Course Notes: IP Networking Online Course

Transcription

1 Course Notes: IP Networking Online Course

2 COPYRIGHT 2013 STAM interactive Solutions Inc. All rights reserved. WARNING The copyright of the Course Notes is owned by STAM Interactive Solutions Inc. and is protected by US copyright laws and other copyright laws by international treaties. Any infringement of the copyright by unauthorized reproduction, adaptation, distribution or any use other than the use permitted under the license agreement is prohibited. As a registered user of the Web Based Training course IP Networking you are allowed to make a single print of these Course Notes. Prepared by: Jayant Kapatker STAM Interactive Solutions Inc USA Tel: (609) Fax: (609) info@staminteractive.com Web: IP Networking Course Notes All Rights Reserved Page 2

3 Navigation Hints As you proceed through the online course, be sure to: Complete each sub-topic for each online topic. Repeat any window, if needed, to review its content. Watch for and click: - The blue buttons (for technical detail) - The flashing mouse symbol to get more information - Glossary Words (highlighted as red) to get definitions IP Networking Course Notes All Rights Reserved Page 3

4 Course Notes: IP Networking Online Course SECTION 1 - INTRODUCTION The concept of Digital Networking is growing rapidly. Communication is the main reason behind the concept of Networking. The two ways in which we can represent data is: Analog: Analog Signals are continuous electrical signals that vary in time. In order to convey information, Analog Signals always propagate in a medium. The disadvantages of the Analog Signals are noise, distortion and instability. Digital: Digital Signals are non-continuous signals that change in individual steps. Digital Signals are characterized by pulses or digits that are discrete in nature. The advantages of Digital Signals are that they are precise, error-free, low cost and they enable rapid storage and retrieval of data. SECTION 2 DIGITAL CONCEPTS Introduction Networking is the process of sharing data among different computers. The data can be of Analog or Digital type. But to share the data between computers, the Analog data is converted into Digital. The data is usually represented in bits and bytes. Bit is a binary digit that takes the value as 0 or 1. This is used to represent the amount of information. A Byte is a unit that collectively represents 8 bits. Basics IP Networking Course Notes All Rights Reserved Page 4

5 Principle A digital signal is a series of digits or symbols. There are many different ways in which a value can be given to this signal. In our day-to-day work we use the decimal system (ten possible values), while in digital signals the binary method is most popular. 1. The binary system is most popular because it best handles noise immunity as it can take only two values 0 or The basic unit of the binary system is called a bit (comes from binary digit). 3. The base 16 hexadecimal (also called hex) is also used quite often in computers because it is a convenient way to express binary values. Writing: The decimal system has ten digits (0,1,2,3,4,5,6,7,8,9) while the binary system has only two values (0,1). The key numbers in a decimal system are units, tens, thousands etc. Apply the same principle, but instead of a base of 10 use a base of 2. The number will look as follows: Decimal Binary Base IP Networking Course Notes All Rights Reserved Page 5

6 Issues 8 bits (binary digits) cover numbers from 0 to 255, 16 bits cover a range from 0 to 65,535 and 32 bits go from 0 to 4,294,967,295 Most digital systems use 8 bits to represent a decimal digit and this is also called a byte. Reading Reading a binary number is similar to reading a decimal number X2 7 X 2 6 X2 5 X2 4 X2 3 X2 2 x2 1 X2 0 Multiply by power of Add = = 155 Equivalent decimal value 155 or (1 x x x 1) Process: The two main processes that are employed in the Digital Networking are A to D Conversion and D to A Conversion. A to D Converter: The A/D Converter converts Analog Signals into the Digital format. The process involves the following steps of Sampling, Quantizing and Encoding of the Analog data to convert it into the Digital format. D to A Converter: The D/A Converters convert the discrete numerical values into a continuous waveform. This process involves three steps, namely Converter, Resampler and Filter. SAMPLING Sampling is a technique used to convert the continuous signal into the Digital Signal. In this process, the value of the signal is measured at certain intervals of time. Each IP Networking Course Notes All Rights Reserved Page 6

