doc/manuals, vty doc: more handover doc clarifications

Related: OS#3487
Change-Id: I1639efb2dbcca4f0e9c33a74f3067606ce5f4209

4 files changed, 55 insertions, 49 deletions

diff --git a/doc/manuals/chapters/handover.adoc b/doc/manuals/chapters/handover.adoc
index 2f9d598c6..bb99751d3 100644
--- a/doc/manuals/chapters/handover.adoc
+++ b/doc/manuals/chapters/handover.adoc
@@ -434,7 +434,8 @@ with the next Measurement Report received.
 
 Configuration settings relevant for algorithm 1 start with `handover1`. For
 further details, please refer to the OsmoBSC VTY Reference
-(<<vty-ref-osmobsc>>) or the telnet VTY online documentation.
+(<<vty-ref-osmobsc>>) or the telnet VTY online documentation. See the
+`handover1` settings on the `config-net` and `config-net-bts` nodes.
 
 ==== Handover Algorithm 2
 
@@ -451,7 +452,8 @@ configurable (see `handover2 penalty-time` configuration items).
 
 Configuration settings relevant for algorithm 2 start with `handover2`. For
 further details, please refer to the OsmoBSC VTY Reference
-<<vty-ref-osmobsc>> or the telnet VTY online documentation.
+<<vty-ref-osmobsc>> or the telnet VTY online documentation. See the `handover2`
+settings on the `config-net` and `config-net-bts` nodes.
 
 ===== Load Distribution
 
@@ -472,8 +474,8 @@ In either case, load distribution will only occur towards neighbor cells that
 adhere to minimum reception levels and distance, see `min rxlev` and `max
 distance`.
 
