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1、Quality of Service Boot Camp,-Michael WileyNetwork Consulting E,1,Classification&Marking ToolsCongestion Management ToolsCongestion Avoidance ToolsTraffic Conditioning Tool,What Exactly Are We Trying to Fix?,Bandwidth Packet Loss DelayJitter(Delay Variation),QoS Service Types,Guaranteed Integrated S
2、ervicesBest Effort(BE)Differentiated Services(DiffServ),IP Precedence/DiffServ Code Point(DSCP),IP Precedence,U,IPv4 ToS,“ToS bits”,DSCP,ECN,DS Field,RFC2474,definition of the Differentiated Services Field(DS Field)in the IPv4 and IPv6 headers,Dec 98 DSCP:Differentiated Service Code Point=6 bits Fir
3、st 3 bits are CSC:Class Selector Codepoint ECN:Explicit Congestion Notification=2 bits PHB:Per-Hop Behavior,Classification&Marking,6,QoS Functions,CongestionManagement,CongestionAvoidance,Link-EfficiencyManagement,TrafficConditioning,ClassificationandMarking,Identify and/or Mark Traffic.,Prioritize,
4、Protect and Isolate Traffic,based on Markings,Discard specific packets to avoid congestion,Control bursts and conform traffic,Fragment and compress for WAN efficiency,Classification What is it?,The component of a QoS feature that recognizes and distinguishes between different traffic streamsThe most
5、 fundamental QoS Building BlockWithout classification all packets would be treated the same,Classification Example,Packet Marking What is it?,The component of QoS that“colors”a packet(frame)so that it can be identified and distinguished from other packets(frames)in QoS treatment802.1p/ISL CoS,IP Pre
6、cedence,DSCP,QoS Group,L2/L3 Marking,VersionLength,Three Bits Used for CoS(User Priority),Three Bits Used for CoS(Class of Service),Len,Standard IPV4:IP Precedence/DiffServ,Layer 2802.1Q/p,Layer 2ISL,Layer 3IPV4,ID,Offset,TTL,Proto,FCS,IP-SA,IP-DA,Data,FCS4 Bytes,Encapsulated Frame 124.5 KBytes,ISL
7、Header26 Bytes,FCS,DATA,PT,TAG4 Bytes,SA,DA,SFD,PREAM.,ToS1 Byte,Where Should I Mark Packets?,WAN,As Close to the Traffic Source as possible!,Classification&Marking Tools,Class-Based MarkingNetwork-Based Application Recognition(NBAR)Policy-Based Routing(PBR)Access Control List/Route-MapDial PeersCom
8、mitted Access Rate(CAR),Class-Based Marking,Available since 12.1(2)T ATM VC Packet marking available since 12.1(5)TMark on Precedence,DSCP,QOS-Group,COSChange the ATM CLP bitPart of the DiffServ Model(CBWFQ Policy-Map)Runs with CEF switchingCSCdt74738(12.2)will allow for marking of locally generated
9、 packets.Also marking of Multicast traffic and others that are forced to fast/process-switch.,Class-Based Marking Example,class-map match-all MARK match access-group 100policy-map SETDSCP class MARK set ip dscp 10interface Ethernet0/0service-policy input SETDSCP access-list 100 permit ip any any,Ste
10、p 1,Step 2,Step 3,Class-Based Marking Verification,Router#sh policy-map int e0/0 Ethernet0/0 Service-policy input:SET-DSCP Class-map:SETDSCP(match-all)94788 packets,7528728 bytes 5 minute offered rate 0 bps,drop rate 0 bps Match:access-group 100 QoS Set ip dscp 10 Packets marked 31596,Network Based
11、Application Recognition(NBAR),Protocol discovery analyzes application traffic patterns in real timeNBAR classifies network traffic using application informationEnables downstream actions based on QoS policies via random early detection class-based queuing,and policingNew applications easily supporte
12、d by loading Packet Description Language Modules,Link Utilization,My Application Is too slow!,Citrix25%Netshow 15%Oracle10%FTP30%HTTP20%,Applications Supported by NBAR,Statefully Inspected Protocols FTPExchangeHTTP(URL and MIME)NetshowRealaudior-commandsOracle SQL*NETSunRPCTFTPStreamWorksVDOLiveCitr
