Traffic Engineering
So what is it? Traffic engineering is actually a set of tools and methods, both in network equipment and transmission lines or failure of the normal case, it will benefit from the infrastructure of a given extract the best services. That is, it should have been installed to optimize the resources. In fact, it is a network engineering or network planning as a complement and improve the measures. Actual network traffic engineering traffic trying to get an optimal way to exist in the physical network.
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About Wikipedia card What is Traffic Engineering? Traffic Engineering in MPLS traffic engineering intelligence to solve problems connected network bandwidth estimation bandwidth measurement re-elastic rules of priority networks connected label stack recovery restore / path optimization signaling properties of network quality of service profile card with the conclusions of Wikipedia sustained rapid development of Internet, people began its service quality, reliability and efficiency of re-thinking, which one of the key solution is to use multi-protocol Label Switching (MPLS) IP network to improve overall performance. This trend has led to traditional routing protocols and ATM integration of the core technology occur, and one of the most important reference is to allow MPLS ATM flow control mechanisms to achieve MPLS Traffic Engineering (Traffic Engineering). What is Traffic Engineering? The current Internet faces two major stress. First, the current routing protocol is essentially connectionless, and therefore the network capacity utilization led to a non-optimal features. Now the routing is only based on destination IP address and the shortest path, and ignored the available link capacity and packet network streams itself. This situation is shown in Figure 1, the super link aggregation will lead to some overload or congestion, and other links are underutilized in the case; second, the current IP service is essentially no quality of service, or so-called Best Effort. But now want to support a wide range of IP technology business, including voice and video. This is in terms of the current IP technology is powerless,
air force one shoes, or powerless. So far, the backbone is provided by the ATM traffic engineering techniques, of course, is a connection-oriented ATM switching technology, from planning and design of its first day on the commitment to provide optimized network traffic engineering mechanisms In fact the technology to do this. However, most of them are due to the current level applications based on TCP / IP technology, ATM technology, traffic control mechanisms on the IP business is indirect control, so the IP technology before considering an increase in their traffic control function,
nike air force 1, or so-called flow project, it is clearly a direct way to provide flow control mechanism. MPLS is in this context was the adoption of ATM had the idea to launch a MPLS Traffic Engineering MPLS related in the previous presentation, we have introduced the concept of MPLS, an MPLS node that is in fact a mark of its deal with the exchange of traffic equipment. ATM and frame relay switches can provide here, the exchange function, the introduction of ATM, the ATM directly to the map marked cell's VPI / VCI. In IP networks, traffic engineering issues discussed are: to solve congestion, to avoid the traffic and resources caused by some invalid mapping the transition of network resources utilization, and other resources are utilized contradictions; the network topology, fast,
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nike air force one high, effective dynamic re-distribution of traffic flow, especially in the line or equipment failure occurs when the network and even more so. Advanced MPLS Traffic Engineering to provide dynamic, real-time automatic resource optimization, the use of so-called Traffic engineering intelligence to solve problems connected to the network resources in order to achieve optimized to reduce the burden of management, MPLS node will be used to establish end to end signaling protocol Label Switching Channels (LSR). Connections can be determined by the user smart (specific route), but also by the path computation algorithm. Currently used in the link state database can be OSPF-TE (OSPF traffic engineering) or IS-IS-TE (IS-IS traffic engineering) library, but the calculation algorithm is the same. There must be clearly aware that there is no additional access restrictions to the minimum computational algorithms will no doubt cost path. If no additional constraints, path algorithm can significantly improve the management of the workload staffing clear route, but to improve the distribution of network traffic and no real contribution. Calculated path bandwidth estimation algorithms in order to improve the effectiveness of distribution of traffic, but also other parameters. Estimated bandwidth is one of them. In fact, each LSP requires an estimate of bandwidth, and each link also has a link congestion factor, and the coefficient is based on link capacity and has been occupied by the LSP to calculate the capacity and the results of the valuation. When adding a new path, each path should be related to re-calculate the path congestion factor. The new connection will choose the link with the lowest form of congestion factor. Although the estimated bandwidth bandwidth measurement to improve the utilization of network resources is a considerable improvement, but this, after all, an estimate. Clearly, the actual volume of business the more accurate the estimate, the higher the effectiveness of path selection. As the aforementioned path computation algorithm