General Questions Part 2 Flashcards
RJ-11 Connector
Registered Jack 11 - 6 position, 2 conductor cable (6P2C) - This is the standard telephone cable used in households.
RJ-45 Connector
Registered Jack 45 - 8 position, 8 conductor cable (8P8C) - This is the standard Ethernet cable.
BNC Connector
Bayonet Neill-Concelman - Coaxial cable connector, used in DS3 WAN links. The cable is often rigid and bulky.
DB-9, DB-25 Connector
D-Sub-miniature or D-Sub - These cable connectors range in size from 9 pins all the way to 50 pins on a single connector end. Ranges from A to E and each connector in the range has a different pin number, often used on older hardware such as modems, printers, and other peripherals.
F-Connector
Standard cable television connector, typically paired with RG-6 coaxial cable.
Fiber Communication
Transmission by light in the visible spectrum. Has no RF signal which makes it very difficult to monitor/tap/listen in on. The signal is slow to degrade and can be sent over miles. No RF interference.
Multi-Mode Fiber
Short-range communications, up to 2 kilometres, inexpensive light source, ie LED.
Single-Mode Fiber
Long-range communications, up to 100 kilometres, expensive light source, ie lasers
UPC (Connector)
Ultra-Polished Connector - Ferrule end-face radius polished at a zero degree angle, high return loss.
APC (Connector)
Angle-Polished Connector - Ferrule end-face radius polished at an eight degree angle, lower return loss.
ST Connector
Straight Tip Connector - half-twist bayonet connector with rounded ends.
SC Connector
Square Connector - round tip that simply uses push and pull force to connect and disconnect connector.
LC Connector
Lucent Connector - this is a smaller square connector that often has a tab that can be pressed down much like the RJ-45 to ensure a secure connection.
MT-RJ
Mechanical Transfer Register Jack - A connector for two fibers in a very small form factor.
T568A
Wiring Standard color code used for wiring eight-position RJ-45 modular plugs. Provides backward compatibility to both one pair and two pair USOC wiring schemes. A is more common in Europe. Cable end:
White-Green Green White-Orange Blue White-Blue Orange White-Brown Brown
T568B
Wiring Standard color code used for wiring eight-position RJ-45 modular plugs. Provides backward compatibility to only one pair of the USOC wiring schemes. B is more common in the USA. Cable end:
White-Orange Orange White-Green Blue White-Blue Green White-Brown Brown
Straight-through cable
A cable that has both modular plugs on the ends with the same pin-outs. Also called patch cables. Pin 1 matches to pin 1, pin 2 matches to pin 2, etc.
Cross-over cable
A cable that has different modular plug pin-outs on each end of the cable. Used when connecting a workstation to a workstation or a switch to a switch. Many devices these days do not need a cross-over cable to connect the devices, instead they use Auto-MDI-X which can automatically detect when to use a straight-through cable vs. a cross-over cable.
Cable Infrastructure
Wire that runs from workstations to patch panels in networking closets. Patch panels then run cable to switches.
66 Block
A type of punchdown block used to connect sets of wires in a telephone system. Used more often for analog voice, but can also be used for some digital links. Need to use wire and a punchdown tool to clip wires into block. Punchdown blocks were the predecessor to patch panels.
110 Block
A type of punchdown block used to terminate runs of on-premises wiring in a structured cabling system. The designation 110 is also used to describe a type of insulation displacement contact (IDC) connector used to terminate twisted pair cables. Need to use wire and a punchdown tool to clip wires into block. Punchdown blocks were the predecessor to patch panels.
Copper Patch Panel
Punch-down block on one side, RJ-45 connector on the other.
Fiber Distribution Panel
Permanent fiber installation - Patch panel at both ends. Fiber can’t be bent so you’ll often find soft looping of the fiber cables in the Distribution panel which is called a service loop.
Transceiver
An adapter/converter that is both a transmitter and a receiver. Provides a modular interface so you can add the transceiver that matches your network.
