Transmission on fiber optic wire requires repeating at distance intervals. The glass fiber requires more protection within an outer cable than copper. For these reasons and because the installation of any new wiring is labor-intensive, few communities yet have fiber optic wires or cables from the phone company’s branch office to local customers (local loop).
In telephony, a local loop is the wired connection from a telephone company’s central office in a locality to its customers’ telephones at homes and businesses. This connection is usually on a pair of copper wires called twisted pair. The system was originally designed for voice transmission only using analog transmission technology on a single voice channel. Today, your computer’s modem makes the conversion between analog signals and digital signals. With Integrated Services Digital Network (ISDN) or Digital Subscriber Line (DSL), the local loop can carry digital signals directly and at a much higher bandwidth than they do for voice only.
Local Loop diagram

Image from: http://www.thenetworkencyclopedia.com/entry/local-loop/
The following are incorrect answers:
New loop This is only a detractor and does not exist
Loopback In telephone systems, a loopback is a test signal sent to a network destination that is returned as received to the originator. The returned signal may help diagnose a problem.
Ingenious loop This is only a detractor and does not exist
Reference(s) used for this question: http://searchnetworking.techtarget.com/definition/local-loop and STEINER, Kurt, Telecommunications and Network Security, Version 1, May 2002, CISSP Open Study Group (Domain Leader: skottikus), Page 14.

The International Standards Organization / Open Systems Interconnection (ISO/OSI) Layers and Characteristics Standard model for network communications enables dissimilar networks to communicate, Defines 7 protocol layers (a.k.a. protocol stack) Each layer on one workstation communicates with its respective layer on another workstation using protocols (i.e. agreed-upon communication formats) “Mapping” each protocol to the model is useful for comparing protocols. Mnemonics: Please Do Not Throw Sausage Pizza Away (bottom to top layer) All People Seem To Need Data Processing (top to bottom layer). Source: STEINER, Kurt, Telecommunications and Network Security, Version 1, May 2002, CISSP Open Study Group (Domain Leader: skottikus), Page 12.

Coaxial cable is called “coaxial” because it includes one physical channel that carries the signal surrounded (after a layer of insulation) by another concentric physical channel, both running along the same axis.
The outer channel serves as a ground. Many of these cables or pairs of coaxial tubes can be placed in a single outer sheathing and, with repeaters, can carry information for a great distance.
Source: STEINER, Kurt, Telecommunications and Network Security, Version 1, May 2002, CISSP Open Study Group (Domain Leader: skottikus), Page 14.

Fraggle is an attack similar to Smurf, but instead of using ICMP, it uses UDP. Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2002, chapter 11: Application and System Development (page 790).

Although it may cause a denial of service to the victim’s system, this type of attack is a Smurf attack. A SYN Flood attack uses up all of a system’s resources by setting up a number of bogus communication sockets on the victim’s system. A Ping of Death attack is done by sending IP packets that exceed the maximum legal length (65535 octets). Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2002, chapter 11: Application and System Development (page 789).

Only fiber optic cables are not affected by crosstalk or interference.
For your exam you should know the information about transmission media:
Copper Cable Copper cable is very simple to install and easy to tap. It is used mostly for short distance and supports voice and data. Copper has been used in electric wiring since the invention of the electromagnet and the telegraph in the 1820s.The invention of the telephone in 1876 created further demand for copper wire as an electrical conductor. Copper is the electrical conductor in many categories of electrical wiring. Copper wire is used in power generation, power transmission, power distribution, telecommunications, electronics circuitry, and countless types of electrical equipment. Copper and its alloys are also used to make electrical contacts. Electrical wiring in buildings is the most important market for the copper industry. Roughly half of all copper mined is used to manufacture electrical wire and cable conductors.
Copper Cable

Image Source –http://i00.i.aliimg.com/photo/v0/570456138/FRLS_HR_PVC_Copper_Cable…
Coaxial cable Coaxial cable, or coax (pronounced ‘ko.aks), is a type of cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a tubular conducting shield. Many coaxial cables also have an insulating outer sheath or jacket. The term coaxial comes from the inner conductor and the outer shield sharing a geometric axis. Coaxial cable was invented by English engineer and mathematician Oliver Heaviside, who patented the design in 1880.Coaxial cable differs from other shielded cable used for carrying lower-frequency signals, such as audio signals, in that the dimensions of the cable are controlled to give a precise, constant conductor spacing, which is needed for it to function efficiently as a radio frequency transmission line.
Coaxial cable are expensive and does not support many LAN’s. It supports data and video
Coaxial Cable

