NETWORKING TECHNOLOGIES :FUNDAMENTALS AND CONCEPTS

• When people use computers to communicate, they use a computer network. This is about computer networks and how they are used to transmit information between computers and ultimately between people. It provides a broad overview and foundation for understanding networks and working in the computer and networking.

• People use computers and networks for a wide variety of reasons.

• Three common reasons that people use networks to send information

• from a source, such as a personal computer (PC), to a destination, such as a printer, are:

Communicate and collaborate (i.e., e-mail)

Share information (i.e., document sharing)

Share resources (i.e., printers and servers)

1. Increased Employee Productivity

Ideas are shared more quickly. Everyone moves faster. The organization is more

competitive.

2. Reduced Communication Costs Network-based communication such as e-mail and

“instant messenger” services are a cost-effective alternatives to phoning and faxing, with the potential to deliver significant savings in long distance charges.

3. Reduced Office Equipment Costs Allows equipment – mainly printers and servers, to be shared with multiple users.

4. Access to Resources Anytime/Anywhere Key files, data, and services can be accessed from

any place on the network. With remote access in place, one can travel or work remotely and still be connected.

make a phone call,watch a television showlisten to the radiolook up something on the Internetplay a video game with someone in

another country

All of these activities depend on robust, reliable networks. Converged network

• Modems - Change digital data into analog for transmission over the line. There are three types: Traditional, DSL and Cable

• Modulator-Demodulator.

V.90-based 56Kbps connections

typical hybrid fiber-coax cable TV network

• A NIC (pronounced "nick") is the hardware component inserted into the PC or workstation that provides connectivity to a network. The NIC provides the interface between the physical networking cable and the software implementing the networking protocols. The NIC is responsible for transmitting and receiving information to and from a network.

Speeds available: 10 Mbps, 10/100 Mbps, 10/100/1000 Mbps

Auto sense: This is where a port that can operate at different speeds has the ability to detect the speed of another port to which it is connected; both ports will automatically configure to use the best common speed.

Duplex mode: Half Duplex - The term half duplex is used to describe data transmission that can occur in two directions over the same communications link, in only one direction at a time.

Full Duplex: The ability of a device or line to transmit data simultaneously in both directions over the same communications link, potentially doubling the throughput of traffic.

All PCs require network interface cards (NIC) to make them ready for network use. Some are supplied with NICs already in them. When choosing a NIC for a PC you should consider:

• The speed of your hub, switch, or print server— Ethernet (10Mbps) or Fast Ethernet (100Mbps). • The type of connection you need—RJ-45 for twisted pair or BNC for coaxial cable. • The type of NIC connector available inside your Computer—ISA or PCI.

Each individual NIC throughout the world carries a unique code, called a Media Access Control (MAC) address. Not two NIC are alike. This address is used to control data communication for the host on the network. A MAC address consists of 12 hexadecimal bits. The first 6 hexadecimal represents the NIC manufacturer and the last 6 hex numbers represents the unique number of a NIC.

When a NIC is attached to a computer, the host computer will use the NIC’s MAC address as its physical address in the network. These physical address from the NIC will be used by the computer to identify themselves in the network.

• Media Access Control (MAC) Addresses• MACs are the 48-bit, hexadecimal

hardware addresses that identify Ethernet interfaces. It is presented like so:

• 01:23:45:67:89:00

Installing the NIC.

• Networking Cables and Connectors• RJ-11: Telephone

STP (Shielded Twisted Pair) cable

• RJ-45: CAT-5, 5e and 6

strip cable jacket

arrange wire pairs

AT&T 258A_EIA 568B

RJ-45 Connector inserted

UTP Cable and RJ-45 connector

• BNC: Coaxial

• Basic Network Devices• Hubs - Simple, Layer 1 devices that

create a single broadcast domain. There are four types: Passive, Active, Intelligent and Switching

• Modems - Change digital data into analog for transmission over the line. There are three types: Traditional, DSL and Cable

• Modulator-Demodulator.

LAN Modems

A LAN Modem is router with a built-in Ethernet hub and two 56K analog modem, allowing several workstations to share a single connection to an ISP or remote office LAN, while transferring files locally among all attached workstations.

• Network Interface Cards (NIC) - Cards with which a PC connects to an Ethernet or wireless network.

• Switch - Layer 2 devices that connects and selects between network segments. Unlike hubs, switches provide packet filtering and forwarding.

