其中创建class时，其中的参数意义如下：
default 这是HTB排队规则的一个可选参数，默认值为0， 当值为0时意味着会绕过所有和rootqdisc相关联的分类，然后以最大的速度出队任何未分类的流量。 rate 这个参数用来设置流量发送的最小期望速率。这个速率可以被当作承诺信息速率(CIR), 或者给某个叶子分类的保证带宽。 ceil 这个参数用来设置流量发送的最大期望速率。租借机制将会决定这个参数的实际用处。 这个速率可以被称作“突发速率”。 burst 这个参数是rate桶的大小(参见令牌桶这一节)。HTB将会在更多令牌到达之前将burst个字节的数据包出队。 cburst 这个参数是ceil桶的大小（参见令牌桶这一节）。HTB将会更多令牌(ctoken)到达之前将cburst个字节的数据包出队。 quantum 这个是HTB控制租借机制的关键参数。正常情况下，HTB自己会计算合适的quantum值，而不是由用户来设定。对这个值的轻微调整都会对租借和整形造成巨大的影响，因为HTB不仅会根据这个值向各个子分类分发流量(速率应高于rate，小于ceil)，还会根据此值输出各个子分类中的数据。 r2q 通常,quantum 的值由HTB自己计算，用户可以通过此参数设置一个值来帮助HTB为某个分类计算一个最优的quantum值。 mtu prio 1.3.4 入向流控入向的流控常见做法是通过把接口的流量重定向到ifb设备，然后在ifb的egress上做流控，间接达到控制入向的目的。简单的使用示例如下：
#modprobe ifb //需要加载ifb模块 #ip link set dev ifb0 up txqueuelen 1000 #tc qdisc add dev eth1 ingress //添加ingress qdisc #tc filter add dev eth1 parent ffff: protocol ip u32 match u32 0 0flowid 1:1 action mirred egress redirect dev ifb0 //重定向流量到ifb #tc qdisc add dev ifb0 root netem delay 50ms loss 1% //在ifb上配置操作，这里使用了netem,也可以和出向一样，配置qdisc, class, filter。 1.3.5 统计查看使用tc qdisc show dev xx 查看qdisc
使用tc class show dev xx 查看class
使用tc filter show dev xx 查看filter，注意这里都是查看默认为root，即出向的规则，如果要查看入向的，需要使用tc filter show dev xx ingress 。
The tc tool allows you to gather statistics of queuing disciplines in Linux. Unfortunately statistic results are not explained by authors so that you often can't use them. Here I try to help you to understand HTB's stats. First whole HTB stats. The snippet bellow is taken during simulation from chapter 3. # tc -s -d qdisc show dev eth0 qdisc pfifo 22: limit 5p Sent 0 bytes 0 pkts (dropped 0, overlimits 0) qdisc pfifo 21: limit 5p Sent 2891500 bytes 5783 pkts (dropped 820, overlimits 0) qdisc pfifo 20: limit 5p Sent 1760000 bytes 3520 pkts (dropped 3320, overlimits 0) qdisc htb 1: r2q 10 default 1 direct_packets_stat 0 Sent 4651500 bytes 9303 pkts (dropped 4140, overlimits 34251) First three disciplines are HTB's children. Let's ignore them as PFIFO stats are self explanatory. overlimits tells you how many times the discipline delayed a packet. direct_packets_stat tells you how many packets was sent thru direct queue. Other stats are sefl explanatory. Let's look at class' stats: tc -s -d class show dev eth0 class htb 1:1 root prio 0 rate 800Kbit ceil 800Kbit burst 2Kb/8 mpu 0b cburst 2Kb/8 mpu 0b quantum 10240 level 3 Sent 5914000 bytes 11828 pkts (dropped 0, overlimits 0) rate 70196bps 141pps lended: 6872 borrowed: 0 giants: 0 class htb 1:2 parent 1:1 prio 0 rate 320Kbit ceil 4000Kbit burst 2Kb/8 mpu 0b cburst 2Kb/8 mpu 0b quantum 4096 level 2 Sent 5914000 bytes 11828 pkts (dropped 0, overlimits 0) rate 70196bps 141pps lended: 1017 borrowed: 6872 giants: 0 class htb 1:10 parent 1:2 leaf 20: prio 1 rate 224Kbit ceil 800Kbit burst 2Kb/8 mpu 0b cburst 2Kb/8 mpu 0b quantum 2867 level 0 Sent 2269000 bytes 4538 pkts (dropped 4400, overlimits 36358) rate 14635bps 29pps lended: 2939 borrowed: 1599 giants: 0 I deleted 1:11 and 1:12 class to make output shorter. As you see there are parameters we set. Also there are level and DRR quantum informations. overlimits shows how many times class was asked to send packet but he can't due to rate/ceil constraints (currently counted for leaves only). rate, pps tells you actual (10 sec averaged) rate going thru class. It is the same rate as used by gating. lended is # of packets donated by this class (from its rate) and borrowed are packets for whose we borrowed from parent. Lends are always computed class-local while borrows are transitive (when 1:10 borrows from 1:2 which in turn borrows from 1:1 both 1:10 and 1:2 borrow counters are incremented). giants is number of packets larger than mtu set in tc command. HTB will work with these but rates will not be accurate at all. Add mtu to your tc (defaults to 1600 bytes). 1.3.6 杂项说明查看统计信息时，看不到统计速度rate等？内核为了性能，默认关闭了显示，可以通过echo 1 > /sys/module/sch_htb/parameters/htb_rate_est来打开。
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