In April 1995, a young Chinese chemistry student at Beijing University lay dying in a Beijing hospital. Although her doctors had performed numerous tests, they could not discover what was killing her. In desperation, a student friend posted an SOS describing her symptoms to several medical bulletin boards and mailing lists o. n the Internet. Around the world, doctors who regularly checked these electronic bulletin boards and lists responded immediately. In Washington D.C., Dr. John Aldus, a physician with the US Department of State, saw the message from China. He had recently served in Beijing; he knew the woman’s doctors. Using the Internet, he forwarded the message to colleagues in America. Soon an inter-national contingent of doctors joined the e-mail discussion. A consensus emerged — the woman might have been poisoned with thallium, a metal resembling lead. A Beijing laboratory confirmed this diagnosis — the thallium concentration in her body was as much as 1 000 times normal. More e-mail communication followed, as treatment was suggested and then adjusted. The woman slowly began to recover. Well over a year later, the international medical community was still keeping track on her condition through the electronic medium that saved her life. This story underscores society’s increasing reliance on a system of global communication that can link you equally easily with someone in the next town or halfway around the world. People in all walks of life use the telephone system every day to solve a problem or make a date or transfer money or hire an employee. They can do these things by making telephone calls from stationary telephones or from handheld mobile telephones, by sending faxes, or by using computers and dialing into the Internet. The expanded telephone-line capacity that has allowed the growth of these forms of communication is a recent phenomenon. The United States has enjoyed domestic telephone service for more than a century, but overseas telephone calls were difficult until relatively recently. For a number of years after World War H, calls to Europe or Asia relied on shortwave radio signals, the electrically active layer of the atmosphere that lies between 50 and 250 miles above the earth’s surface. It sometimes took operator hours to set up a 3-minute call. In 1956, the first transatlantic copper wire cable allowed simultaneous transmission of 36 telephone conversations. Other cables followed; by the early 1960s, overseas telephone calls had reached 5 million per year. Then came satellite communication in the middle 1960s, and by 1980, the telephone system carried some 200 million overseas calls per year. But as demands on the telecommunication system continued to increase, the limitations of current technology became glaringly apparent. The Thomas Sabo classic silver bracelet traditionally offers the greatest capacity for attaching charms. Thomas Sabo Bracelets The number of pendants you can attach is basically up to you. In contrast, pearl, stone and leather bracelets have an integral charm carrier ? in other words, Thomas Sabo a silver link to which you can attach up to three charms.
Cloud computing is a common practice today and there are many providers who offer cloud enablement solutions and infrastructure as a service (IaaS). While moving to a cloud is an easy decision to take, answering where the physical infrastructure is, how it is accessed etc can help you adopt the best deployment models that’ll drive your business forward. Otherwise, it is often confusing to choose from the various options available today. Lets take a look at the common ones and determine how they are characterised for different infrastructure Public Cloud In public clouds, the end users do not own the physical infrastructure and it is hosted at the vendor’s premises. Also, although the customer has no visibility, the data center is run and controlled virtually through simple web interface consoles with which he can manage storage and resources. Public clouds are flexible, elastic and reliable. Their capacity can be increased within minutes and there is quality of service (QoS). The network in the public cloud is not dedicated to any single user, it is a group of pooled resources from which each user chooses what he needs. Each client is given an account in the public cloud, through which they can run their applications as per the requirement. Hence public clouds are suitable mainly for limited budget enterprises who need quick deployment. They are comparatively fast and a cheaper solution to cloud deployment considering the maintenance of the data center is not something that you will need to worry about. Private Cloud A private cloud is setup in the external or internal premises and managed by the organization itself (or a third party by choice) whilst they can setup their own dedicated network. Due to exclusivity and flexibility, this deployment model is considered more secure, private and scalable. Private clouds are usually used by large enterprises who require large amount of resources for setting up a better platform. To set up private clouds, data centers are bought and virtualization technologies are implemented in them in order to enable an exclusive private virtual space for an enterprise. Highly critical applications which require constant monitoring and special maintenance like firewall, security measures, etc are run on private clouds since they need to be tweaked to meet the specific requirements. On the basis of hosting they are classified into externally hosted and on-premise clouds. Clouds