Broadband Access Network Solution Based on Carrier-level Ethernet network RERP technology (1)

SetRERPAs a large-scale ring Ethernet deployment technology, Ethernet network protection solves problems such as weak protection capability of traditional data networks and long fault recovery time, it is an important technical choice and solution for carrier man construction.

1. Requirement Analysis

The operator's IP Man plays an increasingly important role in the whole business operation era. On the one hand, it must comprehensively carry the Internet business, NGN voice business, ICT leased line/private network business, And IPTV Business, on the other hand, with the transition from a mobile base station to an IP address segmentation, IP address backhaul of the mobile base station will be carried on the IP address man in the future. As a comprehensive service bearer platform, IP Man must provide high performance, high reliability, high security, and necessary service quality assurance for related services.
The operator's IP Man is divided into two layers: the metro backbone network and the broadband access network. The Metro backbone network consists of the core layer and business access control layer based on its functions. It generally uses high-end routers and BRAS networks. The Broadband Access Network is a part of the business control points below, provides access and Convergence for individual broadband businesses and major customer leased line/private network businesses. The broadband access network can be further divided into aggregation layer and access layer by function. Generally, layer-2 technology networks of switches are used. Shows the network structure of an IP Man:
In the past, the main ideas of IP Man transformation for various operators were: network routing, expansion of the three-tier network scale and reduction of the second-tier network scale, business node-based localization, service quality differentiation, and network security reinforcement.
For the broadband access network, with the routing transformation of the ip man, the BRAS and SR of the business control points will gradually move down to achieve terminal localization of business nodes, therefore, the convergence layer of the broadband access network moves to the edge of the man. For layer-2 networks under BRAS and SR, redundant links must be added to ensure the reliability of the aggregation layer. To avoid loops, the generation Tree Protocol can only be used, this includes the traditional STP and RSTP/MSTP with faster convergence. However, due to the generation tree convergence time, volatility and compatibility issues, it is rarely used in actual network construction.
On the other hand, as the convergence layer of the broadband access network is marginalized, the convergence nodes are far away from each other and the optical fiber resources are insufficient. Generally, the carrier's physical optical fiber cables use a ring network, such as a single ring, intersection ring, or nested ring. This leads to a lack of point-to-point Optical Fiber Cable Routing Between the aggregation layer and the business control layer. If two-layer dual-homing reliable networking is implemented between the aggregation layer and the business control layer, the optical fiber resources will be wasted seriously. In addition, in terms of reliability, when a physical optical cable is interrupted, multiple aggregation points and BRAS/SR will interrupt the link, which has a great impact on the network stability.
When the region span is very large, such as more than 100km, carriers generally deploy the transmission network from the aggregation node to the business control node. Each aggregation node connects to the BRAS/SR through the transmission link, the reliability of the aggregation layer can be guaranteed by the self-healing characteristics of the transmission network. This mode is often used by operators. However, in recent years, with the complexity of network applications, especially the large amount of traffic generated by P2P applications, the capacity of 2G transmission networks or even 10g transmission networks has reached saturation. In addition, because the transmission network also carries many traditional TDM-based voice and leased line applications, this imposes great restrictions on the expansion of IP Man, if you want to upgrade the transmission network to a larger bandwidth wavelength division system, the cost is too high.
Based on the above analysis, at the broadband access layer of the ip man, due to the physical topology of the optical fiber ring and the limitations and costs of bandwidth expansion based on traditional transmission, therefore, a new solution is required to implement layer-2 high-reliability networking from the aggregation layer to the business control layer. The Ethernet Ring Network Technology of telecom-grade man can solve this problem well with the advantages of low cost and high reliability.