7 measured value is known as Sample. Hence, a Sample refers to a value or a set of values given at some point of time. When Sampling is done, the Discrete Signal will have more frequency components than the Analog Signal. If the Analog Signal has got more frequency components, we need to sample the signal at twice the maximum frequency of the signal. This will reduce the loss of information. This is known as Nyquist Rate. If the signal is sampled at a rate lower than the Nyquist Rate, the signal will exhibit a phenomenon called Aliasing. Aliasing is the presence of unwanted signals in the reconstructed signal. QUANTIZATION In the Sampling process, the continuous signal is converted into the Discrete Signal by sampling at some arbitrary values. With the Quantization process, the Discrete Signal will be converted into the Digital Signal. Hence, Quantization is commonly employed to convert Discrete Signals into Digital Signals. Quantization also plays an important role in the lossy data compression. The lossy and lossless data compression can be distinguished using Quantization. The difference between the original Analog Signal and the reconstructed Digital Signal is called Quantization Error. The difference is because of the rounding or truncating of the discrete values. ENCODING Encoding implies giving a bit value to each sample point. Encoding also includes: Bits which tells other equipment how to interpret data Information about the end of a sync pulse and start of a frame Error protection binary bits to reduce transmission and storage errors Bandwidth IP Networking Course Notes All Rights Reserved Page 7

8 The definition of bandwidth is different for analog and digital systems. The bandwidth in analog systems is defined as the transmission of the frequency range. Bandwidth in Digital Systems is defined as the data rate it can handle. Bandwidth is similar to the speed of liquid through different pipe sizes. The bandwidth of the uncompressed digital signal is very large. No transmission medium can handle this. So generally compression techniques are employed to reduce the bandwidth. SECTION 3 STRUCTURE Networks: Modern computer networks are classified into various categories depending upon the connection and geographical configuration strategy with the physical devices. The various types of networks are: LAN: A LAN is just a small version of a big network. Connected devices to the LAN share the resources of a single processor. This server has the applications such as data storage that can be shared by every one in the office. The people in the office can work on projects together and send instant messages. It can also be used to share a single printer to multiple computers. WAN: A WAN may be located entirely within a state or country, or it may be interconnected around the world. The world's most popular WAN is the Internet. A set of switches and routers are interconnected to form a Wide Area Network. VLAN = Virtual Local Area Network If you have a video system and a data system sharing the same network resources, it can cause confusion. To overcome this shortcoming it is possible to design a network system using Layer 3 Switchers so that tags can be added to identify which virtual network the packet belongs to. MAN: A Metropolitan Area Network combines characteristics of both LANs and WANs. Local access and transport areas are used to define the boundaries for MAN. IP Networking Course Notes All Rights Reserved Page 8

9 A MAN is optimized for a larger geographical area than a LAN, ranging from several blocks of buildings to entire cities. Metropolitan Area Networks can span up to 50km and the devices used are modem and wire/cable. Protocols: A Protocol is a standard format for sending and receiving information, error checking and data compression. A Protocol controls or enables the connection, communication and data transfer between two computing end points. There are different types of Protocols in use such as: ATM: ATM is abbreviated as Asynchronous Transfer Mode. ATM is a high-speed networking standard protocol which is designed to support both voice and data communications. GSM: GSM is the abbreviated form of Global System for Mobile Communication. GSM technology is the most popular standard used in mobile or cellular phones. IP: IP is the abbreviated form of Internet Protocol. The IP is data oriented protocol used for communicating data across a packet-switched internet work. TCP and UDP are two types of IP protocol. UDP has no acknowledgement is acceptable for video transmission DHCP: DHCP is abbreviated as Dynamic Host Configuration Protocol DHCP. DHCP is a protocol used by networked devices to obtain various parameters necessary for the clients to operate in an internet protocol. HTTP: HTTP is the abbreviated form of Hypertext Transfer Protocol. HTTP controls the transactions between a web client and a web server. IP Networking Course Notes All Rights Reserved Page 9

10 FTP: FTP is the abbreviated form of File Transfer Protocol. FTP is an application-layer protocol used to send and receive files between an FTP client and an FTP server. Ethernet Ethernet is the most widely used protocol in transmission of information in a network. Ethernet uses Carrier-Sense Multiple Access with Collision Detection (CSMA/CD) methodology for sending the packets. Each device waits for a pause, break or quiet in the network and then attempts to send a frame. If two devices send the packet at the same time there is a collision, then each device must try again after a pre-determined time. Tip : If data = 50% of the network bandwidth = collisions start causing network congestion, If data = 60% or more of the network bandwidth = the network can come to a grinding halt. This aspect must be taken into account while adding high bandwidth CCTV devices to a network. Each device in the network reads the first 48 bits of the frame and compares it with its own address. If it matches, the device delivers the packet to the network software. If it does not match, the device ignores the frame. Type Speed 10Base T or FX: 10 Mbps 100Base TX or FX: 100 Mbps 1000 Base TX, T4 or FX 1000 Mbps or 1 Gbps (new) Base (proposed) 10 Gbps Internetwork Internet Internet is a collection of LANs and WANs from all over the world, connected together in a way that facilitates the sharing of resources. It is an accessible series of IP Networking Course Notes All Rights Reserved Page 10

