The importance of TCP/IP and its use in the Internet

By: Jagdip Singh
Many people may not know what TCP/IP is, nor what its effect is on the Internet. The fact is, without TCP/IP there would be no Internet. And it is because of the American military that the Internet exists.

During the days of the cold war, the defense department was interested in developing a means of electronic communication which could survive an attack by being able to re-route itself around any failed section of the network.

They began a research project designed to connect many different networks, and many different types of hardware from various vendors. Thus was the birth of the Internet (sorta). In reality, they were forced to connect different types of hardware from various vendors because the different branches of the military used different hardware. Some used IBM, while others used Unisys or DEC.

TCP (Transmission Control Protocol) and IP (Internet Protocol) were the protocols they developed. The first Internet was a success because it delivered a few basic services that everyone needed: file transfer, electronic mail, and remote login to name a few. A user could also use the “internet” across a very large number of client and server systems.

As with other communications protocols, TCP/IP is composed of layers. Each layer has its own responsibility:

IP is responsible for moving data from computer to computer. IP forwards each packet based on a four-byte destination address (the IP number). IP uses gateways to help move data from point “a” to point “b”. Early gateways were responsible for finding routes for IP to follow.

TCP is responsible for ensuring correct delivery of data from computer to computer. Because data can be lost in the network, TCP adds support to detect errors or lost data and to trigger retransmission until the data is correctly and completely received.

How TCP/IP works

Computers are first connected to their Local Area Network (LAN). TCP/IP shares the LAN with other systems such as file servers, web servers and so on. The hardware connects via a network connection that has its own hard coded unique address – called a MAC (Media Access Control) address. The client is either assigned an address, or requests one from a server. Once the client has an address they can communicate, via IP, to the other clients on the network. As mentioned above, IP is used to send the data, while TCP verifies that it is sent correctly.

When a client wishes to connect to another computer outside the LAN, they generally go through a computer called a Gateway (mentioned above). The gateway’s job is to find and store routes to destinations. It does this through a series of broadcast messages sent to other gateways and servers nearest to it. They in turn could broadcast for a route. This procedure continues until a computer somewhere says “Oh yeah, I know how to get there.” This information is then relayed to the first gateway that now has a route the client can use.

How does the system know the data is correct?

As mentioned above, IP is responsible for getting the data there. TCP then takes over to verify it.

Encoded in the data packets is other data that is used to verify the packet. This data (a checksum, or mathematical representation of the packet) is confirmed by TCP and a confirmation is sent back to the sender.

This process of sending, receiving and acknowledging happens for each individual packet sent over the Internet.

When the data is verified, it is reassembled on the receiving computer. If a package is not verified, the sending computer will re-send it and wait for confirmation. This way both computers – both sending and receiving – know which data is correct and which isn’t.

One nice thing about this protocol is that it doesn’t need to stick to just one route. Generally, when you are sending or receiving data it is taking multiple routes to get to its destination. This ensures data accuracy.
Just the facts:

TCP/IP addresses are based on 4 octets of 8 bits each. Each octet represents a number between 0 and 255. So an IP address looks like:
111.222.333.444.

There are 3 classes of IP addresses:

ranges starting with “1” and ending with “126” (i.e.. 1.1.1.1 to 126.255.255.254) are Class A
ranges starting with “128” and ending with 191 (i.e.. 128.1.1.1 to 191.255.255.254) are Class B
ranges starting with 192 and ending with 254 (i.e.. 192.1.1.1 to 254.255.255.254) are Class C ( You will notice that there are no IP addresses starting with “127”. These are reserved addresses.)

Calculating an IP address

One of the things that always confused me was how to convert IP address to their Binary form. It is quite simple really. IP addresses use the Binary numbers (“1”s and “0”s) and are read from right to left.

Each position in the binary address corresponds to a number, from 1 to 128 and look like this:

128 64 32 16 8 4 2 1

To calculate an address, simply add the numbers where a “1” appears.
For example, the following:
00001010 works out to 10. Like this:
0 0 0 0 1 0 1 0
128 64 32 16 8 4 2 1

You can see that the “1”s line up with the 2 and 8 – when you add 2 plus 8 the answer is 10.