13、ix,Static ProtocolsEGPGREICMPIPINIPIPSecEIGRPBGPCU-SeeMeDHCP/BootpDNSFingerGopherHTTPHTTPSIMAP,IRCKerberosL2TPLDAPMS-PPTPMS-SQLServerNetBIOSNFSNNTPNotesNTPPCAnywherePOP3PPTPRIPRSVPSFTP,SHTTPSIMAPSIRCSLDAPSNNTPSMTPSNMPSOCKSSPOP3SSHSTELNETSyslogTelnetX Windows,NBAR Configuration Example,class-map matc
14、h-any foo match protocol http url“/transact/*”match protocol http url payment.htm match protocol SQL*NETpolicy-map bar class foo bandwidth 1000!guarantee min.of 1 Mbps set ip dscp 32!mark traffic as high priority int serial0 service-policy output bar,Step 1,Step 2,Step 3,Policy Based Routing(PBR),in
15、terface Ethernet0/0ip policy route-map labaccess-list 101 permit tcp any host 10.22.1.10route-map lab permit 10match ip address 101set ip precedence 4,Committed Access Rate(CAR)*,Two functionsPacket Classification(Marking)IP precedence.QoS group and DSCP from 12.1(5)T.Access Bandwidth Management thr
16、ough rate limitingCAR is a“Legacy”QoS tool,Congestion Management,21,Queuing Algorithms,First In,First Out(FIFO)Priority Queuing(PQ)Custom Queuing(CQ)Weighted Fair Queuing(WFQ)Class-Based Weighted Fair Queuing(CBWFQ)Low Latency Queuing(LLQ),Transmit Queue vs.Interface Queue,Forwarder,Interface Conges
17、ted?,FIFO/PQ/CQ/WFQInterfaceQueues,TransmitQueue,Yes,No,Always FIFOFull TxQ triggers fancy queuing,(output hold-queue compromise latency/buffering),First In,First Out,Most Simple Queuing AlgorithmPackets leave in order of arrivalFixed Queue Lengths(default 40)results in dropping from tail of queue u
18、nder load.This is called“Tail Drop”,Transmit Queue,Output Line,Priority Queuing(PQ),Traffic Destined for Interface,Classification by:Protocol(IP,IPX,etc.)Incoming Interface(EO,SO,S1,etc.),Interface Buffer Resources,Transmit Queue,Output Line,Interface HardwareEthernetFrame RelayNot ATM per VCSerial
19、LinkEtc.,High,Medium,Normal,Low,Q Length Defined by Q Limit,Classify,Absolute Priority Scheduling,Priority Queuing Overview,Four priority queuesHigh,Medium,Normal,LowPackets not classified by priority-list mechanism fall into normal queueFIFO within priorityWithin priority,may still be unpredictable
20、Resource allocation“Queue Starvation”,Priority Queuing Example,!interface serial 0priority-group 4!priority-list 1 protocol ip high list 10priority-list 1 protocol decnet highpriority-list 1 protocol ip mediumpriority-list 1 queue-limit 10 40 60 90 priority-list 2 protocol decnet medium gt 200priori
21、ty-list 2 protocol bridge highpriority-list 2 protocol ip mediumpriority-list 3 interface ethernet 0 highpriority-list 3 interface ethernet 1 mediumpriority-list 3 interface serial 1 mediumpriority-list 3 default lowpriority-list 4 protocol decnet medium lt 200priority-list 4 protocol ip medium tcp
22、23priority-list 4 protocol ip medium udp 53priority-list 4 protocol ip high!access-list 10 permit 239.1.1.0 0.0.0.255,Priority Queuing Verification(Global),R1#show queueing priorityCurrent priority queue configuration:List Queue Args1 high protocol decnet 1 high protocol ip list 101 medium protocol
23、ip 1 high limit 101 low limit 902 medium protocol decnet gt 2002 high protocol bridge 2 medium protocol ip 3 low default3 high interface Ethernet0 3 medium interface Ethernet1 3 medium interface Serial1 4 medium protocol decnet lt 2004 medium protocol ip tcp port telnet4 medium protocol ip udp port
24、domain4 high protocol ip,Priority Queuing Verification(Interface),R1#show interface serial 0Serial0 is down,line protocol is down Hardware is HD64570 MTU 1500 bytes,BW 1544 Kbit,DLY 20000 usec,rely 255/255,load 1/255 Encapsulation HDLC,loopback not set,keepalive set(10 sec)Last input never,output ne
25、ver,output hang never Last clearing of show interface counters never Input queue:0/75/0(size/max/drops);Total output drops:0 Queueing strategy:priority-list 4 Output queue: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,