is a static way, without considering the actual time-varying link utilization, so the result of a link may be a high or low volume of business estimated. Low flow estimates may cause the actual link traffic overload, we want to avoid causing congestion and packet loss; and high flow estimates may cause the actual link is underutilized, causing unnecessary network of other parts of the potential congestion. Therefore, the bandwidth estimation algorithm to function better approach would be by measuring bandwidth. Periodic measurement of link utilization, the utilization rate fluctuations, the buffer occupancy and buffer occupancy rate fluctuations will be crucial. These new parameters can be regularly published by routing protocols or over a certain threshold trigger release. Take this, you can dynamically calculate the effective bandwidth of aggregate traffic. Bandwidth than the average this method more accurate estimates, thus further improving the utilization of network resources. Internet services, network resiliency is currently critical to the success of the enterprise, so users need different service availability. MPLS control mechanism should be able to provide lines or equipment failure recovery. The traditional method is to use time-out detection, that is a passive way, the new method should take a proactive approach to early detection and fault prediction. The failure of the underlying information and the routing and signaling should be of direct contact in order to trigger the earlier restoration strategies. Connection priority than other connections to some of the connections have higher priority obviously is a universal demand, so the LSR in the MPLS must have this ability, including the priority to establish a connection priority and release connections . It is noteworthy that under fault conditions on the priority attached high priority to shorten the recovery time is very important. Place in a circuitous route, due to the dynamic nature of network failure, the best circuitous route often only be determined at the last minute, so the priority must be dynamic connection configuration. Network reorganization rules in the modern communication network, the network line or equipment failure will affect the result of hundreds, even thousands of LSP. Disorderly release, re-routing and signaling the second switch control system will lead to overload, resulting in network re too long. Therefore, there must be a gentle MPLS restructuring mechanism, then you must specify different priority LSP group restructuring strategy. The benefit also is the ability to more quickly re-occupied after the dissemination of information to the network resources associated MPLS node, to ensure that the restructuring process still has a consideration of optimizing network resources. MPLS label stack of the label stack can significantly improve the ability of the core network recovery time. For example, when the aggregate volume of business in the core network, the tag can be reduced by increasing the layer of the core network, the number of LSP. Once the core of the network fails, only on a smaller number of LSP re-routing to simplify the restructuring task. Recovery Recovery / MPLS network path optimization when the failure of equipment restored, the network should still be restored to its original state of the best allocation of resources. In connectionless networks,
air force 1 shoes, traffic will automatically revert to the shortest path surface, and in the connection-oriented network, you must use a similar mechanism, recovery restore / path optimization is often connected to the network-oriented approach . LSR in the MPLS network can detect the presence of regularly better than the existing LSP path, if present, the old LSP should switch to the new LSP. A typical example is the network fault recovery, the temporary restoration to the original LSP and LSP, another situation is restored to user-specified path. Although the signaling properties of a topology-driven MPLS network, most of the time there is longer than the LSP, on the signaling performance requirements relatively low. However, because the purpose of MPLS as a backbone technology, the fault must be quickly and effectively recover, so, in fact, good or bad the signaling properties of MPLS traffic engineering on the level of automation has a crucial impact. QoS MPLS traffic engineering needs to provide quality of service, specifically for different services, especially the future multimedia services optional / controllable network quality of service. This requires that each of MPLS LSR LSP can be selected for a specific buffer allocation and scheduling priority, and reserve-related network resources. Clearly, a dynamic multi-service network quality of service optimization system for the ultimate success of MPLS is very important. Conclusion MPLS IP network is to provide an important tool for traffic engineering. Although the previous integrated MPLS (Integrated Services) and service differentiation (Differentiated Services) as part of the quality of services to solve the problem, but only MPLS service is the most comprehensive quality assurance system. Through the MPLS traffic engineering technology, the traditional Best Effort IP network can be controlled smoothly evolved into multi-service network. In addition, we must clearly understand that MPLS technology is actually an incarnation of ATM technology, and a pioneer in ATM technology in traffic engineering communications company Marconi has accumulated a wealth of experience, and these experiences can be good in the MPLS switch reflected. Atlas Atlas entry for more extended reading: 1
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