QOS 之 queueing

1、FIFO QUEUE

2、WFQ QUEUE

3、PRIORITY QUEUE

4、CUSTOM QUEUE

5、CLASS　BASED　WEIGHTED　FAIR　QUEUE

6.   Low latency queuing（LLQ）

7.  CLASS　BASED   Low latency queuing

默認情況下<=E1的線路默認啓用的就是WFQ，E1=2.048M,大於E1默認就是FIFO。

 

分類：WFO加權隊列，是基於flow的形式默認分類的，不需要人工干預。默認的是WFO丟棄不是尾丟棄，我們要明白兩個概念 class and flow class 手工定義classification  making像PQ CQ, 而flow基於sou ip  des ip tcp/udp port transport protocol TOS.默認是256個flow。

明白這兩個概念：congestive discard threshold (CDT)
                                  Hold-Queue Out limit (HQL)

加隊：early droping when the congestive discard thresold (CDT)is reached
aggressive droping when the hold-queue out limit (HQO)is reached

也就是說有個一個數據包進入緩存經過flow進入也一個隊列，包的個數大於CDT，如果這個隊列已滿，直接drop，沒有滿insert，包的個數大於HQL，隊列已滿 drop 不是最長隊列的包，會aggerssive drop 最長隊列的那個包，這個數據包insert

調度：finish time=real packet size/(ip precedent+1) FT最小的先發送

看個例子：

A1 的FT=50 A2=60 B1=100 B2=150

所以順序是 A1  A2  B1  B2

其實making優先級是沒有作用，關鍵我們要看action 在低速鏈路上我們默認的隊列機制是WFQ 所以語音的ip pre5 有高的優先級，看以先走

 

R2#show int s1/0
Serial1/0 is up, line protocol is up
  Hardware is M4T
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation HDLC, crc 16, loopback not set
  Keepalive set (10 sec)
  Restart-Delay is 0 secs
  Last input 00:00:50, 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: weighted fair       默認的WFQ
  Output queue: 0/1000/64/0 (size/max total/threshold/drops) 64 CDT  HQL 1000 
     Conversations  0/1/256 (active/max active/max total)   總共flow的個數
     Reserved Conversations 0/0 (allocated/max allocated)
     Available Bandwidth 1158 kilobits/sec
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     1 packets input, 332 bytes, 0 no buffer
     Received 1 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     3 packets output, 646 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 output buffer failures, 0 output buffers swapped out
     2 carrier transitions     DCD=up  DSR=up  DTR=up  RTS=up  CTS=up
 

R2(config-if)#fair-queue 128 1024  37 （CDT  動態Q   RSVP ）

                                      64   256   0  (默認)

R2(config-if)#hold-queue 2000 out    HQO

R2#show queueing fair
Current fair queue configuration:

  Interface           Discard    Dynamic  Reserved  Link    Priority
                      threshold  queues   queues    queues  queues
  Serial1/0           128        1024     37        8       1   
  Serial1/1           64         256      0         8       1   
  Serial1/2           64         256      0         8       1   
  Serial1/3           64         256      0         8       1  

PQ:介紹

priority queueing 默認有四個優先級，默認的是尾丟棄，高優先級的先出去，等優先級高的隊列發出去完了在發送下面的隊列，這個不足容易造成低優先級的隊列餓死！

Router(config)#priority-list 2 ?
  default      Set priority queue for unspecified datagrams
  interface    Establish priorities for packets from a named interface  基於接口（入口）
  protocol     priority queueing by protocol                    基於協議
  queue-limit  Set queue limits for priority queues   限制優先級隊列的大小

1\HIGH

2\MEDIUM

3\NORMAL

4\LOW

access-list 110 permit gre any any
access-list 110 permit ip any host 192.168.1.100
priority-list 1 protocol ip high list 110
priority-list 1 protocol ip medium tcp smtp
priority-list 1 protocol ip normal udp ntp
priority-list 1 protocol ip low tcp www
priority-list 1 queue-limit 40 20 20 20    （20 40 60 80默認)

）

interface Serial1/0
  priority-group 1

Router#show queueing priority
Current DLCI priority queue configuration:
Current priority queue configuration:

List   Queue  Args
1      high   protocol ip          list 110
1      medium protocol ip          tcp port smtp
1      normal protocol ip          udp port ntp
1      low    protocol ip          tcp port www
1      high   limit 40
1      medium limit 20
1      normal limit 20
1      low    limit 20

