Abstract: A SONET/SDH frame providing for an optimized management of K1 and K2 bytes of protection protocol and providing for the management of a number of nodes higher than sixteen, which is the highest number which is provided for at the present time. In practice, the bits of a third byte (K0) of Multiplex Section OverHead are used in such a way that at least one of them represents a Source Node IDentification Extension bit, at least one of them represents a Destination Node IDentification Extension bit and at least one bit of those remaining indicates a change of the information in said first, second or third bytes (K1, K2, K0). In this way, the nodes which can be managed can be even 128 and the switching rate could be highly increased.

Abstract: A frame is described for optimized signalling of Span and Ring events at the same time in a four-fibre terrestrial or transoceanic synchronous telecommunications network with ring topology, by using in MSOH the K bytes and an additional byte K0. The frame is characterized by K0 byte having a first bit to indicate if a ring event is present in the ring and a second bit to indicate if a span event is present in the ring and by K1 byte having Bridge Request field for indication of the type of event and K0 byte having a third bit to indicate if it is a span or ring event.

Abstract: Described is a method of managing multiple failures of different type in telecommunication networks having a ring topology, in particular transoceanic four-fiber MS-SPRING rings. The method is characterized by comprising the step, implemented before realizing the ring type protection, of checking that the necessary low priority channels for the implementation of the ring type protection are available, namely they are not already utilized for performing another protection; in the negative case, it is foreseen the implementation of no ring type protection to prevent the unuseful loss of low priority channels. In case of multiple failures of different type, namely of ring and span types, in the path, the method provides for implementing a ring type protection.

Abstract: Described is a method for managing multiple failures of different type in telecommunications networks with a ring topology, in particular four-fiber transoceanic MS-SPRING rings. The method is characterized by providing at least one additional event signalling bytes in the transmitted frames, the first pair of bytes being used for signalling events of a first type, whereas the at least one additional pair of bytes being used for signalling events of a second type. Typically, the first pair of bytes is exclusively used to signal ring (or span) events, whereas the additional pair of bytes is exclusively used to signal span (or ring) events.

Abstract: Described is a method for managing the transition between a ring failure and a span failure in a telecommunication network with a ring topology protected by a traffic protection mechanism. The method is characterized by the steps of verifying that the protection channels (LP) have been restored; in the affirmative, maintaining the protection corresponding to a ring event for a predetermined time; and, once such predetermined time has elapsed, managing the event as a span event. The time is computed by a timer and it is preferably equal to the Wait Time to Restore (WTR). The method allows the exploitation of the resources available in the ring network in an optimal manner.