-Load distribution will take effect only for already established voice channels.
-An MS will always first establish a voice call with its current cell choice; in
+Load distribution will take effect only for already established channels.
+For example, an MS will always first establish a voice call with its current cell choice; in
 load situations, it might be moved to another cell shortly after that.
 Considering the best neighbor _before_ starting a new voice call might be
 desirable, but is currently not implemented. Consider that RXLEV/RXQUAL ratings
diff --git a/include/osmocom/bsc/handover_cfg.h b/include/osmocom/bsc/handover_cfg.h
index 92b5cd44c..f174aad77 100644
--- a/include/osmocom/bsc/handover_cfg.h
+++ b/include/osmocom/bsc/handover_cfg.h
@@ -96,22 +96,22 @@ static inline const char *tdma2a(bool val)
 		"handover1 ", "window rxlev averaging", "<1-10>", atoi, "%u", as_is, \
 		HO_CFG_STR_HANDOVER1 \
 		HO_CFG_STR_WIN_RXLEV \
-		"How many RxLev measurements are used for averaging\n" \
+		"How many RxLev measurements to use for averaging\n" \
 		"RxLev averaging: " HO_CFG_STR_AVG_COUNT) \
 	\
 	HO_CFG_ONE_MEMBER(unsigned int, hodec1_rxqual_avg_win, 1, \
 		"handover1 ", "window rxqual averaging", "<1-10>", atoi, "%u", as_is, \
 		HO_CFG_STR_HANDOVER1 \
 		HO_CFG_STR_WIN_RXQUAL \
-		"How many RxQual measurements are used for averaging\n" \
+		"How many RxQual measurements to use for averaging\n" \
 		"RxQual averaging: " HO_CFG_STR_AVG_COUNT) \
 	\
 	HO_CFG_ONE_MEMBER(unsigned int, hodec1_rxlev_neigh_avg_win, 10, \
 		"handover1 ", "window rxlev neighbor averaging", "<1-10>", atoi, "%u", as_is, \
 		HO_CFG_STR_HANDOVER1 \
 		HO_CFG_STR_WIN_RXLEV \
-		"How many Neighbor RxLev measurements are used for averaging\n" \
-		"How many Neighbor RxLev measurements are used for averaging\n" \
+		"How many Neighbor RxLev measurements to use for averaging\n" \
+		"How many Neighbor RxLev measurements to use for averaging\n" \
 		"Neighbor RxLev averaging: " HO_CFG_STR_AVG_COUNT) \
 	\
 	HO_CFG_ONE_MEMBER(unsigned int, hodec1_pwr_interval, 6, \
@@ -142,22 +142,22 @@ static inline const char *tdma2a(bool val)
 		"handover2 ", "window rxlev averaging", "<1-10>", atoi, "%u", as_is, \
 		HO_CFG_STR_HANDOVER2 \
 		HO_CFG_STR_WIN_RXLEV \
-		"How many RxLev measurements are used for averaging\n" \
+		"How many RxLev measurements to use for averaging\n" \
 		"RxLev averaging: " HO_CFG_STR_AVG_COUNT) \
 	\
 	HO_CFG_ONE_MEMBER(unsigned int, hodec2_rxqual_avg_win, 1, \
 		"handover2 ", "window rxqual averaging", "<1-10>", atoi, "%u", as_is, \
 		HO_CFG_STR_HANDOVER2 \
 		HO_CFG_STR_WIN_RXQUAL \
-		"How many RxQual measurements are used for averaging\n" \
+		"How many RxQual measurements to use for averaging\n" \
 		"RxQual averaging: " HO_CFG_STR_AVG_COUNT) \
 	\
 	HO_CFG_ONE_MEMBER(unsigned int, hodec2_rxlev_neigh_avg_win, 10, \
 		"handover2 ", "window rxlev neighbor averaging", "<1-10>", atoi, "%u", as_is, \
 		HO_CFG_STR_HANDOVER2 \
 		HO_CFG_STR_WIN_RXLEV \
-		"How many Neighbor RxLev measurements are used for averaging\n" \
-		"How many Neighbor RxLev measurements are used for averaging\n" \
+		"How many Neighbor RxLev measurements to use for averaging\n" \
+		"How many Neighbor RxLev measurements to use for averaging\n" \
 		"Neighbor RxLev averaging: " HO_CFG_STR_AVG_COUNT) \
 	\
 	HO_CFG_ONE_MEMBER(unsigned int, hodec2_pwr_interval, 6, \
@@ -184,7 +184,7 @@ static inline const char *tdma2a(bool val)
 	HO_CFG_ONE_MEMBER(bool, hodec2_as_active, 0, \
 		"handover2 ", "assignment", "0|1", a2bool, "%d", bool2i, \
 		HO_CFG_STR_HANDOVER2 \
-		"Enable or disable in-call channel re-assignment\n" \
+		"Enable or disable in-call channel re-assignment within the same cell\n" \
 		"Disable in-call assignment\n" \
 		"Enable in-call assignment\n") \
 	\
@@ -200,7 +200,7 @@ static inline const char *tdma2a(bool val)
 		HO_CFG_STR_HANDOVER2 \
 		HO_CFG_STR_MIN \
 		"How weak may RxLev of an MS become before triggering HO\n" \
-		"minimum RxLev (dBm)\n") \
+		"minimum RxLev (dBm; note: negative values)\n") \
 	\
 	HO_CFG_ONE_MEMBER(int, hodec2_min_rxqual, 5, \
 		"handover2 ", "min rxqual", "<0-7>", atoi, "%d", as_is, \
@@ -247,27 +247,30 @@ static inline const char *tdma2a(bool val)
 		"handover2 ", "penalty-time max-distance", "<0-99999>", atoi, "%d", as_is, \
 		HO_CFG_STR_HANDOVER2 \
 		HO_CFG_STR_PENALTY_TIME \
-		"Time to suspend handovers after leaving this cell due to exceeding max distance\n" \
+		"Time to suspend handover for a subscriber after leaving this cell due to exceeding max distance;" \
+		" see also 'handover2 retries'\n" \
 		"Seconds\n") \
 	\
 	HO_CFG_ONE_MEMBER(int, hodec2_penalty_failed_ho, 60, \
 		"handover2 ", "penalty-time failed-ho", "<0-99999>", atoi, "%d", as_is, \
 		HO_CFG_STR_HANDOVER2 \
 		HO_CFG_STR_PENALTY_TIME \
-		"Time to suspend handovers after handover failure to this cell\n" \
+		"Time to suspend handover for a subscriber after a failed handover into this cell;" \
+		" see also 'handover2 retries'\n" \
 		"Seconds\n") \
 	\
 	HO_CFG_ONE_MEMBER(int, hodec2_penalty_failed_as, 60, \
 		"handover2 ", "penalty-time failed-assignment", "<0-99999>", atoi, "%d", as_is, \
 		HO_CFG_STR_HANDOVER2 \
 		HO_CFG_STR_PENALTY_TIME \
-		"Time to suspend handovers after assignment failure in this cell\n" \
+		"Time to suspend handover for a subscriber after a failed re-assignment within this cell;" \
+		" see also 'handover2 retries'\n" \
 		"Seconds\n") \
 	\
 	HO_CFG_ONE_MEMBER(int, hodec2_retries, 0, \
 		"handover2 ", "retries", "<0-9>", atoi, "%d", as_is, \
 		HO_CFG_STR_HANDOVER2 \
-		"Immediately retry on handover/assignment failure\n" \
+		"Number of times to immediately retry a failed handover/assignment, before a penalty time is applied\n" \
 		"Number of retries\n") \
 
