PS Attach failure due to SCCP connection refused End user originated

[Spider]

Hi guys,

While analyzing attach failure in a 3G network i find many failures with cause 'SCCP connection refused (end user originated)' sent from the SGSN toward the RNC after a 'L3 GMM attach request, follow on request', these failures affects only few cells, and i'm really confused why it's happening for these cells while the failure is sent from the SGSN.

Any explanations for this behaviour?

[Spider]

An additional information is that the old RAC value is 65534, could this be related to something specific?

[hengbong]

65534 or 65535 would be the value for a LAC in case of out of coverage.
For RAC, it would be 255 or 254 for out of coverage also.

[Spider]

What i remark also that in the GPRS attach request in the field PTMSI-IMSI only the IMEI is indicated, could this be the reason behin this rejection?