BTS_Tests: f_rtpem_activate(): pad TCH/FS frames with 'FF'O
Since recently [1], osmo-bts started to preen incoming FR and EFR RTP
frames for SID errors. In other words, if an incoming frame is a SID
frame, osmo-bts may modify some bits causing a mismatch on our side.
Use 'FF'O as padding pattern for TCH/FS to prevent pseudo-random frames
being treated as SID and modified by osmo-bts. Keep using '00'O for
other modes, because only TCH/FS specific SID frames must have specific
bit positions set to '0'B; for TCH/EFS and TCH/HS it's '1'B.
Change-Id: Ib42b783574caf5cbaf64b2eb5dd1d2b2a6637c2f
Related: [1] osmo-bts.git I89df2f12c49dd5378667cf149d19bde654f80134
Related: OS#6039
diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index 909a331..8fc0fa9 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -2609,10 +2609,11 @@
/* Step 1: configure the RTP parameters */
var integer payload_len := 0;
var octetstring hdr := ''O;
+ var OCT1 pad := '00'O;
select (g_pars.chan_mode) {
case (tr_RSL_ChanMode(RSL_CHRT_TCH_F, RSL_CMOD_SP_GSM1)) /* TCH/FS */
- { payload_len := 33; hdr := 'D0'O; }
+ { payload_len := 33; hdr := 'D0'O; pad := 'FF'O; }
case (tr_RSL_ChanMode(RSL_CHRT_TCH_H, RSL_CMOD_SP_GSM1)) /* TCH/HS */
{ payload_len := 15; hdr := '00'O; }
case (tr_RSL_ChanMode(RSL_CHRT_TCH_F, RSL_CMOD_SP_GSM2)) /* TCH/EFS */
@@ -2636,7 +2637,7 @@
}
/* Pad the payload to conform the expected length */
- payload := f_pad_oct(hdr & payload, payload_len, '00'O);
+ payload := f_pad_oct(hdr & payload, payload_len, pad);
cfg.tx_payloads[0].fixed_payload := payload;
f_rtpem_configure(RTPEM_CTRL, cfg);