초록 ▼

In intermediate network nodes of high speed packet switching networks, when a message is modified, the invention proposes a method and an apparatus for calculating a modified FCS error code. Using the properties of calculations in the Galois Field, the implementation of the invention, specially in t

In intermediate network nodes of high speed packet switching networks, when a message is modified, the invention proposes a method and an apparatus for calculating a modified FCS error code. Using the properties of calculations in the Galois Field, the implementation of the invention, specially in the intermediate Frame Relay network nodes, is reduced to a plurality of simple well known operators (90, 100, 120, 30); the implementation of the invention allows the usage of a plurality of small lookup tables (60, 70, 80, 110) as desired and thus avoiding large amounts of storage resources.

대표청구항 ▼

An apparatus for calculating a modified Frame Check Sequence (FCS) character for a bit stream messages (M) conveyed in a high speed packet switching network using an FCS error code based on a generator polynomial G generating a Galois Field for which the root is aam corresponding to m; means for XOR

An apparatus for calculating a modified Frame Check Sequence (FCS) character for a bit stream messages (M) conveyed in a high speed packet switching network using an FCS error code based on a generator polynomial G generating a Galois Field for which the root is aam corresponding to m; means for XORing the two bit streams corresponding to the initial message and the modified message said messages not including the FCS fields, the result being a delta vector; means for calculating the remainder in the division by the generator polynomial of said delta vector; if the length of the modified bits field is smaller than the degree of G, the remainder being the delta vector itself; means for performing a Galois Field multiplication of the result of the previous step with said remainder; means for adding the result of the previous step with the initial error code, the result being the final error code which is the error code of the modified message.