X-Git-Url: http://git.onelab.eu/?p=iproute2.git;a=blobdiff_plain;f=man%2Fman8%2Ftc-red.8;fp=man%2Fman8%2Ftc-red.8;h=0000000000000000000000000000000000000000;hp=d02b411df9552c5cce9f85773d2c10aa86ab38ec;hb=3331a68859fd71047bb1f309048960b48eab2d83;hpb=2bd4a72f2100be7ad7d9518cb1d49bb2a5b71994 diff --git a/man/man8/tc-red.8 b/man/man8/tc-red.8 deleted file mode 100644 index d02b411..0000000 --- a/man/man8/tc-red.8 +++ /dev/null @@ -1,131 +0,0 @@ -.TH RED 8 "13 December 2001" "iproute2" "Linux" -.SH NAME -red \- Random Early Detection -.SH SYNOPSIS -.B tc qdisc ... red -.B limit -bytes -.B min -bytes -.B max -bytes -.B avpkt -bytes -.B burst -packets -.B [ ecn ] [ bandwidth -rate -.B ] probability -chance - -.SH DESCRIPTION -Random Early Detection is a classless qdisc which manages its queue size -smartly. Regular queues simply drop packets from the tail when they are -full, which may not be the optimal behaviour. RED also performs tail drop, -but does so in a more gradual way. - -Once the queue hits a certain average length, packets enqueued have a -configurable chance of being marked (which may mean dropped). This chance -increases linearly up to a point called the -.B max -average queue length, although the queue might get bigger. - -This has a host of benefits over simple taildrop, while not being processor -intensive. It prevents synchronous retransmits after a burst in traffic, -which cause further retransmits, etc. - -The goal is the have a small queue size, which is good for interactivity -while not disturbing TCP/IP traffic with too many sudden drops after a burst -of traffic. - -Depending on if ECN is configured, marking either means dropping or -purely marking a packet as overlimit. -.SH ALGORITHM -The average queue size is used for determining the marking -probability. This is calculated using an Exponential Weighted Moving -Average, which can be more or less sensitive to bursts. - -When the average queue size is below -.B min -bytes, no packet will ever be marked. When it exceeds -.B min, -the probability of doing so climbs linearly up -to -.B probability, -until the average queue size hits -.B max -bytes. Because -.B probability -is normally not set to 100%, the queue size might -conceivably rise above -.B max -bytes, so the -.B limit -parameter is provided to set a hard maximum for the size of the queue. - -.SH PARAMETERS -.TP -min -Average queue size at which marking becomes a possibility. -.TP -max -At this average queue size, the marking probability is maximal. Should be at -least twice -.B min -to prevent synchronous retransmits, higher for low -.B min. -.TP -probability -Maximum probability for marking, specified as a floating point -number from 0.0 to 1.0. Suggested values are 0.01 or 0.02 (1 or 2%, -respectively). -.TP -limit -Hard limit on the real (not average) queue size in bytes. Further packets -are dropped. Should be set higher than max+burst. It is advised to set this -a few times higher than -.B max. -.TP -burst -Used for determining how fast the average queue size is influenced by the -real queue size. Larger values make the calculation more sluggish, allowing -longer bursts of traffic before marking starts. Real life experiments -support the following guideline: (min+min+max)/(3*avpkt). -.TP -avpkt -Specified in bytes. Used with burst to determine the time constant for -average queue size calculations. 1000 is a good value. -.TP -bandwidth -This rate is used for calculating the average queue size after some -idle time. Should be set to the bandwidth of your interface. Does not mean -that RED will shape for you! Optional. -.TP -ecn -As mentioned before, RED can either 'mark' or 'drop'. Explicit Congestion -Notification allows RED to notify remote hosts that their rate exceeds the -amount of bandwidth available. Non-ECN capable hosts can only be notified by -dropping a packet. If this parameter is specified, packets which indicate -that their hosts honor ECN will only be marked and not dropped, unless the -queue size hits -.B limit -bytes. Needs a tc binary with RED support compiled in. Recommended. - -.SH SEE ALSO -.BR tc (8) - -.SH SOURCES -.TP -o -Floyd, S., and Jacobson, V., Random Early Detection gateways for -Congestion Avoidance. http://www.aciri.org/floyd/papers/red/red.html -.TP -o -Some changes to the algorithm by Alexey N. Kuznetsov. - -.SH AUTHORS -Alexey N. Kuznetsov, , Alexey Makarenko -, J Hadi Salim . -This manpage maintained by bert hubert - -