1 files changed, 19 insertions, 0 deletions
diff --git a/lib/Vyatta/Qos/Util.pm b/lib/Vyatta/Qos/Util.pm
index 3aefbd8..72b4963 100644
--- a/lib/Vyatta/Qos/Util.pm
+++ b/lib/Vyatta/Qos/Util.pm
@@ -319,4 +319,23 @@ sub ethtoolRate {
     return $rate;
 }
 
+# Compute parameters for RED algorithim based on bandwidth and latency
+#
+#                        0.01 * Bandwidth Share * Desired Latency * Network Bandwidth
+# Maximum Threshold = -------------------------------------------------------------------
+#                                    8 bits/byte* 1000 ms/sec
+#
+# Minimum Threshold = 1/2 * Maximum Threshold
+# Avpkt = Average Packet Length
+# Burst = ( 2 * MinThreshold + MaxThreshold) / ( 3 * Avpkt )
+# Limit = 4 * MaxThreshold
+sub RedParam {
+    my ($bandwidth, $latency, $avgpkt) = @_;
+    my $qmax = ($bandwidth * $latency) / 8000;
+    my $qmin = $qmax / 2;
+    my $burst = ( 2 * $qmin + $qmax ) / ( 3 * $avgpkt );
+
+    return ($qmin, $qmax, $burst);
+}
+
 1;