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-rw-r--r--plugins-root/check_icmp.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/plugins-root/check_icmp.c b/plugins-root/check_icmp.c
index 915710b..12fb7b7 100644
--- a/plugins-root/check_icmp.c
+++ b/plugins-root/check_icmp.c
@@ -1322,7 +1322,27 @@ finish(int sig)
1322 } 1322 }
1323 1323
1324 if (host->icmp_recv>1) { 1324 if (host->icmp_recv>1) {
1325 /*
1326 * This algorithm is probably pretty much blindly copied from
1327 * locations like this one: https://www.slac.stanford.edu/comp/net/wan-mon/tutorial.html#mos
1328 * It calucates a MOS value (range of 1 to 5, where 1 is bad and 5 really good).
1329 * According to some quick research MOS originates from the Audio/Video transport network area.
1330 * Whether it can and should be computed from ICMP data, I can not say.
1331 *
1332 * Anyway the basic idea is to map a value "R" with a range of 0-100 to the MOS value
1333 *
1334 * MOS stands likely for Mean Opinion Score ( https://en.wikipedia.org/wiki/Mean_Opinion_Score )
1335 *
1336 * More links:
1337 * - https://confluence.slac.stanford.edu/display/IEPM/MOS
1338 */
1325 host->jitter=(host->jitter / (host->icmp_recv - 1)/1000); 1339 host->jitter=(host->jitter / (host->icmp_recv - 1)/1000);
1340
1341 /*
1342 * Take the average round trip latency (in milliseconds), add
1343 * round trip jitter, but double the impact to latency
1344 * then add 10 for protocol latencies (in milliseconds).
1345 */
1326 host->EffectiveLatency = (rta/1000) + host->jitter * 2 + 10; 1346 host->EffectiveLatency = (rta/1000) + host->jitter * 2 + 10;
1327 1347
1328 if (host->EffectiveLatency < 160) { 1348 if (host->EffectiveLatency < 160) {
@@ -1331,6 +1351,8 @@ finish(int sig)
1331 R = 93.2 - ((host->EffectiveLatency - 120) / 10); 1351 R = 93.2 - ((host->EffectiveLatency - 120) / 10);
1332 } 1352 }
1333 1353
1354 // Now, let us deduct 2.5 R values per percentage of packet loss (i.e. a
1355 // loss of 5% will be entered as 5).
1334 R = R - (pl * 2.5); 1356 R = R - (pl * 2.5);
1335 1357
1336 if (R < 0) { 1358 if (R < 0) {