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By The Numbers |
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The Election Commission of India, which estimates an electorate of 714 million voters, an increase of 43 million over the 2004 election. There are 1,368,430 Electronic voting machine (EVM), available across the country.
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Exams alert |
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Symbiosis Entrance Test (SET - 2009), Date: May. 2, 2009, Management Aptitude Test (MAT) 2009, Date: May. 3, 2009, BITS Admission Test- 2009 (BITSAT 2009), Date: May. 9, 2009, Armed Force Medical College (AFMC) Pune, Admission to MBBS Course 2009 Date: May. 3, 2009, Common Law Admission Test (CLAT), Date: May. 17, 2009. |
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Thus Spake |
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When small men begin to cast big shadows, it means that the sun is about to set. |
- Lin Yutang |
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Interesting Facts |
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The first coin operated machine ever designed was a holy-water dispenser that required a five-drachma piece to operate. It was the brainchild of the Greek scientist Hero in the first century AD.
The normal static electricity shock that zaps your finger when you touch a doorknob is usually between 10,000 and 30,000 volts! |
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Did you know |
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The world's first postage stamp was the penny Black, issued in Britain in May, 1840. A one-cent British Guiana (Guyana) stamp of 1856, of which there is only one example, is thought to be worth £500,000.
A nova (meaning "new star") is a star that suddenly flares up to be many times brighter than it actually is. A really brilliant nova may have been a star which could hardly be seen even with a large telescope. As a nova it becomes visible to the naked eye, but gradually fades again.
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Multiprotocol Label Switching |
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Multi-protocol label switching is the primary packet-switching technique for backbone networking.
MPLS provides a third mechanism (different from IP and ATM) for control and path calculation. MPLS nodes (called Label Switched Routers – LSRs) use a routing protocol such as OSPF to calculate network paths and establish connection-oriented path. The paths are called Label Switched Paths (LSPs) and these paths are built using CR-LDP (Label Distribution Protocol) or RSVP-TE (Resource Reservation Protocol- Traffic Engineering). |
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Smile Please..! |
How great their fathers are |
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Those three boys are in the schoolyard bragging of how great their fathers are.
The first one says: "Well, my father runs the fastest. He can fire an arrow, and start to run, I tell you, and he gets there before the arrow".
The second one says: "Ha! You think that's fast! My father is a hunter. He can shoot his gun and be there before the bullet".
The third one listens to the other two and shakes his head. He then says: "You two know nothing about fast. My father is a civil servant. He stops working at 4:30 and he is home by 3:45"!!
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Hundred dollars
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"I am sorry, madam, but I shall have to charge you hundred dollars for pulling your boy's tooth".
"Hundred dollars! Why, I understood you to say that you charged only twenty dollars for such work"!
"Yes," replied the dentist, "but this youngster yelled so terribly that he scared four other patients out of the office".
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Look, He's Moving!!!
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While driving down a steep and curvy logging road, a group of biologists lose control of their 4-wheel drive "Jimmy" and careen down the hill. The truck piles up at the bottom of the canyon, and everyone aboard perishes. Suprisingly, they all go to heaven. At an orientation they are asked, "When you are in your casket and your friends and family are mourning about your death, what would you like to hear them say about you"?
The first guy, a well known botanist says, "I would like to hear them say that I was one of the greatest botanists of my time, and left an eternal contribution to the botanical world".
The second guy, an ornithologist, says, "I would like to hear that I was a wonderful birder and made a huge difference in the recovery of our bird populations".
The last guy, a scruffy mammalogist, replies, "I would like to hear them say... 'LOOK, HE'S MOVING!!!' "
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From The Editors Desk |
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Heartiest Greetings!
In this issue of Youniverse, we have presented an article on “Multi-protocol label switching (MPLS)”, The article provides introduction, goals, features, characteristics and benefits of MPLS.