hosted by a third party provider outside the user’s physical premises are called externally hosted clouds, whereas when the cloud is provided to the user inside his company’s physical premises, it is an on-premise private cloud. Hybrid Cloud Hybrid clouds are set up connecting the in-house infrastructure with the local network, along with advanced firewall protection, load-balancers, etc and have a high rate of security. Every organization experiences a sudden peak in their load and which causes their network to go haywire. This is an occasional condition when there are unexpected rise in demands and needs to be provided with a solution that can be used only when necessary. This is where hybrid clouds prove beneficial. Hybrid clouds are considered the most secure deployment models, primarily due to their location. They are set up inside the infrastructure, which makes data archival very easy. It basically acts as a cache to the infrastructure, and data can be cached locally and later be trickled up to the cloud provider. In case of an emergency full-system recovery, the saved data just needs to be copied from the local system to the cloud provider, and thus it also handles restores easily. Hybrid clouds take the best features from public and private clouds, tweak them a little higher, and add value to their service. For example, content syndication is a possible option in public clouds, which you cannot use if you implement a private cloud. Similarly, other beneficial features like easier data archival, faster disaster recovery options, QoS optimization and more. The hybrid clouds are secure and scalable and also interoperable. This model is highly advanced yet simplified and reliable. So which one should you go for? The decision as to which cloud you should choose depends on what type of business you own and what your requirements are. We have seen the different types, listed their features and their advantages. Public clouds, like the AWS, are used for short term solutions which do not require high-end security options. These are helpful when you need quick solutions on a limited budget and do not have maintenance facilities. To set up your own private clouds, solutions like vmware etc, are used with which large datacenters can be used to for the enterprises’ growth and development. Hybrids clouds are gaining prominence among large enterprises and are the most preferred of the lot due to their flexibility and high security. They keep critical information close, and safe. Their rapid elasticity helps in expansion and downsizing of resources as per demand. To determine the most suitable cloud for your business seek assistance from expert consultants who can help you in choosing the best cloud solution for your business, show you all the available options, help you set up the cloud and multiply your profits within no time. Let us help you with more. Andy Rauch is the Team leader and IT Project Manager of Proactive tech Computer Technology located in India.
Cisco AP 541N is a robust wireless access point with business-class features including Clustering technology for a single point of administration for multiple access points. With clustering technology, you can configure and manage all access points as a single wireless network, rather than as a collection of individual devices without the need for a wireless controller. Building a large wireless network in businesses or campuses with multiple buildings frequently requires multiple wireless access points to deploy. Wireless access point devices have limitation in the network coverage particularly when the obstacles exist. The number, thickness and location of walls, ceilings, or other objects that the wireless signals must pass through, may limit the range. Typical ranges vary depending on the types of materials and background RF (radio frequency) noise in your environments. Deployment a single access point device to cover a large area with multiple buildings such as large office buildings, multiple storey buildings, may not be adequate in providing good signal strength to the clients. Therefore deployment of multiple access point devices would be a solution to cover dead spots. Setting up and configuring multiple devices are generally performed one by one that may lead to miss-configuration and administration overhead. Cisco introduces AP 541N Wireless Access Point with clustering technology. Clustering technology allows you centralize a single point of administration for multiple access point deployments. What this Product Does Cisco AP 541N Wireless Access Point is powered by the latest wireless technology 802.11n with selectable dual-band frequency either 2.4 GHz or 5 GHz and combined with smart antenna MIMO (multiple-input multiple output) technology to provide much greater resiliency and data throughput. Cisco AP 541N Wireless Access Point supports clustering technology for a single point of administration for multiple access points deployment. Clustering technology makes it easy to set up, configure, and run your network. Clustering is the ability of a wireless access point to form a dynamic, configuration-aware group (called a cluster) with other similarly designed access points in the same network and subnet. All access points in the cluster self-organize, cloning configuration settings from one access point to another and balancing wireless channels to minimize radio interference. The cluster also provides a single point of administration, allowing you to configure and manage all access points as a single wireless network, rather than as a