D316 - Chapter 4

LAN

-Any network where the nodes are within about 1 or 2 km (or about 1 mile) of one another -are based on the 802.3 Ethernet standards maintained by the Institute of Electrical and Electronics Engineers (IEEE).

Enterprise LAN

-Client computers and printers are located in work areas and connected to the network by cabling running through wall conduit. -Laptops and mobile devices connect to the network via wireless access points (APs). -Network servers are separated from client computers in a server room. -Workgroup switches connect each of these blocks to core/distribution switches, routers, and firewalls. -These network appliances allow authorized connections between the clients and servers.

Shielded Twisted Pair (STP)

-Copper twisted-pair cabling with screening and shielding elements for individual wire pairs and/or the whole cable to reduce interference. -provides extra protection against interference -is often used for 10G Ethernet and higher within datacenter networks because it is more reliable than UTP -may also be a requirement in environments with high levels of external interference, such as cable that must be run in proximity to fluorescent lighting, power lines, motors, and generators.

Hub

-Each computer will ignore any frames that do not match its MAC address. However, when lots of computers are in the same collision domain, performance is reduced, as only one computer can send a frame at any one time. -If two computers try to send at the same time, there is a collision, and they must wait for a random period before trying again. The more computers there are, the more collisions. -The computers contend for a share of the media bandwidth and all communications are half-duplex. Half-duplex means that the computer can send or receive, but not at the same time. -As well as the effect of contention on performance, there are no hubs that are compatible with Gigabit Ethernet. These limitations mean that almost all networks are now based on Ethernet switching. -You are only likely to encounter a hub being used in very specific circumstances, such as where legacy equipment must be kept in service.

Managed switches

-Ethernet switch that is configurable via a command-line interface or SDN controller. -will work as an unmanaged switch out-of-the-box, but an administrator can connect to it over a management port, configure security settings, and then choose options for the switch's more advanced functionality -are designed to be bolted into standard network racks. A typical workgroup switch will come with 24 or 48 access ports for client PCs, servers, and printers. These switches have uplink ports allowing them to be connected to other switches. -can be performed over either a web or command line interface

Single-mode fiber (SMF)

-Fiber optic cable type that uses laser diodes and narrow core construction to support high bandwidths over distances of more than five kilometers. -has a small core (8-10 microns) and is designed to carry a long wavelength (1,310 or 1,550 nm) infrared signal, generated by a high-power, highly coherent laser diode. Single-mode cables support data rates up to 10 Gbps or better and cable runs of many kilometers, depending on the quality of the cable and optics.

Multi-mode Fiber. (MMF)

-Fiber optic cable type using LED or vertical cavity surface emitting laser optics and graded using optical multimode types for core size and bandwidth. -has a larger core (62.5 or 50 microns) and is designed to carry a shorter wavelength infrared light (850 nm or 1,300 nm). MMF uses less expensive and less coherent LEDs or vertical cavity surface emitting lasers (VCSELs) and consequently is less expensive to deploy than SMF. However, MMF does not support such high signaling speeds or long distances as single-mode and so is more suitable for LANs than WANs.

Network tap

-Hardware device inserted into a cable run to copy frames for analysis. Taps are either powered or unpowered: -A passive test access point (TAP) is a box with ports for incoming and outgoing network cabling and an inductor or optical splitter that physically copies the signal from the cabling to a monitor port. No logic decisions are made, so the monitor port receives every frame—corrupt or malformed or not—and the copying is unaffected by load. -An active TAP is a powered device that performs signal regeneration, which may be necessary in some circumstances. Gigabit signaling over copper wire is too complex for a passive tap to monitor, and some types of fiber links may be adversely affected by optical splitting. Because it performs an active function, the TAP becomes a point of failure for the links during power loss.

A hub

-Layer 1 (Physical) network device used to implement a star network topology on legacy Ethernet networks, working as a multiport repeater. -is a legacy network hardware device that was used to implement the 10BASE-T and 100BASE-T Ethernet cabling designs. This design is referred to as a "star topology" because each end system is cabled to a concentrator (the hub). -has a number of ports—typically between four and 48—and each computer is cabled to one port -The circuitry in the hub repeats an incoming transmission from a computer attached to one port across all the other ports. In effect, the computers seem to be attached to the same cable. Each computer attached to a hub receives all the traffic sent by other connected devices. This is referred to as a "collision domain."

