PQ:优先级队列?
1,共有四个队列，分为四个优先级别，默认的流量都是normal?
优先级分类：1high?2medium?3normal?4low?默认所有流量都走normal队列每个队列为fifo调度
2,加队：在每一个队列中还是按照fifo的原则加队，按尾丢弃原则丢弃。?
3,调度：只要高优先级有流量就发高优先级的，直到高优先级的数据发完再发低优先级的数据，这样就有可能造成低优先级的数据无带宽可用。
预配置
R1的配置
R1 (config)#int f0/0
R1 (config-if)#ip add 172.16.18.101 255.255.255.0
R1(config-if)#no sh
实验过程：
（1）在R1上创建Access-list,定义不同的流量
R1(config)#access-list 100 permit tcp any any eq www
R1(config)#access-list 101 permit tcp any any eq ftp
R1(config)#access-list 102 permit tcp any any eq telnet
R1(config)#access-list 103 permit tcp any any
（2）在R1上创建优先级列表
R1(config)#priority-list 1 protocol ip high list 100
R1(config)#priority-list 1 protocol ip medium list 101
R1(config)#priority-list 1 protocol ip normal list 102
R1(config)#priority-list 1 protocol ip low list 103
（3）将优先级列表在接口下应用
R1(config)#int f0/0
R1(config-if)#priority-group 1
R1(config)#do sho int f0/0
FastEthernet0/0 is up, line protocol is up
Hardware is DEC21140, address is ca37.0b1c.0000 (bia ca37.0b1c.0000)
Internet address is 172.16.18.101/16
MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,
reliability 255/255, txload 1/255, rxload 1/255
Encapsulation ARPA, loopback not set
Keepalive set (10 sec)
Half-duplex, 100Mb/s, 100BaseTX/FX
ARP type: ARPA, ARP Timeout 04:00:00
Last input never, output 00:00:02, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
Queueing strategy: priority-list 1
Output queue (queue priority: size/max/drops):
high: 0/20/0, medium: 0/40/0, normal: 0/60/0, low: 0/80/0
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
0 packets input, 0 bytes
Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
0 watchdog
0 input packets with dribble condition detected
290 packets output, 30352 bytes, 0 underruns
0 output errors, 0 collisions, 2 interface resets
0 babbles, 0 late collision, 0 deferred
0 lost carrier, 0 no carrier
0 output buffer failures, 0 output buffers swapped out
R1#sho queueing
Current fair queue configuration:（S2/1接口默认是WFQ）
Interface Discard Dynamic Reserved Link Priority
threshold queues queues queues queues
Serial2/0 64 256 0 8 1
Serial2/1 64 256 0 8 1
Serial2/2 64 256 0 8 1
Serial2/3 64 256 0 8 1
Serial3/0 64 256 0 8 1
Serial3/1 64 256 0 8 1
Serial3/2 64 256 0 8 1
Serial3/3 64 256 0 8 1
Current DLCI priority queue configuration:
Current priority queue configuration:
List Queue Args
1 high protocol ip list 100
1 medium protocol ip list 101
1 normal protocol ip list 102
1 low protocol ip list 103
Current custom queue configuration:
Current random-detect configuration:
Current per-SID queue configuration:
R1#sho queueing interface f0/0
Interface FastEthernet0/0 queueing strategy: priority
Output queue utilization (queue/count)
high/65 medium/0 normal/297 low/0
R1#sho queueing priority
Current DLCI priority queue configuration:
Current priority queue configuration:
List Queue Args
1 high protocol ip list 100
1 medium protocol ip list 101
1 normal protocol ip list 102
1 low protocol ip list 103