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1、#CiscoLive#CiscoLiveRobert Barton,Distinguished Architect,Americas SalesBRKEWN-2031The Inner Working of QoS for Modern Wireless Networks 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveEnter your personal notes hereCisco Webex App 3Questions?Use Cisco Webex App to chat wit
2、h the speaker after the sessionFind this session in the Cisco Live Mobile AppClick“Join the Discussion”Install the Webex App or go directly to the Webex spaceEnter messages/questions in the Webex spaceHowWebex spaces will be moderated by the speaker until June 9,2023.12343https:/ 2023 Cisco and/or i
3、ts affiliates.All rights reserved.Cisco PublicBRKEWN-2031Agenda 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public802.11 QoS Building BlocksLegacy QoS:The Enhanced Distributed Channel Access(EDCA)ModelHow QoS Works in Wi-Fi6/6EAireOS Wireless LAN QoS DeploymentsIOS-XE/Catalyst 9800 Qo
4、S DeploymentsNext-Gen QoS:IEEE 802.11be and beyondBRKEWN-20314802.11 QoS Building Blocks 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveComparing Wired and Wireless QoSWired environments are Full Duplex,Wireless is Half Duplex(for now)Half duplex environments are very sus
5、ceptible to collisionsThus,wired QoS is mostly concerned with managing packet loss due to congestion problems(solved with queuing,etc.)6Wireless QoS is focused on a much bigger problem:1.WLAN QoS is mostly concerned with reducing the probabilityprobability of a collision for high-priority traffic,ba
6、sed on its QoS classification2.Managing congestion is a secondary concernBRKEWN-2031 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveCarrier Sense Multiple Access/Collision AvoidanceWired Hubs use CSMA/CD(collision detection)A station must listen to the medium to see if it
7、 is idle before sending its frame.When it seems idle,it sends the frame.After sending,it listens to see if a collision has occurred 802.11 networks use CSMA/CA(collision avoidance)Wireless networks have no way to detect that a collision even occurred!Uses a system of fixed and random wait timers to
8、ensure everyone gets a chance to sendEvery frame must be acknowledgedBRKEWN-20317 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveWi-Fi Media Access is Contention-BasedListen&WaitSendingListen&WaitListen&WaitListen&WaitListen&WaitAccess Point(Listen&Wait)BRKEWN-20318 2023
9、Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveDistributed Coordination Function(DCF)When ready to transmit,all stations must first wait the DCF Interframe space(DIFS)Allows all stations to sense end of frame Tx and allow ACK to be sent backOnce DIFS has counted down to zero,a
10、 random backoff countdown timer(the Contention Window)is generated if the medium is not free.Initially,this value is between zero and a value known as CWminOnce the CW counts down to zero,the frame is transmittedContention Window Period(CW)Time(t)Medium is BusyBegin TransmissionDIFS.SIFS(16 s)Random
11、 Number of Time Slots2x slots(18 s)ACK is SentBRKEWN-20319 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveWhat if Your Frame Doesnt Get Ackd?How do you know the transmission got through okay?The receiving station must send an acknowledgment.If the first attempt didnt work
12、(no ACK received),double the previous CW size and pick a new random number.Keep doing this until the CW reaches a maximum size of 1023 slot times.How many times should the station keep trying?In Cisco APs,the maximum number of attempts is 64 before the frame is discarded.BRKEWN-203110 2023 Cisco and
13、/or its affiliates.All rights reserved.Cisco Public#CiscoLiveConsider an Example of Five Stations Trying to Unicast all at OnceSimplified Example-DCF In Action:Station AStation BStation CStation DStation EFrameDeferDeferDeferFrameDIFSDIFSDeferFrameDIFSFrameBackoff timeBackoff time remainingDeferDefe
14、rDeferDeferBRKEWN-203111 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveWhat Happens When the Client Count Goes Up?WaitWaitWaitWaitWaitWaitWaitWait11acSendingWaitBRKEWN-203112 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveThe Contention Breaki
