Alcatel

Alcatel N.v.

Giovanni Traverso

Alberto Lometti

Luca Gabriele Razzetti

Alberto Bellato

Silvano Frigerio

Sergio Cabrini

Roberto Cardillo

Alessandra Rossi

Claudio Girardi

A virtual concatenation method for optical channels in WDM networks. In transmission, the method includes providing for a plurality of frames, each frame including a byte reserved for a concatenation flag; writing the same predefined value in the concatenation byte of n frames (n=1, 2, 3, . . . ); and transmitting the n frames via n respective channels (&#x3bb;, &#x3bb;, . . . &#x3bb;). In reception, it includes receiving the first reference frame at one instant; reading the concatenation byte value of the reference frame; receiving the remaining signal frames after a respective determined time; reading the value of the concatenation byte of the remaining signal frames; and identifying and aligning all the signal frames with the same concatenation byte value compensating the reception times.

Virtual concatenation of optical channels in WDM networks

A method and circuit are described for improving the pointer processing in the case of synchronous digital hierarchy (SDH) or synchronous optical network (SONET) transmission frames with VC4_4c, VC4_16c and VC4_64c concatenated payloads. The technique proposed by the existing Standards provides for two different state diagrams to be used in the pointer processing algorithm. One state diagram is used in the case of a concatenated payload and the other state diagram is used in the case of a non-concatenated payload. However, no solution is disclosed for automatically going from the states of one diagram to the states of the other diagram. The present invention provides a circuit so constructed that it can be used in an apparatus processing STM-4, STM-16 and STM-64 frames, through which the automatic recognition of the VC4-4c, VC4-16c and VC4-64c payload concatenation can be achieved. Therefore, it is not necessary to configure in advance the concatenation or non-concatenation condition.

Method and circuit for improving the pointer processing in synchronous digital hierarchy (SDH) transmission frames

A method and circuit for mismatch detection in SDH-coded frame trace identifiers within a telecommunication network, wherein received trace identifiers are compared with expected trace identifiers in determined locations of the communication network, to detect if a misconnection event has occurred and generate a corresponding alarm signal. The method comprises the steps of: a) validating the received trace identifier (TI) and issuing a corresponding validation signal (CRC , CNST); b) comparing the received trace identifier (TI) with an expected trace identifier (ETI) and issuing a corresponding validation signal (MTC , MTC ); c) evaluating the validation signal (CRC , CNST) and the match signal (MTC , MTC ); and d) generating a matching state signal (SVAL , SVAL ) according to the result of the evaluation as per step c), wherein steps a) and b) are executed in parallel.

Mismatch detection in SDH frame trace identifiers

The invention relates to a method and circuit arrangement for the realization of the Higher Path Adaptation (HPA) function in Synchronous Digital Hierarchy (SDH) equipment. Such function serves to equalize frequency difference between the synchronisms of signals coming from different nodes of the network. The equalization is carried out through the use of the positive and negative justification technique. The invention, through the alteration of the justification instants, is capable of reducing the capacity of the elastic storage and the generated wander.

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Rovagnate, Italy

Giovanni Traverso