26、0 packets/sec,Custom Queuing,Traffic Destined for Interface,Interface Buffer Resources,Q Length Deferred by Queue Limit,Up to 16,3/10,1/10,Classification by:Protocol(IP,IPX,etc.)Incoming interface(EO,SO,S1,etc.),Allocate Proportion of Link Bandwidth,Classify,Interface HardwareEthernetFrame RelayNot
27、ATM per VCSerial LinkEtc.,2/10,3/10,2/10,Link Utilization Ratio,Transmit Queue,Output Line,Custom Queuing-Queues,Queue#0,Transmission Queue,Queue#1,Queue#2,Queue#3,Queue#4,Queue#5,Queue#6,Queue#9,Queue#10,Queue#11,Queue#12,Queue#13,Queue#14,Queue#15,Queue#7,Queue#16,Queue#8,Control Traffic,Priority(
28、Access)List,Forwarder,Custom Queuing-Notes,Distributes Traffic into FIFO queue by classDe-queues Packets in rotationRemove some number of bytes at mostMove to next queue in round robin order,Custom Queuing Things to Consider,The average packet size of the protocol in the queueIf all FTP traffic goes
29、 to queue 3 with an average packet size of 600 bytes then you will want your byte count for queue 3 to be a multiple of 600Once the byte count value is exceeded,the frame that is currently being transmitted will be completely sentIf the byte count is 100 and the average packet size for the protocol
30、in the queue is 1024,then the queue is actually servicing 1024 each time,not 100Large byte counts(10K)may result in jerky distribution much like priority queuingIf queue 1 has a byte count of 100K then queue 2 may wait a long time before it is servicedTry to keep the weight ratio from the largest to
31、 smallest within 10:1 so a queue isnt starved,Custom Queuing Example,int s0 custom-queue-list 1!queue-list 1 protocol decnet 3 queue-list 1 protocol ip 7 queue-list 2 protocol decnet 2 gt 200 queue-list 2 protocol ip 7 tcp 23 queue-list 2 protocol ip 8 udp 53queue-list 2 protocol ip 9 tcp 23queue-li
32、st 3 protocol decnet 2 lt 200 queue-list 3 protocol ip 1 list 10 queue-list 3 protocol ip 7queue-list 3 default 10 queue-list 4 interface e0 5 queue-list 4 interface ethernet 1 6queue-list 4 interface serial 0 8 queue-list 4 default 10 queue-list 4 protocol arp 4 queue-list 4 protocol bridge 3 queue
33、-list 4 protocol ipx 9!access-list 10 permit 239.1.1.0 0.0.0.255,Custom Queuing Verification(Global),R1#show queueing customCurrent custom queue configuration:List Queue Args1 3 protocol decnet1 7 protocol ip2 2 protocol decnet gt 2002 9 protocol ip tcp port telnet2 8 protocol ip udp port domain3 10
34、 default3 2 protocol decnet lt 2003 1 protocol ip list 103 7 protocol ip4 10 default4 5 interface Ethernet04 6 interface Ethernet14 8 interface Serial04 4 protocol arp4 3 protocol bridge4 9 protocol ipx,Custom Queuing Verification(Interface),R1#show int s0Serial0 is up,line protocol is up Hardware i
35、s HD64570 MTU 1500 bytes,BW 1544 Kbit,DLY 20000 usec,rely 255/255,load 1/255 Encapsulation HDLC,loopback not set,keepalive set(10 sec)Last input never,output never,output hang never Last clearing of show interface counters never Input queue:0/75/0(size/max/drops);Total output drops:0 Queueing strate
36、gy:custom-list 1 Output queues:(queue#:size/max/drops)0:0/20/0 1:0/20/0 2:0/20/0 3:0/20/0 4:0/20/0 5:0/20/0 6:0/20/0 7:0/20/0 8:0/20/0 9:0/20/0 10:0/20/0 11:0/20/0 12:0/20/0 13:0/20/0 14:0/20/0 15:0/20/0 16:0/20/0 5 minute input rate 0 bits/sec,0 packets/sec 5 minute output rate 0 bits/sec,0 packets
37、/sec,Weighted Fair Queuing(WFQ),.,.,.,Reserved queues(RSVP and RTP Priority),IP Precedence 7,IP Precedence 0(Best Effort/Hash queues),.,Q Classification:Source addressDest addressSource portDest.PortTos bits(not prec!)Weight:IP PrecedenceRSVP/RTP PriorityW=32384/(prec+1),Weighted Fair Queuing-Concep
38、ts,Simple Requires very little configurationCongestion is requiredConversations What are they?Weight Whats“weighted”in Weighted Fair Queuing?,WFQ is Easy Stuff!,WFQ is the default queuing method on Interfaces 2MbSimply type“fair-queue”in interface configuration mode to turn it on.,WFQ-Congestion is
