DR002011 NE系列路由器QoS特性 ISSUE 1.00

修訂記錄課程編碼適用產(chǎn)品產(chǎn)品版本課程版本ISSUEDR002011NE路由器ALL1.00開(kāi)發(fā)/優(yōu)化者時(shí)間審核人開(kāi)發(fā)類(lèi)型（新開(kāi)發(fā)/優(yōu)化）張立2009-11-10周進(jìn)軍新開(kāi)發(fā)本頁(yè)不打印0NE系列路由器QoS特性培訓(xùn)目標(biāo)學(xué)完本課程后，您應(yīng)該能：描述

IPQoS的基本概念描述區(qū)分服務(wù)模型描述IPQoS的常用技術(shù)描述基于類(lèi)的QoS2目錄IPQoS概述區(qū)分服務(wù)模型概述IPQoS技術(shù)基于類(lèi)的QoS3目錄IPQoS概述區(qū)分服務(wù)模型概述IPQoS技術(shù)基于類(lèi)的QoS4QoS的概念QoS：QualityofService，服務(wù)質(zhì)量傳輸?shù)膸拏鬏數(shù)臅r(shí)延和抖動(dòng)數(shù)據(jù)的丟包率網(wǎng)絡(luò)中存在資源競(jìng)爭(zhēng)，就存在對(duì)服務(wù)質(zhì)量的要求提高某類(lèi)業(yè)務(wù)的服務(wù)質(zhì)量同時(shí)會(huì)損害其它業(yè)務(wù)的服務(wù)質(zhì)量5帶寬BWmax＝Min(100M,10M,256k,2M,1G)＝256kbps木桶理論：最大帶寬BWmax等于數(shù)據(jù)傳輸路徑上的最小帶寬。100Mbps10Mbps256kbps2Mbps1GbpsBWmax＝256kbpsPC服務(wù)器6端到端時(shí)延端到端時(shí)延等于路徑上所有傳輸時(shí)延、處理時(shí)延與隊(duì)列時(shí)延之和。處理時(shí)延隊(duì)列時(shí)延處理時(shí)延隊(duì)列時(shí)延處理時(shí)延隊(duì)列時(shí)延傳輸時(shí)延傳輸時(shí)延傳輸時(shí)延傳輸時(shí)延7抖動(dòng)抖動(dòng)是因?yàn)槊總€(gè)包的端到端時(shí)延不相等造成的。8丟包丟包可能在傳輸過(guò)程的每一個(gè)環(huán)節(jié)發(fā)生。9如何保證好的QoS更強(qiáng)的處理能力合理的隊(duì)列調(diào)度和擁塞避免機(jī)制更大的鏈路帶寬壓縮和分片數(shù)據(jù)包10如何部署QoSBestEffort：盡力而為IntegratedServicesModel：集成服務(wù)模型RSVP為每個(gè)流預(yù)留資源為每個(gè)流維護(hù)一個(gè)轉(zhuǎn)發(fā)狀態(tài)DifferentiatedServicesModel：區(qū)分服務(wù)模型對(duì)流量進(jìn)行分類(lèi)和標(biāo)記不同類(lèi)型的流量提供不同的服務(wù)11目錄IPQoS概述區(qū)分服務(wù)模型概述IPQoS技術(shù)基于類(lèi)的QoS12區(qū)分服務(wù)模型根據(jù)SLA制定TCA流量分類(lèi)和標(biāo)記流量監(jiān)管……根據(jù)標(biāo)記執(zhí)行PHB……根據(jù)標(biāo)記執(zhí)行PHB……根據(jù)SLA制定TCA流量分類(lèi)和標(biāo)記流量監(jiān)管……13SLA與TCASLA：ServiceLevelAgreement，服務(wù)等級(jí)協(xié)定客戶與服務(wù)提供商之間簽訂的關(guān)于客戶的業(yè)務(wù)流在服務(wù)提供商的網(wǎng)絡(luò)中傳遞時(shí)所應(yīng)當(dāng)獲得的待遇去掉了商業(yè)條款的SLA稱(chēng)為SLS（ServiceLevelSpecification）TCA（TrafficConditioningAgreement）業(yè)務(wù)調(diào)整協(xié)定客戶與服務(wù)提供商之間簽訂的關(guān)于業(yè)務(wù)分類(lèi)準(zhǔn)則以及業(yè)務(wù)模型及相應(yīng)處理的協(xié)定。去掉了商業(yè)條款的TCA稱(chēng)為T(mén)CS（TrafficConditioningSpecification）14標(biāo)記字段VersionIHLTypeOfServiceTotalLength

