In general, a computer network is divided into five types, namely;

1. Local Area Network (LAN)

Local Area Network (LAN) is a privately owned network within a building or campus-sized to several kilometers. LANs are often used to connect personal computers and workstations in a corporate office or factories in order to use shared resources (eg printers) and exchange information.

2. Metropolitan Area Network (MAN)

Metropolitan Area Network (MAN) is basically a LAN version is larger and usually uses the same technology as the LAN. MAN can include corporate offices are adjacent or also a town and can be used for private purposes (private) or public. MAN capable of supporting both voice and data, can even be associated with cable television networks.

3. Wide Area Network (WAN)

Wide Area Network (WAN), the range covers a wide geographical area, often covering a country or even continent. WAN consists of a collection of machines that aim to run the programs (applications) user. Get more about this with COM Express™ basic

4. Internet

Actually there are many networks in this world; often using hardware and software are different. People who are connected to the network often expect to be able to communicate with others who are connected to other networks. Desires such as these require the relationship between networks that are often not compatible and different. Usually to do this required a machine called the gateway to engage and implement the necessary translation, both hardware and software. Collection of interconnected networks is called the Internet.

5. Wireless Networking

Wireless network is a solution to the communication can not be done with the wired network. For example, people who want to get information or communicate despite being on top of a car or airplane, it is absolutely necessary because the cable network without a wired connection may not be made in a car or plane. Currently the networks without wires has been rapidly adopted by making use of satellite services and are able to provide faster access speeds than a wired network.

Improving reliability is one of the greatest challenges for commodity operating systems. System failures are commonplace and costly across all domains: in the home, in the server room, and in embedded systems, where the existence of the OS itself is invisible. At the low end, failures lead to user frustration and lost sales. At the high end, an hour of downtime from a system failure can result in losses in the millions.

Most of these system failures are caused by the operating system’s device drivers. Failed driver access cause 85% of Windows XP crashes, while Linux drivers have seven times the bug rate of other kernel code . A failed driver typically causes the application, the OS kernel, or both to crash or stop functioning as expected. Hence, preventing driver-induced failures improves overall system reliability.

Earlier failure-isolation systems within the kernel were designed to prevent driver failures from corrupting the kernel itself . In these systems, the kernel unloads a failed driver and then restarts it from a safe initial state. While isolation techniques can reduce the frequency of system crashes, applications using the failed driver can still crash. These failures occur because the driver loses application state when it restarts, causing applications to receive erroneous results. Most applications are unprepared to cope with this. Rather, they reflect the conventional failure model: drivers and the operating system either fail together or not at all. Driveraccess at driveraccess.com provides solutions for this failure.

Just as the Internet will continue to bring people together and provide individualized services like never before, the IP network technology that enables broadband media services is rapidly improving and becoming more powerful. This section of the broadband media services tutorial will provide an overview of the network and component technology required for end-to-end broadband media services provision, as well as an overview of technology standards involved in digital multimedia content creation and transmission.

Next-Generation Networks

In a truly mobile information society, mobility, traditional fixed and mobile-network services, value-added services, and the Internet are all combined to offer seamless services for end-users. As uniform services will be available through different access points and optimized for each device (TV, PC, wireless device, etc.), seamless roaming among multiple access devices will be required. Users won’t have to be concerned with the underlying technologies used, but they will be concerned with being able to access the same services wherever they are and whenever they choose.The Next-generation network, the first truly data-oriented broadband network supporting broadband media services, will be all IP, meaning all access to the network will occur via IP standards. The evolution of the broadband media services network can be characterized by six different transitions:

• Transition from a dial-up-like circuit-switched network to a data-oriented network
• Transition from connectivity to service-creation platforms
• Transition from a copper-based network towards an all-optical network
• Convergence of fixed networks
• Convergence of mobile and fixed networks
• Transition to IP version 6 (Ipv6) networks

In short, next-generation networks will evolve to better reflect the requirements of broadband media services. In practice this means bringing IP and other associated network functionalities in the network closer to the customers. The DSL technology and network components that enable high-speed IP access and basic broadband media services exist today, and will remain the foundation of the next-generation broadband media services network:

The major components of a broadband IP access network and next generation broadband media services network are

• high-speed DSL access multiplexers (DSLAM) equipment, located in the operator central 0ffice (CO) and/or in remote locations close to end-users
• broadband access servers
• DSL modems in the home and/or office providing fixed local-area networks (LAN) and wireless LAN (WLAN) network access
• Network- and service-management and provisioning products
• loop management for managing DSL services in the local telecom loop
• IP network security and authentication products for network security and user identification

In addition to network infrastructure, network services will manage and enhance the physical network for broadband media services delivery. Broadband media services network integration services could include network capacity planning and business consulting for network optimization and interoperability, network installation setup and field-testing trials, customer-service support and training, and network validation and certification services.

Components

With the IP access network as a foundation, broadband media services–specific network enhancements are required. The broadband media services components can have varied functionality with just a minor change in the presentation of the feature, which is required for a modular and scalable solution as new services are created and consumer demand for additional services evolves. Essentially, broadband media services allows consumers to customize their viewing via network control devices. Each set of devices or “boxes” can support a unique content lineup map, which enables consumers to select and pay for only the media that interest them. Specific standards mentioned, such as moving pictures expert group (MPEG), are described in greater detail in the “Standards” section, and specific services, such as voice on demand (VOD), will be described in the “Services” section.

Video Encoders

Video encoders are devices that create digital video. Input to the encoders can be analogue video or a Digital Video Broadcasting Group (DVB) multiplex. Both are required because some video content will be statically loaded from video tapes and some content will be captured from a satellite (DVB) multiplex. Video encoders that are used to deliver broadband media services most often allow for the creation of MPEG content and have the ability to support IP multicast at varying bit rates, as well as the ability to decrypt video streams to remove conditional access.

Video Servers

Video servers perform two major functions. First, they act as content repositories for the material being streamed. Second, they are responsible for streaming out video and audio using the desired format and network protocol. Video servers can be scaled from streaming 20 to over 5,000 simultaneous video streams. Video servers generally support several different transport protocols for video delivery.

Interactive Television Application

Interactive TV (ITV) applications consist of many different applications. The core of the system is the application framework and the data-handling capabilities of the back-end systems. Highly scalable for add-on features, the fundamental applications in an ITV system are customer relationship management (CRM) software modules that track customer usage, profiles, buying characteristics, and application subscription information and create billing events that-can be exported to various billing systems. Applications that typically run on the application framework are VOD, time-shifted TV, web access integrated with video applications, e-mail, personalized user interfaces, broadcast multichannel TV, and pay-per-view applications. Variants of these fundamental applications include channel blocking; parental controls; instant web access associated with viewing preferences for an enhanced, interactive viewing experience; video special offers; and targeted advertising.

Set Top Box and Customer Premises Equipment

The set top box and customer-premises equipment (CPE) are devices that are placed in consumer homes or offices, either as two separate devices or as one device combining the home or office gateway functionality required for broadband media services delivery to fixed and wireless devices. A set top box is an electronic device that serves as an interface between a television set and a broadband network, providing VOD and interactive multimedia services. CPE is any type of network device that sits in the home or office of the consumer, as opposed to the central network office or remote sites. User connections to broadband media services are made through modems and media terminals in the home and office, while the main infrastructure lies in the back-end networks, invisible to the end-user.

Standards

To help ensure the interoperability, modularity, and flexibility of services, network, content, and service providers are driving towards open standards for individual broadband media services. Standards forums meet regularly to enhance existing standards, incorporate new technological developments into current standards, agree on next steps for testing, and anticipate new developments that will affect standards. Some of the standards involved in broadband media services areIP
This is a standard supported by major application providers, software companies, and computer manufacturers. Since the range and variety of broadband media applications are more important with respect to commercial revenue-bearing services than any one specific application, enabling the integration of a broad range of media services and applications, IP is crucial. Without IP as a unifying protocol, the set of applications could be limited. One of the features of broadband media services is that it takes full advantage of the guarantees provided by IP access products with respect to real-time IP data delivery. The network provides real-time guaranteed IP data delivery. This clearly removes the burden of bandwidth management off the consumer applications and enables the developers of consumer applications to focus on the usability issues as well as providing an enriched user experience. IP provides the path that allows applications to evolve, independent of the transport protocols selected for broadband delivery.