collection of individual devices without the need for a wireless controller. With clustering, you can share the following information within the cluster • Wireless network identifier (SSID), which is the your unique network name • Security features, such as encryption settings (WPA, WPA2, or WEP), access lists, and MAC address filters (either allowed or denied) • User names and passwords • Quality of service (QoS) settings • Radio settings • Wireless interface settings • Guest welcome screen Cisco AP 541N supports a secure guest access which is easy to setup using easy to follow graphical user interface (GUI). With secure guest access, you can create a security boundary separated from your private networks to allow your business partners and other visitors to access the internet when they visit your business location without granting them any visibility into your business network and without impeding the performance of your business applications. You can also provide a welcome screen to greet visitors using your guest network. Cisco AP 541N access point supports strong security features including advanced Wi-Fi Protected Access (WPA2) encryption, rogue access point detection, access control lists, and MAC address filtering. Cisco AP 541N access point can be operated either in a standalone wireless access point or as part of a larger business network. You can easily add the wireless access points to grow with your business as your needs change, while minimizing operational costs. Deployment can be flexible either using AC power or Power over Ethernet (PoE) to simplify installation in locations where no power outlets are available such as in ceilings to support virtually any deployment. Cisco AP 541N wireless access point is a robust system which can be deployed in stand alone or part of your large business with business class security features to better protect your employees, your guests, and your business. By Ki Grinsing Ki Grinsing was graduated from a technical college (ITS-Surabaya) with the addition of MCSE and CCNA professional certifications. He has prolonged years of working experiences in IT projects. Please visit the articles: Cisco AP541n access point and dgn3500 wireless gateway router
Hou Ziqiang: Institute of Acoustics, Chinese Academy of Engineering Center researcher DSP, China Network Communications Inc., Chief Scientific Adviser A broadband IP MAN MAN traditional telecommunications system using SDH TDM provide dedicated services, systems and high cost, limited bandwidth, laid long period, far from meeting the needs of next-generation broadband MAN. The requirements of the new generation of broadband MAN can be summarized into the following points: (1) scalability, bandwidth can be extended to a few hundreds of Gb / s, and even Tb / s or more; (2) can have as many as several 100 nodes; (3) low cost, including low capital cost and operating costs; (4) to support next-generation IP-based business, can support a variety of physical interfaces, QoS, SLA, monitoring and billing system; (5) support for traditional voice and data services; (6) powerful and easy to use network management system; (7) robust, with a 99.999% working time, hardware redundancy, self-healing fiber ring fault protection capability. Structure in light-line metro Gigabit Ethernet is becoming the mainstream. The current trend is to Ethernet and wavelength division multiplexing (WDM) technologies in the cable line directly into a broadband IP MAN architecture. Now with Gigabit Ethernet will soon become a bit Gigabit Ethernet. DWDM technology in the WAN application of great success, becoming the mainstream, but we can not simply be implanted in the metropolitan area. Interval between adjacent wavelength DWDM systems only 0.8nm (100GHz) or lower, and the frequency accuracy of the laser, monochrome and filter demanding very expensive. However, long-distance wide area network, the use of multiple amplifiers, DWDM system in optical fiber multiple wavelength channels and amplifier sharing, and therefore can still be a significant reduction in WAN costs. The MAN shorter distance (typically 100 km or less), do not use amplifiers to increase the cost of a single fiber is not high, so simple to use and wide area networks like DWDM equipment is not necessarily cost-effective. The solution is to use sparse wavelength division multiplexing (CWDM) technology. It uses 1200 ~ 1700nm wide window, the requirements of the lasers and filters can be greatly reduced, and dramatically reduce costs. Another method is to WDM optical transmission equipment and routing switches combine routing switch port directly drive optical transmission equipment. The simplest case, a fiber optic only way data transmission, to run directly on the bare optical fiber Gigabit Ethernet. If you need multiple streams of data can use wavelength division multiplexing system, gradually increase the wavelength channel as needed. In the routing switches to connect nodes each wavelength channel, which is responsible for routing the exchange of erection ceded / insert effect. This add / drop effect not only on the wavelength of the task can be, even on the data flow packets. With Gigabit Ethernet in optical-line structure to meet the new generation of broadband IP MAN MAN’s requirements and take into account the traditional practice of business, need to address the following issues: (1) According to the SLA, QoS, Bandwidth allocation ; (2) to provide traditional TDM-based telecommunications services, such as leased line, etc.; (3) for access network concentrator, the LAN