 #define HO_CFG_ALL_MEMBERS \
diff --git a/src/osmo-bsc/handover_vty.c b/src/osmo-bsc/handover_vty.c
index 79795115e..e9333ec85 100644
--- a/src/osmo-bsc/handover_vty.c
+++ b/src/osmo-bsc/handover_vty.c
@@ -107,7 +107,8 @@ DEFUN(cfg_net_ho_congestion_check_interval, cfg_net_ho_congestion_check_interval
       "handover2 congestion-check (disabled|<1-999>|now)",
       HO_CFG_STR_HANDOVER2
       "Configure congestion check interval\n"
-      "Disable congestion checking, do not handover based on cell overload\n"
+      "Disable congestion checking, do not handover based on cell load. Note: there is one global congestion check"
+      " interval, i.e. contrary to other handover2 settings, this is not configurable per individual cell.\n"
       "Congestion check interval in seconds (default "
       OSMO_STRINGIFY_VAL(HO_CFG_CONGESTION_CHECK_DEFAULT) ")\n"
       "Manually trigger a congestion check to run right now\n")
diff --git a/tests/handover_cfg.vty b/tests/handover_cfg.vty
index 94c20d962..8fdaf1f08 100644
--- a/tests/handover_cfg.vty
+++ b/tests/handover_cfg.vty
@@ -145,7 +145,7 @@ network
 
 OsmoBSC(config-net-bts)# ### Verify that 'min rxlev' value range stops at -50
 OsmoBSC(config-net-bts)# handover2 min rxlev ?
-  <-110--50>  minimum RxLev (dBm)
+  <-110--50>  minimum RxLev (dBm; note: negative values)
   default     Use default (-100), remove explicit setting on this node
 OsmoBSC(config-net-bts)# handover2 min rxlev -111
 % Unknown command.
@@ -218,14 +218,14 @@ OsmoBSC(config-net)# handover2 ?
   window            Measurement averaging settings
   power             Neighbor cell power triggering
   maximum           Maximum Timing-Advance value (i.e. MS distance) before triggering HO
-  assignment        Enable or disable in-call channel re-assignment
+  assignment        Enable or disable in-call channel re-assignment within the same cell
   tdma-measurement  Define measurement set of TDMA frames
   min               Minimum Level/Quality thresholds before triggering HO
   afs-bias          Configure bias to prefer AFS (AMR on TCH/F) over other codecs
   min-free-slots    Minimum free TCH timeslots before cell is considered congested
   max-handovers     Maximum number of concurrent handovers allowed per cell
   penalty-time      Set penalty times to wait between repeated handovers
-  retries           Immediately retry on handover/assignment failure
+  retries           Number of times to immediately retry a failed handover/assignment, before a penalty time is applied
   congestion-check  Configure congestion check interval
 
 OsmoBSC(config-net)# handover algorithm ?
@@ -238,22 +238,22 @@ OsmoBSC(config-net)# handover1 window ?
   rxqual  Received-Quality averaging
 
 OsmoBSC(config-net)# handover1 window rxlev ?
-  averaging  How many RxLev measurements are used for averaging
-  neighbor   How many Neighbor RxLev measurements are used for averaging
+  averaging  How many RxLev measurements to use for averaging
+  neighbor   How many Neighbor RxLev measurements to use for averaging
 
 OsmoBSC(config-net)# handover1 window rxlev averaging ?
   <1-10>   RxLev averaging: Number of values to average over
   default  Use default (10), remove explicit setting on this node
 
 OsmoBSC(config-net)# handover1 window rxlev neighbor ?
-  averaging  How many Neighbor RxLev measurements are used for averaging
+  averaging  How many Neighbor RxLev measurements to use for averaging
 
 OsmoBSC(config-net)# handover1 window rxlev neighbor averaging ?
   <1-10>   Neighbor RxLev averaging: Number of values to average over
   default  Use default (10), remove explicit setting on this node
 
 OsmoBSC(config-net)# handover1 window rxqual ?
-  averaging  How many RxQual measurements are used for averaging
+  averaging  How many RxQual measurements to use for averaging
 
