Intro to Networks Module 4

Common connectors used with the coax cable:

- Bayonet Neil-Concelman (BNC) - N Type - F Type

Some of the elements defined by the TIA/EIA for the commercial cabling standards for LAN installations:

- Cable types - Cable lengths - Connectors - Cable termination - Methods of testing cable

Coaxial cable & What they consist of

Gets its name from the fact there are two conductor that share the same access. Consists of: - A copper conductor is used to transmit the electronic signals - A layer of flexible plastic insulation surrounds a copper conductor - The insulating material Is surrounded in a woven copper braid, or metallic foil, that acts as the second wire in the circuit and as a shield for the inner conductor. This second layer, or shield, also reduces the amount of outside electromagnetic interference. - The entire cable is covered with the cable jacket to prevent minor physical damage.

Some limitations of wireless:

- Coverage Area: Wireless data communication technologies work well in open environments. However, certain construction materials used in buildings and structures, and the local terrain, will limit the effective coverage. - Interference: Wireless is susceptible to interference and can be disturbed by such common devices as household cordless phones, some types of fluorescent lights, microwave ovens, and other wireless communications. - Security: Wireless communication coverage requires no access to a physical strand of media. Therefore, devices and users, not authorized for access to the network, can gain access to the transmission. Network security is a major component of wireless network administration. - Shared Medium: WLANs operate in half-duplex, which means only one device can send or receive at a time. The wireless medium is shared amongst all wireless users. Many users accessing the WLAN simultaneously results and reduce bandwidth for each user.

4 types of industries Fiber-Optic cabling is being used in:

- Enterprise Networks - Fiber-to-the-Home (FTTH) - Long-Haul Networks - Submarine Cable Networks

The main cable types that are obtained by using specific wiring conventions:

- Ethernet straight-through - Ethernet crossover

Susceptibility of copper cables to a electronica noise can be limited using with these recommendations:

- Selecting the cable type or category most suited to a given networking environment - designing a cable infrastructure to avoid known and potential sources of interference in the building structure - Using cabling techniques that include the proper handling and termination of the cables

Fiber-optic cables are broadly classified into two types:

- Single-mode fiber (SMF) - Multimode fiber (MMF)

Factors that influence throughput:

- The amount of traffic - The type of traffic - The latency created by the number of network devices encounter between source and destination

Advantages of Fiber-Optic Cabling:

- Transmits data over longer distances and at higher bandwidths than any other networking media - Transmits signals with less attenuation than copper wires - Completely immune to EMI and RFI

3 Main types of copper media used in networking:

- unshielded twisted-pair (UTP) cable - Shielded twisted-pair (STP) cable - Coaxial cable

The physical Layer hardware, media, encoding, and signaling standards are defined and governed by the standard organizations:

-International organization for standardization (ISO) -Telecommunications industry Association/electronic industries association (TIA/EIA) -International telecommunication union (ITU) -American national standards institute (ANSI) -Institute of electrical and electronics engineers (IEEE) -National telecommunications regulatory authorities: Federal communication commissions (FCC) in the USA and the European telecommunication standards institute (ETSI)

A combination of factors determine the practical bandwidth of a network:

-The properties of the physical media -The technologies chosen for signaling and detecting Network signals Physical media properties, current technologies, and the laws of physics all play a role in determining the available bandwidth.

Manchester encoding

A digital transmission encoding scheme that represents the transition from positive to ground with a 0 and a negative to positive voltage transition in the middle of the bit period designates a binary 1. The transition occurs at the middle of each bit.

Crosstalk

A disturbance caused by the electric or magnetic fields of a signal on one wire to the signal in an adjacent wire. In telephone service, crosstalk can result in hearing part of another voice conversation from an adjacent circuit. Specifically, when an electrical current flows through a wire, it creates a small, circular and magnetic field around the wire, which can pick up an adjacent wire.