Since an IP address contains 4 of these octets, it can be displayed in binary like:

00001010.00001010.00001010.00001010

Therefore, IP Address 10.129.254.1 would be converted to:

00001010.10000001.11111110.00000001
(8+2) . (128+1) .(128+64+32+8+4+2).(1)

While it’s not important for the average person to know how to figure this stuff out, it is important for someone setting up a small network. That is because TCP/IP also uses what are called subnet masks to determine which addresses are valid. But I won’t get into those for now. And it’s also a neat trick that you can use at parties to show your non-techy friends just how much of a technology geek you are :)

So there you have it – a brief introduction into TCP/IP – the foundation of the Internet.

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WIMAX and HSPA Battle It Out To Usher In Next Wave of E-Commerce by Salil Pillai

Internet has permeated through all walks of lives, and this has tremendously increased the need for better connectivity. Lately, businesses regardless of being offline or online, view internet and its connectivity as an indispensable part of their business process. However, remote areas and their businesses had to be satisfied with the available connectivity, owing to chiefly, higher cost of laying cables where returns would be minimal for the service providers. Growing hunger for internet usage has spurred technology providers into action to produce a slew of connectivity tools. Among them, two distinct technologies called WiMAX and HSPA have emerged to fight it to the hilt for the larger share of connectivity pie.

Worldwide Interoperability for Microwave Access (WiMAX) is the technology that allows user to navigate the internet wireless. It is a telecommunication technology that can carry data to long distances either by point to point links or full mobile access. The key feature of this technology is that it operates on the same Broadband Wireless Access Standard of IEEE 802.16, which was set up in 1999. WiMAX also has the ability to extend local Wi-Fi networks over larger expanse of coverage area by up to 50 kilometers and its backed by Intel, world's largest semiconductor company.

Similarly, High Speed Packet Access (HSPA) too boasts of superior technology akin to that of WiMAX. In a nutshell, it is a collection of mobile telephony protocols that provide better performance over existing radio bandwidth. Equipped with state of the art 3.5G technology, it can touch amazing download speeds of up to 7.2 Mbps. HSPA should be proud to get the support from leading equipment vendors including Ericsson, Nokia Siemens Networks, Nortel, Alcatel and Lucent. Its proven ability to perform extremely well in any condition and download speeds has helped the technology to be absorbed across several countries in a short span of time.

Unfortunately, WiMAX was not without its own problems, in Australia, first WiMAX operator had to shut down its operation due to poor reach to long distances, contrary to its claim. On the other hand, HSPA service was able to produce the desire result in over 50 countries and 150 networks. For example, in some places subscribers could already watch streaming High Definition movies at 1Mbps. HSPA has also got a cost advantage over the other, per month charges as of now is in the realm of $30, whereas one has to shell out $10 more to get the same service from WiMAX.

Since majority of the people spend time outside their workplaces, e-mobility has become an inevitable tool in communication and business. Whether the winner is WiMAX or HSPA, wider expanse of area under internet connectivity through wireless services will enhance people to do day to day business, being anywhere in the world. High speed internet access through wireless technology will propel growth in all areas including business, education and healthcare.

Global internet wireless connectivity will also give an advantage for an entrepreneur who is away from the main markets to get reasonable remuneration for one's products or services. Real time e-mobility effects coupled with long distance internet coverage for one's communication suggests, E-Commerce will be the biggest gainer and is likely to increase its share in the world of business.

About the Author

Toboc, a b2b portal, provides global trade platform for Importers and Exporters from the different regions of the world.

Getting Enough Bandwidth with Better Routing by Robert DeuPree

Getting Enough Bandwidth with Better Routing A common question for network connectivity is "how much bandwidth is enough?" While bandwidth can boil down to upload and download limits from an ISP, the overall question is really one of network speed - how fast is the network connection to the Internet? Network speed is greatly influenced by the routing methods used to direct network traffic; the better the traffic routing, the better the network connection's speed and reliability.

Routing Traffic: BGP The Internet is made up of millions of individual servers, which are all interconnected, like houses on main streets and bystreets. Some central networks, called backbones, have connections to millions of servers, which makes it easier to send traffic along those routes.

