2 – Infrastructure Flashcards
What is UTP?
Unshielded Twisted Pair • The most common type of copper cabling
In the context of cables, what is STP?
Shielded Twisted Pair • Provides additional shielding to protect against interference. • Requires the cable to be grounded, so a grounding wire is added to the groups of twisted pairs.
What is the standard and distance supported by this cable category? Cat 3
10BASE-T (10 Mb) 100 meters
What is the standard and distance supported by this cable category? Cat 5
100 Mb or 1000 Mb (100BASE-TX, 1000BASE-T) 100 meters
What is the standard and distance supported by this cable category? Cat 5e
100BASE-TX, 1000BASE-T (100 Mb or 1000 Mb) 100 meters
What is the standard and distance supported by this cable category? Cat 6
10GBASE-T 37-55 meters
What is the standard and distance supported by this cable category? Cat 6A
10GBASE-T 100 meters
What is the standard and distance supported by this cable category? Cat 7
10GBASE-T 100 meters
What is plenum-rated cable?
Meant for running through a plenum (a ceiling where airspace is circulating, which has fire-safety requirements). Typically not as flexible as regular PVC cable.
What types of Coaxial cables are there?
RG-6 • used in TV, digital cable, and high-speed internet over cable RG-59 • used as patch cables, not for long distances
What types of connectors are used with Coaxial cable?
BNC • Bayonet Neill-Concelman • Connector that you push in and twist to lock in place. • Often used in DS3 WAN links F-Connector • Often used with cable television / cable modem • Threaded connector, screws into place
What is a DB-25?
D-subminiature, or D-sub • “D” indicates shape of connector, B indicates size • 25 pins • DB-25 was one of the most popular serial connector types early on in computing. Not seen much today. • Often-color coded pink. • used for all kinds of different things: printing, modems, mice, networking.
What is a DB-9?
D-sub 9 • “D” indicates shape of connector, B indicates size • Technically, it’s properly a DE-9, since it is a size E D-sub rather than size B. • 9 pins • Can be color-coded green/teal. • Still seen today, often as a serial console interface for infrastructure devices
Single-mode vs. multimode fiber
Multimode • for short range, up to 2 km • uses an inexpensive light source, ex. LED • wider core, light disperses into multiple modes Single-mode • long range, up to 100 km • expensive light source; laser beams • narrow core, allows single mode of light
UPC vs. APC
UPC • Ultra-polished connector (or, Ultra-physical contact connector) • Ferrule end-face radius polished at 0 degree angle • high return loss (signal reflects back directly) APC • Angle-polished connector (or, Angled-physical contact connector) • Ferrule end-face radius polished at an 8 degree angle • Lower return loss (signal reflects back at angle, instead of back to source) • Higher insertion loss
What is an ST?
Straight Tip • Fiber connector • Round bayonet, push and twist to lock • long ferrule sticks out
What is an SC?
Subscriber Connector, or Standard Connector, or Square Connector • square shaped • round ferrule, but does not stick out as much as an ST conenctor • pushes into place, no lock
What is an LC?
Lucent Connector • aka Local Connector • “Little Connector” • smaller than SC, square shape, round ferrule that does not stick out much • locks into place with a tab like an RJ45
What is an MT-RJ?
Mechanical Transfer Registered Jack • smallest form of fiber connector • TX and RX fibers in the same form factor • Roughly same size as RJ45
When would you use a crossover cable?
When connecting “like” devices, such as switch-to-switch, or station-to-station. However, auto-MDX is enabled on most modern Ethernet devices. It examines the signal and automatically decides to use cross-over.
What is the order of colors for TIA/EIA 568A?
white / green green white / orange blue white / blue orange white / brown brown
What is the order of colors for TIA/EIA 568B?
white / orange orange white / green blue white / blue green white / brown brown
What is a 66 block?
• Type of patch panel • The left side is patched straight across to the right side • Often used in analog and voice connections, and old digital standards. • wires are punched into block
What is a 110 block?
• Designed to replace the 66 block • supports higher speed networks, Cat 5 and 6 cables • wires are punched into block, then connecting block is added on top of it, and additional wires are punched into connecting block • may have RJ45 connectors on the other side
What is a fiber distribution panel?