Duplex Communication
Two fibers, one fiber only permits transmits and the other that only permits receives.
Bi-Directional (BiDi) Transceivers
A fiber that allows traffic in both directions over a single fiber (signals use two different wavelengths). Can reduce the number of fiber runs by half.
GBIC (Transceiver)
Gigabit Interface Converter - Relatively early and large devices that support both copper and fiber that is common on Gigabit networks. Standard was effectively replaced by SFPs.
SFP (Transceiver)
Small Form-factor Pluggable - Commonly used to provide 1 Gbit/s fiber, 1 Gbit/s copper also available.
SFP+ (Transceiver)
Enhanced Small Form-factor Pluggable - Same size as SFP transceivers and is common with 10 Gigabit Ethernet. Supports data rate up to 16 Gbit/s.
QSFP (Transceiver)
Quad Small Form-factor Pluggable - 4-channel SFP with each channel providing 1 Gbit/s for a total of 4 Gbit/s. Essentially 4 SFPs in one.
QSFP+ (Transceiver)
Enhanced Quad Small Form-factor Pluggable - 4-channel SFP with each channel providing 10 Gbit/s for a total of 40 Gbit/s. Essentially 4 SFP+s in one.
100BASE-TX
100BASE-TX also called “Fast Ethernet” can carry traffic at the nominal rate of 100 Mbit/s. Often carried over Category 5 or better and can run a maximum of 100 meters between devices.
1000BASE-T
1000BASE-T also called “Gigabit Ethernet” can carry traffic at the nominal rate of 1 Gbit/s. Often carried over Category 5 or better twisted pair copper cables and can run a maximum of 100 meters between devices. Frequency use of 125 MHz.
1000BASE-SX
1000BASE-SX can carry traffic at the nominal rate of 1 Gbit/s. This is Gigabit Ethernet using NIR (Near Infrared) light wavelength. Often carried over multi-mode fiber and can run a maximum of 220 meters to 500 meters, depending on fiber type.
1000BASE-LX
1000BASE-LX can carry traffic at the nominal rate of 1 Gbit/s. This is Gigabit Ethernet using long wavelength lasers. Carried over both Multi-mode and Single-mode fiber. Multi-mode can run a maximum of 550 meters whereas the Single-mode fiber can run a maximum of 5 kilometers.
10 Gbit/s Ethernet
10GBASE-T can carry traffic at the nominal rate of 10 Gbit/s. Often carried over Category 6 or better twisted pair copper cables and can run varying lengths depending on cabling used. Cat 6 can run a maximum of 55 meters, both Cat 6A (Augmented) and Cat 7 can run a maximum of 100 meters. Frequency use of 500 MHz.
Hub
A hub is a network hardware device used for connecting multiple network devices or workstations together. It acts as a repeater so traffic going in one port is repeated to every other port on the hub in half-duplex communication mode. A hub works at the physical layer (layer 1) of the OSI model. Hubs also participates in collision detection, forwarding a jam signal to all ports if it detects a collision.
Bridge
A bridge is a computer networking device that creates a single aggregate network from multiple communication networks or network segments, “bridges” networks together. Bridges allow the ability to connect different topologies and different physical networks together. Bridges operate at the OSI Layer 2 and most bridges these days are simply wireless access points. Bridges distributes traffic based on MAC address and makes forwarding decisions in software.
Switch
OSI layer 2 device which forwards traffic based on data link address. Switches are the core of an enterprise network and can provide Power over Ethernet (PoE).
Routers inside of switches are sometimes called “layer 3 switches”.
- Switch (Layer 2)
- Router (Layer 3)
Router
OSI layer 3 device which routes traffic between IP subnets. Capable of supporting both copper and fiber networks and can connect diverse network types together.
Routers inside of switches are sometimes called “layer 3 switches”.
- Switch (Layer 2)
- Router (Layer 3)