IdentificationFlags

FragmentOffset

TTLProtocol

HeaderChecksumSourceAddressDestinationAddressOptionsRIPPrecedenceTOSRRDSCP15IPPrecedence和TOSRIPPrecedenceTOS000Routine001Priority010Immediate011Flash100FlashOverride101Critical110InternetworkControl111NetworkControl最小延遲最大吞吐量最大可靠性最小開(kāi)銷(xiāo)16DSCP：DiffServCodePoint一個(gè)DSCP值對(duì)應(yīng)一個(gè)BA一個(gè)BA被指定一個(gè)PHB一個(gè)PHB被一組QoS機(jī)制實(shí)現(xiàn)RRDSCP(RFC2474)DefaultPHBClassSelector(IPPrecedence)PHBExpeditedForwarding(EF)PHBAssuredForwarding(AF)PHB17DefaultPHBDefaultDSCP：000000DefaultPHBFIFO，先進(jìn)先出Tail-drop，尾丟棄Tail-dropFIFO18CSPHB為了與不支持DSCP的節(jié)點(diǎn)兼容使用高三位比特對(duì)應(yīng)IPPrecedenceCS類(lèi)DSCP值Precedence值Precedence類(lèi)Default0000000RoutineCS10010001PriorityCS20100002ImmediateCS30110003FlashCS41000004OverrideFlashCS51010005CriticalCS61100006InternetworkControlCS71110007NetworkControl19EFPHBDSCP值：101110保證最小的延遲保證一定的優(yōu)先帶寬超過(guò)規(guī)定帶寬的流量被丟棄20AFPHB保證一定數(shù)量的帶寬如果有空余帶寬，可以占用額外帶寬CCCDD0類(lèi)別丟棄可能性Class1Class2Class3Class4低丟棄率001010010010011010100010中丟棄率001100010100011100100100高丟棄率00111001011001111010011021目錄IPQoS概述區(qū)分服務(wù)模型概述IPQoS技術(shù)基于類(lèi)的QoS22目錄IPQoS技術(shù)3.1分類(lèi)和標(biāo)記3.2監(jiān)管和整形3.3擁塞管理3.4擁塞避免23流量分類(lèi)和標(biāo)記流量分類(lèi)及標(biāo)記是部署QoS

的基礎(chǔ)可以根據(jù)ACL和報(bào)文長(zhǎng)度對(duì)流量進(jìn)行分類(lèi)可以使用DSCP、IPPrecedence進(jìn)行流量標(biāo)記（著色）24分類(lèi)和標(biāo)記技術(shù)分類(lèi)和標(biāo)記技術(shù)包括Policy-BasedRouting（PBR），策略路由QoSPolicyPropagationthroughBGP（QPPB），通過(guò)BGP傳遞QoS策略其它CommittedAccessRate（CAR），承諾訪問(wèn)速率基于類(lèi)的分類(lèi)和標(biāo)記25目錄IPQoS技術(shù)3.1分類(lèi)和標(biāo)記3.2監(jiān)管和整形3.3擁塞管理3.4擁塞避免26流量監(jiān)管與整形流量監(jiān)管（Traffic-policing）監(jiān)督進(jìn)入網(wǎng)絡(luò)中某一流量的規(guī)格，限制它在一個(gè)允許的范圍之內(nèi)，若某一連接的報(bào)文流量過(guò)大，就丟棄報(bào)文或重新設(shè)置該報(bào)文的優(yōu)先級(jí)流量整形（Traffic-shaping）與流量監(jiān)管的作用一樣，它主要是對(duì)流量監(jiān)管中需要丟棄的報(bào)文進(jìn)行緩存——通常是放入緩存區(qū)或隊(duì)列中27監(jiān)管與整形的應(yīng)用企業(yè)網(wǎng)S0流量整形S0RTARTB流量監(jiān)管ISP28TokenBucket：令牌桶CIR溢出的令牌Size＝CBS+EBS順從流量(Conform)超額流量(Excess)待發(fā)送流量令牌桶29CAR：CommittedAccessRate需由此接口發(fā)送的報(bào)文繼續(xù)發(fā)送丟棄通過(guò)令牌桶分類(lèi)不需流量監(jiān)管的報(bào)文需要流量監(jiān)管的報(bào)文30配置流量監(jiān)管企業(yè)網(wǎng)S0S0RTARTBISPqos

