What is the best choice for IP router bearer?

At present, the development of IP routers is very rapid. Here we mainly introduce the comparison and analysis of PTN and L3 IP/MPLS, including the main problems of IP/MPLS: Using IP/MPLS through L3 and so on. The application of enhanced Ethernet should be positioned to carry the fixed broadband access service. This kind of application positioning can provide less than Ms protection for data services through the ring topology. It directly uses Ethernet to carry the IP router service, avoiding overhead caused by inter-protocol conversion and encapsulation.

It can effectively access and schedule big-granularity (GE and 10GE) data services, and implement Fault Locating and performance monitoring using the OAM mechanism of enhanced Ethernet technology; based on Ethernet, it is easy to carry out data services from multiple points to multiple points. The enhanced Ethernet technology can meet the needs of large-scale deployment of IPTV and other services due to its good support for multicast; to create a new network, you can not only reduce the network construction cost, but also shorten the payback period compared to other methods.

Comparison and Analysis of PTN and L3 IP/MPLS

The IP/MPLS scheme is mainly used in combination with MPLS technologies to make up for some inherent limitations of the Ethernet technology to meet operational requirements. In essence, it is through the superposition of layer-3 MPLS and layer-2 networks, use layer-3 MPLS technology to simulate layer-2 Ethernet services. Base station return solution based on IP/MPLS generally uses IP routers to provide bearer services at the network core, while Ethernet devices are used to access services at the network edge. In this architecture, Ethernet/REP is used in the access layer to achieve ring network or star topology access. IP/MPLS technology is used in the convergence layer to the core layer for comprehensive access to all services in the city at the same time, the Convergence layer device also provides traffic aggregation and service IP router SR functions. At the same time, it can meet the diversified needs of the entire business: Transmission-oriented, Internet-oriented, wireless access and IMS.

GE or 10GE links can be used to establish a ring network between the access layer and the aggregation layer. If multiple pairs of optical fibers exist between the convergence layer and the access layer, you can also use the multi-link GE binding method to flexibly expand the bandwidth. The aggregation data center uses an IP/MPLS network to converge and classify Ethernet-connected businesses. The service identifiers are mapped from Layer 2 VLAN information to Label information to carry services in Layer 3 mode, l3 gateway locations can be deployed on aggregation nodes or RNC machine room nodes, MPLS-OAM works with E-OAM to monitor business availability.

IP/MPLS problems: Using IP/MPLS to pass through layer-3

The network structure usually uses dual-homing Multi-Level Interconnection, especially when the access network uses tree-type and star-type interconnection structures, which wastes a lot of optical fiber resources. To extend the IP network to a man or edge access network, due to the N2 problem, the network is too complex and has poor scalability. The QoS capability is insufficient to ensure the performance requirements of real-time services, and the multi-service support capability of IP/MPLS is poor, it is difficult to provide multi-service interfaces such as TDM and ATM, and complicated technologies such as expensive circuit simulation are required.

Due to the lack of the synchronous clock transmission function, the network cannot work synchronously and can not meet the carrying requirements of 3G services. In the bearer network built based on a layer-3 IP router, considering the robustness and Network Protection of the network, the "dual-attribution" and "Mesh" methods are often used for network networking. When the two methods are used for networking, a large number of IP router ports are used. In actual network creation, many ports are used. Because IP router ports are expensive, their network construction costs remain high.

Through the superposition of layer-3 MPLS and layer-2 network, layer-3 MPLS technology is used to simulate layer-2 Ethernet services and can process point-to-point leased lines, however, when processing points to multiple points, the whole network needs to adopt the VPLS method and require full mesh connection, so the cost is too high. MPLSVPN features complex implementation, difficult maintenance and positioning, high technical requirements for network maintenance personnel, high maintenance costs, low efficiency, lack of Carrier-level OAM and Protection Switching mechanisms, and low reliability; statistics over the years show that the network survivability and reliability of the IP network are relatively poor. For example, the current reliability of the IP router itself is only 99.9%, there are still many gaps from the requirements of the Telecom Level 5 9.

In order to meet the real-time requirements of new businesses, STP fast convergence, fast route convergence, and MPLS fast re-routing support capabilities need to be further improved in existing IP router/switch networks. Therefore, the use of IP Routers/switches to build a bearer network that meets the needs of new businesses, in fact, it is also necessary to upgrade the existing IP router network throughout the network, the construction cost is very high, cost-effective. Because the IP router cannot be pushed to the edge of the network, if the IP/MPLS Router network is used to carry the 3G base station return service, the IP router still needs to work with edge access devices to provide an end-to-end Layer 2 Transfer Function. Such a solution will inevitably compromise network performance, interconnection, and synchronization metrics, making it difficult to provide telecom-level services. Problems solved by PTN: PTN transforms non-connection, unknown forwarding behavior, weak control or uncontrolled sub-network into a connection-based, predictable behavior, and Controllable network suitable for transmission, it also integrates grouping features such as flexibility, scalability, statistics reuse, network end-to-end OAM and protection, connection-oriented, QoS, timed synchronization, and other transmission features.

Prospect prediction: IP/MPLS multi-service and networking capabilities are strong, transmission and OAM capabilities are weak, and kernel group switching is the problem: high investment, high failure rate, and high power consumption. It is mainly used to carry broadband services, the business of the bearer base station needs to be verified. It has recently been applied to the core layer and is gradually extended to the aggregation and access layers in the middle and long directions.