Our regular section on Exam Alerts informs you of the important dates of the upcoming entrance examinations. The section on “Complex simplicities” provides an introduction to the concepts of Gateway GPRS Support Node (GGSN), Very High Bitrate Digital Subscriber Line (VHDSL) and Quality of Service.
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Complex Simplicities |
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Gateway GPRS Support Node (GGSN)
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The Gateway GPRS Support Node (GGSN) is a main component of the GPRS network. The GGSN is responsible for the inter-working between the GPRS network and external packet switched networks, like the Internet and X.25 networks.
From an external network's point of view, the GGSN is a router to a sub-network, because the GGSN ‘hides’ the GPRS infrastructure from the external network. When the GGSN receives data addressed to a specific user, it checks if the user is active. If it is, the GGSN forwards the data to the SGSN serving the mobile user, but if the mobile user is inactive, the data are discarded.
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Very High Bitrate Digital Subscriber Line (VHDSL) |
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VDSL or VHDSL (Very High Bitrate DSL) is a DSL technology providing faster data transmission over a single flat untwisted or twisted pair of copper wires. These fast speeds mean that VDSL is capable of supporting high bandwidth applications such as HDTV, as well as telephone services (Voice over IP) and general Internet access, over a single connection. VDSL is deployed over existing wiring used for POTS (Plain Old Telephone Service) and lower-speed DSL connections. This standard was approved by ITU in November 2001. |
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Quality of Service (QoS) |
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In the field of computer networking and other packet-switched telecommunicati-on networks, the traffic engineering term Quality of Service (QoS) refers to resource reservation control mechanisms rather than the achieved service quality. Quality of service is the ability to provide different priority to different applications, users, or data flows, or to guarantee a certain level of performance to a data flow. For example, a required bit rate, delay, jitter, packet dropping probability and/or bit error rate may be guaranteed. |
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Interesting Facts |
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The first coin operated machine ever designed was a holy-water dispenser that required a five-drachma piece to operate. It was the brainchild of the Greek scientist Hero in the first century AD. |
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The normal static electricity shock that zaps your finger when you touch a doorknob is usually between 10,000 and 30,000 volts! |
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Nose prints are used to identify dogs, just like humans use fingerprints! |
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"Dreamt" is the only English word that ends in the letters "mt"! |
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The longest word in the English language with no vowels is Rhythms! |
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The creator of the NIKE Swoosh symbol was paid only $35 for the design. |
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Warner Chappel Music owns the copyright to the song 'Happy Birthday'. They make over $1 million in royalties every year from the commercial use of the song. |
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A leech is a worm that feeds on blood. It will pierce its victim's skin, fill itself with three to four times its own body weight in blood, and will not feed again for months. Leeches were once used by doctors to drain "bad blood" from sick patients. |
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The American Society for Prevention of Cruelty to Animals (ASPCA) was formed in 1866. |
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The blue whale is the loudest animal on Earth. The call of the blue whale reaches levels up to 188 decibels. This extraordinarily loud whistle can be heard for hundreds of miles underwater. The second-loudest animal on Earth is the Howler Monkey. |
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In 1957, the Shipping port Atomic Power Station in Pennsylvania, the first nuclear facility to generate electricity in the United States, went on line. (It was taken out of service in 1982). |
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The Chinese were using aluminum to make things as early as 300 AD Western civilization didn't rediscover aluminum until 1827. |
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In 1959, the Soviet space probe "Luna Two" became the first man made object to reach the moon as it crashed onto the lunar surface. |
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Olympus Mons on Mars is the largest volcano in our solar system. |
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In 17th century Holland, tulips were valued higher than many precious metals and gems. A single bulb is said to have sold for more than $2,000. |
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Pinks are so called not because of their color but because of the ragged edges, or pinks, on each petal.The color pink is actually named after the flower. |