Unshielded Twisted Pair (UTP)

-Media type that uses copper conductors arranged in pairs that are twisted to reduce interference. Typically, cables are 4-pair or 2-pair. -is made up of four copper conductor wire pairs. Each pair of insulated conductors is twisted at a different rate from the other pairs, which reduces interference. -the electrical signals sent over each pair are balanced. This means that each wire carries an equal but opposite signal to its pair. This is another factor helping to identify the signal more strongly against any source of interference. However, the electrical signaling method is still only reliable over limited range. The signal suffers from attenuation, meaning that it loses strength over long ranges. Most UTP cable segments have a maximum recommended distance of 100 m (328 feet).

Coaxial Cable

-Media type using two separate conductors that share a common axis categorized using the Radio Grade (RG) specifications. -is a different type of copper cabling, also carrying electrical signals. Where twisted pair uses balancing to cancel out interference, coax uses two conductors that share the same axis. The core signal conductor is enclosed by plastic insulation (dielectric), and then a second wire mesh conductor serves both as shielding from EMI and as a ground.

SAN

-Network dedicated to provisioning storage resources, typically consisting of storage devices and servers connected to switches via host bus adapters. -is isolated from the main network. It is only accessed by servers, not by client PCs and laptops -SAN clients are servers running databases or applications -Provisioning a shared storage pool as a SAN is more flexible and reliable than using local disks on each server machine -use connectivity technologies such as Fiber Channel and Internet SCSI (iSCSI).

Direct Burial

-Outside plant (OSP) is cable run on the external walls of a building or between two buildings. This makes the cable vulnerable to different types of weathering: --Aerial cable is typically strung between two poles or anchors. The ultraviolet (UV) rays in sunlight plus exposure to more extreme and changing temperatures and damp conditions will degrade regular PVC. --Conduit can provide more protection for buried cable runs. Such cable can still be exposed to extreme temperatures and damp conditions, however, so regular PVC cable should not be used. --Direct burial cable is laid and then covered in earth or cement/concrete.

The IEEE 802.3 standards

-are designated x BASE- Y , where x is the nominal data rate and Y is the cable type. For example: --100BASE-T refers to Fast Ethernet over copper twisted pair cabling. Fast Ethernet works at 100 Mbps. --1000BASE-T refers to Gigabit Ethernet over copper twisted pair cabling. Gigabit Ethernet works at 1000 Mbps (or 1 Gbps). --1000BASE-T is the mainstream choice of standard for most LANs. --10GBASE-T refers to a copper cabling standard working at 10 Gbps.

Copper wire

-carries electrical signals, which are sensitive to interference and attenuation. The light pulses generated by lasers and LEDs are not susceptible to interference and suffer less from attenuation. Consequently, optical cabling can support much higher bandwidth links, measured in multiple gigabits or terabits per second, and longer cable runs, measured in miles rather than feet.

MAC address

-consists of 48 binary digits, making it six bytes in size. -is typically represented as 12 digits of hexadecimal. Hex is a numbering system often used to represent network addresses of different types. A hex digit can be one of sixteen values: 0-9 and then A, B, C, D, E, F. Each hex digit represents half a byte (or four bits or a nibble). The 12 digits of a MAC address might be written with colon or hyphen separators or no separators at all—for example, 00:60:8c:12:3a:bc or 00608c123abc .

The TIA/EIA-568 standard

-defines two methods for terminating twisted pair: T568A/T568B. -In T568A, pin 1 is wired to green/white, pin 2 is wired to green, pin 3 is wired to orange/white, and pin 6 is wired to orange. -In T568B, the position of the green and orange pairs is swapped over, so that orange terminates to 1 and 2 and green to 3 and 6. -When cabling a network, it is best to use the same termination method consistently. A straight through Ethernet cable is wired with the same type of termination at both ends. -Using T568A at one end and T568B at the other creates a crossover cable. Crossover cables were once used to connect computers directly, but Gigabit Ethernet interfaces can perform the crossover automatically, even if standard cable is used.

The nominal indoor range for Wi-Fi is

-is 45 m (150 feet) over 2.4 GHz and 30 m (100 feet) over 5 GHz. -Depending on the wireless standard used, building features that may block the signal, and interference from other radio sources, clients are only likely to connect at full speed from a third to a half of those distances.