Key characteristics of UTP cable:

1. The outer jacket protects the copper wires from physical damage 2. Twisted-pairs protect the signal from interference 3. Color-coded plastic insulation electrically isolates wires from each other and identifies each pair

3 components of an access point

1. The wireless antennas 2. Several ethernet switchports 3. And Internet port

Ethernet crossover

A cable used to interconnect similar devices. For example, to connect a switch to a switch, a host to a host, or a router to a router. One end T568A, other end T568B However, crossover cables are now consider legacy as NICs use medium-dependent interface crossover (auto-MDIX) to automatically detect the cable and make the internal connection.

WLAN NIC

A device with a WLAN NIC is enabled for a wireless connection to the network Wireless local area network NICs

Ethernet NIC

A device with a ethernet NIC is enabled for a wired connection to the network

Encoding

A method of converting a stream of data bits into a pre-defined "code" Codes are groupings of bits used to provide a predictable pattern. They can be recognized by both the sender and the receiver Encoding is the method or pattern used to represent digital information. this is similar to how Morse code encodes a message using a series of dots in the dashes. Also known as line encoding

Bandwidth

Bandwidth is the capacity at which a medium can carry data. Digital bandwidth measures the amount of data that can flow from one place to another in a given amount of time. Measured in kilobits per second (kbps), megabits per second (Mbps), or gigabits per second (Gbps) Bandwidth is sometimes thought of as the speed that bits travel, however this is not accurate. For example, in both 10 Mbps and 100 Mbps ethernet, the bits are sent at the speed of electricity. The difference is the number of bits that are transmitted per second.

Coaxial cables and cable Internet installations:

Cable service providers provide Internet connectivity to their customers by replacing portions of the coaxial cable and supporting amplification elements with fiber-optic cable. However, the wiring inside the customers premises is still coax cable.

Why are cables put into categories?

Cables are placed on into categories based on their ability to carry hire bandwidth rates. Cables in higher categories are designed and constructed to support higher data rates Category 5e is now the minimally acceptable cable type, with Category 6 being the recommended type for new building installations.

Coaxial cables and wireless installations

Coaxial cables attach antennas to wireless devices. The coaxial cable carries radio frequency (RF) energy between the antennas and the radio equipment.

Shielded twisted-pair (STP) cable

Combines the techniques of shielding to counter EMI and RFI, and wire twisting to counter crosstalk. Provides better noise protection than UTP cabling. However, compared to UTP cable, STP cable is significantly more expensive and difficult to install. Also uses the RJ-45 connector like UTP

Multimode fiber (MMF)

Consists of a larger core and uses LEDE mirrors to send light pulses. Specifically, light from an LED enters the multi mode fiber at different angles. Popular in LANs because they can be powered by low-cost LEDs Provides bandwidth up to 10 Gb/s over link lengths of up to 550 meters.

Single-mode fiber (SMF)

Consists of a very small core and uses expensive laser technology to send a single ray of light. Popular in long-distance situations spanning hundreds of kilometers, such as those required in long haul telephony and cable TV applications.

Cancellation (in UTP cabling)

Designers now pair wires in a circuit. When two wires in an electrical circuit are placed close together, their magnetic fields are the exact opposite of each other. Therefore the two magnetic fields cancel each other and also cancel out any outside EMI and RFI signals

Copper cabling is limited by

Distance Electromagnetic Interface (EMI) or radio frequency Interface (RFI) Crosstalk

Wireless Access Point (AP)

Do you concentrate the wireless signals from users and connect to the existing copper-based network infrastructure, such as ethernet. Home and small business wireless routers integrate the functions of a router, switch, and access point into one device.

Electromagnetic Interface (EMI) or radio frequency Interface (RFI)

EMI and RFI signals can distort and corrupt the data signals being carried by copper media. Potential sources of EMI and RFI include radio waves and electromagnetic devices, such as fluorescent lights or electric motors

Category 6 Cable

Has an added separator between each wire pair to support higher speeds. Supports up to 10 Gbps

Major Highlighted difference between MMF and SMF:

Is the amount of dispersion. Dispersion refers to the spreading out of a light pulse overtime. Increase dispersion means increase loss of signal strength. MMF has a greater dispersion than SMF. (This is why MMF can only travel up to 500 meters before signal loss)

Terms used to measure the quality of bandwidth include:

Latency, throughput, goodput

NIC

Network interface card Network interface cards connected a device to the network

To counter the negative affects of crosstalk, some types of copper cables have

Opposing circuit wire pairs twisted together, which affectively cancels the crosstalk.

