CLASSES OF IP ADDRESS

IP Address Classes and Their Formats

Since networks vary in size, there are four different address formats or classes to consider when applying to NIC for a network number:

• Class A addresses are for large networks with many devices.
• Class B addresses are for medium-sized networks.
• Class C addresses are for small networks (fewer than 256 devices).
• Class D addresses are multicast addresses.

The first few bits of each IP address indicate which of the address class formats it is using. The address structures look like this:

Class A

0

Network (7 bits)

Local address (24 bits)

Class B

10

Network (14 bits)

Local address (16 bits)

Class C

110

Network (21 bits)

Local address (8 bits)

Class D

1110	Multicast address (28 bits)

The IP address is usually expressed as four decimal numbers, each representing eight bits, separated by periods. This is sometimes known as the dot address and, more technically, as dotted quad notation. For Class A IP addresses, the numbers would represent "network.local.local.local"; for a Class C IP address, they would represent "network.network.network.local". The number version of the IP address can (and usually is) represented by a name or series of names called the domain name.

The Internet's explosive growth makes it likely that, without some new architecture, the number of possible network addresses using the scheme above would soon be used up (at least, for Class C network addresses). However, a new IP version, IPv6, expands the size of the IP address to 128 bits, which will accommodate a large growth in the number of network addresses. For hosts still using IPv4, the use of subnets in the host or local part of the IP address will help reduce new applications for network numbers. In addition, most sites on today's mostly IPv4 Internet have gotten around the Class C network address limitation by using the Classless Inter-Domain Routing (CIDR) scheme for address notation.

					Class Leading bits Start End CIDR equivalent Default subnet mask Class A 0 0.0.0.0 127.255.255.255 /8 255.0.0.0 Class B 10 128.0.0.0 191.255.255.255 /16 255.255.0.0 Class C 110 192.0.0.0 223.255.255.255 /24 255.255.255.0 Class D (multicast) 1110 224.0.0.0 239.255.255.255 /32 Class E (reserved) 1111 240.0.0.0 255.255.255.255 /32

canopy antenna

Motorola Canopy

Type of signal:	LOS (line-of-sight Line-of-sight propagation Line-of-sight propagation refers to electro-magnetic radiation including light emissions traveling in a straight line. The rays or waves are diffracted, refracted, reflected, or absorbed by atmosphere and obstructions with material and generally cannot travel over the horizon or behind obstacles.... ), NLOS
Maximum range (miles)	120 miles PtMP Point-to-multipoint For general information for point-to-multipoint communication, refer to Link #Point-to-multipoint.Point-to-multipoint communication is a term that is used in the telecommunications field which refers to communication which is accomplished via a specific and distinct type of multipoint connection, providing multiple paths from a single locat... , 155 miles PtP Point-to-point Point-to-point may refer to:* Point-to-point construction, an electronics assembly technique* Network_topology#Point-to-point* Point-to-Point Protocol , part of the Internet protocol suite...
Minimum range:	500 m (The Subscriber Modules (SMs) do not like having a "full blast" signal)
Maximum data throughput (Mbit/s)	21Mbit/s for PtMP, 300 Mbit/s using PTP 600.

Motorola

Motorola

Motorola, Inc. is an United States, multinational, Fortune 100, telecommunications company based in Schaumburg, Illinois. It is a manufacturer of wireless telephone handsets, also designing and selling wireless network infrastructure equipment such as cellular transmission base stations and signal amplifiers....
Canopy is a wireless networking system designed for WISPs (wireless internet service providers) available in point-to-point and point-to-multipoint

Point-to-multipoint

For general information for point-to-multipoint communication, refer to Link #Point-to-multipoint.Point-to-multipoint communication is a term that is used in the telecommunications field which refers to communication which is accomplished via a specific and distinct type of multipoint connection, providing multiple paths from a single locat...
configurations. It includes both the original Motorola-designed products using the Canopy protocol and the PtP backhauls that were rebranded from Orthogon Systems which Motorola acquired in 2006.

Typical setup

A typical Canopy setup consists of a cluster of up to 6 co-located standard access point

Access Point

Access Point can refer to:*Access Point , a location on Anvers Island, Antarctica*Wireless access point, a wireless networking device...
s, each with a 60 degree horizontal beamwidth

Beamwidth

In telecommunication, the term beamwidth has the following meanings:1. In the radio regime, of an antenna pattern, the angle between the half-power points of the main lobe, when referenced to the peak effective radiated power of the main lobe....
antenna, to achieve 360 degree coverage. Also included would be one or more backhauls or otherwise out-of-band links (to carry data to/from other network ocations) and a Cluster Management Module (CMM) to provide power and synchronization to each Canopy AP or Backhaul Module(BM).

