Basic Networking Part #5

Net work Cables and Stuff:

First part of Physical In the network is cables, you will commonly find three types of cables used these are the,1- coaxial cable no More used commonly ,2- twisted pair commonly used and 3- fiber optic Newly Used for High Speed and long distance

Cables standards
there are three main cabling standards:

1. EIA/TIA 568A - This is the American standard and was the first to be published (1991).
2. ISO/IEC 11801 - The International standard for structured cabling systems.
3. CENELEC EN 50173 - The European cabling standard.     

Thick Coaxial Cable
This type cable is usually yellow in color and used in what is called thick nets, and has two conductors. This coax can be used in 500-meter lengths. The cable itself is made up of a solid center wire with a braided metal shield and plastic sheathing protecting the rest of the wire.

Thin Coaxial Cable Type1
As with the thick coaxial cable is used in thick nets the thin version is used in thin nets. This type cable is also used called or referred to as RG-58. The cable is really just a cheaper version of the thick cable.

Fiber Optic Cable Type 2
As we all know fiber optics are pretty darn cool and not cheap. This cable is smaller and can carry a vast amount of information fast and over long distances.

Twisted Pair Cables
These come in two flavors of unshielded and shielded.

Shielded Twisted Pair (STP)
Is more common in high-speed networks. The biggest difference you will see in the UTP and STP is that the STP use's metallic shield wrapping to protect the wire from interference.

-Something else to note about these cables is that they are defined in numbers also. The bigger the number the better the protection from interference. Most networks should go with no less than a CAT 3 and CAT 5 is most recommended.

-Now you know about cables we need to know about connectors. This is pretty important and you will most likely need the RJ-45 connector. This is the cousin of the phone jack connector and looks real similar with the exception that the RJ-45 is bigger. Most commonly your connector are in two flavors and this is BNC (Bayonet Naur Connector) used in thicknets and the RJ-45 used in smaller networks using UTP/STP.

Unshielded Twisted Pair (UTP)

This is the most popular form of cables in the network and the cheapest form that you can go with. The UTP has four pairs of wires and all inside plastic sheathing. The biggest reason that we call it Twisted Pair is to protect the wires from interference from themselves. Each wire is only protected with a thin plastic sheath.

Ethernet Cabling Speed and Standard

Now to familiarize you with more on the Ethernet and it's cabling we need to look at the 10's. 10Base2, is considered the thin Ethernet, thin net, and thin wire which uses light coaxial cable to create a 10 Mbps network. The cable segments in this network can't be over 185 meters in length. These cables connect with the BNC connector. Also as a note these unused connection must have a terminator, which will be a 50-ohm terminator.
 

1	1 Mbps	Voice Only (Telephone Wire)
2	4 Mbps	LocalTalk & Telephone (Rarely used)
3	16 Mbps	10BaseT Ethernet
4	20 Mbps	Token Ring (Rarely used)
5	100 Mbps (2 pair) 1000 Mbps (4 pair)	100BaseT Ethernet Gigabit Ethernet
5e	1,000 Mbps	Gigabit Ethernet
6	10,000 Mbps	Gigabit Ethernet

An important part of designing and installing an Ethernet is selecting the appropriate Ethernet medium. There are four major types of media in use today: Thick wire for 10BASE5 networks, thin coax for 10BASE2 networks, unshielded twisted pair (UTP) for 10BASE-T networks and fiber optic for 10BASE-FL or Fiber-Optic Inter-Repeater Link (FOIRL) networks. This wide variety of media reflects the evolution of Ethernet and also points to the technology's flexibility. Thick wire was one of the first cabling systems used in Ethernet but was expensive and difficult to use. This evolved to thin coax, which is easier to work with and less expensive.

Basic Networking Part # 4

Protocols:Defination: A protocol is nothing more than a set of rules that that govern the format of messages so they can be exchanged successfully. A network protocol is a set of rules that allow for communication between network devices
Network protocols are standards that allow computers to communicate. A protocol defines how computers identify one another on a network, the form that the data should take in transit, and how this information is processed once it reaches its final destination. Protocols also define procedures for handling lost or damaged transmissions or "packets." TCP/IP (for UNIX, Windows NT, Windows 7 and other platforms), IPX (for Novell NetWare), Now Novell also using TCP/IP. DECnet (for networking Digital Equipment Corp. computers), AppleTalk (for Macintosh computers), and NetBIOS/NetBEUI (for LAN Manager and Windows NT networks, Windows Server 2003 or 2008) are the main types of network protocols in use today.

