Asynchronous transfer mode (A.T.M.) protocol adapter for a high speed cell switching system

Asynchronous Transfer Mode (A.T.M.) Protocol Adapter for a cell switching system comprising a receive part based on a pipeline structure comprising the following elements that successively perform the following operations in order to convert a cell being received from an ATM line adapter into a cell comprising a routing header and a payload;

• means (920) receiving the cell comprising a LI/VP/VC field, with LI defining from which line the cell entered into the Protocol Adapter, and VP/VC defining the ATM Virtual Path and Virtual Circuit assigned to the connection to which the cell belong;
• means (920) for accessing a first table (924) in order to generate an input index used for addressing a second table (922) returning the following parameters assigned to the considered LI/VP/VC:
• Connection Index, a REASSEMBLY index;
• an OPERATION AND MAINTENANCE (OAM) index, a CELL EXTRACT index, a SWITCH ROUTING HEADER (S.R.H.) index used for controlling both the routing process and multicast operations that will be executed into the switching system;
• and an OUTPUT Index characterizing a specific operation which is to be performed in the destination Protocol Adapter that will receive the cell after it is routed throughout the switching system;
• means (Policing block 925) using said CONNECTION index for addressing a third table (POLICY AND PARAMETERS COUNTERS table 936), that permits to check the conformance of the incoming cell to the Generic Cell Rate Algorithm (GCRA);
• means (AAL5 block 930) for) using said REASSEMBLY index for determining whether the current cell should be reassembled in accordance with the AAL5 format and performed reassembly;
• or should be directly forward to the next pipeline element without any reassembly;
• means (OAM block 935) using said OAM index for, determining whether the received cell belongs to a connection for which a decision of OAM performance monitoring as specified in the I.610 ITU Recommendation was made, and performed related OAM performance monitoring operations;
• means (SWITH HEADER INSERT block 940) for appending a SRH index to the cell being processed by said receive pipeline circuit, said SRH index being using for both controlling the routing mechanism within the switching system and the different multicast operations therein involved;
• means (VP/OI swap block 945) for inserting said OUTPUT index within the cell in lieu of bits of said VP field and a Header Correction Code (H.E.C.) field.