carl1precedence45aclnumber2001rule0permitsource55aclnumber2002rule0permitsource55interfaceSerial0

qoscarinboundacl2001cir8000cbs15000000ebs0greenpassreddiscard

qoscarinboundacl2002cir8000cbs15000000ebs100000greenremark-prec-pass0reddiscard

qoscarinboundcarl1cir8000cbs15000000

ebs0greenremark-prec-pass3redremark-prec-pass031配置流量監(jiān)管[RTB]display

qoscarinterfaceSerial0Interface:Serial0Direction:Inbound

Rule(s):If-matchACL2001CIR8000(bps),CBS15000000(bit),EBS0(bit)ConformAction:passExceedAction:discardConformed:0/0(Packets/Bytes)Exceeded:0/0(Packets/Bytes)

Rule(s):If-matchACL2002CIR8000(bps),CBS15000000(bit),EBS100000(bit)ConformAction:remarkip-precedence0andpassExceedAction:discardConformed:0/0(Packets/Bytes)Exceeded:0/0(Packets/Bytes)

Rule(s):If-matchCARL1CIR8000(bps),CBS15000000(bit),EBS0(bit)ConformAction:remarkip-precedence3andpassExceedAction:remarkip-precedence0andpassConformed:0/0(Packets/Bytes)Exceeded:0/0(Packets/Bytes)32GTS：GenericTrafficShapingGTS隊(duì)列丟棄的報(bào)文需由此接口發(fā)送的報(bào)文繼續(xù)發(fā)送通過(guò)令牌桶分類(lèi)不需流量整形的報(bào)文需要流量整形的報(bào)文33配置流量整形企業(yè)網(wǎng)S0S0RTARTBISPaclnumber2001rule0permitsource55#interfaceSerial0

qos

gts

acl2001cir8000cbs15000000ebs0queue-length50034配置流量整形[RTA]display

qos

gtsinterfaceSerial0Interface:Serial0

Rule(s):If-matchACL2001CIR8000(bps),CBS15000000(bit),EBS0(bit)QueueLength:500(Packet)QueueSize:0(Packet)Passed:0/0(Packets/Bytes)Discarded:0/0(Packets/Bytes)Delayed:0/0(Packets/Bytes)35LR：LineRate需由此接口發(fā)送的報(bào)文發(fā)送的報(bào)文隊(duì)列令牌桶LR限制的是接口發(fā)送報(bào)文的總速率。36配置LR企業(yè)網(wǎng)S0S0RTARTBISPinterfaceSerial0link-protocolppp