Although each network protocol is different, they all share the same physical cabling.Ethernet CAT5 or CAT6 or Fiber. This common method of accessing the physical network allows multiple protocols to peacefully coexist over the network media, and allows the builder of a network to use common hardware for a variety of protocols. This concept is known as "protocol independence,"

Some Important Protocols and their job:

	Finger DNS	Obtains information about a user from their profile. Domain Name Service: translates computer names into addresses and addresses into names.
	Whois	Obtains information about domain registration.
	Daytime	Network Time Protocol. Gets the time from a server.
	HTTP	Hypertext Transfer Protocol. Used for the Web.
	SMTP	Simple Mail Transfer Protocol. Used for sending email.
	POP	Post Office Protocol. Used for fetching email.
	FTP	File Transfer Protocol. Exchanges files with a server.
	NNTP	Network News Transfer Protocol. Posts or reads Usenet news.
	TCP	Transmission Control Protocol. Basic Internet protocol.
	UDP	User Datagram Protocol. Packet-based protocol.

Now I’ll disscuss the most important protocol suite known today from its wide usage in the Internet world is TCP/IP: Transmission Control Protocol (TCP) / Internet Protocol (IP).

Introduction to TCP/IP Networks:

TCP/IP-based networks play an increasingly important role in computer networks. Perhaps one reason for their appeal is that they are based on an open specification that is not controlled by any vendor.

What Is TCP/IP?TCP stands for Transmission Control Protocol and IP stands for Internet Protocol. The term TCP/IP is not limited just to these two protocols, however. Frequently, the term TCP/IP is used to refer to a group of protocols related to the TCP and IP protocols such as the User Datagram Protocol (UDP), File Transfer Protocol (FTP), Terminal Emulation Protocol (TELNET), and so on.

The Origins of TCP/IP (Basic of TCP/IP)In the late 1960s, DARPA (the Defense Advanced Research Project Agency), in the United States, noticed that there was a rapid proliferation of computers in military communications. Computers, because they can be easily programmed, provide flexibility in achieving network functions that is not available with other types of communications equipment. The computers then used in military communications were manufactured by different vendors and were designed to interoperate with computers from that vendor only. Vendors used proprietary protocols in their communications equipment. The military had a multi vendor network but no common protocol to support the heterogeneous equipment from different vendors.

Basic Networking Part # 3

The OSI Model:
Open System Interconnection (OSI) reference model has become an International standard and serves as a guide for networking. This model is the best known and most widely used guide to describe networking environments. Vendors design network products based on the specifications of the OSI model. It provides a description of how network hardware and software work together in a layered fashion to make communications possible. It also helps with trouble shooting by providing a frame of reference that describes how components are supposed to function.

There are seven to get familiar with and these are the physical layer, data link layer, network layer, transport layer, session layer, presentation layer, and the application layer.

• Physical Layer, is just that the physical parts of the network such as wires, cables, and there media along with the length. Also this layer takes note of the electrical signals that transmit data throughout system.
• Data Link Layer, this layer is where we actually assign meaning to the electrical signals in the network. The layer also determines the size and format of data sent to printers, and other devices. Also I don't want to forget that these are also called nodes in the network. Another thing to consider in this layer is will also allow and define the error detection and correction schemes that insure data was sent and received.
• Network Layer, this layer provides the definition for the connection of two dissimilar networks.
• Transport Layer, this layer allows data to be broken into smaller packages for data to be distributed and addressed to other nodes (workstations).
• Session Layer, this layer helps out with the task to carry information from one node (workstation) to another node (workstation). A session has to be made before we can transport information to another computer.
• Presentation Layer, this layer is responsible to code and decode data sent to the node.
• Application Layer, this layer allows you to use an application that will communicate with say the operation system of a server. A good example would be using your web browser to interact with the operating system on a server such as Windows NT, which in turn gets the data you requested.

Network Architectures:

Ethernet

Ethernet is the most popular physical layer LAN technology in use today. Other LAN types include Token Ring, Fast Ethernet, Fiber Distributed Data Interface (FDDI), Asynchronous Transfer Mode (ATM) and LocalTalk. Ethernet is popular because it strikes a good balance between speed, cost and ease of installation. These benefits, combined with wide acceptance in the computer marketplace and the ability to support virtually all popular network protocols, make Ethernet an ideal networking technology for most computer users today. The Institute for Electrical and Electronic Engineers (IEEE) defines the Ethernet standard as IEEE Standard 802.3. This standard defines rules for configuring an Ethernet network as well as specifying how elements in an Ethernet network interact with one another. By adhering to the IEEE standard, network equipment and network protocols can communicate efficiently.