PoE

-is a means of supplying electrical power from a switch port over ordinary data cabling to a powered device (PD), such as a voice over IP (VoIP) handset, camera, or wireless access point. PoE is defined in several IEEE standards: -802.3af allows powered devices to draw up to about 13 W. Power is supplied as 350mA@48V and limited to 15.4 W, but the voltage drop over the maximum 100m (328 feet) of cable results in usable power of around 13 W. -802.3at (PoE+) allows powered devices to draw up to about 25 W, with a maximum current of 600 mA. -802.3bt (PoE++ or 4PPoE) supplies up to about 51 W (Type 3) or 73 W (Type 4) usable power.

A Cat specification

-is a particular twisted pair cable construction method rated for use with given Ethernet standards -Higher Cat specification cable is capable of higher data rates. Cat specifications are defined in the TIA/EIA-568-C Commercial Building Telecommunications Cabling Standards.

plenum space

-is a void in a building designed to carry heating, ventilation, and air conditioning (HVAC) systems -is typically a false ceiling, though it could also be constructed as a raised floor. As it makes installation simpler, this space has also been used for communications wiring in some building designs. -is an effective conduit for fire, as there is plenty of airflow and no fire breaks. -If the plenum space is used for heating, there may also be higher temperatures. Therefore, building regulations require the use of fire-retardant plenum cable in such spaces. -Plenum cable must not emit large amounts of smoke when burned, be self-extinguishing, and meet other strict fire safety standards.

Fiber optic cable

-is contained in a protective jacket and terminated by a connector. -Network cable type that uses light signals as the basis for data transmission. Infrared light pulses are transmitted down the glass core of the fiber. The cladding that surrounds this core reflects light back to ensure transmission efficiency. Two main categories of fiber are available; multi-mode, which uses cheaper, shorter wavelength LEDs or VCSEL diodes, or single-mode, which uses more expensive, longer wavelength laser diodes. At the receiving end of the cable, light-sensitive diodes re-convert the light pulse into an electrical signal. Fiber optic cable is immune to eavesdropping and EMI, has low attenuation, supports rates of 10 Gb/s+, and is light and compact.

Data cable for a typical office

-is installed as a structured cabling system. With structured cabling, the network adapter port in each computer is connected to a wall port using a flexible patch cord. Behind the wall port, permanent cable is run through the wall and ceiling to an equipment room and connected to a patch panel. The port on the patch panel is then connected to a port on an Ethernet switch. -A structured cabling system uses two types of cable termination: --Patch cords are terminated using RJ45 plugs crimped to the end of the cable. --Permanent cable is terminated to wall ports and patch panels using insulation displacement connectors (IDC), also referred to as "punchdown blocks." -The 100 m distance limitation is for the whole link, referred to as "channel link." Each patch cord can only be up to 5 m long. Permanent link uses solid cable with thicker wires. Patch cords use stranded cable with thinner wires that are more flexible but also suffer more from attenuation.

Cat specification

-is printed on the cable jacket along with the cable type (UTP or F/UTP, for instance). Cat 5 cable supports the older 100 Mbps Fast Ethernet standard. It is no longer commercially available. A network cabled with Cat 5 will probably need to be rewired to support Gigabit Ethernet.

PoE enabled switch

-is referred to as endspan power sourcing equipment (PSE). -When a device is connected to a port on a PoE switch, the switch goes through a detection phase to determine whether the device is PoE enabled. --If so, it determines the device's power consumption and sets an appropriate supply voltage level. --If not, it does not supply power over the port and, therefore, does not damage non-PoE devices.

Infrastructure mode

-means that each client device (station) is configured to connect to the network via an access point (AP). In 802.11 documentation, this is referred to as an infrastructure "Basic Service Set" (BSS). The MAC address of the AP's radio is used as the Basic Service Set Identifier (BSSID).

The screening/shielding elements of shielded cable

-must be bonded to the connector to prevent the metal from acting as a large antenna and generating interference. -Modern F/UTP and S/FTP solutions (using appropriate cable, connectors, and patch panels) facilitate this by incorporating bonding within the design of each element.

Unmanaged switches

-performs its function without requiring any sort of configuration. You just power it on and connect some hosts to it, and it establishes Ethernet connectivity between the network interfaces without any more intervention. -You might find unmanaged switches with four or eight ports used in small networks. There is an unmanaged four-port switch embedded in most of the SOHO router/modems supplied by Internet Service Providers (ISPs) to connect to their networks.

Ethernet Switches

-solution to hub collisions -like a hub, this provisions one port for each device that needs to connect to the network -unlike a hub, it can decode each frame and identify the source and destination MAC addresses. It can track which MAC source addresses are associated with each port. When it receives an incoming frame, the switch intelligently forwards it to the port that is a match for the destination MAC address.