ipaddress52

qos

lrcir25000cbs50000ebs0[RTA]display

qos

lrinterfaceSerial0Interface:Serial0CIR25000(bps),CBS50000(bit),EBS0(bit)Passed:103/82416(Packets/Bytes)Delayed:52/64392(Packets/Bytes)ActiveShaping:NO37目錄IPQoS技術(shù)3.1分類(lèi)和標(biāo)記3.2監(jiān)管和整形3.3擁塞管理3.4擁塞避免38常用隊(duì)列調(diào)度機(jī)制FIFO：FirstInFirstOut，先進(jìn)先出隊(duì)列PQ：PriorityQueuing，優(yōu)先級(jí)隊(duì)列CQ：CustomQueuing，自定義隊(duì)列WFQ：WeightedFairQueuing，加權(quán)公平隊(duì)列CBQ：Class-basedQueuing，基于類(lèi)的隊(duì)列39FIFO：FirstInFirstOutFIFO需由此接口發(fā)送的報(bào)文隊(duì)列出隊(duì)調(diào)度離開(kāi)接口的報(bào)文圖示說(shuō)明：緊急報(bào)文次緊急報(bào)文非緊急報(bào)文40FIFO隊(duì)列的優(yōu)缺點(diǎn)優(yōu)點(diǎn)：處理簡(jiǎn)單、速度快并且延遲小不需要配置，易于使用缺點(diǎn)：有多個(gè)流時(shí)帶寬分配不公平會(huì)引起延時(shí)及抖動(dòng)41配置FIFO隊(duì)列[RTA]displayinterfaceSerial0……QoSmax-bandwidth:64KbpsOutputqueue:(Urgentqueue:Size/Length/Discards)0/50/0Outputqueue:(Protocolqueue:Size/Length/Discards)0/1000/0Outputqueue:(FIFOqueuing:Size/Length/Discards)0/256/0……[RTA]interfaceSerial0[RTA-Serial0]qosfifoqueue-length300[RTA]displayinterfaceSerial0……QoSmax-bandwidth:64KbpsOutputqueue:(Urgentqueue:Size/Length/Discards)0/50/0Outputqueue:(Protocolqueue:Size/Length/Discards)0/1000/0Outputqueue:(FIFOqueuing:Size/Length/Discards)0/300/0……42PQ：PriorityQueuingTOP需由此接口發(fā)送的報(bào)文隊(duì)列出隊(duì)調(diào)度離開(kāi)接口的報(bào)文圖示說(shuō)明：緊急報(bào)文次緊急報(bào)文非緊急報(bào)文分類(lèi)MIDDLENOMORLBOTTOM43PQ的調(diào)度機(jī)制Top隊(duì)列空？Middle隊(duì)列空？硬件隊(duì)列系統(tǒng)（TXQ）NYNormal隊(duì)列空？Bottom隊(duì)列空？發(fā)送報(bào)文重新檢查T(mén)op隊(duì)列NNNYYY44PQ的優(yōu)缺點(diǎn)優(yōu)點(diǎn)：提供低時(shí)延的數(shù)據(jù)轉(zhuǎn)發(fā)缺點(diǎn)：每一個(gè)單一的隊(duì)列都擁有FIFO隊(duì)列的所有缺點(diǎn)可能產(chǎn)生“餓死”現(xiàn)象45配置PQE0S0

qos

pql1default-queuemiddle

qos

pql1queuetopqueue-length30

qos

pql1queuemiddlequeue-length30

qos

pql1protocolip

acl3001queuetop

qos

pql1inbound-interfaceEthernet0queuemiddle#aclnumber3001rule0permittcpdestination-porteqtelnet#interfaceSerial0

qos

pq

pql146配置PQ[RTA]display

qos

pqinterfaceSerial0Interface:Serial0Outputqueue:(Protocolqueue:Size/Length/Discards)0/1000/0Outputqueue:(Priorityqueuing:PQL1Size/Length/Discards)Top:0/30/0Middle:0/30/0Normal:0/60/0Bottom:0/80/0[RTA]display

qos

pqlCurrentPQLConfiguration:ListQueueParams------------------------------------------------------1MiddleDefaultQueue1TopLength301MiddleLength301TopProtocolip

acl30011MiddleInbound-interfaceEthernet047CQ：CustomQueuing需由此接口發(fā)送的報(bào)文隊(duì)列出隊(duì)調(diào)度離開(kāi)接口的報(bào)文圖示說(shuō)明：緊急報(bào)文其它各類(lèi)報(bào)文分類(lèi)……共17個(gè)隊(duì)列，其中Q0是優(yōu)先隊(duì)列，隊(duì)列里的報(bào)文會(huì)獲得優(yōu)先調(diào)度。Q0Q1Q2Q16優(yōu)先隊(duì)列48CQ的調(diào)度機(jī)制當(dāng)前隊(duì)列有待發(fā)送報(bào)文？超過(guò)當(dāng)前隊(duì)列的發(fā)送閾值？硬件隊(duì)列系統(tǒng)（TXQ）N發(fā)送報(bào)文NY下一個(gè)隊(duì)列Y按每個(gè)隊(duì)列定義的字節(jié)數(shù)輪詢(xún)發(fā)送，每個(gè)隊(duì)列占用的帶寬比率等于本隊(duì)列定義的字節(jié)數(shù)與所有隊(duì)列字節(jié)數(shù)之和的比值。49CQ的優(yōu)缺點(diǎn)優(yōu)點(diǎn)：避免了類(lèi)似PQ產(chǎn)生的“餓死”現(xiàn)象保證在發(fā)生擁塞時(shí)1-16隊(duì)列能夠分配到指定額度的帶寬隊(duì)列長(zhǎng)度可以設(shè)置為0，理論上該隊(duì)列為無(wú)限長(zhǎng)缺點(diǎn)：不能根據(jù)報(bào)文的優(yōu)先級(jí)決定調(diào)度權(quán)重每一個(gè)單一的隊(duì)列都擁有FIFO隊(duì)列的所有缺點(diǎn)帶寬分配不準(zhǔn)確產(chǎn)生抖動(dòng)50配置CQE0S0