inside the building to solve the same mutual segregation between different users, each user multi-service flows, respectively management (to improve different QoS) and billing issues, and to provide video broadcast multicast, asymmetric approach to service; (4) fiber-optic ring is cut protection and fault recovery. Current L2/L3 integrated Gigabit Ethernet Routing Switch backplane capacity has reached hundreds of Gb / s, packets per second by volume of more than 100 million; the third layer can be wire-speed IP / IPX routing and the second non-blocking switching; support redundant ports, spanning tree, multi-choice routing and redundant router protocol to increase system reliability; can provide hundreds of 1000Base-X ports; to provide bandwidth management, priority and policy-based QoS; can easily through HTTP, SNMP, RMON, CLI for flexible local and remote management. Some devices can support thousands of IEEE802.1Q VLANs, and is compatible with the link aggregation IEEE802.1ad technology to combine multiple Gigabit Ethernet ports into a trunk, the load balancing between multiple ports. For the Ethernet MAN, the most difficult is how to connect without providing end-to-IP Internet connection, TDM circuit emulation. Some companies (such as Extreme) products are beginning to provide IPTDM business. Core network of VMAN and VLAN with access networks, transmission delay can be fixed voice and video, as the public telephone network to provide the equivalent of IPTDM E1 channels, but this is not true TDM channel. RAD’s TDM overIP, in a transparent T1/E1 IP line circuit, the method is: the data package insert synchronous bit stream, plus IP header into the IP network transmission, data packets transmitted through the IP network to the finishing point synchronized clock in the end of reconstruction, excluding header, to provide synchronous bit stream. Of course, the transmission of IP network data stream to give QoS guarantees, the user interface, standards-based leased line (T1, E1); 10/100Base-T Ethernet network interface is a low cost; you can configure QoS options: VLAN for the first second floor of priority (802.1D), ToS priority for the IP layer to determine, UDP port for the fourth level priority packet delay variation compensation. This system has the external / adaptive clock regeneration, processing delay is very short (less than 1ms), scalable, backup and redundancy management and diagnostics. This device can be used to provide TDME1 IP Internet line, than SDH and ATM networks to provide the E1 cheaper. Metro Ethernet SDH equipment not in use, when the fiber loop is cut off, like how to like SDH self-healing within the 50ms restoration is needed to solve the problem. Currently the first layer in the network to the third layer are solutions. DWDM system in optical light path switching can be completed within the fault recovery in 50ms. The second layer of resilient packet ring (ResilientPacketRing, RPR) can be carried out as quickly as SDH fault recovery, and can transfer data using loop back up some. The latest routing switch can be completed in the third layer ring network or mesh network fails, fast fault recovery. One way is to calculate well in advance of possible failure of the recovery path routing table, once found fault monitor rapid conversion to the backup path; Another approach is to use MPLS to achieve fault recovery. New generation of Gigabit Routing Switch hot-swappable modules and components, system software, and a double-double system configuration, to achieve carrier-grade reliability; a flexible management capabilities, it is convenient to local or remote, by browsing Used SNMP, RMON command for flexible management. 1. RPR Multi-Service I am an expert from Chinese Manufacturers, usually analyzes all kind of industries situation, such as plastic toothbrush holder , the swatter.
Abstract: This paper, the development of the global optical network situation is briefly introduced, then elaborated on some form next-generation optical networks and the corresponding key technologies. Keywords: Metro optical networks; long-distance optical network; Multi-Service Transport Platform (MSTP); Resilient Packet Ring (RPR); Multi-protocol Label Switching (MPLS), wavelength division multiplexing (WDM); Raman amplifier ( RamanAmplifier); Automatic Switched Optical Network (ASON); Generalized Multi-Protocol Label Switching (GMPLS) 1. Overview End of last century, the new century, the global telecommunications market had a bubble, optical networking market was a serious recession, operators are no longer blind pursuit of high capacity and high bandwidth, but more emphasis on capital expenditure (CAPEX), operating expenses (OPEX) and return on investment (ROI) and other financial indicators, more value system equipment performance and low cost, multi-business solutions more attention, more attention can save labor costs of the intelligent configuration and scheduling function. After several years of sharpening and the shock, since 2004, signs optical networking market, particularly evident. Optical network is a basic network, after all, once the business grew, the bearing pressure optical network will increase accordingly. If the pursuit of long-haul optical network with high bandwidth, large capacity, then the pursuit of metro optical networks are multi-service and flexibility. So far, the global long-distance optical network bandwidth becomes saturated or even excess carriers in long-distance optical network investment ratio decreased or remained stable. However, due to the urgent need for practical