WLAN

-uses radios and antennas for data transmission and reception -are based on the IEEE 802.11 series of standards. IEEE 802.11 is better known by its brand name, Wi-Fi

Most networks distinguish between two basic roles for the computers:

1. A server computer is dedicated to running network applications and hosting shared resources. 2. A client computer allows end users to access the applications and resources to do work.

It is important to understand the performance characteristics of the two main frequency bands used by the IEEE 802.11 standards:

2.4ghz and 5ghz

You need to connect a permanent cable to the back of a patch panel. Which networking tools might help you?

A cable stripper to remove the jacket insulation and a punchdown tool to terminate the wire pairs into insulation displacement connector (IDC) blocks.

Injector

A device that can supply Power over Ethernet (PoE) if the Ethernet switch ports do not support it.

You are performing a wiring job, but the company wants to purchase the media and components from another preferred supplier. The plan is to install a network using copper cabling that will support Gigabit Ethernet. The customer is about to purchase Cat 5e cable spools. What factors should they consider before committing to this decision?

Cat5e will meet the requirement and will cost the least. Cat 6 offers better performance without adding too much cost. Cat 6A would be the best choice for supporting future requirements, but it is likely to cost more than the customer is budgeting for.

Most Wi-Fi networks are configured in what is technically referred to as

Infrastructure mode

structured cabling

Installing cable in this type of system involves the use of cable strippers, punchdown tools, and crimpers.

Each Ethernet NIC port has a unique hardware/physical address

MAC address

Basic Service Set Identifier (BSSID)

MAC address of an access point supporting a basic service area.

Larger workgroups and corporate networks require additional functionality in their switches. Switches designed for larger LANs are

Managed switches

Twisted pair cable

Network cable construction with insulated copper wires twisted about each other. A pair of color-coded wires transmits a balanced electrical signal. The twisting of the wire pairs at different rates acts to reduce interference and crosstalk.

You are planning to install a network of wireless access points with power supplied over data cabling. Each access point requires a 20W power supply. What version of PoE must the switch support to fulfill this requirement?

PoE+ (802.3at) or PoE++/4PPoE (802.3bt).

Frequency bands

Portion of the microwave radio-frequency spectrum in which wireless products operate, such as 2.4 GHz band or 5 GHz band.

Fiber optic cables fall into two broad categories

Single mode and multi mode

Power over Ethernet (PoE)

Specification allowing power to be supplied via switch ports and ordinary data cabling to devices such as VoIP handsets and wireless access points. Devices can draw up to about 13 W (or 25 W for PoE+).

Which fiber optic connector uses a small form factor design?

The Lucent Connector (LC).

You are reviewing network inventory and come across an undocumented cable reel with "CMP/MMP" marked on the jacket. What installation type is this cable most suitable for?

The cable is plenum cable, rated for use in plenum spaces (building voids used with HVAC systems).

Modular switch

These provide a power supply and fast communications backplane to interconnect multiple switch units. This enables the provisioning of hundreds of access ports via a single compact appliance.

Cable tester

Two-part tool used to test successful termination of copper cable by attaching to each end of a cable and energizing each wire conductor in turn with an LED to indicate an end-to-end connection.

Patch panel

Type of distribution frame used with twisted pair cabling with IDCs to terminate fixed cabling on one side and modular jacks to make cross-connections to other equipment on the other. -The cables running through the walls are terminated to insulation displacement connector (IDC) punchdown blocks at the back of the panel. -The other side of the patch panel has prewired RJ45 ports. A patch cord is used to connect a port on the patch panel to a port on an Ethernet switch. This cabling design makes it easier to change how any given wall port location is connected to the network via switch ports

Patch cord

Type of flexible network cable typically terminated with RJ45 connectors. Ethernet patch cords cannot be longer than five meters.

Permanent Cable

Type of solid network cable typically terminated to punchdown blocks that is run through wall and ceiling spaces.

A workstation must be provisioned with a 4 Gbps network link. Is it possible to specify a single NIC to meet this requirement?

Yes. On an NIC with 4 gigabit Ethernet ports, the ports can be bonded to establish a 4 Gbps link.

A network consultant is recommending the use of S/FTP to extend a cable segment through a factory. Is this likely to be an appropriate cable choice?

Yes. Shielded/foiled twisted pair (S/FTP) will provide the best protection from the external interference sources likely to be generated by factory machinery.