Router#show int s1/0
Serial1/0 is up, line protocol is up 
  
 Queueing strategy: priority-list 1
  Output queue (queue priority: size/max/drops):
     high: 0/40/0, medium: 0/20/0, normal: 0/20/0, low: 0/20/0

CQ 介紹：尾丟棄 調度輪詢調度 17個class

R2(config)#queue-list 1 ?
  default        Set custom queue for unspecified datagrams
  interface      Establish priorities for packets from a named interface   基於接口
  lowest-custom  Set lowest number of queue to be treated as custom  默認0是先執行 我們在這可以設置
  protocol       priority queueing by protocol                                    基於協議
  queue          Configure parameters for a particular queue     對queue配置響應的參數
   stun           Establish priorities for stun packets 

 

access-list 110 permit gre any any
access-list 110 permit ip any any precedence critical
queue-list 1 interface Ethernet0/0 2
queue-list 1 protocol ip 3 tcp www
queue-list 1 protocol ip 3 list 110
queue-list 1 queue 2 limit 3000
queue-list 1 queue 3 limit 3000

 

interface Serial1/0
 no ip address
 serial restart-delay 0
 custom-queue-list 1

R2#show queueing custom
Current custom queue configuration:

List   Queue  Args
1      2      interface Ethernet0/0        
1      3      protocol ip          tcp port www
1      3      protocol ip          list 110
1      2      limit 3000
1      3      limit 3000

R2(config)#queue-list 1 lowest-custom 2   隊列0 1 是優先級最高的相當於PQ+CQ

LLQ 介紹 ：對語音流量設置優先 相當於PQ+WFQ

在WFQ的基礎之上設置

 

this is used for links with speed less than 1.544Mbps(T1)

R1(config)#int s1/0
R1(config-if)#ip rtp
R1(config-if)#ip rtp pr
R1(config-if)#ip rtp priority ?
  <2000-65535>  Lower bound of UDP destination port

R1(config-if)#ip rtp priority 16384 16383  ？

R1(config-if)#ip rtp priority 16384 16383 ?
  <0-2000>  Maximum allowed bandwidth in kbps

R1(config-if)#ip rtp priority 16384 16383 100(爲語音預留的帶寬)

 

CLASS　BASED　WEIGHTED　FAIR　QUEUE介紹：

 

 64+1（default）  手工分類+制定帶寬    尾丟棄   輪詢轉發

bandwidth 

bandwidth percent  總帶寬的百分比
bandwidth remaining percent  實際可用的帶寬百分比（總帶寬的百分比*0.75*Y%）

bandwith（av）=bandwith（total）*0.75—MWrtp

 

class-map match-all VTOP  

 match ip rtp 16384 16383
用NBAR抓的流量 用NBAR抓流量是比較簡單的，可以根據特定的協議去抓
我們還可以用ACL抓流量

（access-list 110 permit ip any any precedence 5

class-map match-all VTOP

match access-group 110）

class-map match-all WWW
 match protocol http

policy-map CBWFQ
 class VTOP
  bandwidth percent 50
 class WWW
  bandwidth percent 20
 class class-default
  bandwidth percent 30

interface Serial1/0
 R2(config-if)#max-reserved-bandwidth 100

no ip address
 serial restart-delay 0
 max-reserved-bandwidth 100
 service-policy output CBWFQ
 hold-queue 2000 out

我們還可以在默認的定義爲WFQ

 

class class-default
fair-queue

LLQ

 

low-latency queueing 低延遲隊列 相當於WFQ+PQ 首先接口隊列要是WFQ
R1(config)#int s1/0
R1(config-if)#ip rtp
R1(config-if)#ip rtp pr
R1(config-if)#ip rtp priority ?
  <2000-65535>  Lower bound of UDP destination port

R1(config-if)#ip rtp priority 16384 16383  ？

R1(config-if)#ip rtp priority 16384 16383 ?
  <0-2000>  Maximum allowed bandwidth in kbps

R1(config-if)#ip rtp priority 16384 16383 100(爲語音預留的帶寬)

max-reserved-bandwith percent(%)
實際帶寬=全部帶寬*75%-帶寬RTP（爲語音預留的帶寬）

 

CBLLQ 可以設置PQ讓其優先 有PQ你就先走

 

policy-map CBWFQ
class VTOP
 priority  percent 50  強制優先