11 interconnected computer networks that transmit data by packet switching using the standard Internet Protocol. Internet security is provided either by filtering the packets going through the router or by adding a Firewall system. A Firewall system runs on a computer and offers the highest level of security and administration features. Intranet: Intranet is an organized, private and secured computer network system that uses the same concepts and protocols of internet but operates on local area network. An intranet is formed in such a way that all the information, applications such as sharing the files, sending instant messages and other resources of the organization s employees needs are accessible via intranet. Control and security measures are also available to restrict the access and user accounts. Extranet: Extranet is also called Inter-Organization Inter-Networking and provides many different applications and advantages. It allows different organizations to share information securely without the need to go through an open system like the Internet. A manufacturer can set up an extranet with a supplier to enhance productivity. We can share parts of the company s Intranet with the external Internet. A courier company can provide product tracking to customers through the Internet. Topology: A Topology defines the arrangement of nodes, cables, and connectivity devices that make up the network The main topologies are: Bus: A Bus Topology is one in which all the devices connect to a common, shared cable. Bus Topology uses a common backbone to connect all the network devices in a network in a linear shape. A single cable functions as the shared communication IP Networking Course Notes All Rights Reserved Page 11

12 medium for all the devices attached with this cable with an interface connector. Star: Star Networks are one of the most common computer network topologies in which they require all the devices to be connected to a central hub. The hub or concentrator receives signals from other network devices and routes the signals to the proper destinations. This acts as a conduit to transmit messages. The Star Topology reduces the chance of network failure by connecting all the systems to a central node. Ring: Ring Topologies are wired in a circle. Each node is connected to its neighbors on either side, and data passes around the ring in one direction only. Each device is a receiver and also a transmitter and serves as a repeater that passes the signal on to the next device in the ring. Because the signal is regenerated at each device, signal degeneration is low. Mesh: Mesh Topology works on the concept of routes. In Mesh Topology, a message sent to the destination can take the shortest or easiest possible route to reach its destination. The topology in which every device connects to every other device is called a full Mesh Topology unlike in the partial mesh in which every device is indirectly connected to the other devices. Tree: Tree Topologies are comprised of multiple Star Topologies on a Bus. Tree Topologies integrate multiple Star Topologies together onto a Bus. Only the hub devices can connect directly with the tree bus and each hub functions as a root of a tree of the network devices. Architecture Networking is linking two or more computing devices together for the purpose of sharing data. Networks are built with a mix of computer hardware and computer software. Networking is that which goes into connecting computers together. The connectivity between computers, users, companies is called Networking. IP Networking Course Notes All Rights Reserved Page 12

13 Peer-Peer Peer to Peer is a type of network in which each work station has equivalent capabilities and responsibilities. Peer-to-Peer LANs are commonly set up in small organizations or in schools, where the primary benefit of a network is shared storage, printers, and enhanced communication. These are simpler but they usually do not offer the same performance under heavy loads. Client-Server: A Client/Server network relationship is one in which a distinction exists between the computers that make network resources available (called the servers) and the computers that use the resources (called the clients, or workstations). A pure Client/Server network is one in which all the available network resources such as files, directories, applications, and shared devices are centrally managed and hosted, and then are accessed by the client computers. No client computers share their resources with other client computers or with the servers. Transmission There are 3 ways to transmit data over the network. Unicast Unicast transmission is the sending of messages to a single network destination identified by a unique address. Unicast is a one-to one connection between the client and the server. Unicast transmission can use up a lot of bandwidth. For example, if the same information has to be transmitted to 5 clients the bandwidth usage will be 5 times greater, each client using their own packet. Broadcast Broadcasting refers to transmitting a packet that will be received by every device on the network. Not all network technologies support broadcast addressing nor is there any form of Internet-wide broadcast. IP Networking Course Notes All Rights Reserved Page 13

