-MB full duplex connection can carry 200 MB of data at any time. In addition, because a switch forms a miniature network between a node and itself (with no other nodes involved), there is no chance of data collision.

802.x Standards

family of networking standards developed by the IEEE in 1980 to address the rapid developments in networking technology. The 802.x standards are divided into subcategories to address different networking requireme

Network adapters LED lights

green and amber, indicating connectivity and activity, respectively. When the green light is on, the device has network connectivity; a flashing green light means intermittent connectivity. The activity light flickers when data is being transferred through the interface, but constant flickering might indicate a busy network or a problem that should be investigated. Dual-speed NICs might also have a speed light to show at which speed the NIC is transferring data.

Half duplex network adapter

half duplex network adapter can send or receive data, but not both, at any one time

802.3at

iEEE standard which Is an update to 802.3af and describes Power over Ethernet Plus (PoE+) technology, which enables networks to deliver electrical power and standard data over Ethernet cabling. With PoE+, up to 30 W of power can be supplied to each powered device, with 25.5 W being assured to the powered device.

MAC Address

physical address, is a unique, hardware-level address assigned to every networking device by its manufacturer.

Power over Ethernet (PoE) +

provides up to 25.5 W of power per port and is backward compatible with all existing IEEE 802.3af devices. PoE+ allows for a broader range of devices to be powered such as: • Cameras with pan/tilt/zoom capabilities • Door controllers • Point-of-sale terminals

Ethernet

set of networking technologies and media access methods specified for LANs. IEEE has defined the 802.3 specifications and standards for Ethernet implementations. Ethernet enables computers to communicate over small distances using a wired medium. Ethernet has evolved as the most widespread technology for wired LANs. Most Ethernet networks use twisted pair cables at the access layer (where computers plug in) and either high-speed twisted pair or fiber optic cable for the network backbone. In today's networks, we tend to associate Ethernet only with Layer 2, because Ethernet can now be carried on a variety of physical media and is not restricted to only thick or thin coaxial cable.

MAC address

use the hexadecimal numeral system.