摘要 |
The invention concerns in-line monitoring of a communication link between two stations in a frame-based communication network wherein the said two stations employ a compression algorithm for the transmission of frames and a corresponding decompression algorithm for the reception and decompression of the frames, the said algorithms requiring the maintenance at a transmitting station of a compression history in terms of the number of frames transmitted since a datum point and the maintenance of a corresponding compression history at a receiving station in terms of the number of frames received, the frames each including an identification of the compression sequence so that the receiving station can detect mismatch between the compression sequence and the receiving sequence. The monitoring method comprises detecting frames transmitted from one of the stations to the other, detecting whether frames are compressed, decompressing compressed frames and maintaining a compression history corresponding to that maintained by the receiving station.
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