Manageable Hubs and Switches

Manageable Hubs and Switches are network devices that connects computers together and form a local area network. Aside from basic connectivity, these manageable devices have many useful features that are not present in any ordinary hubs and switches. These features are:

• VLAN (Virtual LAN) - A logical association that allows users to communicate as if they were physically connected to a single LAN, independent of the actual physical configuration of the network.

• Port Security – A feature that disables or enables a particular port on the switch or hub.

• Stackability – A feature that allows switches to be connected physically by a matrix cable and be treated as a single device.

• Link Aggregation – allows 2 – 4 of the switch’s ports to be combined together and treated as a single pipe.

switch_hub

• Router - A layer 3 device that separates network segments into different broadcast domains. Routers are high-level devices that provide an enormous amount of administration and monitoring features and allow for highly complex networks.

Using a router to share a broadband (cable or DSL) modem connection

A Router Helps Protect Your Home Network from Outside Access

Typical home network

typical wireless network

WRT54G2 v1

wireless adapter

• Star - These networks are centrally administrated and nodes can be easily connected or disconnected using network media. This is most commonly seen in 10BASE-t, 100BASE-TX or 1000BASE-T networks.

Star

• Bus - Nodes “tap” into a central line. These networks are almost completely obsolete, as faults with individual nodes bring the entire network down.

Bus

• Mesh - Expensive to implement, mesh networks are easy to maintain and extremely reliable. They also work over great distances.

MESH

• Ring - Uses expensive, proprietary technology that passes a “token” packet around the ring in order to cut down on network collisions.

Ring

• Point to Point - These are simple, ad-hoc networks where one point goes to one other point. They are simple to set up and maintain, but would be expensive if they were the sole topology in a network.

Point to Point

• Point to Multipoint - This network type describes most WAN and VPN setups, like frame-relay. They’re used to connect physically distant devices.

Point to Multipoint

• Hybrid - Most networks are actually hybrids, being composed of one or all of these various topologies.

Project Network Topology and Physical Layout Design:

NETWORK TOPOLOGY DESIGN (using packet tracer simulation ) - employ segmenting the whole campus network into several number of nodes using routers to boost network performance and increases the bandwidth available to each user for network and internet connection.

• Peer to peer• A peer-to-peer network topology means

that each network device is a client and there is no central system. These are mainly used in home or small business networks. Shared resources require computers to be configured independently for access.

• Client/server• A number of client machines are all

administered, authenticated and given access to shared resources through a central server or servers. This type of topology is much easier to maintain as users can be defined in one central location.

client-server LAN

• VPN• A VPN is a private, secure connection

through the public Internet. It allows a “point-to-point” connection between a remote user and a LAN. The connection uses encryption and authentication.

• VLAN• VLANs (Virtual Local Area Networks) are

groups of network nodes that form a single, logical broadcast domain. VLANs use a switch operating at Layer 2, but sometimes need a Layer 3 device to allow VLANs to communicate with each other.

• Network Protocols• Transmission Control Protocol (TCP)

- TCP is a transport layer, host-to-host, connection-oriented protocol. It enables two hosts to establish a connection and exchange network data.

• User Datagram Protocol (UDP)• UDP is a transport layer,

connectionless, unreliable, low overhead protocol. UDP doesn’t offer the assurances of TCP.

• File Transfer Protocol (FTP)• The FTP is an Application layer

protocol that allows a user to upload or download files between hosts

• Secure File Transfer Protocol (SFTP)• SFTP is similar to FTP but comes

with SSH to provide encryption over insecure networks such as the Internet.

• Trivial File Transfer Protocol (TFTP)• TFTP is also similar to FTP but works with

UDP, using less bandwidth than FTP. 

• Email Protocols • Simple Mail Transport Protocol

(SMTP) is used to send e-mail. Post Office Protocol 3 (POP3) and Internet Message Access Protocol 4 (IMAP4) are used to receive emails.

• Secure Shell (SSH) • SSH is a suite of protocols that uses the

RSA public-key encryption technology authentication

• Internet Control Message Protocol (ICMP)• ICMP is a network layer protocol providing

management and control

• Address Resolution Protocol (ARP)• ARP is a Network layer protocol that

resolves network (IP) addresses into hardware (MAC) addresses. ARP uses the address resolution cache table built into every NIC.

• Internet Group Multicast Protocol (IGMP)

• IGMP is a Network layer protocol that is used by an Internet computer to report its multicast group membership to adjacent routers.

• Telnet• Telnet is a terminal emulation protocol

and program that uses TCP for transport, and most often used for server and network device remote administration.