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Butterflies have their skeletons on the outside of their bodies, called the exoskeleton.This protects butterflies and keeps water inside their bodies so they don't dry out. Since butterflies are cold blooded (they do not produce metabolic heat like humans) it is necessary for them to warm up their flight muscles.This is done by basking in the sun in order to absorb heat. |
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Did you know |
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The world's first postage stamp was the penny Black, issued in Britain in May, 1840. A one-cent British Guiana (Guyana) stamp of 1856, of which there is only one example, is thought to be worth £500,000. |
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A nova (meaning "new star") is a star that suddenly flares up to be many times brighter than it actually is. A really brilliant nova may have been a star which could hardly be seen even with a large telescope. As a nova it becomes visible to the naked eye, but gradually fades again. |
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Deep-sea prawns are often bright red in color. They use the red color as camouflage, as red is difficult to see in deep waters and many deep-sea fish are color blind and cannot see red. One fish, though, has eyes that can pick up red. It also shines its own red light to hunt for the prawns. |
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There is no land at the North Pole - it is a floating raft of ice. In 1958, Naurilus, the US submarine, was the first to cross the Arctic Ocean - a distance of 2,945 km (1,830 miles) - by travelling underneath the North Pole. |
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The largest active volcano on Earth is Mauna Loa, in Hawaii. It is 4,168m (13,677ft) high, and one eruption lasted for one-and-a-half years. |
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A special substance found in the scales of some fish (especially herrings) is used to make a paint. This paint is coated on to glass beads to make imitation pearls. |
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Ice made of salt water does not contain any salt. That is the biggest relief for people like the Eskimos, who live in icy regions and are surrounded by ice all year long. All they have to do is melt the ice and their fresh drinking water is ready. |
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The traditional Chinese painting is calligraphy (eight brush strokes). Many other brush strokes are used too. They each have a special purpose. For example, a certain stroke is used to paint bamboo, another to paint trees, and one to make rocks and mountains. Most Chinese paintings express nature. Landscapes, birds, and flowers are very popular subjects. |
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Bougainville is the largest island in the Solomons, a group of South Pacific islands North East of Australia. Some of the island natives use an alphabet of only 11 letters, the shortest alphabet on earth. This alphabet includes the same five vowels as our alphabet: a, e, i, o, and u. But there are only six consonants in the Bougainville alphabet: b, g, k, p, r, and t. |
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Waitomo Cave, an underground cavern on New Zealand's North Island, never sees daylight. But there's plenty of "natural light" in this cave, produced by thousands of tiny glowing worms! Visitors to Waitomo Cave descend into a cavern 100 feet long and 50 feet wide. They then ride a boat along an underground river. All around them on the ceiling and walls of the cave are thousands and thousands of glowworms. The tails of larva of a certain kind of moth flicker with blue-green lights. |
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Multiprotocol Label Switching |
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Multi-protocol label switching is the primary packet-switching technique for backbone networking. |
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MPLS provides a third mechanism (different from IP and ATM) for control and path calculation. MPLS nodes (called Label Switched Routers – LSRs) use a routing protocol such as OSPF to calculate network paths and establish connection-oriented path. The paths are called Label Switched Paths (LSPs) and these paths are built using CR-LDP (Label Distribution Protocol) or RSVP-TE (Resource Reservation Protocol- Traffic Engineering). These LSPs are connection-oriented rather than connectionless and they can be provisioned manually analogous to PVCs that have been set up for traffic engineering. LSPs are independent of underlying link-layer (Layer-2) protocols.
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The MPLS protocol is a critical component for extending best-effort IP networks to include support for traffic engineering, quality of service (QoS) and virtual private network (VPN). |
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| Introduction |
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MPLS stands for "Multi-protocol label switching". Multi-protocol because this technique is applicable to any network layer protocol. In an MPLS network incoming packets are assigned a "Label" by a "Label Edge Router" and then packets are forwarded along a "Label Switched Path (LSP)" where each "Label Switched Router (LSR)" make forwarding decision based solely on the contents of the label. At each hop, the LSR strips off the existing label and applies a new label, which tells the next-hop how to forward the packet.