Image Source –http://www.tlc-direct.co.uk/Images/Products/size_3/CARG59.JPG
Fiber optics An optical fiber cable is a cable containing one or more optical fibers that are used to carry light. The optical fiber elements are typically individually coated with plastic layers and contained in a protective tube suitable for the environment where the cable will be deployed. Different types of cable are used for different applications, for example long distance telecommunication, or providing a high-speed data connection between different parts of a building.
Fiber optics used for long distance, hard to splice, not vulnerable to cross talk and difficult to tap. It supports voice data, image and video. Radio System Radio systems are used for short distance,cheap and easy to tap. Radio is the radiation (wireless transmission) of electromagnetic signals through the atmosphere or free space.
Information, such as sound, is carried by systematically changing (modulating) some property of the radiated waves, such as their amplitude, frequency, phase, or pulse width. When radio waves strike an electrical conductor, the oscillating fields induce an alternating current in the conductor. The information in the waves can be extracted and transformed back into its original form.
Fiber Optics

Image Source –http://aboveinfranet.com/wp-content/uploads/2014/04/fiber-optic-cab…
Microwave radio system Microwave transmission refers to the technology of transmitting information or energy by the use of radio waves whose wavelengths are conveniently measured in small numbers of centimetre; these are called microwaves. Microwaves are widely used for point-to-point communications because their small wavelength allows conveniently-sized antennas to direct them in narrow beams, which can be pointed directly at the receiving antenna. This allows nearby microwave equipment to use the same frequencies without interfering with each other, as lower frequency radio waves do. Another advantage is that the high frequency of microwaves gives the microwave band a very large information-carrying capacity; the microwave band has a bandwidth 30 times that of all the rest of the radio spectrum below it. A disadvantage is that microwaves are limited to line of sight propagation; they cannot pass around hills or mountains as lower frequency radio waves can.
Microwave radio transmission is commonly used in point-to-point communication systems on the surface of the Earth, in satellite communications, and in deep space radio communications. Other parts of the microwave radio band are used for radars, radio navigation systems, sensor systems, and radio astronomy.
Microwave radio systems are carriers for voice data signal, cheap and easy to tap.
Microwave Radio System

Image Source –http://www.valiantcom.com/images/applications/e1_digital_microwave_…
Satellite Radio Link
Satellite radio is a radio service broadcast from satellites primarily to cars, with the signal broadcast nationwide, across a much wider geographical area than terrestrial radio stations. It is available by subscription, mostly commercial free, and offers subscribers more stations and a wider variety of programming options than terrestrial radio.
Satellite radio link uses transponder to send information and easy to tap.
The following answers are incorrect:
Copper Cable -Copper cable is very simple to install and easy to tap. It is used mostly for short distance and supports voice and data.
Radio System -Radio systems are used for short distance,cheap and easy to tap.
Satellite Radio Link -Satellite radio link uses transponder to send information and easy to tap.
The following reference(s) were/was used to create this question:
CISA review manual 2014 page number 265 & Official ISC2 guide to CISSP CBK 3rd Edition Page number 233

A modem is a device that translates data from digital form and then back to digital for communication over analog lines. Source: Information Systems Audit and Control Association, Certified Information Systems Auditor 2002 review manual, Chapter 3: Technical Infrastructure and Operational Practices (page 114).