Customers of the system receive service through subscriber modules (SMs) aimed towards the AP. The SMs should be mounted on the tall point of a building to get a reliable connection else Fresnel zone

Fresnel zone

File:FresnelSVG.svgIn optics and radio telecommunication, a Fresnel zone, named for physicist Augustin-Jean Fresnel, is one of a number of concentric ellipsoids of revolution which define volumes in the radiation pattern of a circular aperture ....
obstruction will weaken the signal. Under ideal operating conditions connections at distances up to 3.5 miles can be achieved using equipment with integrated antennas

Antenna (radio)

An 'antenna' is a transducer designed to transmitter or receive Electromagnetic radiations. In other words, antennas convert electromagnetic waves into electrical currents and vice versa....
. Network operators can opt to install reflector dishes or Stinger antennas, or to use Canopy models that accept external antennas at one or both ends of the link to increase coverage distance.

Most Canopy equipment receives its power using Power over Ethernet

Power over Ethernet

Power over Ethernet or PoE technology describes a system to transfer electrical power, along with data, to remote devices over standard twisted-pair cable in an Ethernet network....
, however, none of its standards comply with IEEE 802.3af.

In general, the 900 MHz version is more effective for use in outlying areas because of its ability to penetrate through trees. However, it requires careful installation due to the easy propagation of interference on that band.

Comparison with other wireless networking systems

Canopy-protocol products have many advantages over wi-fi

Wi-Fi

Wi-Fi is a trademark of the Wi-Fi Alliance, founded in 1999 as Wireless Internet Compatibility Alliance , comprising more than 300 companies, whose products are certified by the Wi-Fi Alliance, based on the IEEE 802.11 standards ....
and other WLAN

Wireless LAN

A wireless LAN is a wireless local area network that links two or more computers or devices using Spread spectrum or OFDM modulation technology based to enable communication between devices in a limited area....
protocols:

• transmission timing is explicitly controlled, so that all APs on all towers can be synchronized by GPS to prevent interference. APs of the same band can be placed right next to each other, and back-to-back units can use the exact same frequency.
• designed for WISP use; polling-based (prevents one SM from "hogging" bandwidth), excellent interference rejection and easy management.
• simple to install and configure and highly reliable.

Switches and routers

network switch is a small hardware device that joins multiple computers together within one local area network (LAN). Technically, network switches operate at layer two (Data Link Layer) of the OSI model.

Network switches appear nearly identical to network hubs, but a switch generally contains more intelligence (and a slightly higher price tag) than a hub. Unlike hubs, network switches are capable of inspecting data packets as they are received, determining the source and destination device of each packet, and forwarding them appropriately. By delivering messages only to the connected device intended, a network switch conserves network bandwidth and offers generally better performance than a hub.

As with hubs, Ethernet implementations of network switches are the most common. Mainstream Ethernet network switches support either 10/100 Mbps Fast Ethernet or Gigabit Ethernet (10/100/1000) standards.

Different models of network switches support differing numbers of connected devices. Most consumer-grade network switches provide either four or eight connections for Ethernet devices. Switches can be connected to each other, a so-called daisy chaining method to add progressively larger number of devices to a LAN.

ROUTERS

In packet-switched networks such as the Internet, a router is a device or, in some cases, software in a computer, that determines the next network point to which a packet should be forwarded toward its destination. The router is connected to at least two networks and decides which way to send each information packet based on its current understanding of the state of the networks it is connected to. A router is located at any gateway (where one network meets another), including each point-of-presence on the Internet. A router is often included as part of a network switch.

Ask your router questions at ITKnowledgeExchange.com

A router may create or maintain a table of the available routes and their conditions and use this information along with distance and cost algorithms to determine the best route for a given packet. Typically, a packet may travel through a number of network points with routers before arriving at its destination. Routing is a function associated with the Network layer (layer 3) in the standard model of network programming, the Open Systems Interconnection (OSI) model. A layer-3 switch is a switch that can perform routing functions.

An edge router is a router that interfaces with an asynchronous transfer mode (ATM) network. A brouter is a network bridge combined with a router.

For home and business computer users who have high-speed Internet connections such as cable, satellite, or DSL, a router can act as a hardware firewall. This is true even if the home or business has only one computer. Many engineers believe that the use of a router provides better protection against hacking than a software firewall, because no computer Internet Protocol address are directly exposed to the Internet. This makes port scans (a technique for exploring weaknesses) essentially impossible. In addition, a router does not consume computer resources as a software firewall does. Commercially manufactured routers are easy to install, reasonably priced, and available for hard-wired or wireless networks.

