城域网络发展趋势探讨

分组化和觅带化是下一代城域网络发展的趋势，但是向IP城域网络发展过程中，时分复用（TDM）和IP业务将长期共存。分组传送网（PTN）是兼顾TDM业务与IP化的发展方向而产生的产物，作为PTN技术的两种典型代表，传送／多协议标签交换（TMPLS）和运营商骨干桥接／运营商骨干传输（PBB／PBT）实现了分组交换，能够支持端到端链接、监控和快速的保护倒换，此外还实现了控制和传送的分离，是城域网络的发展方向之一。

Discuss of Metro Area Network development

The trend of next generation Metro Area Network (MAN) is packet and broadband, but the co-existence of TDM and IP traffic must be considered during the development process of All IP MAN. Packet Transport Network (PTN) adapts to the trend of All IP, and at the same time gives attention to TDM traffic. Packet switching is implemented in the representatives of PTN technology: TMPLS and PBB/PBT. The technology can provide end-to-end link and inspection, fast protection and restoration, and separation of control from transport. In a word, TMPLS and PBB/PBT are a major trend for MAN development.