In a Synchronous Digital Hierarchy (SDH) based communications network comprising a plurality of Intermediate Systems (IS), the IS being divided between at least one IS--IS Area and at least one non-IS--IS Area, an IS--IS Area being an area within which a routeing protocol forming part of the Network Layer (Layer 3) of the Open Systems Interconnection including routeing (OSI), is provided for routeing messages between areas, a method is provided wherein static routes (Manual Adjacencies (MA) are created at IS within the IS--IS Area to point to routes to a group of one or more Network Equipments (NEs) within the non-IS--IS Area and where a failure occurs in a link to or within a group and messages from the IS--IS Area to the non-IS--IS Area are looped to the originating IS--IS Area, identification of the NEs from which messages have been looped are removed from the respective MAs allowing routeing of messages via alternative MAs.