SDH management network: architecture, routing and addressing

CCITT recommendation G.784 provides several options for the implementation of routing and addressing schemes within the synchronous digital hierarchy (SDH) management network (SMN). In addition, equipment manufacturers and network operators have identified a hierarchical topology for the SDH network. Based on these routing and addressing options and network topologies, the network operators need to implement an efficient, robust and cost effective management structure. Two alternatives have been identified as possible implementation strategies for the SMN. The first option makes use of an X.25 packet switched network, as well as the SDH data communications channels (DCCs). Here the complexities of implementing a wide area packet switched network are alleviated by making use of the X.25 network with a static routing scheme. The protocol specified in Annex C of G.784 can be used for this implementation, but the authors identify serious deficiencies in the standards. Hence, its use would require a proprietary solution or considerable effort in the CCITT standardisation arena. The second option uses the DCC exclusively to provide the communications network. The standard protocol stack as specified in CCITT recommendation G.784 is used. Dynamic routing is provided by the intermediate system to intermediate system (IS-IS) routing protocol. The first option may be implemented in the initial stages. A gradual migration path can be adopted to take advantage of the second option with the advance of SDH equipment and its management capabilities.<
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