14 Multicast Multicasting sends data only to interested destinations by using special routers and address assignments. Unlike broadcasting, which sends packets to all the clients in the network, multicasting send packets to selected groups only. Multitask enabled routers can help in creating these groups. SECTION 4 BASICS OF NETWORK Reference Models There are two types of Reference Model 1. OSI 2. TCP/IP 1. OSI: The OSI (Open Systems Interconnection Reference Model) model defines all the methods and protocols needed to connect one system to another system over a network. This model separates the methods and protocols needed for a network connection into seven different layers. Physical Layer: The Physical Layer, which is the first layer in the OSI model, defines the properties of the physical medium that is used to define a network connection. Data-Link Layer: The Data Link Layer provides flow, error control and the synchronization to the Physical Layer. Network Layer: The Network Layer provides a means to send data packets from the source to the destination via one or more networks. Transport Layer: The Transport Layer is responsible for error free transfer of messages. This acts as the connection between the source and the destination for reliable data delivery. IP Networking Course Notes All Rights Reserved Page 14

15 Session Layer: After the connection is made, the Session Layer manages the communication between the source and the destination. Presentation Layer: The Presentation Layer receives the data from the lower level layers and transforms it to make it presentable to the system. Application Layer: The Application Layer is the lowest of all the layers. It provides the user interface for communications. 2. TCP/IP: TCP/IP doesn t refer to a single protocol but is a suite of protocols. This also has a number of applications that enable a computer to communicate with other computers in a network. Application Layer: The Application Layer is a combination of Presentation, Session and Application Layer of the OSI model. Transport Layer: The responsibilities of the Transport Layer include end to end message transfer with error and flow control. Internet Layer: The Internet Layer is also called as TCP/IP Network Layer. This layer is responsible for the end to end delivery of the data i.e. from the source to the destination. Network Access Layer: In TCP/IP, this layer is a combination of the Data Link Layer and the Physical Layer. The TCP/IP model makes use of existing layers rather than defining its own. IP Addressing: IP V4 IP Address = Internet Protocol Address. IP Networking Course Notes All Rights Reserved Page 15

16 This IP address version 4.0 is unique and is made up of four sets of numbers separated by dots. Example: Any IP address has two parts. One part is the network address, while the second part gives the device address within the network. There are 3 classes of addresses Class A, B and C. No of Networks Devices/Network Class A million Class B 16,320 65,536 Class C 4.2 million 256 The number of networks and devices has exploded in the recent past. This means that the availability of IP addresses is getting exhausted. One solution to overcome the IP address shortage is to provide temporary addresses to devices as and when they connect to the Internet. Network Address Translation (NAT) is another solution to reduce the need for a device IP address. Here the Router, which is the starting point of the network, has a permanent IP address. All the devices connected to this network use this IP address. The router has the address list of the devices Network Interface card (NIC). The NAT uses this address to communicate within the network. This is also known as the IPX (Internet Protocol Exchange). IP V6 Due to the shortage of IP addresses, IP address version 6 is replacing version 4. Version 6 has a 128 bit IP address. The numbers of possible IP addresses are so many that they will never be exhausted. Size = 128 bits or 16 bytes. This IP address is divided into 8 parts x:x:x:x:x:x:x:x Where x is a 16 bits hexadecimal field (0-9,A,B,C,D,E,F) IP Networking Course Notes All Rights Reserved Page 16

17 A typical address :0000:1234:17C5:0000:C1C0:ABCD:0876 Maximum number of IP Addresses is or 300 x Currently, the world population is 6 x The number of possible IP v6 addresses thus seems inexhaustible. Address Breakdown Unlike version 4, which has Class A, B and C addresses, Version 6 is classless.. The first 3 parts of the address indicates the Network address, the fourth part shows the subnet address and last 4 parts cover the device address. Network Address = 48 bits Subnet Address = 16 bits Device Address = 64 bits Because of the huge number of possible IP v6 addresses, Port Forwarding, DHCP allocation of addresses, and Private IP address will not be required. Each and every network device will have its own static IP address. Transition Phase Upgrading from version 4 to version 6 will not be easy. Many of the current devices are not IPv6 ready. But new IP ready devices can handle both version 4 and 6, including infrastructure, like routers and servers in the Internet. This will be an intermediate phase and finally over time all devices will only have IPv6 addresses. IP v4 IP v6 Bit 32 bits 128 No of parts 4 8 Writing in Decimal Hexadecimal No of Addresses 4 x x Classes A,B and C Classless IP Networking Course Notes All Rights Reserved Page 17