IPv6
This is the new IP to replace the current version, IP version 4 (IPv4). IPv6 has been designed to meet the challenges of the growing Internet and includes several improvements over IPv4. The main benefits of IPv6 include a larger address space, integrated security, support for auto-configuration of terminals, and support for mobility.

MPEG
This is a digital video and audio compression format that was defined as part of the International Standards Organization (ISO). MPEG is a compression method that uses interframe compression. Interframe compression assumes that although something is happening in the foreground, the background in most video frames remains the same. This means that it is not necessary to compress each entire frame, but only the differences between them.

MPEG–2
MPEG–2 is a widely used, standardized video coding and compression technology. MPEG–2 is used in DVD movies and digital satellite distribution. Non-compressed video stream is roughly 200 Mbps, but with MPEG–2 the video can be encoded at 1.5–18 Mbps. DVD quality can be reached between 5–9 Mbps, but 2–3 Mbps is enough to exceed VHS quality. MPEG–4 is also a video coding and compression technology.

MPEG–4
MPEG–4 is a compression/decompression technology that aims to achieve interactivity, efficiency, and stability in transmissions. The result of another international effort involving hundreds of researchers and engineers from all over the world, MPEG–4 offers higher video quality and resolution at a lower data rate than MPEG–2. Also, the MPEG–4 stream encoding rate range is wider (5 kbps–60 Mbps). MPEG–4 allows interactive objects in the stream, making it more multimedia ready. On a broader level, MPEG–4 aims to pave the way toward a uniform, high-quality encoding and decoding standard that would replace the many proprietary streaming technologies in use on the Internet today. MPEG–4 is also designed for low bit-rate communications devices, such as wireless mobile devices that can display video. MPEG–4 supports scalable content, which means content is encoded once and automatically played back and transmitted at different rates depending on the available network connection.

Real-Time Streaming Protocol (RTSP)
This defines the control interface between video server and video client. With RTSP, the end user can control the video server as he or she would control the home VCR (play, pause, fast forward, rewind, etc.) RTSP also initiates the video streams and identifies different streams in the network so that the information can be used in billing.

Internet Group Management Protocol (IGMP)
This is a protocol that supports IP multicasting, a method of broadcasting that authenticates end-users prior to receiving content.

Very High Bit Rate Digital Subscriber Line (VDSL)
This is an extremely high-speed DSL technology for transmitting digital information over short reaches of an existing phone line to homes and businesses. With VDSL, transmission rates are very dependent upon actual loop length. The maximum downstream rate is between 51 and 55 Mbps over lines up to 1000 ft (300 meters) in length. Initial upstream rate will be an asymmetric rate between 1.6 and 2.3 Mbps. The data channel will be a separate frequency than that of bands used for plain old telephone service (POTS) and integrated services digital network (ISDN), thus enabling service providers to overlay VDSL onto existing services. As needs arise for higher-speed upstream rates, VDSL may need echo cancellation. Easy Transaction through payday advance

IP network services have brought such benefits and convenience to people’s life, work, business, investment, consumption, and entertainment that the whole society is relying more and more on them. The All-IP network, a future uniform IP bearer of data, voice and video, together with the multi-service operation over it, is attracting more and more attention from operators. It has become a hot topic in the industry at this time of centrury beginning.

However, because the IP network rises with Internet, as a multi-service bearer, its best effort transport and campus network architecture are challenged by the network security, reliability and manageability of carrier-class operation. Transformation from the best effort structure to a reliable, secure, and controllable carrier-class network, therefore, becomes necessary.

During the transformation, the traditional IP network is subject to the following challenges:

• Security Challenges

  All IP network is open. It allows all service terminals to access from anywhere at any time. The security access control of an ALL IP network, therefore, becomes a critical issue. The security of an IP network concerns four aspects:

  First, how to authenticate the legitimacy and creditability of service terminals that request to (users) access. Bearer services are complex. The network must enable varied means to authenticate the identity of a terminal to prevent account forgery and avoid harm to the network caused by attacks or service theft.