 OsmoBSC(config-net)# handover1 window rxqual averaging ?
   <1-10>   RxQual averaging: Number of values to average over
@@ -286,22 +286,22 @@ OsmoBSC(config-net)# handover2 window ?
   rxqual  Received-Quality averaging
 
 OsmoBSC(config-net)# handover2 window rxlev ?
-  averaging  How many RxLev measurements are used for averaging
-  neighbor   How many Neighbor RxLev measurements are used for averaging
+  averaging  How many RxLev measurements to use for averaging
+  neighbor   How many Neighbor RxLev measurements to use for averaging
 
 OsmoBSC(config-net)# handover2 window rxlev averaging ?
   <1-10>   RxLev averaging: Number of values to average over
   default  Use default (10), remove explicit setting on this node
 
 OsmoBSC(config-net)# handover2 window rxlev neighbor ?
-  averaging  How many Neighbor RxLev measurements are used for averaging
+  averaging  How many Neighbor RxLev measurements to use for averaging
 
 OsmoBSC(config-net)# handover2 window rxlev neighbor averaging ?
   <1-10>   Neighbor RxLev averaging: Number of values to average over
   default  Use default (10), remove explicit setting on this node
 
 OsmoBSC(config-net)# handover2 window rxqual ?
-  averaging  How many RxQual measurements are used for averaging
+  averaging  How many RxQual measurements to use for averaging
 
 OsmoBSC(config-net)# handover2 window rxqual averaging ?
   <1-10>   RxQual averaging: Number of values to average over
@@ -344,7 +344,7 @@ OsmoBSC(config-net)# handover2 min ?
   rxqual  How bad may RxQual of an MS become before triggering HO
 
 OsmoBSC(config-net)# handover2 min rxlev ?
-  <-110--50>  minimum RxLev (dBm)
+  <-110--50>  minimum RxLev (dBm; note: negative values)
   default     Use default (-100), remove explicit setting on this node
 
 OsmoBSC(config-net)# handover2 min rxqual ?
@@ -383,9 +383,9 @@ OsmoBSC(config-net)# handover2 max-handovers ?
   default   Use default (9999), remove explicit setting on this node
 
 OsmoBSC(config-net)# handover2 penalty-time ?
-  max-distance       Time to suspend handovers after leaving this cell due to exceeding max distance
-  failed-ho          Time to suspend handovers after handover failure to this cell
-  failed-assignment  Time to suspend handovers after assignment failure in this cell
+  max-distance       Time to suspend handover for a subscriber after leaving this cell due to exceeding max distance; see also 'handover2 retries'
+  failed-ho          Time to suspend handover for a subscriber after a failed handover into this cell; see also 'handover2 retries'
+  failed-assignment  Time to suspend handover for a subscriber after a failed re-assignment within this cell; see also 'handover2 retries'
 
 OsmoBSC(config-net)# handover2 penalty-time max-distance ?
   <0-99999>  Seconds
@@ -404,7 +404,7 @@ OsmoBSC(config-net)# handover2 retries ?
   default  Use default (0), remove explicit setting on this node
 
 OsmoBSC(config-net)# handover2 congestion-check ?
-  disabled  Disable congestion checking, do not handover based on cell overload
+  disabled  Disable congestion checking, do not handover based on cell load. Note: there is one global congestion check interval, i.e. contrary to other handover2 settings, this is not configurable per individual cell.
   <1-999>   Congestion check interval in seconds (default 10)
   now       Manually trigger a congestion check to run right now
 
@@ -437,14 +437,14 @@ OsmoBSC(config-net-bts)# handover2 ?
   window            Measurement averaging settings
   power             Neighbor cell power triggering
   maximum           Maximum Timing-Advance value (i.e. MS distance) before triggering HO
-  assignment        Enable or disable in-call channel re-assignment
+  assignment        Enable or disable in-call channel re-assignment within the same cell
   tdma-measurement  Define measurement set of TDMA frames
   min               Minimum Level/Quality thresholds before triggering HO
   afs-bias          Configure bias to prefer AFS (AMR on TCH/F) over other codecs
   min-free-slots    Minimum free TCH timeslots before cell is considered congested
   max-handovers     Maximum number of concurrent handovers allowed per cell
   penalty-time      Set penalty times to wait between repeated handovers
-  retries           Immediately retry on handover/assignment failure
+  retries           Number of times to immediately retry a failed handover/assignment, before a penalty time is applied
 