18 Devices: DNS Servers: Domain Name System (DNS) server converts a readable web name ( to an IP address ( ) or vice versa. This server is usually a part of the ISP network. Some large networks have their own DNS server. DHC Servers: The Dynamic Host Configuration (DHC) server assigns IP addresses to the devices that are connected to the network. In a large network, a fixed IP address may not be possible due to addresses shortage. The DHC server controls and assigns IP addresses to devices. This way a device that is switched off does not occupy a valuable IP address. Specialized Servers: A wide range of servers is connected to the Internet, with specialized functions. A file server stores all the files, server routes all the s, and a proxy server allows the fast delivery of web server pages. Ports and Sockets: A Port is a 16-bit number that is used in communication process to identify the source and destination nodes. Both source and destination will have unique Port Numbers. Socket is a combination of the IP Address and a Port Number. The Socket uniquely identifies a single network process over the entire network. Port is for sending and receiving host. Sometimes Socket and Port Number are used interchangeably. Port Forwarding: The concept of port forwarding is required when a device in a private network wants to communicate with devices in the public network and vice versa. Port forwarding allows remote computers (for example, computers on the Internet) to connect to a specific computer or service within a private local-area network (LAN). IP Networking Course Notes All Rights Reserved Page 18

19 Private Network: The devices in the Private Network use the Reserved Class IP address so that they can communicate with each other. They cannot communicate with devices in the public network using their private IP address. Beside the Private IP address, the devices in the private network are also allocated a unique port number. Public Network: Each device in the Public Network will need a Class A, B or C class IP address. The devices in the private network are not visible to the devices in the public network and hence they are not able to communicate directly. DSL: ADSL or DSL ADSL = Asymmetric Digital Subscriber Line Principle: ADSL uses high-speed modulation techniques to send around 1.5 Mbps to 9 Mbps (compared to 56.6 kb per sec for modems) of information downstream from the device to the central office (CO) and 640 kb per sec upstream from the CO to the device. It is asymmetrical because the upstream and downstream are not the same. The modulation techniques create 256 channels, each with a bandwidth of 4 khz. The video signal is then sent in a parallel mode through these channels on a single telephone cable. SECTION 5 COMPONENTS The different components used in the network are covered in this section Software: Software programs are required to run the system. Like a computer, the network also has operating and application software. Network Operating System (NOS) organizes and manages all the activities in the network. IP Networking Course Notes All Rights Reserved Page 19

20 The types of software used in the network are: Application software Server software Management software NIC: NIC = Network Interface Card NIC is used to connect a computer to the Ethernet or to a network. This NIC acts like a link between the two computers to transmit and receive data on the LAN. The NIC assigns a unique MAC Address to each system. These addresses are used to direct traffic between computers. MAC vs. IP Address MAC Address = Occupant s Name living in the house IP Address = Street address of the house The NIC also provides a physical connection between the networking cable and the computer s internal bus. Network Interface Cards are available to support all the network standards and the bus architectures. Most NIC cards have both BNC and RJ- 45 connectors. Servers: A server is a powerful computer with a high RAM and hard disk capacity that performs specific tasks on a network. Some examples are: File server for storing files Database server for storing company records Application server for storing all the application software. Video server for storing video images Audio server for storing sound files. Hub: IP Networking Course Notes All Rights Reserved Page 20

21 Hub is a device and is found in the older networks. It is a central location where the devices connect to the hub through an RJ-45 connector called a port. It can be compared to an airport hub, where flights come from one location and then go to a different destination. Hubs usually have 4, 8 or 16 ports. Uplinking the hubs serially can expand the capacity. Only one device can communicate at any one time. This slows down the data transfer, resulting in lower bandwidths. Hubs are of two types: Active Hub: Amplifies the data packet received by it and then sends it to the other ports. The incoming data is regenerated allowing the devices to be kept at long distances from the hub. Passive Hub: Directly forwards the data packet to the other ports without any amplification. Being a Passive Hub, the maximum recommended distance of the device from the hub is 185 meters. Switch: A Network Switch is a hardware component that is similar to hub and has replaced the hub in most modern networks. This device joins multiple systems together within a LAN. Switches also direct the data packets from one system to other. Unlike hubs, these apply some intelligence and then forward the data packets. When the switch receives a data packet, it determines the source and the destination and forwards it appropriately to the intended device. Bridge: A Network Bridge connects two or more segments of a network into one. Bridges also direct data from one LAN to another LAN. The advantage of a bridge is that it reduces the amount of traffic over a network as this will not send all the data packets to the network. Bridges use two methods to direct the data traffic between the IP Networking Course Notes All Rights Reserved Page 21