You are completing a network installation as part of a team. Another group has cabled wall ports to a patch panel. Is any additional infrastructure required?

Yes. The patch panel terminates cabling, but it does not establish any connections between the cable segments. You must install a networking appliance to act as a concentrator and connect the cable segments. On modern networks, this means installing a switch and cabling it to the patch panel ports using RJ45 patch cords.

If a switch does not support PoE

a device called a "power injector " (or "midspan") can be used. One port on the injector is connected to the switch port. The other port is connected to the device. The overall cable length cannot exceed 100m.

To terminate cable

a small section of outer jacket must be removed to expose the wire pairs. This must be done without damaging the insulation on the inner wire pairs. A cable stripper is designed to score the outer jacket just enough to allow it to be removed. Set the stripper to the correct diameter, and then place the cable in the stripper and rotate the tool once or twice. The score cut in the insulation should now allow you to remove the section of jacket.

Within an enterprise LAN or datacenter

a storage area network (SAN) provisions access to a configurable pool of storage devices that can be used by application servers.

Regulatory impacts

also include a limit on power output, constraining the range of Wi-Fi devices. Devices operating in the 5 GHz band must implement dynamic frequency selection (DFS) to prevent Wi-Fi signals from interfering with nearby radar and satellite installations.

RJ45 connectors

are also referred to as "8P8C," standing for eight-position/eight-contact. Each conductor in four-pair Ethernet cable is color-coded. Each pair is assigned a color (orange, green, blue, and brown). The first conductor in each pair has a predominantly white insulator with stripes of the color; the second conductor has an insulator with the solid color.

Network sniffing

can also be facilitated using a switched port analyzer (SPAN)/mirror port. This means that the sensor is attached to a specially configured port on a network switch. The mirror port receives copies of frames addressed to nominated access ports (or all the other ports).

Twisted-pair

can also be used with RJ11 connectors. Unlike the four-pair cable used with Ethernet, RJ11 is typically used to terminate two-pair cable, which is widely used in telephone systems and with broadband digital subscriber line (DSL) modems.

Shielded Twisted Pair

can be referred to generically as "STP," but several types of shielding and screening exist: 1. Screened cable has one thin outer foil shield around all pairs. Screened cable is usually designated as screened twisted pair (ScTP) or foiled/unshielded twisted pair (F/UTP), or sometimes just foiled twisted pair (FTP). 2. Fully shielded cabling has a braided outer screen and foil-shielded pairs and is referred to as "shielded/foiled twisted pair" (S/FTP). There are also variants with a foil outer shield (F/FTP).

Twisted pair cabling for Ethernet

can be terminated using modular RJ45 connectors

An access point

can establish a wireless-only network, but it can also work as a bridge to forward communications between the wireless stations and a wired network. The wired network is referred to as the "distribution system" (DS). The access point will be joined to the network in much the same way as a host computer is—via a wall port and cabling to an Ethernet switch. An enterprise network is likely to use Power over Ethernet (PoE) to power the AP over the data cabling

An optical fiber

consists of an ultra-fine core of glass to convey the light pulses. The core is surrounded by glass or plastic cladding, which guides the light pulses along the core. The cladding has a protective coating called the "buffer."

Switch operation

each switch port is a separate collision domain, and the negative effects of contention are eliminated. Each computer has a full duplex connection to the network and can send and receive simultaneously at the full speed supported by the network cabling and NIC. -when a computer sends a frame, the switch reads the source address and adds it to its MAC address table. If a destination MAC address is not yet known, the switch floods the frame out of all ports.

Patch cords

for fiber optic can come with the same connector on each end (ST-ST, for instance) or a mix of connectors (ST-SC, for instance). Fiber optic connectors are quite easy to damage and should not be repeatedly plugged in and unplugged. Unused ports and connectors should be covered by a dust cap to minimize the risk of contamination.

Subscriber Connector (SC)

has a push/pull design that allows for simpler insertion and removal than fiber channel (FC) connector. There are simplex and duplex versions, though the duplex version is just two connectors clipped together. It can be used for single- or multi-mode.

A solution to the issue of collisions was first provided by

inserting Ethernet bridges between hubs to break up collision domains. Ethernet bridges were quickly refined into the Ethernet switch appliances that underpin almost all modern office networks.

Straight Tip (ST)

is a bayonet-style connector that uses a push-and-twist locking mechanism; it is used mostly on older multi-mode networks.