Fast Ethernet

For Ethernet networks that need higher transmission speeds, the Fast Ethernet standard (IEEE 802.3u) has been established. This standard raises the Ethernet speed limit from 10 Megabits per second (Mbps) to 100 Mbps with only minimal changes to the existing cable structure. There are three types of Fast Ethernet: 100BASE-TX for use with level 5 UTP cable, 100BASE-FX for use with fiber-optic cable, and 100BASE-T4 which utilizes an extra two wires for use with level 3 UTP cable. The 100BASE-TX standard has become the most popular due to its close compatibility with the 10BASE-T Ethernet standard. For the network manager, the incorporation of Fast Ethernet into an existing configuration presents a host of decisions. Managers must determine the number of users in each site on the network that need the higher throughput, decide which segments of the backbone need to be reconfigured specifically for 100BASE-T and then choose the necessary hardware to connect the 100BASE-T segments with existing 10BASE-T segments. Gigabit Ethernet is a future technology that promises a migration path beyond Fast Ethernet so the next generation of networks will support even higher data transfer speeds.

Token Ring

Token Ring is another form of network configuration which differs from Ethernet in that all messages are transferred in a unidirectional manner along the ring at all times. Data is transmitted in tokens, which are passed along the ring and viewed by each device. When a device sees a message addressed to it, that device copies the message and then marks that message as being read. As the message makes its way along the ring, it eventually gets back to the sender who now notes that the message was received by the intended device. The sender can then remove the message and free that token for use by others.

Various PC vendors have been proponents of Token Ring networks at different times and thus these types of networks have been implemented in many organizations.

FDDI

FDDI (Fiber-Distributed Data Interface) is a standard for data transmission on fiber optic lines in a local area network that can extend in range up to 200 km (124 miles). The FDDI protocol is based on the token ring protocol. In addition to being large geographically, an FDDI local area network can support thousands of users.

Basic Networking Part 2

For Part 1  Please click here

http://networking-gulf.blogspot.com/2011/05/basic-networking-part-1.html
For Gulf  IT Jobs Click Here
http://gulfworking.blogspot.com/2011/05/jobs-in-dubai-united-arab-emirates.html

Categories of Network:

Network can be divided in to two main categories:

• Peer-to-peer.
• Server – based.

In peer-to-peer networking there are no dedicated servers or hierarchy among the computers. All of the computers are equal and therefore known as peers. Normally each computer serves as Client/Server and there is no one assigned to be an administrator responsible for the entire network.

Peer-to-peer networks are good choices for needs of small organizations where the users are allocated in the same general area, security is not an issue and the organization and the network will have limited growth within the foreseeable future.

The term Client/server refers to the concept of sharing the work involved in processing data between the client computer and the most powerful server computer.

The client/server network is the most efficient way to provide:

• Databases and management of applications such as Spreadsheets, Accounting, Communications and Document management.
• Network management.
• Centralized file storage.

The client/server model is basically an implementation of distributed or cooperative processing. At the heart of the model is the concept of splitting application functions between a client and a server processor. The division of labor between the different processors enables the application designer to place an application function on the processor that is most appropriate for that function. This lets the software designer optimize the use of processors--providing the greatest possible return on investment for the hardware.

Client/server application design also lets the application provider mask the actual location of application function. The user often does not know where a specific operation is executing. The entire function may execute in either the PC or server, or the function may be split between them. This masking of application function locations enables system implementers to upgrade portions of a system over time with a minimum disruption of application operations, while protecting the investment in existing hardware and software.

IPv6 or IPng (IP Next generation) Basic Networking

 I will dicuss about Brief introduction about IPV6

IPv6 is short for "Internet Protocol Version 6". IPv6 is the "next generation" protocol designed by the IETF (The Internet Engineering Task Force) to replace the current version Internet Protocol, IP Version 4 ("IPv4"). The IP v 6 specifications are in rfc2460. 

Most of today's internet uses IPv4, which is now nearly twenty years old. IPv4 has been remarkably resilient in spite of its age, but it is beginning to have problems. Most importantly, there is a growing shortage of IPv4 addresses, which are needed by all new machines added to the Internet. It wil give 3200 IP for each 1meter at whole earth (Include Land and Water).

IPv6 fixes a number of problems in IPv4, such as the limited number of available IPv4 addresses. It also adds many improvements to IPv4 in areas such as routing and network autoconfiguration. IPv6 is expected to gradually replace IPv4, with the two coexisting for a number of years during a transition period.

IPv6 is the long-anticipated upgrade to the Internet's main communications protocol, which is known as IPv4.

IPv4 uses 32-bit addresses and can support 4.3 billion devices connected directly to the Internet. IPv6, on the other hand, uses 128-bit addresses and supports a virtually unlimited number of devices – 2 to the 128th power.