If an ISP is connected to a single Internet backbone, then they only have one route to use to send traffic. However, this means if that backbone goes down, the network connection goes down. For redundancy, most ISPs have connections to at least two backbones, and traffic is routed between those backbones.

When there are multiple backbones to choose from, there has to be some way to identify the most efficient route. The most common routing logic is border gateway protocol (BGP) which counts the number of networks (autonomous system, or AS, hops) that each route has between the starting server and the destination server.

For example, one person wants to send an email from their home account with SBC Global to their friend at MSN. SBC is on one network, and MSN is on another. Route A reports six AS hops between SBC and MSN, and Route B has three AS hops between them. With BGP routing, the traffic is sent on Route B.

Performance-Based Routing The big limitation of BGP is that it only gauges AS hops rather than other more important factors, like latency. Route B from the last example has only three AS hops, meaning traffic only has to cross three networks to reach its destination. However, BGP routing only counts AS hops - it cannot account for the number of individual routers in an autonomous system. Route B may only cross three networks, but if Network 1 has five routers, Network 2 has four routers, and Network 3 has eight routers, the traffic has to go through 17 routers before it can reach its destination. If Route A crosses six networks but each network only has a single router, the traffic only has to pass through six routers. That means that Route A may be significantly faster than Route B, but BGP routing has no way to recognize that, so it sends traffic down the slower route.

Performance-based routing offsets the limits of BGP, and takes a more intelligent approach to traffic routing, by looking at other factors than AS hops: * Performance metrics like latency, jitter, and packet loss * Current network load * Connection type, such as T1 or OC3

Latency can be either the time to send a packet one-way or the round-trip time, like the time to send ICMP packets (ping) to one server and receive the response. Jitter is the fluctuation in latency times. For example, if the first trip time is 3ms and the next is 105ms and the next is 20ms, there is a large swing between trip times, and, therefore, there is high jitter on the connection. Packet loss is the number of packets (information) which never reach their destination. The current load is how much traffic is currently on that connection, and the connection type indicates how much traffic the network can handle effectively.

By looking at the actual quality of the network connection, performance-based routing can select much faster, more reliable routes.

What Better Routing Really Means Poor routing can corrupt or interrupt packets, requiring information to be resent and increasing the overall time it takes to do anything on the network. While simple tasks like web browsing may not be affected by poor network performance, a number of vital applications can be impaired by poor routing protocols in ways that may not be apparent in a simple upload/download size summary: * Any kind of media application, such as streaming video or audio * Potentially business-critical applications like voice over IP (VoIP) or video conferencing * Upload and download times * Email delivery * Remote network applications like VPNs

American Internet Services' San Diego colocation facilities feature the best service and equipment available in the colocation industry. http://www.americanis.net

About the Author

American Internet Services' San Diego colocation facilities feature the best service and equipment available in the colocation industry. http://www.americanis.net

Gigabit Ethernet for Metro Area Networks

Gigabit Ethernet has been deployed in the metro space, providing low cost, easily managed bandwidth for intensive applications like video, storage, and ASPs. 10 Gigabit Ethernet (IEEE 802.3a) will make the use of Ethernet in the Metro area even more attractive. IDC projects that GigE revenues in the U.S., marked at $155 million in 2001, will grow at 36.7% per year over the next five years, to $741 million in 2006.

MAN at Work (GigE-POWERED)

Gigabit Ethernet is the protocol powering more and more MANs and WANs. If you’re on the frontlines of this deployment or want to be, there’s no better source of insight than this guide from top GigE-in-MANs specialist Paul Bedell. Packed with details and guidance you won’t find elsewhere, Gigabit Ethernet for Metro Area Networks rolls out well-organized information on the technology, the standards, the applications, and the market players. It's all wrapped up with a look at some case studies that prove the value of GigE in today's MAN.