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In MPLS data transmission occurs on Label Switched Paths. LSPs are a sequence of labels. LSPs are established either prior to data transmission (control-driven) or upon detection of a certain flow of data (data-driven). |
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| Goal of MPLS |
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The initial goal of MPLS was to bring the speed of layer-2 switching at layer-3. Label based switching methods allows routers to make forwarding decision based on the content of label rather than by performing a complex route lookup based on destination IP address. This justification for MPLS is no longer perceived as the main benefit, since layer-3 switches (ASIC based routers) are able to perform route lookup at sufficient speed. MPLS brings many other benefits to IP based network like Traffic Engineering and support for VPN. |
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The MPLS technology addresses following requirements |
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It integrates the label-swapping paradigm (switching cells when ATM is used as the underlying link layer) with network layer routing |
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It improves the price-per-performance of network layer routing |
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It facilitates scalability through traffic aggregation |
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It provides greater flexibility in the delivery of new routing services, thereby improving the potential of traffic engineering |
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It supports the delivery of services with guaranteed QoS |
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MPLS Features
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Traffic Engineering |
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Efficient Link Utilization |
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Class of Service (CoS) |
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Differentiated types of service across an MPLS network |
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Virtual Private Networks (VPNs) |
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A VPN is a private connection over an shared network |
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| MPLS nodes |
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The nodes that participate in the MPLS mechanism can be classified as "Label Edge Routers (LERs)" and "Label Switching Routers (LSRs)". |
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A LSR is a high-speed router in the core of a MPLS network that participates in the establishment of LSPs using appropriate MPLS signaling protocol and high-speed switching of the traffic on the established paths. |
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A LER operates on the boundaries (edge) of MPLS network. It supports multiple ports connected to dissimilar networks (e.g. frame relay, ATM, Ethernet) and forwards traffic received from these networks on to the MPLS network after establishing LSPs. For a given flow the LER acting as a entry point is called "Ingress LER" and the LER acting as exit point is referred as "Egress LER". |
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| Labels |
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A label in its simplest form identifies the path a packet should traverse. A label is carried or encapsulated in a layer-2 header along with the packet. The receiving router examines the packet for its label content to determine the next hop. On receiving a packet from non-MPLS domain the LER first analyzes the network layer header and decides "Forward Equivalence Class (FEC)" to which the packet belongs to and assigns one label to it. The FEC is a representation of a group of packets that share the same requirements for their transport. |
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MPLS is intended to run over multiple link layers. The lower link layer can be ATM, Frame Relay or PPP/LAN. The label values are derived from the underlying data link layer. If the link layer is ATM then VPI/VCI values and in case of frame relay the DLCI value can be used for label encoding. |
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MPLS Characteristics
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Mechanisms to manage traffic flows of various granularities (Flow Management) |
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Is independent of Layer- 2 and Layer-3 protocols |
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Maps IP- address to fixed length labels |
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Interfaces to existing routing protocols (RSVP, OSPF) |
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Supports ATM, Frame-Relay and Ethernet |
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MPLS Operation
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The following steps must be taken for a data packet to travel through an MPLS domain. |
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Label creation and distribution |
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Table creation at each router |
