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RPL-MRHOF: when squaring etx, do so only in path/rank calculation, not in link_metric

This commit is contained in:
Simon Duquennoy 2017-06-27 11:00:09 +02:00
parent f25b76bd43
commit 0d357a5c84
1 changed files with 17 additions and 13 deletions
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30
core/net/rpl-lite/rpl-mrhof.c
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@ -72,23 +72,24 @@
#define RPL_MRHOF_SQUARED_ETX 1
#endif /* RPL_MRHOF_CONF_SQUARED_ETX */
#if !RPL_MRHOF_SQUARED_ETX
/* Configuration parameters of RFC6719. Reject parents that have a higher
* link metric than the following. The default value is 512. */
#define MAX_LINK_METRIC 512 /* Eq ETX of 4 */
/* Reject parents that have a higher path cost than the following. */
#define MAX_PATH_COST 32768 /* Eq path ETX of 256 */
#if !RPL_MRHOF_SQUARED_ETX
/* Hysteresis of MRHOF: the rank must differ more than PARENT_SWITCH_THRESHOLD_DIV
* in order to switch preferred parent. Default in RFC6719: 192, eq ETX of 1.5.
* We use a more aggressive setting: 96, eq ETX of 0.75.
*/
#define PARENT_SWITCH_THRESHOLD 192 /* Eq ETX of 1.5 */
#else /* !RPL_MRHOF_SQUARED_ETX */
#define MAX_LINK_METRIC 2048 /* Eq ETX of 4 */
#define PARENT_SWITCH_THRESHOLD 512 /* Eq ETX of 2 */
#define PARENT_SWITCH_THRESHOLD 512 /* Eq ETX of 2. More than in the
non-squared case because squatinf cases extra jitter. */
#endif /* !RPL_MRHOF_SQUARED_ETX */
/* Reject parents that have a higher path cost than the following. */
#define MAX_PATH_COST 32768 /* Eq path ETX of 256 */
/*---------------------------------------------------------------------------*/
static void
reset(void)
@ -100,15 +101,18 @@ static uint16_t
nbr_link_metric(rpl_nbr_t *nbr)
{
const struct link_stats *stats = rpl_neighbor_get_link_stats(nbr);
if(stats != NULL) {
return stats != NULL ? stats->etx : 0xffff;
}
/*---------------------------------------------------------------------------*/
static uint16_t
link_metric_to_rank(uint16_t etx)
{
#if RPL_MRHOF_SQUARED_ETX
uint32_t squared_etx = ((uint32_t)stats->etx * stats->etx) / LINK_STATS_ETX_DIVISOR;
return (uint16_t)MIN(squared_etx, 0xffff);
uint32_t squared_etx = ((uint32_t)etx * etx) / LINK_STATS_ETX_DIVISOR;
return (uint16_t)MIN(squared_etx, 0xffff);
#else /* RPL_MRHOF_SQUARED_ETX */
return stats->etx;
return etx;
#endif /* RPL_MRHOF_SQUARED_ETX */
}
return 0xffff;
}
/*---------------------------------------------------------------------------*/
static uint16_t
@ -138,7 +142,7 @@ nbr_path_cost(rpl_nbr_t *nbr)
#endif /* RPL_WITH_MC */
/* path cost upper bound: 0xffff */
return MIN((uint32_t)base + nbr_link_metric(nbr), 0xffff);
return MIN((uint32_t)base + link_metric_to_rank(nbr_link_metric(nbr)), 0xffff);
}
/*---------------------------------------------------------------------------*/
static rpl_rank_t