Also see bridge, gateway, hub, and switch.

Getting started with routers

To explore how routers are used in the enterprise, here are some additional resources:

A router by any other name is still a router: Learn about what a router does, the difference between a router and a switch, and what to consider when selecting a router for your home or your business.

Tasks for initial router configuration: Unlike some devices, routers require quite a bit of configuration before they will be useful. This tip examines the minimum tasks needed to get a Cisco router working.

Ten quick router security tips: Network administrators need to know the basics in router security. This quick tip lists10 basic router security tips.

Juniper routers

Juniper is a leading provider of core routing, edge routing and network security solutions for IP-based enterprise and carrier-class networks. Network Hardware Resale was one of the first to offer pre-owned, refurbished and used Juniper equipment and maintains the capital and resources to carry the largest inventory of second-hand Juniper product available on the market. Popular items include the:

• Juniper M5 Series Routers
• Juniper M10 Series Routers
• Juniper M20 Series Routers
• Juniper M40 Series Routers
• Juniper M160 Series Routers
• Juniper T320 Series Routers

Information Outlet

In a telephone wiring system in a building, a connection device designed for a fixed location (usually on a wall) in which telephone wiring terminates; the outlet contains a female jack to receive a male plug that is inserted into it. Such outlets are used to connect a telephone, FAX, telephone answering machine, etc., to a telephone line.

I/O MODULES

1746 I/O Module Overview

The 1746 I/O product line provides more than 60 modules to meet your application needs in a modular assembly—including intelligent I/O modules.

• Digital I/O modules provide 4 through 32 I/O per module.
  
  • Digital I/O circuits interface to on/off sensors/actuators.
    
  • Ladder logic has direct access to I/O values.
    
  • Input modules, output modules, and combination input/output modules.
    
  • Ac and DC input modules.
    
  • Ac, dc, and relay-contact output modules.
    
• Analog I/O modules provide 4 through 16 I/O per module.
  
  • D/A and A/D conversions interface analog signals to data-table values
    
  • Ladder logic has direct access to I/O values.
    
  • Input modules, output modules, and combination input/output modules.
    
  • A high level of resolution for accurate control in a broad range of analog applications.
    
• Intelligent I/O modules are available to enhance your control system. These modules include a high-speed counter module, a BASIC language module, a motion control module, and communication modules. Each provides a unique easy-to-use interface between the I/O circuits (digital and/or analog) and the CPU.
  

This modular hardware design uses cost- and space-effective means to add I/O to your control system. These modules can be used:

• In a local I/O chassis of an SLC modular-hardware controller.
  
• At a location remote from the processor, in an I/O chassis with a 1747-ACN15 or -ACNR15 I/O adapter on a ControlNet link with the processor.
  
• At a location remote from the processor, in an I/O chassis with a 1747-ASB I/O adapter on a Universal Remote I/O link with the processor.
  

Benefits

• Hardware-platform sharing makes spare-parts stocking convenient.
  
• Combinations of input and outputs in the same digital and analog modules provide expansion capabilities without sacrificing space or increasing cost.
  
• Variety of voltages creates a precise power fit for your application.
  
• No need to disconnect wiring to replace module of 16 or more I/O; removable terminal blocks are shipped with I/O modules.
  
• Broad range of signal interfaces to AC and DC sensors/actuators for a wide variety of applications.
  
• LED indicators show input/output status for easier troubleshooting.
  
• Modules available in different densities (32 I/O per module max) for greater flexibility and cost savings.
  
• 1746 I/O modules include optical coupling and filter circuitry for signal noise reduction.
  
• A wide range of analog signal levels including standard analog inputs and outputs, and direct thermocouple and RTD temperature inputs.
  

modular jacks

The DECconnect Modified Modular Jack (MMJ) is a variation of the 6P6C modular connector and was developed by Digital Equipment Corporation. The main difference from the conventional modular connector is that the hook is toward the side instead of the center of the plug, making it impossible to insert a standard modular cable plug such as those used telephone or Ethernet applications. MMJ connectors are used on Digital minicomputers, such as the PDP-11, VAX and Alpha based machines and to connect terminals, printers or serial console servers.

The six conductors of the DECconnect MMJ connector are used for the main signals in RS-423 serial communication: Tx and Rx for the data transmission and DSR and DTR for handshaking. The transmit and receive signals are differential, i.e. each signal is the voltage difference between two conductors, as opposed to a voltage on a single connector relative to a common reference. But one can in practice wire these signals to an RS-232 device, which uses the common reference method, by combining the lower voltage sides of each signal to the RS-232 signal ground line. For this type of connection there are a number of models of conversion adapter.