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Label-switched path creation |
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Label insertion / table lookup |
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Packet forwarding |
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| Advantages of Migrating to MPLS (Multiprotocol Label Switching) |
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Cost-Effective: MPLS services can save a company between 10% to 25% compared to Frame Relay and ATM data services. If voice and data capabilities are added, the savings can jump up to approximately 40% for the entire network |
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QoS Capabilities: One main advantage of using MPLS services is its QoS capabilities. This is of upmost importance for companies utilizing voice and video |
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Performance Upgrade: Increased response time and improved application performance are advantages for utilizing MPLS services. This reduces the number of "hops" between network points, which are the "any-to-any" features MPLS offers |
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Disaster Recovery: MPLS services offer data backup/disaster recovery capabilities by connecting data centers and other key sites in multiple redundant ways to the cloud. Unlike Frame Relay and ATM networks which require either switched or backup permanent-virtual-circuits, MPLS services allow remote sites to quickly and easily reconnect to backup locations, when applicable. This flexibility is a major advantage of MPLS over Frame Relay and ATM |
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Future-Proofing the Network: Businesses realize MPLS is "the wave of the future" and are making the switch from Frame Relay and ATM services to MPLS. This switch is mainly for fear that they will be left behind. Competition is tight among businesses in all industries, so having a more cost-effective and more efficient network system gives them a fighting chance |
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Competitors to MPLS |
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MPLS can exist in both IPv4 environment (IPv4 routing protocols) and IPv6 environment (IPv6 routing protocols). The major goal of MPLS development - the increase of routing speed - is no longer relevant because of the usage of ASIC, TCAM and CAM-based switching. Therefore the major usage of MPLS is to implement limited traffic engineering and Layer 3/Layer 2 "service provider type" VPNs over existing IPv4 networks. The main competitors to MPLS are Provider Backbone Bridges (PBB), and MPLS-TP that also provide services such as service provider Layer 2 and Layer 3 VPNs. L2TPv3 has been suggested as a competitor, but has not reached any wider success. |
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IEEE 1355 is a completely unrelated technology that does something similar in hardware. |
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IPv6 references: Grossetete, Patrick, IPv6 over MPLS, Cisco Systems 2001; Juniper Networks IPv6 and Infranets White Paper; Juniper Networks DoD's Research and Engineering Community White Paper. |
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Benefits of MPLS |
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MPLS provides networks with a more efficient way to manage applications and move information between locations. With the convergence of voice, video and data applications, business networks face increasing traffic demands. MPLS enables class of service (CoS) tagging and prioritization of network traffic, so administrators may specify which applications should move across the network ahead of others. This function makes an MPLS network especially important to firms that need to ensure the performance of low-latency applications such as VoIP and their other business-critical functions. MPLS carriers differ on the number of classes of service they offer and in how these CoS tiers are priced. |
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Conclusion
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Multiprotocol Label Switching offers a more manageable and cost-effective network solution. Not only is the system simpler, but also more responsive, scalable and flexible by offering multiple services. |
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Gateway GPRS Support Node (GGSN) |
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The Gateway GPRS Support Node (GGSN) is a main component of the GPRS network. The GGSN is responsible for the inter-working between the GPRS network and external packet switched networks, like the Internet and X.25 networks.
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From an external network's point of view, the GGSN is a router to a sub-network, because the GGSN ‘hides’ the GPRS infrastructure from the external network. When the GGSN receives data addressed to a specific user, it checks if the user is active. If it is, the GGSN forwards the data to the SGSN serving the mobile user, but if the mobile user is inactive, the data are discarded. On the other hand, mobile-originated packets are routed to the right network by the GGSN.
