Backbone cabling consists of the backbonecables, intermediate and main cross-connects, mechanicalterminations, and patch cords or jumpers used forbackbone-to-backbone cross-connection. Backbonecabling also includes cabling betweenbuildings.”
To make sure every MAC addresses is unique, thefirst 24 bits of the address identify the NIC'smanufacturer. Manufacturer's are assigned thesenumbers, called an Organizationally Unique Identifier (OUI),by the Institute of Electrical and Electronics Engineers(IEEE).
A collision is the situation that occurswhen two or more devices attempt to send a signal along the sametransmission channel at the same time. In ethernet networks, thedominant type of local area network (LAN), collisionsoccur when two nodes attempt to send packetssimultaneously.
Minimizing cable clutter can also help preventairflow blockages. In a typical rack system, airflow throughthe chassis is typically designed to move from front toback.
What statement correctly identifies the purpose of asoftware patch? A software patch is a major change to asoftware package that enhances the functionality andfeatures of the software, while also correcting bugs andvulnerabilities.
-A cable bend radius determines the total numberof bends that can exist in an overall cable beforedata is impaired. -A cable bend radius is the radiusof the maximum arc into which you can loop the cable withoutimpairing data.
A rack unit (abbreviated U or RU) is aunit of measure defined as 1 3⁄4 inches(44.45 mm). For example, a typical full-size rack cage is42U high, while equipment is typically 1U, 2U, 3U, or 4Uhigh.
When a piece of equipment is designed to be larger thana single rack unit (1U), it will be referred to as amultiple of rack units and written such s 2U, or 6U.This would mean an 6U server is 10.5″ or 266.7 mm inheight.
A rack unit is a unit of measure used to describethe height of a server, network switch or other similar devicemounted in a 19-inch rack or a 23-inch rack. Onerack unit is 44.45 mm (1.75 in) high. For example, a"4U half-rack" DVCAM deck would occupy 4Uspace (4 × 1.75 inches) height × 9.5 incheswidth.
For electronic equipment racks (e.g., 19 or 23 incheswide), the term 1U is used to define one rack unit of height. To beprecise, 1U equals 1.75-inches (44.45mm) of rack height. Therefore,a 2U rack mount height would be 2 x 1.75”,which equals 3.5-inches high. A 3U height would be 3 x1.75” = 5.25-inches.
Define: Rack Unit “U” or“RU” This three hole group is defined as a RackUnit (RU) or sometimes just call a “U”. 1Uoccupies 1.75″ (44.45 mm) of vertical space. Manufacturers ofrackmount equipment make their product lines based upon how manyRUs that the equipment occupies in the serverrack.
42U Racks: 42U Server Racks are the mostcommon rack height sold for data centers. 42U = 42Rack Units on your Mounting Rails = 73.5" of rackmount space available.
A data center rack is a type of physical steeland electronic framework that is designed to house servers,networking devices, cables and other data center computingequipment. This physical structure provides equipment placement andorchestration within a data center facility.
The Standard Rack Unit
This size of each server is called a U or a RU(Unit or Rack Unit). For the sake of standardization,the size of a single U or RU is 1.75 inches in height (44.45mm).A rack server, also called a rack-mountedserver, is a computer dedicated to use as a serverand designed to be installed in a framework called a rack.The rack contains multiple mounting slots called bays, eachdesigned to hold a hardware unit secured in place withscrews.
A network interface card (NIC) is ahardware component, typically a circuit board or chip, which isinstalled on a computer so that it can connect to a network. TheNIC uses the OSI model to send signals at the physicallayer, transmit data packets at the network layer andoperate as an interface at the TCP/IP layer.
An Ethernet switch operates at the data linklayer (layer 2) of the OSI model to create a separatecollision domain for each switch port.
The Open Systems Interconnection model (OSImodel) is a conceptual model that characterizes andstandardizes the communication functions of a telecommunication orcomputing system without regard to its underlying internalstructure and technology. The model partitions acommunication system into abstraction layers.
The TCP/IP model consists of fivelayers: the application layer, transportlayer, network layer, data link layer andphysical layer.
How does the NIC (network interface card)work? A computer's network card works by taking thedata given to it by the CPU and sending it to a destination. Ittranslates the data into a form that can be transferred via cablesand then translates the data it receives back into data usable bythe computer.
SSL or TLS encryption takes place at thepresentation layer, Layer 6 of the OSI model.In this tip, learn why encryption is so important and howcertain hacker attacks can still circumvent SSL or TLS and threatenyour networks. Layer 6 of the OSI model is thepresentation layer.
The OSI Model and NetworkingProtocols
Network devices that operate at thislayer include Layer 2 switches (switching hubs) andbridges. It is responsible for moving data packets from onenetwork interface card (NIC) to another, across a sharedtransmission medium. Physical addressing is handled at the MACsublayer.It consists of the cabling (cable,connectors and network interface cards). The PHY refers toanything relating to the hardware that sends and receives data.Network protocols have physical layer components likeEthernet operating over twisted pair or fiber opticcabling or wireless links.
The so-called "official" internet standard MTU is576, but the standard rating for Ethernet is an MTUof 1500.