qos

cql10default-queue15

qos

cql10queue1queue-length25

qos

cql10queue1serving3000

qos

cql10queue2queue-length30

qos

cql10queue2serving5000

qos

cql10inbound-interfaceEthernet0queue1

qos

cql10protocolip

tcpftpqueue2interfaceSerial0

qos

cq

cql1051配置CQ[RTA]display

qos

cqinterfaceSerial0Interface:Serial0Outputqueue:(Protocolqueue:Size/Length/Discards)0/1000/0Outputqueue:(Customqueuing:CQL10Size/Length/Discards)0:0/20/01:0/25/02:0/30/03:0/20/04:0/20/05:0/20/06:0/20/07:0/20/08:0/20/09:0/20/010:0/20/011:0/20/012:0/20/013:0/20/014:0/20/015:0/20/016:0/20/0[RTA]display

qos

cqlCurrentCQLConfiguration:ListQueueParams------------------------------------------------------1015DefaultQueue101Length25101Serving3000102Length30102Serving5000101Inbound-interfaceEthernet0102Protocolip

tcpftp52WFQ：WeightedFairQueuing需由此接口發(fā)送的報(bào)文隊(duì)列出隊(duì)調(diào)度離開(kāi)接口的報(bào)文圖示說(shuō)明：各類(lèi)報(bào)文分類(lèi)……Q1Q2Q3QnWFQ使用HASH算法對(duì)流進(jìn)行動(dòng)態(tài)分類(lèi)，保證高優(yōu)先級(jí)報(bào)文獲得更多帶寬。53WFQ的優(yōu)缺點(diǎn)優(yōu)點(diǎn)：配置簡(jiǎn)單保證所有流的吞吐量缺點(diǎn)：由于其分類(lèi)算法復(fù)雜，所以處理較慢WFQ無(wú)法保證關(guān)鍵業(yè)務(wù)的穩(wěn)定帶寬，多個(gè)低優(yōu)先級(jí)的流會(huì)淹沒(méi)高優(yōu)先級(jí)的流用戶不能自定義類(lèi)不能保證固定帶寬54配置WFQE0S0interfaceSerial0

qos

wfqqueue-length500queue-number2048[RTA]display

qos

wfqinterfaceSerial0Interface:Serial0Outputqueue:(Protocolqueue:Size/Length/Discards)0/1000/0Outputqueue:(WeightedFairqueuing:Size/Length/Discards)0/500/0Hashedqueues:0/0/2048(Active/Maxactive/Total)55目錄IPQoS技術(shù)3.1分類(lèi)和標(biāo)記3.2監(jiān)管和整形3.3擁塞管理3.4擁塞避免56擁塞避免機(jī)制當(dāng)擁塞發(fā)生時(shí)，路由器可以：進(jìn)行尾丟棄WFQ可以采用比較智能的丟棄方式能不能避免擁塞的發(fā)生？RED：RandomEarlyDetection，隨機(jī)早期檢測(cè)WRED：WeightedRandomEarlyDetection，加權(quán)隨機(jī)早期檢測(cè)57尾丟棄的缺點(diǎn)TCP全局同步TCP饑餓高延時(shí)和高抖動(dòng)無(wú)差別的丟棄帶寬平均使用帶寬時(shí)間飽和帶寬58RED：RandomEarlyDetection平均隊(duì)列長(zhǎng)度丟棄概率10%100%20（丟棄下限）40（丟棄上限）不丟棄隨機(jī)丟棄尾丟棄最大丟棄概率59WRED：WeightedRandomEarlyDetection平均隊(duì)列長(zhǎng)度丟棄概率10%100%2040最大丟棄概率AF21AF22253035AF2360配置WRED平均隊(duì)列長(zhǎng)度丟棄概率10%100%2040最大丟棄概率Precedence0123Precedence4567103061配置WREDinterfaceSerial0link-protocolppp