Connection-oriented protocols such as TCP provides reliability.
It is the responsibility of such protocols in the transport layer to ensure every byte is accounted for. The network layer does not provide reliability. It only privides the best route to get the traffic to the final destination address.
For your exam you should know the information below about OSI model:
The Open Systems Interconnection model (OSI) is a conceptual model that characterizes and standardizes the internal functions of a communication system by partitioning it into abstraction layers. The model is a product of the Open Systems Interconnection project at the International Organization for Standardization (ISO), maintained by the identification ISO/IEC 7498-1.
The model groups communication functions into seven logical layers. A layer serves the layer above it and is served by the layer below it. For example, a layer that provides error-free communications across a network provides the path needed by applications above it, while it calls the next lower layer to send and receive packets that make up the contents of that path. Two instances at one layer are connected by a horizontal.
OSI Model

Image source: http://www.petri.co.il/images/osi_model.JPG
PHYSICAL LAYER The physical layer, the lowest layer of the OSI model, is concerned with the transmission and reception of the unstructured raw bit stream over a physical medium. It describes the electrical/optical, mechanical, and functional interfaces to the physical medium, and carries the signals for all of the higher layers. It provides:
Data encoding: modifies the simple digital signal pattern (1s and 0s) used by the PC to better accommodate the characteristics of the physical medium, and to aid in bit and frame synchronization. It determines:
What signal state represents a binary 1 How the receiving station knows when a “bit-time” starts How the receiving station delimits a frame
DATA LINK LAYER The data link layer provides error-free transfer of data frames from one node to another over the physical layer, allowing layers above it to assume virtually error-free transmission over the link. To do this, the data link layer provides:
Link establishment and termination: establishes and terminates the logical link between two nodes. Frame traffic control: tells the transmitting node to “back-off” when no frame buffers are available. Frame sequencing: transmits/receives frames sequentially. Frame acknowledgment: provides/expects frame acknowledgments. Detects and recovers from errors that occur in the physical layer by retransmitting non-acknowledged frames and handling duplicate frame receipt.
Frame delimiting: creates and recognizes frame boundaries.
Frame error checking: checks received frames for integrity.
Media access management: determines when the node “has the right” to use the physical medium.
NETWORK LAYER The network layer controls the operation of the subnet, deciding which physical path the data should take based on network conditions, priority of service, and other factors. It provides:
Routing: routes frames among networks.
Subnet traffic control: routers (network layer intermediate systems) can instruct a sending station to “throttle back” its frame transmission when the router’s buffer fills up.
Frame fragmentation: if it determines that a downstream router’s maximum transmission unit (MTU) size is less than the frame size, a router can fragment a frame for transmission and re-assembly at the destination station.
Logical-physical address mapping: translates logical addresses, or names, into physical addresses.
Subnet usage accounting: has accounting functions to keep track of frames forwarded by subnet intermediate systems, to produce billing information.
Communications Subnet The network layer software must build headers so that the network layer software residing in the subnet intermediate systems can recognize them and use them to route data to the destination address.
This layer relieves the upper layers of the need to know anything about the data transmission and intermediate switching technologies used to connect systems. It establishes, maintains and terminates connections across the intervening communications facility (one or several intermediate systems in the communication subnet).
In the network layer and the layers below, peer protocols exist between a node and its immediate neighbor, but the neighbor may be a node through which data is routed, not the destination station. The source and destination stations may be separated by many intermediate systems.
TRANSPORT LAYER The transport layer ensures that messages are delivered error-free, in sequence, and with no losses or duplications. It relieves the higher layer protocols from any concern with the transfer of data between them and their peers.
The size and complexity of a transport protocol depends on the type of service it can get from the network layer. For a reliable network layer with virtual circuit capability, a minimal transport layer is required. If the network layer is unreliable and/or only supports datagrams, the transport protocol should include extensive error detection and recovery.
The transport layer provides:
Message segmentation: accepts a message from the (session) layer above it, splits the message into smaller units (if not already small enough), and passes the smaller units down to the network layer. The transport layer at the destination station reassembles the message.
Message acknowledgment: provides reliable end-to-end message delivery with acknowledgments.
Message traffic control: tells the transmitting station to “back-off” when no message buffers are available.
Session multiplexing: multiplexes several message streams, or sessions onto one logical link and keeps track of which messages belong to which sessions (see session layer).
Typically, the transport layer can accept relatively large messages, but there are strict message size limits imposed by the network (or lower) layer. Consequently, the transport layer must break up the messages into smaller units, or frames, prepending a header to each frame.
The transport layer header information must then include control information, such as message start and message end flags, to enable the transport layer on the other end to recognize message boundaries. In addition, if the lower layers do not maintain sequence, the transport header must contain sequence information to enable the transport layer on the receiving end to get the pieces back together in the right order before handing the received message up to the layer above.
End-to-end layers Unlike the lower “subnet” layers whose protocol is between immediately adjacent nodes, the transport layer and the layers above are true “source to destination” or end-to-end layers, and are not concerned with the details of the underlying communications facility. Transport layer software (and software above it) on the source station carries on a conversation with similar software on the destination station by using message headers and control messages.
SESSION LAYER The session layer allows session establishment between processes running on different stations. It provides:
Session establishment, maintenance and termination: allows two application processes on different machines to establish, use and terminate a connection, called a session.
Session support: performs the functions that allow these processes to communicate over the network, performing security, name recognition, logging, and so on.
PRESENTATION LAYER The presentation layer formats the data to be presented to the application layer. It can be viewed as the translator for the network. This layer may translate data from a format used by the application layer into a common format at the sending station, then translate the common format to a format known to the application layer at the receiving station.
The presentation layer provides:
Character code translation: for example, ASCII to EBCDIC. Data conversion: bit order, CR-CR/LF, integer-floating point, and so on. Data compression: reduces the number of bits that need to be transmitted on the network. Data encryption: encrypt data for security purposes. For example, password encryption.
APPLICATION LAYER The application layer serves as the window for users and application processes to access network services. This layer contains a variety of commonly needed functions:
Resource sharing and device redirection Remote file access Remote printer access Inter-process communication Network management Directory services Electronic messaging (such as mail) Network virtual terminals
The following were incorrect answers:
Application Layer -The application layer serves as the window for users and application processes to access network services. Network layer -The network layer controls the operation of the subnet, deciding which physical path the data should take based on network conditions, priority of service, and other factors.
Physical Layer -The physical layer, the lowest layer of the OSI model, is concerned with the transmission and reception of the unstructured raw bit stream over a physical medium. It describes the electrical/optical, mechanical, and functional interfaces to the physical medium, and carries the signals for all of the higher layers.
The following reference(s) were/was used to create this question:
CISA review manual 2014 Page number 260 and Official ISC2 guide to CISSP CBK 3rd Edition Page number 287 and http://en.wikipedia.org/wiki/Tcp_protocol