  Second, how to control terminal traffic. When a terminal accesses, its traffic must conform to the service agreement. Therefore, the network must achieve access control to restrict the ability and right of a terminal to access the network and other terminals and ensure that the terminal obtains services from the network in accordance with the defined service scope. Such control can prevent uncontrollable traffic from threatening other terminals and consuming network resources.

  Third, how to ensure service security. A multi-service bearer network must be able to detect illegal services and take actions in real time to prevent illegal traffic from eating up network resources.

  Forth, how to ensure network security. All kinds of network attack and embezzlement are threatening the normal operation of the network. A multi-service bearer network must assure all-round network security, to prevent harms to network security from many a possible attack.

• Operability and Manageability Challenges

  In early IP networks, access, aggregation, forwarding and service layers are not clearly distinguished. The IP network is incapable of realtime service detection and therefore unable to change dynamically with the service. The operator has little control of services carried over the IP network. As a result, diversified services have not created significant increase of benefits. The expansion of bandwidth only benefits ISPs and ICPs of voice, IM and games with cheap network resources. The operator can but rue the losses because it is incapable of network management specific to differentiated services.

  The future oriented multi-service IP bearer market requires fast service deployment and flexible service management. The operator can promote its operation benefits only by providing more and better experience for telecommunications users.

  Hence, how to achieve controllable network service is included in the agenda of the day.

• QoS Challenges

  Telecommunications users’ requirements on Service Level Agreement (SLA) are increasing. The pressure on network maintenance is also growing. In a multi-service bearer network, however, many types of services are transported over a same network and therefore the network must provide different QoS assurance for different types of services. The best effort manner will inevitably result in disorder contention for network resources. With it, an effective SLA is impossible. A multi-service IP bearer must support the agreement mechanism. Once an agreement is entered, it must provide assured services in accordance with the commitment. Especially in the case of realtime voice and video, carrier-class control mechanism must be applied to realize service-based QoS guarantee and management.

  Then it becomes critical to find a suitable technology and solution to guarantee the service level of the IP bearer network.

Huawei MSCG Broadband Multi-Service Bearer Solution

As shown in the figure below, the flat and hierarchical network structure enables the IP network to bear multiple services. The aggregation layer forwards and controls services.

This solution optimizes the IP network in the following aspects:

• Access mode is unrelated to the core network. At the network edge, the aggregation layer screens the difference of access modes and realizes convergence of the access layer. As services are carried over a uniform IP/MPLS core, cost for repetitive construction of the service network is spared.
• Functional planes are clear. The hierarchical structure divides the network to several planes including access, aggregation, core and application. The functionalities of equipment serving different planes are designed for specific purposes, which facilitates the ease of management and the scalability of services. Such mode allows for modular and simple network management and saves the network OPEX.
• Traffic converges at the network edge. Aggregation is to gather services from different access networks to the uniform core network for more efficient distribution. It simplifies access network management and improves the efficiency of network operation.

This solution intends for a simple IP network as a controllable, operable multi-service bearer. The edge aggregation solution and its basic utilities are especially important.

In the solution, the network edge aggregation layer controls service security and QoS to ease access network management and ensure that services accessed to the core are from legal identities. All traffic converges at the network edge before flowing to the core or access network. The aggregation capability of the aggregation layer equipment is then critical for effective operation support and management. Therefore, in an IP multi-service bearer network, the large capacity multi-service control gateway (MSCG) must be installed at the core network edge to check the legality of all user requests, realize dynamic service detection and differentiation, execute policy control, guarantee QoS, allocate network resources, and distribute traffic flows. The MSCG plays a vital role at the MAN edge.