22 network segments. Transparent Bridging: Bridges build a table of addresses as they receive data packets. If the destination address is not specified, the bridge will direct the data packet to all the segments except the one it came from. This is mostly employed in Ethernets. Source Route Bridging: The Source computer mentions the destination address and the path information inside the data packet. This is mostly employed in Token Ring Networks. Routers: Routers operate at the network layer of the OSI model. They forward the information to its destination on the network or the internet. Routers maintain tables that are checked each time a packet needs to be redirected from one interface to another. The routes may be added manually to the routing table or may be updated automatically using various protocols. Although primarily used to segment traffic, routers have additional useful features. A router may create or maintain a table of the available routes and their conditions, and then use this information along with distance and cost algorithms to determine the best route for a given packet. Gateway: A Gateway is a network point that acts as an entrance to other network. Gateways can operate at any layer of the OSI layer. Typically, a gateway converts one protocol stack to another. A gateway, which is a router by itself, transfers, accepts and relays packets only across networks using similar protocols. A gateway must understand the protocols used by each network linked into the router. Gateways are slower than bridges, switches and routers. Repeaters: Any network cabling will have a maximum distance defined to direct the network traffic. Beyond that if at all data is transmitted, then the data in the packet may be IP Networking Course Notes All Rights Reserved Page 22

23 lost. So to avoid any loss of data, repeaters are used in the networks, to boost the signal. The Repeater receives the signal from the computers, regenerates the signal and directs it to the other devices on the LAN network. SECTION 6 INSTALLATION Cabling: A Cable is a collection of wires that are bound together with a protective jacket or sheath. This is a medium through which information is passed from one device to another device. There are several types of cables which are commonly used. Depending on the network size, protocol, and topology, a cable of our choice can be selected. The various types of cables that are commonly used are: Co-axial: Coaxial cables are used to carry radio signals, video signals and data signals. A coaxial cable consists of two conductors that share a common axis. The cable impedance can be any value among is 50, 60, 75 and 93 ohms based on our application. The most popular cables in use are RG-58, RG-62, and RD-11. The typical band width or speed is 10Mbps.Thicker coaxial cables can transmit much faster. Fiber Optics: The fiber optics cable transmits light easily rather than electronic signals and eliminates the problem of electrical interference. It has the capability to carry information at very great speeds. The fiber optic cable consists of a center glass core surrounded by several layers of protective materials. Fibers are used to carry the signals and travel along them to avoid electromagnetic interference. Fiber optics has a wide range of applications such as, in cable television signals, internet communications, and telecommunications. Unshielded Twisted Pair: Unshielded Twisted Pair is abbreviated as UTP. UTP cabling is a form of wiring in which two conductors are wound together for the purpose of canceling out electromagnetic interference from external sources. Usually 2, 4, 6, or 8 wires will be enclosed in a plastic coating. The greater the IP Networking Course Notes All Rights Reserved Page 23

24 number of twists, the better is the protection against electromagnetic interference. Shielded Twisted Pair: Shielded Twisted Pair is abbreviated as STP. STP is a form of wiring in which two copper wires are twisted together and coated with an insulating coating that functions as ground for the wire. Shielded Twisted Pair wires can carry data at a faster speed than Unshielded Twisted Pair wires. Wireless: Wireless network is the transfer of information over a distance without the use of electrical conductors or wires. Wireless network is commonly associated with a telecommunications network whose interconnections between nodes are implemented without the use of wires. Wireless telecommunications networks are generally implemented with remote information transmission system that uses electromagnetic waves, such as radio waves. A quick comparison of the bandwidth of the different transmission methods: Type UTP Cable STP Cable Coaxial Cable Fiber Optics Microwave RF Infrared Bandwidth 4 to 100Mbps 150 Mbps 4 Mbps 100 to 2000 Mbps 10 Mbps 2Mbps 4 Mbps Troubleshooting: Troubleshooting a network problem can be daunting, especially for a complex network. Troubleshooting network problems is beyond the scope of this program. A few simple and common problems are discussed here. Link Lights: Check the color of the Light Emitting Diodes (LED) that is found in most network devices. A green light would indicate the successful transmission of data. A IP Networking Course Notes All Rights Reserved Page 24

