MSTP refers to the access, processing, and transmission of multiple services such as TDM, ATM, and Ethernet based on the SDH platform. MSTP provides a unified network management system (NMS) for multiple service nodes.
The MAN MSTP construction solution is a feasible metropolitan area network (MAN) construction scheme between the traditional SDH+ATM solution and the future all-optical ASON network. MSTP is obviously better than SDH. It mainly provides multiple port types, flexible service provision, WDM upgrade and capacity expansion, maximum utility fiber bandwidth utilization, and small-granularity bandwidth management. Because it is based on the existing SDH transmission network, it can be well compatible with the existing technology to ensure the existing investment. The MSTP can be integrated with the WDM technology to ensure the smooth upgrade of the network. To some extent, the MSTP can be one of the low-cost solutions of the Metro-WDM.
The MSTP series equipment is a metropolitan area network (MAN) node. It is a bridge area where the data network and the voice network are integrated. MSTP can be applied to each layer of the MAN. For the backbone layer: Carries and schedules large-capacity high-speed SDH, IP, and ATM services between central nodes and provides protection. For the aggregation layer: Converges SDH, IP, and ATM services from the access layer to the backbone layer. For the access layer: MSTP implements the access of services required by users.
MSTP is based on the SDH technology. Therefore, MSTP supports the traditional TDM services. The difficulty of the technology is how to use the SDH to support the IP service, that is, how to map the IP data to the SDH frame.
Early MSTP uses PPP (RFC1661, RFC1662, and RFC2615) to map IP data. IP over SDH (or Packet over SONET-POS) is implemented through the process of IP packet ->PPP packet ->HDLC encapsulation ->SDH VC. This method is mature and applicable to multiple protocols. However, it is not designed for SDH, and therefore the overhead is high during frame alignment, and the transmission efficiency is related to the transmission content, therefore, the efficiency is low.
Technical Features of MSTP
1) Inherits the advantages of the SDH technology. For example, good network protection switching performance and good support for TDM services.
2) Supporting Multiple Physical Interfaces: The MSTP equipment is responsible for service access, convergence, and transmission. Therefore, the MSTP equipment must support multiple physical interfaces to support the access and processing of multiple services. Common interface types are as follows: TDM interfaces (T1/E1 and T3/E3), SDH interfaces (OC-N/STM-M), Ethernet interfaces (10/100BaseT and GE), and POS interfaces.
3) Supporting Multiple Protocols: To support multiple services, MSTP must support multiple protocols and enhance the intelligence of the network edge by supporting multiple protocols. Different types of transport streams are separated by aggregating, switching, or routing different services.
4) Supporting multiple types of optical fiber transmission: MSTP is classified into different types according to different locations on the network. When MSTP is located on the core backbone network, the lowest signal type is OC-48 and can be extended to OC-192 and dense wavelength division multiplexing (DWDM). When MSTP is located at the edge access and aggregation layers, the signal type starts from OC-3/OC-12 and can be extended to OC-48 that supports DWDM in the future.