When connecting two DTE devices such as a computer and a printer, the Digital BC16E crossover cable is used.

patch panel

A patch panel or patch bay is a panel, typically rackmounted, that houses cable connections. One typically shorter patch cable will plug into the front side, whereas the back holds the connection of a much longer and more permanent cable. The assembly of hardware is arranged so that a number of circuits, usually of the same or similar type, appear on jacks for monitoring, interconnecting, and testing circuits in a convenient, flexible manner.

Patch panels offer the convenience of allowing technicians to quickly change the path of select signals, without the expense of dedicated switching equipment. This was first used by early telephone exchanges, where the telephone switchboard (a massive array of patch panels) and a large room full of telephone operators running it was ubiquitous.

Uses and connectors

In recording studios, television and radio broadcast studios, and concert sound reinforcement systems, patchbays are widely used to facilitate the connection of different devices, such as microphones, electric or electronic instruments, effects (e.g., compression, reverb, etc.), recording gear, amplifiers, or broadcasting equipment. Patchbays make it easier to connect different devices in different orders for different projects, because all of the changes can be made at the patchbay. As well, patchbays make it easier to troubleshoot problems such as ground loops; even small home studios and amateur project studios often use patchbays, because it groups all of the input jacks into one location. This means that devices mounted in racks or keyboard instruments can be connected without having to hunt around behind the rack or instrument with a flashlight for the right jack. Using a patchbay also saves wear and tear on the input jacks of studio gear and instruments, because all of the connections are made with the patchbay.

Normalling

Patch bays may be half-normal or full-normal, "normal" indicating that the top and bottom jacks are wired together internally. When a patch bay has half-normal wiring, its switching contacts flow through the bottom jacks of the bottom row while connected to the top row; plugging into the output connection will split the signal. If a patch bay is wired to full-normal, then it includes switching contacts in both rows of jacks

Switches

Dedicated switching equipment can be an alternative to patch bays in some applications. Switchers can make routing as easy as pushing a button, and can provide other benefits over patch bays, including routing a signal to any number of destinations simultaneously. However, switching equipment that can emulate the capabilities of a given patch bay is much more expensive.

Example: a 16-point S-Video patch panel, with 8 patch cables, may cost $300.00^{[citation needed]}, and connect 8 inputs and 8 outputs. An S-Video matrix routing switcher with the same capability (8x8) would probably cost between $2,000.00 and $4,000.00 new, though it would probably have more capabilities, including audio-follow-video and built-in distribution amplifiers.

There are various types of switchers for audio and video, from simple selector switches to sophisticated production switchers. However, emulating or exceeding the capabilities of audio and/or video patch bays requires specialized devices like routing switchers and matrix routers (aka "crosspoint switchers").

Like patch panels, switching equipment for nearly any type of signal is available, including analog and digital video and audio, as well as RF (cable TV), MIDI, telephone, networking, electrical, and just about anything else.

Switching equipment may be electronic, mechanical, or electro-mechanical. Some switcher hardware can be controlled via computer and/or other external devices. Some have automated and/or pre-programmed operational capabilities. There are also software switcher applications used to route signals and control data within a "pure digital" computer environment

Computer networking is the engineering discipline concerned with communication between computer systems or devices. Networking, routers, routing protocols, and networking over the public Internet have their specifications defined in documents called RFCs.^[1] Computer networking is sometimes considered a sub-discipline of telecommunications, computer science, information technology and/or computer engineering. Computer networks rely heavily upon the theoretical and practical application of these scientific and engineering disciplines. There are three types of networks: 1.Internet. 2.Intranet. 3.Extranet. A computer network is any set of computers or devices connected to each other with the ability to exchange data.^[2] Examples of different networks are:

• Local area network (LAN), which is usually a small network constrained to a small geographic area. An example of a LAN would be a computer network within a building.
• Metropolitan area network (MAN), which is used for medium size area. examples for a city or a state.
• Wide area network (WAN) that is usually a larger network that covers a large geographic area.
• Wireless LANs and WANs (WLAN & WWAN) are the wireless equivalent of the LAN and WAN.

All networks are interconnected to allow communication with a variety of different kinds of media, including twisted-pair copper wire cable, coaxial cable, optical fiber, power lines and various wireless technologies.^[3] The devices can be separated by a few meters (e.g. via Bluetooth) or nearly unlimited distances (e.g. via the interconnections of the Internet^[4]).