qos

wfqqueue-length64queue-number256

qos

wred

qos

wred

ip-precedence4low-limit20high-limit40discard-probability10

qos

wred

ip-precedence5low-limit20high-limit40discard-probability10

qos

wred

ip-precedence6low-limit20high-limit40discard-probability10

qos

wred

ip-precedence7low-limit20high-limit40discard-probability10[RTA]display

qos

wredinterfaceSerial0Interface:Serial0CurrentWREDconfiguration:Exponent:9(1/512)PrecedenceLowHighDiscardRandomTailLimitLimitProbabilityDiscardDiscard-----------------------------------------------------------01030100011030100021030100031030100042040100052040100062040100072040100062目錄IPQoS概述區(qū)分服務(wù)模型概述IPQoS技術(shù)基于類(lèi)的QoS63基于類(lèi)的QoS基于類(lèi)的QoS是一種新的QoS命令下發(fā)方式將原來(lái)的QoS命令整合為三大部分流分類(lèi)（trafficclassifier）采用一定的規(guī)則識(shí)別出符合某類(lèi)特征的報(bào)文流動(dòng)作（trafficbehavior）對(duì)報(bào)文做的一些QoS動(dòng)作集合流量策略（trafficpolicy）流分類(lèi)與流動(dòng)作的組合64流分類(lèi)使用TrafficClassifier命令來(lái)定義流量類(lèi)TrafficClassifier以ACL為基礎(chǔ)，但又不同于ACL分類(lèi)的依據(jù)包括報(bào)文的優(yōu)先級(jí)協(xié)議類(lèi)型MAC地址輸入接口VLAN優(yōu)先級(jí)端口號(hào)65配置TrafficClassifier[RTA]trafficclassifierClass1[RTA-classifier-Class1]if-match?8021pSpecify802.1pparameters

aclSpecifyACLtomatchanySpecifyanypacketstomatchclassifierSpecifytrafficclassifiertomatchdestination-macSpecifydestinationMACaddresstomatch

dscpSpecifyDSCP(DiffServ

CodePoint)tomatchinbound-interfaceSpecifyaninboundinterfacetomatch

ip-precedenceSpecifyIPprecedencetomatchipv6Specifyipv6aclnumber

mpls-expSpecifyMPLSEXPvaluetomatchnotRuleofnotmatchingthestatementprotocolSpecifyprotocoltomatch

qos-local-idSpecifyQoSlocalIDfeature

rtpSpecifyRTPporttomatchsource-macSpecifysourceMACaddresstomatch66流動(dòng)作基于類(lèi)的標(biāo)記動(dòng)作基于類(lèi)的流量監(jiān)管和整形動(dòng)作CBQ動(dòng)作基于類(lèi)的WRED動(dòng)作67配置基于類(lèi)的標(biāo)記動(dòng)作[RTA]trafficbehaviorBehavior1[RTA-behavior-Behavior1]remark?8021pSpecify802.1pparameters

atm-clpRemarkatm-clp

dscpRemarkDSCP(DiffServ

CodePoint)

fr-deRemarkfr-de

ip-precedenceRemarkIPprecedence

mpls-expRemarkMPLSEXP68配置基于類(lèi)的流量監(jiān)管和整形動(dòng)作[RTA]trafficbehaviorBehavior1[RTA-behavior-Behavior1]carcircir[cbs

cbs

ebs

ebs][green

action[red

action]][RTA]trafficbehaviorBehavior1[RTA-behavior-Behavior1]gtscircir[cbs

cbs[ebs

ebs

[queue-lengthqueue-length

]]][RTA]trafficbehaviorBehavior1[RTA-behavior-Behavior1]lrcircir[

cbs

cbs[ebs

ebs

]]或者[RTA-behavior-Behavior1]lrpercentcir