本实验限速设备是用一台Cisco2811路由器来完成，本实验分两种方法来做
先看下路由器的flash:
yourname#dir
Directory of flash:/
1 -rw- 25438028 Oct 22 2010 02:25:58 +00:00 c2800nm-ipbase-mz.124-15.T.bin
2 -rw- 1505280 Oct 22 2010 02:26:08 +00:00 common.tar
3 -rw- 931840 Oct 22 2010 02:26:16 +00:00 es.tar
4 -rw- 1038 Oct 22 2010 02:26:20 +00:00 home.shtml
5 -rw- 112640 Oct 22 2010 02:26:26 +00:00 home.tar
6 -rw- 415956 Oct 22 2010 02:26:34 +00:00 sslclient-win-1.1.4.176.pkg
7 -rw- 2748 Oct 22 2010 02:26:38 +00:00 sdmconfig-2811.cfg
8 -rw- 35316 Apr 5 2011 06:09:42 +00:00 crashinfo_20110405-060943
9 -rw- 42068 Apr 5 2011 06:30:26 +00:00 crashinfo_20110405-063027
128733184 bytes total (100229120 bytes free)
以下是实验过程
第一步：用ACL定义要做限速网段或ip地址，一会做分类的时候要调用
access-list 102 permit ip 192.168.1.0 0.0.0.255 any
access-list 102 permit ip any 192.168.1.0 0.0.0.255
access-list 102 permit ip any 192.168.1.0 0.0.0.255
第二步：定义class-map ,调用第一步的ACL
class-map match-all 102
match access-group 102
第三步：定义policy-map，调用class-map，做速率限制
policy-map 102
class 102
police 256000 8000 conform-action transmit exceed-action drop
第四步：把policy-map应用到接口上
interface FastEthernet0/1
service-policy input 102
service-policy output 102
*Apr 5 06:24:04.023: %IP_VFR-4-FRAG_TABLE_OVERFLOW: FastEthernet0/1: the fragment table has reached its maximum threshold 16
yourname#sh policy-map int f0/1
FastEthernet0/1
Service-policy input: 102
Class-map: 102 (match-all)
2746 packets, 672324 bytes
5 minute offered rate 20000 bps, drop rate 0 bps
Match: access-group 102
police:
cir 256000 bps, bc 8000 bytes
conformed 2746 packets, 672324 bytes; actions:
transmit
exceeded 0 packets, 0 bytes; actions:
drop
conformed 90000 bps, exceed 0 bps
Class-map: class-default (match-any)
13407 packets, 1753107 bytes
5 minute offered rate 49000 bps, drop rate 0 bps
Match: any
Service-policy output: 102
Class-map: 102 (match-all)
3506 packets, 2954143 bytes
5 minute offered rate 68000 bps, drop rate 44000 bps
Match: access-group 102
police:
cir 256000 bps, bc 8000 bytes
conformed 2243 packets, 1195420 bytes; actions:
transmit
exceeded 1263 packets, 1758723 bytes; actions:
drop
conformed 162000 bps, exceed 239000 bps
Class-map: class-default (match-any)
15064 packets, 18750663 bytes
5 minute offered rate 430000 bps, drop rate 0 bps
Match: any
yourname#
根据上面信息可以知道已经有流量被drop，也是就是超出限制的部分流量，还有一个单位是要注意的，是bit而不是Byte。下面是迅雷的截图
实验前：
实验后：
上面是第一种做限速的方法，下面我们来看另外一种简单方法
首先也是定义ACL：
access-list 102 permit ip 192.168.1.0 0.0.0.255 any
access-list 102 permit ip any 192.168.1.0 0.0.0.255
access-list 102 permit ip any 192.168.1.0 0.0.0.255
然后直接在接口下启用rate-limit：
interface FastEthernet0/1
rate-limit input access-group 102 256000 1500 2000 conform-action transmit exceed-action drop
rate-limit output access-group 102 256000 1500 2000 conform-action transmit exceed-action drop
rate-limit input access-group 102 256000 1500 2000 conform-action transmit exceed-action drop
rate-limit output access-group 102 256000 1500 2000 conform-action transmit exceed-action drop
这就可以了，限速效果跟第一种方法相当
上面两种方法的配置是对整个ip地址段来限速，如果我们要对ip段中的每一个ip进行限速25.6KB/s的话，就要用下面的方法了：
access-list 121 permit ip host 192.168.0.21 any
access-list 121 permit ip any host 192.168.0.21
!
access-list 122 permit ip host 192.168.0.22 any
access-list 122 permit ip any host 192.168.0.22
!
access-list 123 permit ip host 192.168.0.23 any
access-list 123 permit ip any host 192.168.0.23
!
class-map match-all 121
match access-group 121
!
class-map match-all 122
match access-group 122
!
policy-map xiansu
class 121
police 2560000 8000 conform-action transmit exceed-action drop
class 122
police 2560000 8000 conform-action transmit exceed-action drop
!
interface FastEthernet0/1
service-policy input xiansu
service-policy output xiansu
上面是对192.168.0.21，192.168.0.21限速256KB/s，要是限制整个段的ip，那就自己慢慢写吧。
本文出自 “cuter” 博客，转载请务必保留此出处http://cuter.blog.51cto.com/822595/535784