• Transport Layer Security (TLS)• TLS replaces SSL and/or HTTPS in

providing a secure mode of transport for data from server to client.

• Session Initiation Protocol (SIP)• SIP is a VoIP call control protocol that uses

a URL to address a specific endpoint.

• Dynamic Host Configuration Protocol (DHCP)

• DHCP is used by devices to request IP addresses and local network configuration parameters.

wifi alliance

1. TCP/IP - Transmission Control Protocol/Internet Protocol. TCP is normally used in conjunction with IP in a TCP/IP-based network. The two protocols working together provide for connectivity between applications of networked computers. Originally a UNIX standard, TCP/IP is now supported on almost all platforms, and is the protocol of the Internet.

IP represents the scheme by which two devices (both with IP addresses) communicate. TCP manages the flow of IP packets, ensuring that the packets remain error-free and reach their destination correctly.

Hosts and networks IP addressing is based on the concept of hosts and networks. A host is essentially anything on the network that is capable of receiving and transmitting IP packets on the network, such as a workstation or a router. It is not to be confused with a server: servers and client workstations are all IP hosts. 

• IPv4• IPv4 addresses employs a 32-bit

addressing scheme that is presented in a format called dotted decimal notation, like so:

• 192.168.10.235

• IPv6• IPv6 employs a 128-bit addressing

scheme divided into eight 16-bit hexadecimal numbers separated by colons, like so:

• 2342:0000:1F1F:0100:0010:0100:11B0:AFFF

• IP Address Classes

• Subnetting• Subnetting is the process of subdividing an

assigned IP address into smaller networks or subnets.

• Classless Inter-Domain Routing (CIDR)• CIDR is a routing scheme used to mitigate the

address shortage in IPv4 by drawing together a number of networks into one large routing table entry. A routing protocol must be classless to support CIDR.

• Network Address Translation (NAT)

• NAT allows administrators to translate one public IP address into public network access for many private IP addresses.

An IP address is 32 bits wide, and as discussed, it is composed of two parts: the network number, and the host number [1, 2, 3]. By convention, it is expressed as four decimal numbers separated by periods, such as "200.1.2.3" representing the decimal value of each of the four bytes. Valid addresses thus range from 0.0.0.0 to 255.255.255.255, a total of about 4.3 billion addresses. An IP address is a numbering system based on Octal numbering notation.

xxxxxxxx.xxxxxxxx.xxxxxxxx.xxxxxxxx

1

2

4

8

16

32

64

128

11001011. 01010111.10000000.00000010203 87 128 2

Subnet MaskExample:•Network: 192.168.12.0•4 workgroups (Logistics, Administration, Engineering, and Human Resources) that needed to be separated logically.• required to build 4 sub networks from 192.168.12.0

HR Admin

Eng’g

192.168.12.x(00000000)network Hosts

Logistics

Subnet Mask

HR Admin

Logistics Eng’g

192.168.12.x(00000000)

NetworkHosts

Borrow 2 bits:

• 00 – Logistics = 00

• 01 – Engineering = 64

• 10 – Human Resource = 128

• 11 – Admin = 192

Logistics use 192.168.12.1- 62 Subnet mask 255.255.255.192

Engineering use 192.168.12.65 – 126 Subnet mask 255.255.255.192

Human Resource use 192.168.12.126 – 190 Subnet mask 255.255.255.192

Admin use 192.168.12.193 – 254 Subnet mask 255.255.255.192

NETWORK PHYSICAL LAYOUT DESIGN (using Microsoft Office Visio 2003)

• Wired Equivalent Privacy (WEP)• WEP provides either 64- or 128-bit

encryption for data packets over radio• frequencies providing a similar level of

security as wired Ethernet networks. WEP does not offer end-to-end security because it uses the lower level layers in the OSI model.

• Remote Authentication Dial-In User Service (RADIUS)

• RADIUS is used as an authentication and accounting server, storing username and password combinations for use with a variety of different services. RADIUS is typically used in conjunction with 802.11i to authenticated pre-shared

• wireless keys

• Wi-Fi Protected Access (WPA)• WPA offers improved data encryption and

user authentication over WEP using the wireless device’s hardware-specific MAC address as a means of ensuring that only authorized users access the network. The current version WPA2 uses

• Advanced Encryption Standard (AES).

• Frame relay - Frame Relay is a packet switching technology used as a replacement to leased lines because frame relay connections are more cost effective. A frame relay connection is able to virtually connect to a number of different remote sites through point-to-point and point-to-multipoint connections.

