edge: Disable GPRS/EGPRS mixed mode

Currently the plain 'egprs' command enables EGPRS but doesn't prevent
phones from being served in GPRS mode if they do not support EGPRS.
This involves complex frame allocation implementations in dynamic
mode, especially if 8PSK is being used. This is due to the inability
of non-EGPRS phone to decode 8PSK USF and ES/P altogether. Since
polling has a higher priority than USF, collisions will have to be
prevented by the PCU by never using an GPRS USF if it refers to a FN
that is already being used for polling.

This commit just disables mixed usage by ignoring GPRS-only request
if EGPRS is enabled.

The following VTY command (config-pcu node) is changed:

  egprs     ->   egprs only

Sponsored-by: On-Waves ehf

4 files changed, 21 insertions, 5 deletions

diff --git a/src/bts.cpp b/src/bts.cpp
index eb07918..1c10596 100644
--- a/src/bts.cpp
+++ b/src/bts.cpp
@@ -57,6 +57,7 @@ static const struct rate_ctr_desc bts_ctr_description[] = {
 	{ "tbf.reused",			"TBF Reused           "},
 	{ "tbf.alloc.algo-a",		"TBF Alloc Algo A     "},
 	{ "tbf.alloc.algo-b",		"TBF Alloc Algo B     "},
+	{ "tbf.failed.egprs-only",	"TBF Failed EGPRS-only"},
 	{ "rlc.sent",			"RLC Sent             "},
 	{ "rlc.resent",			"RLC Resent           "},
 	{ "rlc.restarted",		"RLC Restarted        "},
diff --git a/src/bts.h b/src/bts.h
index 52154cb..e467c1e 100644
--- a/src/bts.h
+++ b/src/bts.h
@@ -215,6 +215,7 @@ public:
 		CTR_TBF_REUSED,
 		CTR_TBF_ALLOC_ALGO_A,
 		CTR_TBF_ALLOC_ALGO_B,
+		CTR_TBF_FAILED_EGPRS_ONLY,
 		CTR_RLC_SENT,
 		CTR_RLC_RESENT,
 		CTR_RLC_RESTARTED,
@@ -288,6 +289,7 @@ public:
 	void tbf_reused();
 	void tbf_alloc_algo_a();
 	void tbf_alloc_algo_b();
+	void tbf_failed_egprs_only();
 	void rlc_sent();
 	void rlc_resent();
 	void rlc_restarted();
@@ -425,6 +427,7 @@ CREATE_COUNT_INLINE(tbf_ul_freed, CTR_TBF_UL_FREED)
 CREATE_COUNT_INLINE(tbf_reused, CTR_TBF_REUSED)
 CREATE_COUNT_INLINE(tbf_alloc_algo_a, CTR_TBF_ALLOC_ALGO_A)
 CREATE_COUNT_INLINE(tbf_alloc_algo_b, CTR_TBF_ALLOC_ALGO_B)
+CREATE_COUNT_INLINE(tbf_failed_egprs_only, CTR_TBF_FAILED_EGPRS_ONLY)
 CREATE_COUNT_INLINE(rlc_sent, CTR_RLC_SENT)
 CREATE_COUNT_INLINE(rlc_resent, CTR_RLC_RESENT)
 CREATE_COUNT_INLINE(rlc_restarted, CTR_RLC_RESTARTED)
diff --git a/src/pcu_vty.c b/src/pcu_vty.c
index fe3009b..97be4c7 100644
--- a/src/pcu_vty.c
+++ b/src/pcu_vty.c
@@ -55,9 +55,7 @@ static int config_write_pcu(struct vty *vty)
 
 	vty_out(vty, "pcu%s", VTY_NEWLINE);
 	if (bts->egprs_enabled)
-		vty_out(vty, " egprs%s", VTY_NEWLINE);
-	else
-		vty_out(vty, " no egprs%s", VTY_NEWLINE);
+		vty_out(vty, " egprs only%s", VTY_NEWLINE);
 
 	vty_out(vty, " flow-control-interval %d%s", bts->fc_interval,
 		VTY_NEWLINE);
@@ -171,8 +169,8 @@ DEFUN(cfg_pcu,
 
 DEFUN(cfg_pcu_egprs,
       cfg_pcu_egprs_cmd,
-      "egprs",
-      EGPRS_STR)
+      "egprs only",
+      EGPRS_STR "Use EGPRS and disable plain GPRS\n")
 {
 	struct gprs_rlcmac_bts *bts = bts_main_data();
 
diff --git a/src/tbf.cpp b/src/tbf.cpp
index 1f0576a..db63a08 100644
--- a/src/tbf.cpp
+++ b/src/tbf.cpp
@@ -609,6 +609,13 @@ struct gprs_rlcmac_ul_tbf *tbf_alloc_ul_tbf(struct gprs_rlcmac_bts *bts,
 	struct gprs_rlcmac_ul_tbf *tbf;
 	int rc;
 
+	if (egprs_ms_class == 0 && bts->egprs_enabled) {
+		LOGP(DRLCMAC, LOGL_NOTICE,
+			"Not accepting non-EGPRS phone in EGPRS-only mode\n");
+		bts->bts->tbf_failed_egprs_only();
+		return NULL;
+	}
+
 	LOGP(DRLCMAC, LOGL_DEBUG, "********** TBF starts here **********\n");
 	LOGP(DRLCMAC, LOGL_INFO, "Allocating %s TBF: MS_CLASS=%d/%d\n",
 		"UL", ms_class, egprs_ms_class);
@@ -679,6 +686,13 @@ struct gprs_rlcmac_dl_tbf *tbf_alloc_dl_tbf(struct gprs_rlcmac_bts *bts,
 	struct gprs_rlcmac_dl_tbf *tbf;
 	int rc;
 
+	if (egprs_ms_class == 0 && bts->egprs_enabled) {
+		LOGP(DRLCMAC, LOGL_NOTICE,
+			"Not accepting non-EGPRS phone in EGPRS-only mode\n");
+		bts->bts->tbf_failed_egprs_only();
+		return NULL;
+	}
+
 	LOGP(DRLCMAC, LOGL_DEBUG, "********** TBF starts here **********\n");
 	LOGP(DRLCMAC, LOGL_INFO, "Allocating %s TBF: MS_CLASS=%d/%d\n",
 		"DL", ms_class, egprs_ms_class);