• Permanent fiber installation, with patch panels at both ends. • provides room for fiber to gentle loop around inside, since fiber does not have a tight bend radius.
What is a transceiver?
A device that is both a transmitter and a receiver, usually in a single component In networking, it usually refers to a modular interface. You can add whatever transceiver is needed into a slot on a switch.
What is a BiDi transceiver?
A Bi-Directional Transceiver • Supports traffic in both directions (TX and RX) within a single fiber, by using two different wavelengths.
What is a GBIC?
Gigabit Interface Converter • An early transceiver standard. • Commonly used on Gigabit and fibre channel networks. • both copper and fiber support • relatively large compared to newer standards of transceivers • effectively replaced by SFPs
What is an SFP?
Small Form-factor Pluggable • Commonly used to provide 1 Gbit/s fiber. Also available for copper (RJ45) • about 1/3 the size of the GBIC
What is SFP+?
Enhanced Small Form-factor Pluggable • Exactly the same form factor as SFPs • Supports data rates up to 16 Gbit/s • Common with 10 Gigabit Ethernet
What is a QSFP?
Quad Small Form-factor Pluggable • Effectively, 4 SFPs put into a single transceiver. • Only somewhat larger than one SFP. • 4-channel SFP = Four 1 Gbit/s = 4 Gbit/s • QSFP+ is 4-channel SFP+ = 40 Gbit/s • Also available to support BiDi on QSFP and QSFP+
What is a hub?
Operates at OSI layer 1, since no forwarding decisions are being made. • Operates at Half-duplex • Only at 10 Mb / 100 Mb speed • A hub is a “Multi-port repeater.” Any traffic going into one port is repeated to every other port.
What is this standard? 1000BASE-SX
Standard for Gigabit Ethernet over fiber • Uses NIR (Near infrared) wavelength • Usually multi-mode • Distance of 220 to 500 meters, depending on fiber type
What is this standard? 1000BASE-LX
Standard for Gigabit Ethernet over fiber • Uses long wavelength laser • Distance: - Multi-mode fiber for 550 meters - Single-mode fiber for 5 kilometers
Where are bridges still commonly found in networks today?
Wireless Access Points are bridges. They bridge wired Ethernet to wireless.
What is ASIC?
Application-Specific Integrated Circuit
What is a firewall?
At its most basic level, a firewall is a device that makes decisions on whether traffic is allowed or denied through the network based on Layer 4 information (such as a TCP or UDP port number). Though, modern firewalls can also make those decisions based on info as high as Layer 7. These may be referred to as “Next Generation” firewalls. Many firewalls can also function as a Layer 3 device (router) and as a VPN concentrator.
What is an AAA?
Authentication • Identify you, and prove you are who you say you are Authorization • Based on your identification and authentication, determine what access you are given Accounting • Record resources used, login time, data transmitted, etc. RADIUS is one of the more common AAA protocols.
What is RADIUS?
Remote Authentication Dial-In User Service • One of the more common AAA protocols. • Centralized authentication for users. • Can authenticate users to routers, switches, firewalls, etc. Can grant VPN access, server authentication, etc. • Available on almost any server OS.
What is UTM?
Unified Threat Management A device that performs several security services at the edge of a network. • URL filter / content inspection • malware inspection • spam filter • CSU / DSU It may also be a combined appliance that also provides: • firewall • VPN concentrator • router, swtich • IDS/IPS
What is an NGFW?
Next Generation Firewall Analyzes every packet and frame, and makes a security decision to allow or deny the traffic. Also called: • Layer 7 firewall • Application Layer Gateway • Stateful multilayer inspection • Deep Packet Inspection
What is the difference between a NAS and a SAN?
A NAS provides file-level access (if part of a file changes, the whole file must be saved and written. A SAN provides block-level access, very efficient with reading and writing.
What are Jumbo Frames?
• Six times the size of payload as a normal Ethernet Frame. • Normal Ethernet frames can support 1500 bytes of payload. • Jumbo frames can carry up to 9216 bytes of payload, but 9000 is the accepted norm since its more compatible with the 1500 size, as a multiple. • Using Jumbo frames increases transfer efficiency per packet size, since there are fewer packets to switch and route. • But for it to work, ALL devices on your network between you and the storage device must support Jumbo frames. The devices usually have an option that needs to be turned on.
