Hi Anak Galer,

On Mon, Sep 17, 2012 at 04:31:22AM +0700, anak galer wrote:

I want asking about protocol GSM header like this. ex :

/* A-bis Interface Management Messages */ NM_MT_ESTABLISH_TEI = 0x21,

where it came from 0x21, explain please. anyone have more reference

You found that value in the following file: libosmocore/include/osmocom/gsm/protocol/gsm_12_21.h

If you read the beginning of the file, it states:

/* GSM Network Management messages on the A-bis interface * 3GPP TS 12.21 version 8.0.0 Release 1999 / ETSI TS 100 623 V8.0.0 */

This is the exact specification number and specification version that the value was taken from. You can obtain the specification free of charge from both ETSI and 3GPP.

Regards, Harald