tbf: Implement delayed release of a downlink TBF
Currently a DL TBF is immediately closed, when the LLC queue is
drained. This will lead to a new DL assignment if data is received
afterwards. In addition, it is not possible to keep the PACCH open
to poll the MS for UL establishment requests there.
GSM 44.060, 9.3.1a suggests to delay the release of an inactive TBF
for some time (max 5s).
This commit mainly changes create_new_bsn() to send LLC dummy
commands as filler if no LLC data is available until keep_open()
returns false. The keep_open() functions returns true unless a
configurable time has passed after the LLC data store drained. By
default, that time is not set which causes keep_open() to always
return false, so that delayed release is effectively disabled.
The following VTY commands are added:
- dl-tbf-idle-time <1-5000> to set the delay in ms
- no dl-tbf-idle-time to disable delayed release
Ticket: #556
Sponsored-by: On-Waves ehf
diff --git a/src/pcu_vty.c b/src/pcu_vty.c
index 578a10b..9b597ad 100644
--- a/src/pcu_vty.c
+++ b/src/pcu_vty.c
@@ -105,6 +105,9 @@
vty_out(vty, " two-phase-access%s", VTY_NEWLINE);
vty_out(vty, " alpha %d%s", bts->alpha, VTY_NEWLINE);
vty_out(vty, " gamma %d%s", bts->gamma * 2, VTY_NEWLINE);
+ if (bts->dl_tbf_idle_msec)
+ vty_out(vty, " dl-tbf-idle-time %d%s", bts->dl_tbf_idle_msec,
+ VTY_NEWLINE);
return CMD_SUCCESS;
}
@@ -287,6 +290,31 @@
return CMD_SUCCESS;
}
+#define IDLE_TIME_STR "keep an idle DL TBF alive for the time given\n"
+DEFUN(cfg_pcu_dl_tbf_idle_time,
+ cfg_pcu_dl_tbf_idle_time_cmd,
+ "dl-tbf-idle-time <1-5000>",
+ IDLE_TIME_STR "idle time in msec")
+{
+ struct gprs_rlcmac_bts *bts = bts_main_data();
+
+ bts->dl_tbf_idle_msec = atoi(argv[0]);
+
+ return CMD_SUCCESS;
+}
+
+DEFUN(cfg_pcu_no_dl_tbf_idle_time,
+ cfg_pcu_no_dl_tbf_idle_time_cmd,
+ "no dl-tbf-idle-time",
+ NO_STR IDLE_TIME_STR)
+{
+ struct gprs_rlcmac_bts *bts = bts_main_data();
+
+ bts->dl_tbf_idle_msec = 0;
+
+ return CMD_SUCCESS;
+}
+
DEFUN(show_tbf,
show_tbf_cmd,
"show tbf all",
@@ -343,6 +371,8 @@
install_element(PCU_NODE, &cfg_pcu_fc_interval_cmd);
install_element(PCU_NODE, &cfg_pcu_alpha_cmd);
install_element(PCU_NODE, &cfg_pcu_gamma_cmd);
+ install_element(PCU_NODE, &cfg_pcu_dl_tbf_idle_time_cmd);
+ install_element(PCU_NODE, &cfg_pcu_no_dl_tbf_idle_time_cmd);
install_element(PCU_NODE, &ournode_end_cmd);
install_element_ve(&show_bts_stats_cmd);