IPv6 Background

The Internet Engineering Task Force (IETF), a standards body, created IPv6 as a replacement to IPv4 in 1998, when it became clear that the Internet would eventually run out of IPv4 addresses.

IPv6's primary goal is to increase the Internet's address space, but the protocol also has some enhancements, including autoconfiguration, easier network renumbering and built-in security through the IPsec protocol.

IPv6 has been slow to gain adoption, but momentum began picking up in 2009. Hurricane Electric and NTT America said their IPv6 traffic doubled in 2009, while Google added IPv6 support to several applications including Search, Docs, Gmail and News.

The push towards IPv6 has continued in 2010, with Comcast and Verizon announcing their first public trials of the protocol.

The U.S. federal government is a proponent of IPv6, setting a mandate of June 2008 for all agencies to demonstrate that their backbone networks are capable of carrying IPv6 traffic. After July 2010, the Federal Acquisition Regulation will be changed to require agencies to purchase only IPv6-capable IT systems.

Experts are urging U.S. network managers to prepare their external facing Web sites to support IPv6 by 2012 or risk upsetting IPv6-enabled visitors with lower-grade connectivity.

As of March 2010, experts said that IPv6 had grown to represent 1% of all Internet traffic.

IPv6 Transition Mechanisms

The Internet engineering community has developed several transition mechanisms that will allow network operators to gradually migrate from IPv4 to IPv6.

One option, called Dual Stack, allows network operators to run IPv4 and IPv6 side-by-side on their networks.

Another option is carrier-grade NAT that would allow multiple customers to share a single, public IPv4 address.
For more info please click here:


http://networking-gulf.blogspot.com/2011/05/basic-networking-part-1.html

Free VPN Internet Access In Gulf

Top 15 free VPN for secure Anonymous Surfing.

First of all, lets talk about what is VPN i.e. Virtual Private Network. Basically it’s a private network which lets users to connect to other users or remote sites using a public network usually internet. It uses “virtual” connections routed through the Internet from the company’s private network to the remote site or employee instead of physical connections. In short , it is private network constructed within a public network infrastructure, such as the global Internet.

WHY YOU NEED VPN

• To protect privacy, either on a LAN or a public hotspot.
• Anonymous Internet Surfing
• Full anonymity by hiding your real IP address.
• Bypass geographical blocks from certain websites
• Unlike a proxy, you get secured connection for all programs you are using
• Quality Network ensures your VPN service will be fast wherever you are in the world
• Protection against your ISP
• Bypass ISP Blocking for VOIP Applications like Skype

LOGMEIN HAMACHI

It’s a great free VPN service from the well known guys who are behind the Logmein Service of remote apps management. It’s free for non-commercial and personal use.

Some of its features are :

• No hardware required – A quick, simple and easy-to-use VPN that just works
• Secure communications – Encrypted tunneling across public and private networks
• Flexible networking – Combines the ease of an SSL VPN with the connectivity of an IP-sec VPN
• Web-based management – Deploy to anyone, manage from anywhere, access anytime
• Free for non-commercial usage – Absolutely free for non-commercial use

ULTRAVPN

It is a free VPN client/server SSL VPN solution based on OpenVPN. It encrypts and anonymizes your network connection making your connection safe and secure.

You need to download nad install the client and create a (username, password) to use this service.

 

ALONWEB

It’s another free VPN service which offers both free and paid options. The traffic through alonweb is encrypted, which makes it impossible to intercept it while its flowing over the web.

Free service offers its users connection via two servers: Netherlands and Panama.Limitations exist for free wervice though. Here’s the limitations list

• 1GB of data traffic per month is available,
• Maximum HTTP request size is 2Mb
• Heavy traffic consuming protocols and games are blocked

These limitations are good enough for an average user and should not bother about it.

PACKETIX.NET

Its a japanese free VPN solution with technology developed by SoftEther Corporation.

You can use PacketiX.NET online test service for free.Here’s what you can do with this service.

You can create your private Virtual VPN Hub. You can configure and use the hub for free.You can use all functions the PacketiX VPN software has to offer, such as creating a remote connection to your home network or uniting local networks at different sites. With our system, you won’t need to set up a VPN server with a global IP address yourself. The VPN server administration is done over an easy web interface.

ITSHIDDEN

Itshidden is part of Port 80 Limited(Seychelles) company providing both free VPN and paid services of VPN . It creates a secure connection encrypting all the data protecting your privacy and securing you. You dont need to install any software. ItsHidden.com works on all Platforms including Windows, Mac, Linux, IPhone etc

YOUR FREEDOM

This one is basically not a VPN service but its performs almost the same function with great ease, hence i included this in this list.