engineering, ultra-long distance transmission which has evoked strong concern about some of the technical bottlenecks have been resolved, the pace is accelerating business. In addition, including the storage network (SAN) business, including data services is rising, image and multimedia services rather potential, will amount to anything. Many operators are moving in multi-service operator (MSO) the direction of evolution, voice, data and image go hand in hand makes the “TriplePlay” the word is very compelling. Construction of metro operators in full swing, the real purpose is to achieve network optimization is aimed at long-distance backbone network and access network between the user remove the “fault” phenomenon. We know that Metro is the metro optical network business network carrier, if the optical network (such as the traditional SDH and WDM) is only “fool” to send a business signal, then the business layer of pressure would be enormous. Now, the incumbent operators are building networks to modify their thinking, new operators is one step, adopt a new generation of optical networking equipment with the joint network service layer equipment. 2. On the next-generation optical network Not mentioned here, the next generation of optical networks is to allow everyone to think that is a long way off. In other words, a new generation of optical network seems more practical, more relevant. As voice services and TDM services can not instantly disappear, “a new generation of SDH” despite being classified as transitional technology, but it does have the vitality, the kind of “SDH degraded from a system to an interface “too early to say, especially for the Third World and less developed regions have operators. Two features is the new generation SDH multi-service and intelligent, multi-service performance evolved from SDH MSTP, intelligent performance as the introduction of GMPLS / ASON control plane to realize flexible bandwidth allocation, the business end scheduling and dynamic protection and restoration of function. Has been the requirements of the industry is high-capacity WDM and transparent transmission. But the new generation of WDM equipment, other than to provide large capacity, high bandwidth, long distance transmission, while also providing rapid multi-service access and its own optical layer protection. 3. On the next-generation WDM networks Long distance transmission is the next generation WDM network one of the key technologies. At present, the worldwide well-known optical communication system vendors offer large capacity, ultra-long distance DWDM transmission systems to support SDH / SONET / GE and many other business interface, the capacity can be smoothly extended to the T-bit level, the wavelength range covering C + L band can be G.652, G.655 fiber to achieve thousands of kilometers of radio relay transmission. The key technologies include: Distributed Raman and EDFA hybrid amplifier technology, super-band FEC technology, NRZ and RZ modulation pattern, dynamic power balancing, distributed dispersion management technology. Among them, the distributed Raman amplifier with large gain bandwidth, gain flatness, the distribution can be adjusted according to signal characteristics of the gain spectrum. Currently, the new standard for the Raman amplifier has been G.665 ITU-TSG15 allowed to pass through. One of the highlights next-generation WDM network that is unique for the metropolitan area has many designs, including multi-service OTU, T-MUX, optical layer protection. For example, Metro WDM can not rely on the client layer (eg SDH) protection switching facility, which has its own recovery to share with the section of the protection and optical channel shared protection. Some metro OADM equipment serial / parallel optical switch integrated design approach, using a unique “upgrade interface” real guarantee “online upgrade” will not interrupt existing business. In addition, for the metro access network applications, operators can choose a compact, cost-effective CWDM equipment, enabling rapid capacity expansion and network optimization. 4. On the next-generation SDH network About next-generation SDH, we naturally think of MSTP equipment, it can be based on a variety of SDH line rates to achieve, including 155Mb / s, 622 Mb / s, 2.5 Gb / s and 10Gb / s and so on. On the one hand, MSTP retains the inherent cross-SDH capabilities and traditional SDH / PDH service interfaces, TDM services continue to meet the demand; the other hand, MSTP provides ATM processing, Ethernet transparent transmission, L2 Ethernet switching, RPR processing , MPLS processing capabilities to meet the convergence of data services, carding and integration needs. Currently, the most preferred GFP MSTP to provide excellent package of order, and virtual concatenation and LCAS are adapted to the different needs of bandwidth and can in some particles within the link capacity adjustment. In addition to Ethernet functions, MSTP the RPR feature the original Ethernet switching module to overcome the disadvantage of slow, can achieve quick within 50ms protection switching, in addition, RPR provides a fair method to ensure the link bandwidth rational use, to maximize the situation to prevent link congestion. The use of MPLS functionality can MSTP networking capability extends from the ring lattice network, you can pseudo-wire (PW) approach to multi-client services (including Ethernet, ATM and frame relay) to access and together, and through I am Cheap On Sales writer, reports some information about parrot 3400 ls gps , garmin gns 530.