A gateway is used to connect two networks using dissimilar protocols at the lower layers or it could also be at the highest level of the protocol stack.
Important Note: For the purpose of the exam, you have to remember that a gateway is not synonymous to the term firewall.
The second thing you must remembers is the fact that a gateway act as a translation device.
It could be used to translate from IPX to TCP/IP for example. It could be used to convert different types of applications protocols and allow them to communicate together. A gateway could be at any of the OSI layers but usually tend to be higher up in the stack.
For your exam you should know the information below:
Repeaters A repeater provides the simplest type of connectivity, because it only repeats electrical signals between cable segments, which enables it to extend a network. Repeaters work at the physical layer and are add-on devices for extending a network connection over a greater distance. The device amplifies signals because signals attenuate the farther they have to travel. Repeaters can also work as line conditioners by actually cleaning up the signals. This works much better when amplifying digital signals than when amplifying analog signals, because digital signals are discrete units, which makes extraction of background noise from them much easier for the amplifier. If the device is amplifying analog signals, any accompanying noise often is amplified as well, which may further distort the signal. A hub is a multi-port repeater. A hub is often referred to as a concentrator because it is the physical communication device that allows several computers and devices to communicate with each other. A hub does not understand or work with IP or MAC addresses. When one system sends a signal to go to another system connected to it, the signal is broadcast to all the ports, and thus to all the systems connected to the concentrator.
Repeater

Image Reference-http://www.erg.abdn.ac.uk/~gorry/course/images/repeater.gif
Bridges A bridge is a LAN device used to connect LAN segments. It works at the data link layer and therefore works with MAC addresses. A repeater does not work with addresses; it just forwards all signals it receives. When a frame arrives at a bridge, the bridge determines whether or not the MAC address is on the local network segment. If the MAC address is not on the local network segment, the bridge forwards the frame to the necessary network segment.
Bridge