A TRACEABLE MAP TO HELP YOU—
* Learn the importance of the new 10 GigE IEEE 802.3ae standard
* Line up GigE against SONET, ATM, Frame Relay, and legacy dedicated transport modes (DS-n) in metro networks
* Size up manufacturers, products, and service providers, including nontraditional players
* Understand the roles of CLECs (Competitive Local Exchange Carriers) and ELECs (Enterprise Local Exchange Carriers)
* Integrate complementary technologies such as DWDM, Resilient Packet Ring (RPR), and next-generation SONET
* Build new features with Ethernet in the MAN, WAN, and LAN
* Get on top of technological trends, next-generation design approaches, and business models for MANs and WANs
* Solve real-world deployment and compatability issues

Voice & Data Communications

Understand cutting-edge telecommunication and networking technologies using this straightforward, real-world implementation guide. Fully revised to cover all of the latest transmission protocols, Voice & Data Communications Handbook, Fifth Edition covers all the bases-from analog transmission, VPNs, and LANs to DSL, CATV, WiFi, VoIP, and GSM. This authoritative volume covers the ins-and-outs of each vital topic, supplies practical examples and solutions, and provides helpful self-tests. You'll also find up-to-date information on regulatory standards, switches, routers, frame relay, and security procedures.

• Use new wireless technologies
• Understand the building blocks of analog transmission-bandwith, amplitude, and frequency
• Provide transparent communications using the OSI model and seven-layer architecture
• Comply with local and federal regulations and RBOCs
• Transmit information using routers, SS7, PBX, and KTS switches
• Send and receive data across TCP/IP, wireless, cellular, and optical systems
• Create a connection using a modem
• Connect to multiple VPNs and LANs using frame relay, ATM, and MPLS
• Deploy high-speed broadband access with cable modems, xDSL, and CATV
• Get details on VoIP, SIP, and voice over data services
• Increase bandwidth using IP telephony techniques and PBX equipment

MPLS Fundamentals

A comprehensive introduction to all facets of MPLS theory and practice

• Helps networking professionals choose the suitable MPLS application and design for their network
• Provides MPLS theory and relates to basic IOS configuration examples
• The Fundamentals Series from Cisco Press launches the basis to readers for understanding the purpose, application, and management of technologies

MPLS has emerged as the new networking layer for service providers throughout the world. For many service providers and enterprises MPLS is a way of delivering new applications on their IP networks, while consolidating data and voice networks. MPLS has grown to be the new default network layer for service providers and is finding its way into enterprise networks as well. This book focuses on the building blocks of MPLS (architecture, forwarding packets, LDP, MPLS and QoS, CEF, etc.). This book also reviews the different MPLS applications (MPLS VPN, MPLS Traffic Engineering, Carrying IPv6 over MPLS, AToM, VPLS, MPLS OAM
etc.).
You will get a comprehensive overview of all the aspects of MPLS, including the building blocks, its applications, troubleshooting and a perspective on the future of MPLS.

Border Gateway Protocol (BGP)

The Border Gateway Protocol (BGP) is the core routing protocol of the Internet. It works by maintaining a table of IP networks or 'prefixes' which designate network reachability among autonomous systems (AS). It is described as a path vector protocol. BGP does not use traditional IGP metrics, but makes routing decisions based on path, network policies and/or rulesets.

Since 1994, version four of the protocol has been in use on the Internet. All previous versions are now obsolete. The major enhancement in version 4 was support of Classless Inter-Domain Routing and use of route aggregation to decrease the size of routing tables. From January 2006, version 4 is codified in RFC 4271, which went through well over 20 drafts from the earlier RFC 1771 version 4. The RFC 4271 version corrected a number of errors, clarified ambiguities, and also brought the RFC much closer to industry practices.

BGP was created to replace the EGP routing protocol to allow fully decentralized routing in order to allow the removal of the NSFNet Internet backbone network. This allowed the Internet to become a truly decentralized system.

Very large private IP networks can also make use of BGP. An example would be the joining of a number of large Open Shortest Path First (OSPF) networks where OSPF by itself would not scale to size. Another reason to use BGP would be multihoming a network for better redundancy either to a multiple access points of a single ISP (RFC 1998) or to multiple ISPs.

Most Internet users do not use BGP directly. However, since most Internet service providers must use BGP to establish routing between one another (especially if they are multihomed), it is one of the most important protocols of the Internet. Compare this with Signalling System 7 (SS7), which is the inter-provider core call setup protocol on the PSTN.