Category 3 Cable

Originally used for voice communication over voice lines, but later used for data transmission

The physical layer standards address three function areas:

Physical components, Encoding, Signaling

Wireless NIC adapters

Provide wireless communication capability to network hosts

The OSI physical Layer

Provides the means to transport the bed to make up a data link Layer frame across the network media. The layer except a complete frame from the data link layer and then close it as a series of signals that are transmitted to the local media. The encoded bits that comprise a frame or received by either an end device or an intermediate device.

Latency

Refers to the amount of time, including delays, for dad to travel from one given point to another.

Names of fiber patch cords

SC-SC multimode patch cord (orange) LC-LC Single-mode patch cord (yellow) ST-LC multimode patch cord (orange) SC-ST Single-mode patch cord (yellow)

Category 7 Cable

Supports 10 Gbps Some manufacturers are making cables exceeding the TIA/EIA Category 6a specifications, these are referred to as Category 7

Category 8 Cable

Supports 40 Gbps

unshielded twisted pair (UTP) cable

The most common networking media UTP cabling, terminated with RJ-45 connectors, is used for interconnecting network hosts with intermediary network devices, such as switches and routers. In LANs, UTP cable consists of four pairs of color-coded wires that have been twisted together and then encased in a flexible plastic sheath that protects from minor physical damage. The twisting of wires helps protect against signal interferes from other wires.

Ethernet Straight-through

The most common type of networking cable. It's commonly used to enter connect a host to a switch and I switched to a router. Both ends T568A or both ends T568B

Physical components

The electronica hardware devices, media, and other connectors that transmit the signals that represent the bits. Hardware components such as NICs, Interfaces and connectors, cable materials, and cable designs are all specified in the standards associated with the physical later.

Throughput

The measure of the transfer a bits across the media over given period of time Throughput usually does not match the specified bandwidth in physical layer implementations. Throughput is usually lower than the bandwidth

Goodput

The measure of usable data transferred over given period of time. Goodput is throughput minus traffic overhead for establishing sessions, acknowledgment, encapsulation, and retransmitted bit. Goodput is always lower than throughput, which is generally lower than bandwidth.

Signaling

The physical layer must generate the electrical, optical, or wireless Signals that represent the "1" and "0" the media. The way bits are represented is called the signaling method. The physical layer standards must define what type of signal represents a "1 "and what type of signal represents a "0" This can be a simple as a change in the level of electrical signal or optical pulse for example, a long pause might represent a 1 where as a Short pulse might represent a 0. This is similar to the signaling method used in Morse code, which may use a series of on-off tones, lights, or clicks to send over telephone wires or between ships at sea.

Varying the number of twists per wire (in UTP cabling)

To further enhance the cancellation affect of paired circuits, designers vary the number of twist of each wire in a cable. UTP cable must follow precise specific Quetion's governing how many twists or breeds are permitted per meter of cable.

True or false: Not all physical connections are equal, in terms of the performance level, when connecting to a network.

True

Long-Haul Networks

Used by service providers to connect countries and cities

Enterprise Networks

Used for backbone cabling applications and interconnecting Infrastructure devices

Category 5e Cable

Used for data transmission. Supports 1000 Mbps

Category 5 Cable

Used for data transmission. Supports 100Mbps

Rollover cable

Used to connect a workstation to a router or switch console port A Cisco proprietary

Fiber-to-the-Home (FTTH)

Used to provide always-on broadband services to homes and small businesses

Submarine Cable Networks

Used to provide reliable high-speed, high-capacity solutions capable of surviving in harsh undersea environments up to transoceanic distances.

How does a Device connect to the network?

Using a NIC A device may have a ethernet NIC or a WLAN NIC, or both

To counter the negative affects of EMI and RFI, some types of copper cables are

Wrapped in metallic shielding and require proper grounding connections.

Fiber patch cords

required for interconnecting infrastructure devices The use of the color distinguishes between single-mode and multi mode patch cords. A yellow jacket is for single-mode fiber cables and orange or aqua for multimode fiber cables