Image Reference-http://www.oreillynet.com/network/2001/01/30/graphics/bridge.jpg
Routers Routers are layer 3, or network layer, devices that are used to connect similar or different networks. (For example, they can connect two Ethernet LANs or an Ethernet LAN to a Token Ring LAN.) A router is a device that has two or more interfaces and a routing table so it knows how to get packets to their destinations. It can filter traffic based on access control lists (ACLs), and it fragments packets when necessary. Because routers have more network-level knowledge, they can perform higher-level functions, such as calculating the shortest and most economical path between the sending and receiving hosts.
Router and Switch

Image Reference-http://www.computer-networking-success.com/images/router-switch.jpg
Switches Switches combine the functionality of a repeater and the functionality of a bridge. A switch amplifies the electrical signal, like a repeater, and has the built-in circuitry and intelligence of a bridge. It is a multi-port connection device that provides connections for individual computers or other hubs and switches.
Gateways Gateway is a general term for software running on a device that connects two different environments and that many times acts as a translator for them or somehow restricts their interactions. Usually a gateway is needed when one environment speaks a different language, meaning it uses a certain protocol that the other environment does not understand. The gateway can translate Internetwork Packet Exchange (IPX) protocol packets to IP packets, accept mail from one type of mail server and format it so another type of mail server can accept and understand it, or connect and translate different data link technologies such as FDDI to Ethernet.
Gateway Server

Image Reference-http://static.howtoforge.com/images/screenshots/556af08d5e43aa76826…
The following answers are incorrect:
Repeater -A repeater provides the simplest type of connectivity, because it only repeats electrical signals between cable segments, which enables it to extend a network. Repeaters work at the physical layer and are add-on devices for extending a network connection over a greater distance. The device amplifies signals because signals attenuate the farther they have to travel.
Bridges -A bridge is a LAN device used to connect LAN segments. It works at the data link layer and therefore works with MAC addresses. A repeater does not work with addresses; it just forwards all signals it receives. When a frame arrives at a bridge, the bridge determines whether or not the MAC address is on the local network segment. If the MAC address is not on the local network segment, the bridge forwards the frame to the necessary network segment.
Routers -Routers are layer 3, or network layer, devices that are used to connect similar or different networks. (For example, they can connect two Ethernet LANs or an Ethernet LAN to a Token Ring LAN.) A router is a device that has two or more interfaces and a routing table so it knows how to get packets to their destinations. It can filter traffic based on access control lists (ACLs), and it fragments packets when necessary.
Following reference(s) were/was used to create this question: CISA review manual 2014 Page number 263 Official ISC2 guide to CISSP CBK 3rd Edition Page number 229 and 230

Attenuation is the loss of signal strength as it travels. The longer a cable, the more at tenuation occurs, which causes the signal carrying the data to deteriorate. This is why standards include suggested cable-run lengths. If a networking cable is too long, attenuation may occur. Basically, the data are in the form of electrons, and these electrons have to “swim” through a copper wire. However, this is more like swimming upstream, because there is a lot of resistance on the electrons working in this media. After a certain distance, the electrons start to slow down and their encoding format loses form. If the form gets too degraded, the receiving system cannot interpret them any longer. If a network administrator needs to run a cable longer than its recommended segment length, she needs to insert a repeater or some type of device that will amplify the signal and ensure it gets to its destination in the right encoding format. Attenuation can also be caused by cable breaks and malfunctions. This is why cables should be tested. If a cable is suspected of attenuation problems, cable testers can inject signals into the cable and read the results at the end of the cable.
The following answers are incorrect:
Crosstalk -Crosstalk is one example of noise where unwanted electrical coupling between adjacent lines causes the signal in one wire to be picked up by the signal in an adjacent wire.
Noise -Noise is also a signal degradation but it refers to a large amount of electrical fluctuation that can interfere with the interpretation of the signal by the receiver.
Delay distortion -Delay distortion can result in a misinterpretation of a signal that results from transmitting a digital signal with varying frequency components. The various components arrive at the receiver with varying delays.
Following reference(s) were/was used to create this question: CISA review manual 2014 Page number 265 Official ISC2 guide to CISSP CBK 3rd Edition Page number 229 & CISSP All-In-One Exam guide 6th Edition Page Number 561