25 red light will indicate a faulty device or cable connection. Device vs. Server: If most of the devices connected to the server are not working, then the problem is usually with the server. If only a single device is not working, then the problem is with the device. Cabling Issues: To connect the device to a hub requires a patch cable. To connect two hubs requires either a patch cable or crossover cable. Depending upon the cable type used, the hub setting should be modified. The following should also be checked: Broken cable Incorrect connections Total cable length Cable shorts Connector problems Slow Network Response: Slow network response could be due to excessive collision of packets. It could be a jabbering network card that is stuck in the transmit mode. Check if the light of the network card is continuously green. IP Addresses: Check if more than two devices have the same IP address. This can cause errors. Tools: Hardware Crossover Cable: Crossover cable is typically used to connect two hubs. It can also be used to test communications between two devices, bypassing the hub. Tone Generator and Tone Locator: This combination of devices is used on telephone systems to locate and trace cable runs. Software: Protocol Analyzer: It is a software program, which helps to decode, examine and IP Networking Course Notes All Rights Reserved Page 25

26 analyze the packets passing through the network. This analysis can help understand network traffic and also isolate network problems. Performance Monitoring Tool: This software tool helps monitor network performance and can display statistics regarding the traffic flow through different network devices. Connections: Four types of connections are popularly used namely: Peer to Peer: The PC is directly connected to the network camera using a category 5 crossover cable with RJ-45 connector. Intranet: Intranet is an internal or private LAN network. If you are connecting the network camera to a hub in the internal network, you will need to use a Straight Category Cable with RJ-45 connector. Internet-Single: A single camera is connected to the internet using cable or xdsl modem. Internet-Multiple: To connect multiple cameras to the internet, a router must be connected to the cable or xdsl modem. Commands IPconfig IPconfig command in a Windows environment provides all the IP related information about the device Ping Ping = Packet Internet Groper Ping is a utility used to test the reachability of a host on an IP network and it measures the round-trip time taken for packets sent from the originating host to a IP Networking Course Notes All Rights Reserved Page 26

27 destination computer. ARP ARP = Address Resolution Protocol The ARP or Address Resolution Protocol allows you to identify the MAC address and the IP address for devices in the network. Knowing the MAC address comes in handy for a number of troubleshooting operations. Tracert Tracert = Trace Route Tracert is a Windows based command-line tool that you can use to trace the path that an Internet Protocol (IP) packet takes to its destination from a source. It will provide the list of routers and also the incremental time taken for the packet to reach each router location. Security There are different ways to secure information being sent over IP networks. Username and password authentication IP address filtering IEEE 802.1X HTTPS or SSL/TLS VPN (Virtual Private Network) Username and password authentication Using a username and password authentication is the most basic method of protecting data on an IP network, and may be sufficient where high levels of security are not required. The passwords can be encrypted or unencrypted when they are sent; the former provides better security. IP address filtering In IP address filtering security is provided by giving or denying access rights to defined IP addresses. This way you can limit which devices in the network can have IP Networking Course Notes All Rights Reserved Page 27

28 access to the required information IEEE 802.1X IEEE 802.1X is the standard protocol for allowing hosts and users to be authenticated to the network before obtaining a connection. It provides effective access control to wireless and other networks. In today s enterprise networks, IEEE 802.1X is becoming a basic requirement for anything that is connected to a network. HTTPS or SSL/TLS HTTPS (Hyper Text Transfer Protocol Secure) is identical to HTTP but with one key difference: the data transferred is encrypted using Secure Socket Layer (SSL) or Transport Layer Security (TLS). This security method applies encryption to the data itself, which makes it possible for data to be securely viewed using a web browser. The use of HTTPS, however, can slow down the communication link and, therefore, the frame rate of the video. VPN (Virtual Private Network) VPN = Virtual Private Network VPN provides security through encryption and authentication technologies that protect data in transit from unauthorized access and attacks. This way a private network is setup using the public network. IP Networking Course Notes All Rights Reserved Page 28