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The GGSN is the anchor point that enables the mobility of the user terminal in the GPRS/UMTS networks. In essence, it carries out the role in GPRS equivalent to the Home Agent in Mobile IP. It maintains routing necessary to tunnel the Protocol Data Units (PDUs) to the SGSN that service a particular MS (Mobile Station). |
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The GGSN converts the GPRS packets coming from the SGSN into the appropriate packet data protocol (PDP) format (e.g., IP or X.25) and sends them out on the corresponding packet data network. In the other direction, PDP addresses of incoming data packets are converted to the GSM address of the destination user. The readdressed packets are sent to the responsible SGSN. For this purpose, the GGSN stores the current SGSN address of the user and his or her profile in its location register. The GGSN is responsible for IP address assignment and is the default router for the connected user equipment (UE). The GGSN also performs authentication and charging. |
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Very High Bitrate Digital Subscriber Line (VHDSL) |
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VDSL or VHDSL (Very High Bitrate DSL) is a DSL technology providing faster data transmission over a single flat untwisted or twisted pair of copper wires. These fast speeds mean that VDSL is capable of supporting high bandwidth applications such as HDTV, as well as telephone services (Voice over IP) and general Internet access, over a single connection. VDSL is deployed over existing wiring used for POTS (Plain Old Telephone Service) and lower-speed DSL connections. This standard was approved by ITU in November 2001. |
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Second-generation VDSL2 systems (ITU-T G.993.2 Approved in February 2006) utilize bandwidth of up to 30 MHz to provide data rates exceeding 100 Mbit/s simultaneously in both the upstream and downstream directions. The maximum available bit rate is achieved at a range of about 300 meters; performance degrades as the loop attenuation increases. |
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Currently, the standard VDSL uses up to 7 different frequency bands, which enables customization of data rate between upstream and downstream depending on the service offering and spectrum regulations. First generation VDSL standard specified both QAM (Quadrature amplitude modulation) and DMT (Discrete Multi-Tone modulation.) In 2006, ITU-T standardized VDSL in recommendation G.993.2 which specified only DMT modulation for VDSL2. |
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Quality of Service (QoS) |
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In the field of computer networking and other packet-switched telecommunication networks, the traffic engineering term Quality of Service (QoS) refers to resource reservation control mechanisms rather than the achieved service quality. Quality of service is the ability to provide different priority to different applications, users, or data flows, or to guarantee a certain level of performance to a data flow. For example, a required bit rate, delay, jitter, packet dropping probability and/or bit error rate may be guaranteed. Quality of service guarantees are important if the network capacity is insufficient, especially for real-time streaming multimedia applications such as voice over IP, online games and IP-TV, since these often require fixed bit rate and are delay sensitive, and in networks where the capacity is a limited resource, for example in cellular data communication. In the absence of network congestion, QoS mechanisms are not required. |
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Applications requiring QoS |
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A defined Quality of Service may be required for certain types of network traffic, for example: |
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Streaming multimedia may require guaranteed throughput to ensure that a minimum level of quality is maintained |
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IPTV offered as a service from a service provider such as AT&T's U-verse |
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IP telephony or Voice over IP (VOIP) may require strict limits on jitter and delay |
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Video Teleconferencing (VTC) requires low jitter and latency |
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Alarm signaling (e.g., Burglar alarm) |
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Dedicated link emulation requires both guaranteed throughput and imposes limits on maximum delay and jitter |
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A safety-critical application, such as remote surgery may require a guaranteed level of availability (this is also called hard QoS) |
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A remote system administrator may want to prioritize variable, and usually small, amounts of SSH traffic to ensure a responsive session even over a heavily-laden link |
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Online games, such as fast paced real time simulations with multiple players. Lack of QoS may produce 'lag' |
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These types of service are called inelastic, meaning that they require a certain minimum level of bandwidth and a certain maximum latency to function. |
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By contrast, elastic applications can take advantage of however much or little bandwidth is available. Bulk file transfer applications that rely on TCP are generally elastic.
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From The Editors Desk |
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| Kayalvizhi |
| Email - kayal@mindlogicx.com |
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| Heartiest Greetings! |
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In this issue of Youniverse, we have presented an article on “Multi-protocol label switching (MPLS)”, The article provides introduction, goals, features, characteristics and benefits of MPLS.
Our regular section on Exam Alerts informs you of the important dates of the upcoming entrance examinations. The section on “Complex simplicities” provides an introduction to the concepts of Gateway GPRS Support Node (GGSN), Very High Bitrate Digital Subscriber Line (VHDSL) and Quality of Service.
We hope that you would find the information presented in this issue of Youniverse interesting and useful. |
We welcome your thought, views, comments and suggestions to share information as knowledge. |
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| Editor |
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Feedback |
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Please provide us with your feedback on how you feel about the Youniverse newsletter.You can also send us your queries on the VEDAS services. |
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