Local Loop Access Model
Support DDN / ATM / SDH / MPLS / XDSL Leverage the advantages from northern and southern china network.Combine the first class of service. Provide secure,reliable and managed network solutions FR
Frame relay introdution
Frame relay aimed to make more efficient use of existing physical resources, which allow for the underprovisioning of data services by telecommunications companies (telcos) to their customers, as clients were unlikely to be utilizing a data service 100 percent of the time. In more recent years, frame relay has acquired a bad reputation in some markets because of excessive bandwidth overbooking by these telcos.
The technical features of Frame relay
High efficiency ---- frame relay consists of an efficient data transmission technique used to send digital information. It is a message forwarding "relay race" like system in which data packets, called frames, are passed from one or many start-points to one or many destinations via a series of intermediate node points. High cost effectiveness ---- Frame relay take good use of the network resources, it can deliver the free resources to different users, other customers can enjoy the free resource when there are no jam over the network High reliability ---- Frame relay uses the concept of shared-access and relies on a technique referred to as "best-effort", whereby error-correction practically does not exist and practically no guarantee of reliable data delivery occurs High flexibility ----- regarding the network design, Frame Relay has very simple protocol, tiny modification over the current network equipments should be enough to upgrade the network. And it will be very convenient to operate. Local loop access
Frame Relay is able to support multi business model, and it is open to transparent to the high level protocol, the local loop can be accessed conveniently. Frame Relay can also be one alternative way of access to ATM network since ATM and Frame Relay are based on the same switching technology.
Frame Relay’s application
Frame relay can deliver the resource dynamically, it will be helpful for large data transaction.
ATM
ATM Introduction
Asynchronous Transfer Mode (ATM) is a network protocol which encodes data traffic into small fixed-sized cells. The standards for ATM were first developed in the mid 1980s. The goal was to design a single networking strategy that could transport real-time video and audio as well as image files, text and email. Two groups, the International Telecommunications Union and the ATM Forum were involved in the creation of the standards.
The technical features of ATM network
ATM was designed to implement a low-jitter network interface. However, to be able to provide short queueing delays, but also be able to carry large datagrams, it had to have cells. ATM broke up all packets, data, and voice streams into 48-byte chunks, adding a 5-byte routing header to each one so that they could be reassembled later. The choice of 48 bytes was political rather than technical. Since the time ATM was designed, networks have become much faster. A 1500 byte (12000-bit) full-size Ethernet packet takes only 1.2 µs to transmit on a 10 Gbit/s optical network, removing the need for small cells to reduce jitter. Some consider that this removes the need for ATM in the network backbone. Additionally, the hardware for implementing the service adaptation for IP packets is expensive at very high speed. ATM traffic contracts are part of the mechanism by which "Quality of Service" (QoS) is ensured. There are four basic types (and several variants) which each have a set of parameters describing the connection Most traffic classes also introduce the concept of Cell Delay Variation Tolerance (CDVT) which defines the "clumping" of cells in time. To maintain network performance it is possible to police virtual circuits against their traffic contracts. If a circuit is exceeding its traffic contract, the network can either drop the cells or mark the Cell Loss Priority (CLP) bit (to identify a cell as discardable farther down the line). Basic policing works on a cell by cell basis, but this is sub-optimal for encapsulated packet traffic (as discarding a single cell will invalidate the whole packet). connection has to be established for two parties to be able to send cells to each other. In ATM this is called a VC ("Virtual Connection"). It can be a PVC ("Permanent Virtual Connection"), which is created dministratively, or an SVC("Switched Virtual Connection"), and that a route exists for the connection. MPLS VPN
MPLS VPN Introduction
Multi Protocol Label Switching (MPLS) is a data-carrying mechanism that belongs to the family of packet-switched networks. MPLS operates at an OSI Model layer that is generally considered to lie between traditional definitions of Layer 2 (Data Link Layer) and Layer 3 (Network Layer), and thus is often referred to as a "Layer 2.5"protocol. It was designed to provide a unified data-carrying service for both circuit-based clients and packet-switching clients which provide a datgagram service model. It can be used to carry many different kinds of traffic,including IP packets, as well as native ATM,SONET,and Ethernet frames.
The technical features of MPLS-VPN
MPLS provides networks with a more effcient 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 tther business-critical functions.MPLS carriers differ on the number of classes of service they offer and in how these CoS tiers are priced.
The Application of MPLS-VPN
The CE can be connected to the PE of local telecom carriers. The location of CE is fixed. MPLS-VPN feed the requirement of those customer who need high QOS,real time and managed network. DSL leased line
DSL leased line introduction
DSL technology can provide high QOS by accessing ATM network via analog line, and it can also suport wide range of bandwidth options from 256K to 4M. Point to point or multi-pionts connection are also available based on DSL network.
The Technical Feature of DSL Network
The same speed for upload and download No certification needed,flexible to use Supports bandwidth from 512K to 2M Provide Layer 2 and Layer 3 acceess mode No routers needed because the Ethernet interface The Application of DSL
Suitable for small and middle size of companies and organization,goverment internet access.