What is FC?
Fiber Channel • A high-speed topology specifically built for Storage Area Networks (SANs). • Connects servers directly to storage devices, so they appear and operate as local disks. • Supports rates of 2, 4, 8, and 16 Gb/s • Supported over both fiber and copper • Requires an FC switch, and the server (initiator) needs a FC interface.
What is FCoE?
Fiber Channel over Ethernet • Use FC over an existing Ethernet network. • FC switch is not required. • Allows you to use the Ethernet card in a device, rather than an FC adapter/interface. • Since it is done at the Ethernet frame level, the traffic is not routable.
What is FCIP?
Fiber Channel over IP • Tunnels / Encapsulates FC data within IP packets. • Allows it to be routed to different IP subnets.
What is iSCSI?
Internet Small Computer Systems Interface • A type of SAN • Allows a remote disk to appear as, and operate as, a local disk. • Send SCSI commands over an IP network. • Not proprietary, no special hardware or interfaces needed, widely supported in software and many operating systems. • Since it uses IP, it is easily routable.
What is InfiniBand?
• A high-speed switching technology, and type of SAN • Designed for high speeds with low latency, common in research environments and supercomputers. • 100 Gb/s and 200 Gb/s are common. And, those links can then be aggregated together in 4x, 8x, and 12x links. • An alternative to Fiber Channel. • Uses its own specialized switches and adapter cards. • Allows connection to SAN using either copper or fiber, using QSFP connectors.
What types of SAN topologies exist?
Fiber Channel FCoE and FCIP iSCSI Infiniband
What is a CPE?
Customer Premises equipment The device that you connect to your side of the demarcation point. If its a tradition T1 or T3 connection, your CPE may be a CSU or DSU.
What is Split horizon?
Split horizon is a method of preventing a routing loop in a network. • It follows this basic principle: Information about the routing for a particular packet is never sent back in the direction from which it was received. • Split-horizon route advertisement is a method of preventing routing loops in distance-vector routing protocols by prohibiting a router from advertising a route back onto the interface from which it was learned.
What is Persistent MAC learning?
Persistent MAC learning, also known as Sticky MAC, is a port security feature that enables an interface to retain dynamically learned MAC addresses when the switch is restarted or if the interface goes down and is brought back online. This can be used to prevent someone from unplugging their office computer and connecting their own laptop to the network jack without permission, since the switch port connected would only allow the computer with the original MAC address to gain connectivity.
What is Sticky MAC?
Persistent MAC learning, also known as Sticky MAC, is a port security feature that enables an interface to retain dynamically learned MAC addresses when the switch is restarted or if the interface goes down and is brought back online. This can be used to prevent someone from unplugging their office computer and connecting their own laptop to the network jack without permission, since the switch port connected would only allow the computer with the original MAC address to gain connectivity.
What is: SCADA
Supervisory Control and Data Acquisition
What is: ICS
Industrial Control System or, possibly, Internet Connection Sharing
What is: IS-IS
Intermediate System to Intermediate System
What would this type of network be used for? SCADA/ICS
SCADA/ICS is used in industrial control systems, such as an assembly-line network.
What is: DWDM
Dense Wavelength-Division Multiplexing • a high-speed optical network type commonly used in MANs (metropolitan area networks). • DWDM uses as many as 32 light wavelengths on a single fiber, where each wavelength can support as many as 160 simultaneous connections.
What types of connectors are used with Twister Pair cables?
RJ-45 RJ-11 DB-9 DB-25
What are the pros and cons of fiber, when compared to copper?
Pros: • much higher bandwidth • much longer distances • immune to EMI • better security, more difficult to tap Cons: • significantly more expensive • more difficult to install
What is DOCSIS?
Data Over Cable Service Interface Specification A standard that permits the addition of high-bandwidth data transfer to an existing cable television system. Most people today call these ‘cable modems’, but technically they are DOCSIS modems.
What is DSL?
Digital Subscriber Line High-bandwidth data connection over ordinary copper telephone lines.