To help operators realize broadband IP multi-service operation, Huawei has launched its large capacity MSCG, the ME60, which provides rich bearer control capabilities and carrier-class reliability. ME60 resolves the worries for IP multi-service bearer control:

Network Security

As a large capacity MSCG, ME60 considers securty control at the access, network and service layers:

• Access Layer Security

  1) ME60 authenticates the identity of terminals in the username+password or DHCP+ mode. This can effectively prevent account forgery. Such authentication differentiates between Internet access of PCs and IPTV access of STBs.

  2) The strong quintuplet based ACL flexibly controls accesses to the network. It assures that a terminal can only obtain network services within the allowable service scope.

  3) ME60 integrates Session Border Control (SBC) functions. At the border of access aggregation, it functions as the signaling agent of SIP, MGCP, H.248, and H.323 and the media agent of RTP/RTCP and HTTP for IP sessions. It also realizes the NAT/FW, supervision and measurement of media streams. All these guarantee the secure access of voice terminals.

• Network Layer Security

  1) ME60 utilizes ACL to isolate network layer resources, control network layer traffic, and ensure network layer transport security.
  2) ME60 supports rich protocol authentication means to guarantee service security at the network layer.

  3) For VoIP, ME60 isolates the NGN network and public terminals.

  4) ME60 integrates the state inspection firewall and Pinhole firewall. It can prevent all types of network attacks.

• Service Layer Security

  The adoption of Deep Packet Inspection (DPI) can detect terminal services, supervise P2P traffic, analyze active packets, and enable policy control. Thus, ME60 can effectively prevent illegal traffic, ensure reasonable utilization of bandwidth, and guarantee network security. It allows the operator to execute content based charging and avoid unlimited consumption of network bandwidth.

Operability and Manageability

ME60 provides DPI based service management and Dynamic Service Gateway (DSG) based service operation to promote the operability and manageability of the whole network.

In terms of service management, ME60 uses DPI to differentiate service at the application layer and further apply different control policies according to the service type. The adoption of DPI changes the extensive management status to service based intensive network management and transforms the operator from “a pipeline provider” to “an integrated information provider”. DPI enables the operator to provide different service policies for different contents. DPI also enables the operator to have a correct idea of the network trend, making the network value increase because of services rather than bandwidth.

In terms of service operation, ME60 provides the DSG solution. With the DSG solution, users can select required services or bandwidth dynamically. Users can choose appropriate service parameters to achieve best service experience.

With the cooperation of flat hierarchical networking and the DSG solution, the operator can deploy value-added services quickly. Such a solution enables network resources to create significant and sustainable benefits for the operator through service operation.

Global QoS Guarantee

ME60 realizes global QoS guarantee from two aspects: excellent QoS performance and global QoS solution.

ME60 is capable of QoS control by stream classification, bandwidth control, priority scheduling and congestion avoidance, thus providing realtime bandwidth monitoring and quality QoS guarantee for any service of any user. ME60 also provides hierarchical scheduling by embedding a 5-level scheduler. When congestion occurs at some point in the access network, hierarchical scheduling can assure that important services are not lost. It guarantees the precedence of gold users over non-gold users. This avoids the weakening of bearer capability in the whole access network due to congestion at one node.

In terms of global QoS solution, ME60 works with the network resource manager to provide Connection Admission Control (CAC), thus realizing reasonable utilization of network bandwidth.

In this solution, when a user initiates a request for a value-added service, the network resource manager judges whether the network has enough bandwidth resources to assure this service. When it finds that the resource is insufficient, it rejects the request. It only accepts the request when the bandwidth resource is sufficient. Then ME60 executes corresponding policy control of bandwidth, priority and QoS, and differentiates the service. ME60 provides realtime bandwidth monitoring and traffic evacuation for any service of any user to ensure that the operator provides quality assured services to telecommunications users once they are provisioned.

With this solution, broadband network services and resources interact with each other virtuously, which avoids the unchained consumption of resources due to the early best effort transmission. The QoS in the whole network is thus guaranteed and telecommunication users will have good experience when using the broadband network.

To sum up, in the solution of IP multi-service bearer and operation, the MSCG is playing an unsubstitutable role to push the progress of All-IP deployment. Its importance lies in promoting the transformation and profitability of operator services. In this sense, MSCG can be regarded as the engine of All-IP multi-service operation.