Monitoring OAM cell assisted method to detect bit errors occurri

Details Monitoring OAM cell assisted method to detect bit errors occurri Monitoring OAM cell assisted method to detect bit errors occurri

1999-07-06

2000-05-09

Baker, Stephen M.

Error detection/correction and fault detection/recovery

Pulse or data error handling

Digital data error correction

370248, 714704, 714712, H03M 1300, H04B 346

Patent

active

060618256

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

The invention relates to a monitoring OAM cell assisted method enabling continuous intrasystem determination of bit errors which have occurred in ATM useful cells with a useful information field and a cell head on an ATM transmission link. This method comprises the generation of control bits by evaluating bits of ATM useful cells with a selected target address in the cell head prior to feeding the ATM useful cells into the ATM transmission link, whereupon said control bits are additionally encoded thus generating further control bits. As a next step, in addition to the ATM useful cells, the monitoring OAM cells are transmitted on the ATM transmission link together with the one control bits and the further control bits. The further control bits of the monitoring OAM cells received at the other end of the ATM transmission link are then examined as to whether the respective monitoring OAM cells were transmitted without error and the bit errors which have occurred in the related received ATM useful cells are determined by means of the one control bits of the monitoring OAM cells recognized as having been transmitted error-free.
In a known method of this kind (Andreas Wolf, `Leistungsmessungen in ATM-Netzen`, NTZ volume 47, issue 6, 1994, pages 408 to 413) monitoring OAM cells are used for continuous intrasystem monitoring of an ATM transmission link. For this purpose, the monitoring OAM cells are introduced into the cell stream of the ATM useful cells. EDC data (EDC: error detecting code) contained in the useful data of said monitoring OAM cells allows the detection of bit errors in ATM useful cells. In practice, only ATM useful cells with a selected target address in the cell head are used. According to the above-quoted prior art, the useful data of the monitoring OAM cells furthermore include ECB data (ECB: error check bits) allowing the detection of bit errors in the monitoring OAM cell in question. To be more precise, this is the cyclic supplementation of an Abramson code which makes it possible to detect up to three bit errors. If, during a verification of the ECB data, errors are detected in one of the monitoring OAM cells, such cell is eliminated and not used for evaluation.


OBJECTS OF THE INVENTION

It is the object of the present invention to provide a method for detecting bit errors which have occurred in ATM useful cells on an ATM transmission link, which method allows the detection of almost all bit errors in ATM useful cells with the selected target address in the cell head.
This object is accomplished according to the invention in that the monitoring OAM cells which were recognized as having been transmitted defectively are corrected by means of their further control bits and thus converted into error-free monitoring OAM cells. The one control bits of these monitoring OAM cells are then used for detecting the bit errors which have occurred in the received ATM useful cells with the selected target address in the cell head.
The essential advantage of this method is that--after the correction of the monitoring OAM cells which were recognized as having been transmitted defectively--a larger total of monitoring OAM cells is available for evaluation, making it possible to more reliably determine bit errors in the ATM useful cells with the selected target address in the cell head than by means of the known method.
To ensure that the monitoring OAM cells fed into the cell stream are of a predetermined constant cell length, it is considered advantageous to use a block code for additional encoding.
A very efficient type of encoding is BCH encoding (BCH: Bose Chaudhuri Hocquenghem) or CCF encoding (CCF: cross-correlation function) and it is thus considered advantageous to use a CCF code or a BCH code as the block code. The essential advantage of using a BCH code or a CCF code is that these codes allow the detection and correction of up to 30 bit errors in each monitoring OAM cell--which is clearly more than is possible with the known method which--as already set out above--det

REFERENCES:
patent: 5440565 (1995-08-01), Miyamoto et al.
patent: 5541926 (1996-07-01), Saito et al.
patent: 5570357 (1996-10-01), Van Tetering et al.
patent: 5579303 (1996-11-01), Kiriyama
patent: 5633868 (1997-05-01), Baldwin et al.
patent: 5661722 (1997-08-01), Miyagi
patent: 5675587 (1997-10-01), Okuyama et al.
patent: 5717689 (1998-02-01), Ayanoglu
patent: 5875177 (1999-02-01), Uriu et al.
patent: 5878063 (1999-03-01), Kawasaki et al.
patent: 5886989 (1999-03-01), Evans et al.
patent: 5887000 (1999-03-01), Adachi et al.
PCT International Search Report, PCT/DE/02274, Mar. 1998.
Nishimura et al., "Asynchronous Transfer Mode Network for Broadband ISDN", Hitachi Review, vol. 43, No. 2, pp. 47-52, Apr. 1994.
Wolf, "Leistungmessungen in ATM-Netzen", NTZ Nachrichtentechnische Zeitschrift, vol. 47, No. 6, Jun. 1, 1994, pp. 408-413.
Ohta et al., "A Cell Loss Recovery Method using FEC in ATM Networks", IEEE Journal on Selected Areas in Communications, vol. 9, No. 9, Dec. 1, 1991, pp. 1471-1483.
Wolf, "Auswahl einer Optimalen Codierung fuer Testzelln in ATM-Netzen", NTZ Nachrichtentechnische Zeitschrift, vol. 47, No. 7, Jul. 1994, pp. 484-487.

Affiliated with

Also associated with

Rating

Monitoring OAM cell assisted method to detect bit errors occurri does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Monitoring OAM cell assisted method to detect bit errors occurri, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Monitoring OAM cell assisted method to detect bit errors occurri will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1075829