39、Required,As with all queuing mechanisms,congestion must be present for WFQ to workWhy?Because if there is no congestion,there is no need to queue packets,WFQ-What is a“Conversation”Anyway?,A conversation is a specific communication between two nodesIt is possible that two nodes are having multiple c
40、onversationsA communication is classified as a conversation based upon:-Source&Destination IP Address-Port Numbers-Protocol Numbers-ToS Values,Sounds Fair But,Whats“Weighted?”,Instead of giving all queues equal bandwidth,you can give some more than othersThis is done by activating the“weighting”fact
41、or with IP PrecedenceWeight=4096/(Precedence+1)Prior to 12.0(5)TPrecedence 0=4096Precedence 2=1365After 12.0(5)T:Weight=32384/(Precedence+1)Lower Weight=Higher PriorityConversation queue with a weight of 2048 will drain roughly twice as fast as a queue with packets having a weight of 4096,Class-Base
42、d WFQ(CBWFQ),Classify,.,.,Default class-queue,WFQ System(unclassified traffic),OR,Class queuesMax:63(64 including the default class-queue),CBWFQ,Scheduling based on Finish Time,Class#1,Per class(ACL),Forwarder,Per flow(hash),Flow#1,class-default,CBWFQ,64 Classes(63+default)Bandwidth x(min guarantee)
43、wRED within classes“default class”:class-default fair-queue&queue-limit fair-queue&RED bandwidth&queue-limit bandwidth&RED,CBWFQ-Notes,By default sum of BWclasses=75%BW 75%of min CIR in Frame-Relay75%of SCR on ATM VBR nrt(99%on 7500)The default sum bandwidth can be overriddenFIFO queuing per class(d
44、efault 64 pkts)VIP/FlexWAN can do fair-queue on any class.7200/3600/2600 do fair queue on default class only.Default class 7200/3600 etc is WFQ.Default class VIP is FIFO,but can do WFQ,CBWFQ 75%Rule,Add up:Class bandwidthsRSVP maximum reserved bandwidthThe result must be less than or equal to 75%of
45、the interface bandwidth or FR DLCI CIRLeaves headroom for call signaling,SNMP,management(LMI)and routing trafficUse the max-reserved-bandwidth command to alter this,but is not recommended,Modular QoS CLI(MQC),Configuring Classification policyAssociate policies to classAttaching policies to interface
46、(in/out),Modular QoS CLI,class-map PQ match access-group Access group destination-address Destination address input-interface Select an input interface to match ip IP specific values mpls Multi Protocol Label Switching specific values(exp)notdo not match protocol Protocol qos-group Qos-group source-
47、address Source address,Modular QoS CLI,policy-map test class PQ bandwidth Bandwidth priority Strict Scheduling Priority for this Class queue-limit Queue Max Threshold for Tail Drop random-detect Enable Random Early Detection as drop policy service-policy Configure QoS Service Policy-hierarchical set
48、 Set QoS values(prec,DSCP,exp,FRde,CLP)shape Traffic Shaping-GTS police traffic policing(conform,exeed,violate),Hierarchical policy(1),Allow multi level policingpolicy-map udp-hierarchyclass nfs bandwidth class tftp bandwidth policy-map server-hierarchyclass server-A bandwidth class server-B bandwid
49、th,Hierarchical policy(2),policy-map tcp-hierarchyclass http bandwidth class ftp bandwidth class telnet bandwidth service-policy server-hierarchypolicy-map bandwidth-allocation-policyclass udp bandwidth service-policy udp-hierarchyclass tcp bandwidth service-policy tcp-hierarchy,CBWFQ-Example,4 clas
50、ses(multimedia,www,ftp,best effort)Congested link is 10 MbpsMinimum required BW:Multimedia-3 MbpsWWW-2.25 MbpsFTP-1.5 MbpsBE-750 Kbps,CBWFQ-Example,Class DeclarationRouter(config)#class-map multimediaRouter(config-cmap)#match access-group 101Router(config-cmap)#class-map ftpRouter(config-cmap)#match