It provides both a free and paid service. Free service limits to six hours of usage per day (up to 18 hours per week). You need to install a client on your system and a user name & password to use this.

GPASS

This is another free VPN service product of the World’s Gate, Inc which offers Internet solutions for information freedom in China and other regions.

You need to install a software client to use this.

ANCHORFREE HOTSPOT SHIELD

Hotspot Shield is a free VPN service which protects your entire web surfing session; securing your connection at both your home Internet network & Public Internet networks (both wired and wireless).

Hotspot Shield protects your identity by ensuring that all web transactions (shopping, filling out forms, downloads) are secured through HTTPS.

Here also, you need to download and install a client to use it on your computer.

LOKI NETWORK PROJECT FREE VPN SERVICE

Loki Network Project is free VPN service and SSL based free VPN server. It is an opportunity to protect your private data (IP address, e-mail/FTP/HTTP passwords, web-sites visited, uploaded/downloaded files and etc…) and bypass certain Internet access limitations you may have at your location.

You need to download and install its free VPN Client software  to create your own security schema.

FREEVPN BY WSC

Its another free VPN offering almsot same features as others.

CYBERGHOST

This a German VPN service offering both free  and paid services. The free VPN service got some limitation of 10 GB per month but are good enough for a average user.

ALWAYSVPN

FREEDUR

LINKIDEO

Just a word of caution for everyone here. The free VPN services may not be as good as the paid ones. You may experience slow speed, downtimes etc. But its all like, you dont need them everytime. Just check them out and leave your feedback here. I would love to hear from you.

Update:

We added two more in the list. Checkout ProXPN and SecurityKISS

Basic Networking Part-1

Computer Networking (Part 1)
Networking is very large , here i will dicuss only with basic Networking.
Now a days Computer Networking and Telecommunication is almoste same Basic Idea needs.
What is Network
A network is any collection of independent computers that communicate with one another over a shared network medium.A computer network is a collection of two or more connected computers. When these computers are joined in a network, people can share files and peripherals such as modems, printers, tape backup drives, or CD-ROM drives. When networks at multiple locations are connected using services available from phone companies, people can send e-mail, share links to the global Internet, or conduct video conferences in real time with other remote users. As companies rely on applications like electronic mail and database management for core business operations, computer networking becomes increasingly more important.

Every network includes:

• At least two computers Server or Client workstation.
• Networking Interface Card's (NIC)
• A connection medium, usually a wire or cable, although wireless communication between networked computers and peripherals is also possible.
• Network Operating system software, such as Microsoft Windows NT or 2000, Novell NetWare, Unix and Linux.

Types of Networks:

LANs (Local Area Networks)

A network is any collection of independent computers that communicate with one another over a shared network medium. LANs are networks usually confined to a geographic area, such as a single building or a college campus. LANs can be small, linking as few as three computers, but often link hundreds of computers used by thousands of people. The development of standard networking protocols and media has resulted in worldwide proliferation of LANs throughout business and educational organizations.

WANs (Wide Area Networks)

Wide area networking combines multiple LANs that are geographically separate. This is accomplished by connecting the different LANs using services such as dedicated leased phone lines, dial-up phone lines (both synchronous and asynchronous), satellite links, and data packet carrier services. Wide area networking can be as simple as a modem and remote access server for employees to dial into, or it can be as complex as hundreds of branch offices globally linked using special routing protocols and filters to minimize the expense of sending data sent over vast distances.

Internet

The Internet is a system of linked networks that are worldwide in scope and facilitate data communication services such as remote login, file transfer, electronic mail, the World Wide Web and newsgroups.

With the meteoric rise in demand for connectivity, the Internet has become a communications highway for millions of users. The Internet was initially restricted to military and academic institutions, but now it is a full-fledged conduit for any and all forms of information and commerce. Internet websites now provide personal, educational, political and economic resources to every corner of the planet.

Intranet

With the advancements made in browser-based software for the Internet, many private organizations are implementing intranets. An intranet is a private network utilizing Internet-type tools, but available only within that organization. For large organizations, an intranet provides an easy access mode to corporate information for employees.

MANs (Metropolitan area Networks)

The refers to a network of computers with in a City.

VPN (Virtual Private Network)

VPN uses a technique known as tunneling to transfer data securely on the Internet to a remote access server on your workplace network. Using a VPN helps you save money by using the public Internet instead of making long–distance phone calls to connect securely with your private network. There are two ways to create a VPN connection, by dialing an Internet service provider (ISP), or connecting directly to Internet.