• Key Frame Relay Terms• ˚ Virtual Circuits (VC): the frame relay

connections.• ˚ Committed Information Rate (CIR): the

maximum amount of data bandwidth contracted by the provider.

• ˚ Burst: an amount of extra bandwidth provided based on need and network demand.

• ˚ Data Link Connection Identifier (DLCI): Identifies each individual VC.

• T1/E1/J1• The T-series connections are digital carrier

transmission systems. ISPs and large companies employ either T1 or T3 transmission lines for access to the Internet.

• Common T-series lines and their speeds include:

• ˚ T1 operates at1.544 Mbps using 24 voice channels• ˚ T3 operates at 44.746 Mbps using 672 voice channels• ˚ E1 operates at 2.048 MBps using 30 voice channels• ˚ E3 operates at 34.368 MBps using 480 voice channels• ˚ J1 operates at 1.544 Mbps using 24 voice channels• ˚ J3 operates at 32.064 Mbps using 480 voice channels

• ˚ T1 operates at1.544 Mbps using 24 voice channels• ˚ T3 operates at 44.746 Mbps using 672 voice channels• ˚ E1 operates at 2.048 MBps using 30 voice channels• ˚ E3 operates at 34.368 MBps using 480 voice channels• ˚ J1 operates at 1.544 Mbps using 24 voice channels• ˚ J3 operates at 32.064 Mbps using 480 voice channels

• E designates European; J designates Japanese. Note the difference in speeds.

• DSL• Digital Subscriber Line or DSL is a high-

speed Internet access technology carrying both digital voice and digital data and is used by businesses and consumers.

• Broadband Cable• This also provides high-speed Internet

access technology carrying digital data and uses coaxial cable. cable modems convert analog signals into digital data. Cable companies offer a range of bandwidths from 256 Mbps to 1024 Mbps upload speed to 512 Mbps to 3 Mbps download speed.

• OC-x/SONET• The base rate for OCx using fiber optic

media is called OC-1 and operates at 51.84 Mbps. The Synchronous Optical Network (SONET ) also uses various OCx speeds on optical fiber.

• Wireless• There are a couple of different wireless

technologies which are currently used for Wide Area Networks. These include microwave point-to-point connections, satellite and WiMAX (802.16). WiMAX uses some of the same concepts as the 802.11 technologies, but over a larger area.

• ATM• Asynchronous Transfer Mode (ATM)

provides a high speed solution for large scale WANs. ATM splits traffic into 53 byte cells which are transferred across the ATM network extremely quickly. ATM also offers a large number of QoS options for traffic which allow traffic priority to be very refined.

• MPLS• Multi Protocol Label Switching (MPLS) is a

packet switching technique which enables packets to be tagged or labeled to differentiate different types of traffic. These types can be anything from different streams requiring high QoS requirements like VoIP or they can be used to form a VPN to safely transport traffic between multiple companies’ branches.

• Firewall - Firewalls sit in the DMZ, between an intranet and the Internet and provide packet filtering to keep unauthorized access from the protected network.

WAN Connection Types    WAN Services

A WAN is a data communications network that operates beyond a LAN's geographic scope. One way that a WAN is different from a LAN is that you must subscribe to an outside WAN service provider, such as PLDT and Globe Telecoms to use WAN carrier network services. A WAN uses data links, such as Analog Telephone and Frame Relay, that are provided by carrier services to access bandwidth over wide-area geographies. A WAN connects the locations of an organization to each other, to locations of other organizations, to external services (such as databases), and to remote users. WANs generally carry a variety of traffic types, such as voice, data, and video.

• Cross Connects - The location where different cable sections come together

• Patch Panels - A collection of terminated circuits which can be patched together.

WIRING DISTRIBUTION AND NETWORK CABLING TOOLS

• Command Line Interface Tools• Be familiar with the following command line

tools:• ˚ Traceroute (or tracert)• ˚ ipconfig• ˚ ifconfig (for Linux)• ˚ ping• ˚ ARP ping• ˚ ARP

• ˚ nslookup• ˚ hostname• ˚ dig (for Linux)• ˚ mtr (for Linux)• ˚ route• ˚ nbtstat• ˚ netstat

It has become appallingly obvious that our technology has exceeded our humanity. Albert Einstein (1879-1955)  

Technology is a way of organizing the universe so that man doesn't have to experience it. Max Frisch  

Technology is a gift of God. After the gift of life it is perhaps the greatest of God's gifts. It is the mother of civilizations, of arts and of sciences. Freeman Dyson   - Infinite in All Directions