 OsmoBSC(config-net-bts)# handover algorithm ?
   1        Algorithm 1: trigger handover based on comparing current cell and neighbor RxLev and RxQual, only.
@@ -456,22 +456,22 @@ OsmoBSC(config-net-bts)# handover1 window ?
   rxqual  Received-Quality averaging
 
 OsmoBSC(config-net-bts)# handover1 window rxlev ?
-  averaging  How many RxLev measurements are used for averaging
-  neighbor   How many Neighbor RxLev measurements are used for averaging
+  averaging  How many RxLev measurements to use for averaging
+  neighbor   How many Neighbor RxLev measurements to use for averaging
 
 OsmoBSC(config-net-bts)# handover1 window rxlev averaging ?
   <1-10>   RxLev averaging: Number of values to average over
   default  Use default (10), remove explicit setting on this node
 
 OsmoBSC(config-net-bts)# handover1 window rxlev neighbor ?
-  averaging  How many Neighbor RxLev measurements are used for averaging
+  averaging  How many Neighbor RxLev measurements to use for averaging
 
 OsmoBSC(config-net-bts)# handover1 window rxlev neighbor averaging ?
   <1-10>   Neighbor RxLev averaging: Number of values to average over
   default  Use default (10), remove explicit setting on this node
 
 OsmoBSC(config-net-bts)# handover1 window rxqual ?
-  averaging  How many RxQual measurements are used for averaging
+  averaging  How many RxQual measurements to use for averaging
 
 OsmoBSC(config-net-bts)# handover1 window rxqual averaging ?
   <1-10>   RxQual averaging: Number of values to average over
@@ -504,22 +504,22 @@ OsmoBSC(config-net-bts)# handover2 window ?
   rxqual  Received-Quality averaging
 
 OsmoBSC(config-net-bts)# handover2 window rxlev ?
-  averaging  How many RxLev measurements are used for averaging
-  neighbor   How many Neighbor RxLev measurements are used for averaging
+  averaging  How many RxLev measurements to use for averaging
+  neighbor   How many Neighbor RxLev measurements to use for averaging
 
 OsmoBSC(config-net-bts)# handover2 window rxlev averaging ?
   <1-10>   RxLev averaging: Number of values to average over
   default  Use default (10), remove explicit setting on this node
 
 OsmoBSC(config-net-bts)# handover2 window rxlev neighbor ?
-  averaging  How many Neighbor RxLev measurements are used for averaging
+  averaging  How many Neighbor RxLev measurements to use for averaging
 
 OsmoBSC(config-net-bts)# handover2 window rxlev neighbor averaging ?
   <1-10>   Neighbor RxLev averaging: Number of values to average over
   default  Use default (10), remove explicit setting on this node
 
 OsmoBSC(config-net-bts)# handover2 window rxqual ?
-  averaging  How many RxQual measurements are used for averaging
+  averaging  How many RxQual measurements to use for averaging
 
 OsmoBSC(config-net-bts)# handover2 window rxqual averaging ?
   <1-10>   RxQual averaging: Number of values to average over
@@ -562,7 +562,7 @@ OsmoBSC(config-net-bts)# handover2 min ?
   rxqual  How bad may RxQual of an MS become before triggering HO
 
 OsmoBSC(config-net-bts)# handover2 min rxlev ?
-  <-110--50>  minimum RxLev (dBm)
+  <-110--50>  minimum RxLev (dBm; note: negative values)
   default     Use default (-100), remove explicit setting on this node
 
 OsmoBSC(config-net-bts)# handover2 min rxqual ?
@@ -601,9 +601,9 @@ OsmoBSC(config-net-bts)# handover2 max-handovers ?
   default   Use default (9999), remove explicit setting on this node
 
 OsmoBSC(config-net-bts)# handover2 penalty-time ?
-  max-distance       Time to suspend handovers after leaving this cell due to exceeding max distance
-  failed-ho          Time to suspend handovers after handover failure to this cell
-  failed-assignment  Time to suspend handovers after assignment failure in this cell
+  max-distance       Time to suspend handover for a subscriber after leaving this cell due to exceeding max distance; see also 'handover2 retries'
+  failed-ho          Time to suspend handover for a subscriber after a failed handover into this cell; see also 'handover2 retries'
+  failed-assignment  Time to suspend handover for a subscriber after a failed re-assignment within this cell; see also 'handover2 retries'
 
 OsmoBSC(config-net-bts)# handover2 penalty-time max-distance ?
   <0-99999>  Seconds