SOHO LAN

is a business-oriented network possibly using a centralized server, in addition to client devices and printers, but often using a single networking appliance to provide LAN and Internet connectivity. This is often referred to as a "SOHO router," "Internet router," or "broadband router."

The core of a fiber-optic connector

is a ceramic or plastic ferrule that ensures continuous reception of the light signals. -Several connector form factors are available: straight tip, subscriber connector, and Lucent connector

Lucent Connector (LC)

is a small form factor connector with a tabbed push/pull design. LC is similar to SC, but the smaller size allows for higher port density.

2.4GHz standard

is better at propagating through solid surfaces, giving it the longest signal range. However, the 2.4 GHz band does not support a high number of individual channels and is often congested, with both other Wi-Fi networks and other types of wireless technology, such as Bluetooth®. Also, microwave ovens work at frequencies in the 2.4 GHz band. Consequently, with the 2.4 GHz band, there is increased risk of interference, and the maximum achievable data rates are typically lower than with 5 GHz.

5 GHz standard

is less effective at penetrating solid surfaces and so does not support the maximum ranges achieved with 2.4 GHz standards, but the band supports more individual channels and suffers less from congestion and interference, meaning it supports higher data rates at shorter ranges.

Powering powered devices through a switch

is more efficient than using a wall-socket AC adapter for each appliance. It also allows network management software to control the devices and apply energy-saving schemes, such as making unused devices go into sleep states and power capping.

Detailed layers of a coaxial cable.

is now mostly used for CCTV installations and as patch cable for Cable Access TV (CATV) and broadband cable modems. Coax for CATV installations is typically terminated using a screw-down F-type connector.

loopback plug

is used to test a NIC or switch port. You can make a basic loopback plug from a 6" cable stub where the wires connect pin 1 to pin 3 and pin 2 to pin 6. When you connect a loopback plug to a port, you should see a solid link LED showing that the port can send and receive. -A loopback plug made from a cable stub is unlikely to work with Gigabit Ethernet ports. You can obtain manufactured Gigabit port loopback testers.

The most popular type of network cable is

of a copper wire construction called " unshielded twisted pair" (UTP) .

100BASE-T

refers to Fast Ethernet over copper twisted pair cabling. Fast Ethernet works at 100 Mbps.

1000BASE-T

refers to Gigabit Ethernet over copper twisted pair cabling. Gigabit Ethernet works at 1000 Mbps (or 1 Gbps). - is the mainstream choice of standard for most LANs.

10GBASE-T

refers to a copper cabling standard working at 10 Gbps.

Cat 6A

supports 10 Gbps over 100 m, but the cable is bulkier and heavier than Cat 5e and Cat 6, and the installation requirements more stringent, so fitting it within pathways designed for older cable can be problematic. TIA/EIA standards recommend Cat 6A for health care facilities, with Power over Ethernet (PoE) 802.3bt installations, and for running distribution system cable to wireless access points.

On some older SOHO routers, the LAN interfaces are implemented as a hub. These do not support 1 Gbps operation.

true

Most private or enterprise WANs

use cabling and equipment leased from an ISP to interconnect two or more LAN sites. For example, a company might use a WAN to connect branch office sites to the LAN at its head office.

Outside plant (OSP) cable types

use special coatings to protect against UV and abrasion and are often gel filled to protect against temperature extremes and damp conditions. Direct burial cable may also need to be armored to protect against chewing by rodents.

General purpose (non-plenum) cabling

uses PVC jackets and insulation. Plenum-rated cable uses treated PVC or fluorinated ethylene polymer (FEP). This can make the cable less flexible, but the different materials used have no effect on bandwidth. Data cable rated for plenum use under the US National Electrical Code (NEC) is marked as CMP or MMP on the jacket. General-purpose cables are marked as CMG or MMG for PVC jackets, and CM or MP for plenum-rated cables.

Copper cabling

uses electrical signaling to communicate data. Other types of Ethernet work over fiber optic cabling. Fiber uses pulses of light to communicate data.

Fiber cabling

uses pulses of light to communicate data.

The IEEE 802.11a standard

uses the 5 GHz frequency band only. The data encoding method allows a maximum data rate of 54 Mbps. The 5 GHz band is subdivided into 23 non-overlapping channels, each of which is 20 MHz wide.

Cat 5e

would still be an acceptable choice for providing Gigabit Ethernet links for client computers, but most sites would now opt to install Cat 6 cable. The improved construction standards for Cat 6 mean that it is more reliable than Cat 5e for Gigabit Ethernet, and it can also support 10 Gbps, though over reduced range.