15、ng Point(802.11ac)(source:IEEE 802.11-15/0351r2)0%20%40%60%80%100%120%1 5 10 25 50 75 100Throughput(%)Clients5%-10%contention premium30%-50%50%-60%10%-30%As more clients associate and transmit,WLAN contention increases for all clients,degrading performance for allBRKEWN-203113Legacy QoS:The Enhanced
16、 Distributed Channel Access(EDCA)Model 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLive802.11e Introduced the Enhanced Distributed Channel Access(EDCA)Model in 2005802.11e was tasked with bringing QoS to Wi-FiEDCA was introduced by IEEE 802.11e in 2005,and has been adopted
17、 by the Wi-Fi Alliance as Wireless Multimedia(WMM)WMM is now a mandatory part of modern Wi-Fi802.11a/b/g are based on DCF(no QoS)802.11a/b/g are based on DCF(no QoS)802.11n/ac are based on EDCA(QoS is supported)802.11n/ac are based on EDCA(QoS is supported)Continual improvements,including the 802.11
18、-2016“rollup”BRKEWN-203115 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLive#1 Access Categories(ACs)BackgroundBest EffortVideoVoice1,20,34,56,7Application DataWhen wireless frames are transmitted,a 3-bit QoS value known as the User Priority User Priority(UP)is written into
19、 the 802.11 headerUP Values:BRKEWN-203116Contention 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveDefault DSCP UP Mapping TableTraffic TypeTraffic TypeDSCPDSCP802.11e 802.11e UP/UP/WMMWMMAccess CategoryAccess CategoryVoice46(EF)6VoiceInteractive Video34(AF41)5VideoCall S
20、ignaling24(CS3)3Best EffortTransactional/Interactive Data18(AF21)3Best EffortBulk Data10(AF11)2BackgroundBest Effort0(BE)0Best EffortBRKEWN-203117 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveReconciles RFC 4594 with IEEE 802.11Summarizes our internal consensus on DSCP-
21、to-UP mappingAdvocates DSCP-trust in the upstream direction(vs.UP-to-DSCP mapping)RFC 8325 Mapping DiffServ to IEEE 802.11 https:/tools.ietf.org/html/rfc8325BRKEWN-203118 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLive#2 Assign Backoff Timers for the Access CategoryEDCA m
22、anages the ACs in the following way:Variable Arbitration Interframe Spacing(AIFS)Variable CWminand CWmaxvalues depending on traffic typeValues shown are“slot times”9s per slot in 802.11EDCA/WMM ACAIFS NumberCWminCWmaxLegacy DCFDIFS 215*1023*For 802.11a/g.802.11b uses 31 Voice237Video2715Best Effort3
23、151023Background7151023BRKEWN-203119 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveUnderstanding the Effect of EDCA TimersBy combining these timers,the theoretical probability of higher priority frames getting serviced first is greatly improved(but is not guaranteed in e
24、very case)Simply having a queue doesnt give you QoS how you manage the queue is what matters.BRKEWN-203120 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLive#3 Transmission Opportunity(TXOP)TXOP is a timer a station keeps sending until its TXOP timer counts down to zeroDCF h
25、ad no such thing send one frame and then start again!Why is video smaller than the other TXOPs?EDCA/WMM ACTXOP(s)TXOP(Units)Voice208065Video4096128Best Effort252879Background252879BRKEWN-203121 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveReal Time Voice vs.Real Time Vi
26、deo Traffic ProfileTraffic Profile Helps Model TXOP TimersBRKEWN-203122 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLive#4 Transmission Specification(TSpec)TSpec is basically Call Admission Control-management of the number of voice and video traffic flows per AP radioClien
27、t signals to AP to request its traffic stream be added to AP(ADDTS)TSpec includes data rate,packet size,number of stream&moreADDTS Request:Can I add a voice stream to this channel?I need 88 Kbps etc.ADDTS Response:Sorry,theres no room for this traffic!BRKEWN-203123 2023 Cisco and/or its affiliates.A
28、ll rights reserved.Cisco Public#CiscoLiveSummary:Four Key 802.11e QoS EnhancementsEnhanced Distributed Channel Access(EDCA):Enhanced Distributed Channel Access(EDCA):1.Establishment of four Access Categories and 3-bit User Priority QoS field2.New timers replacing legacy static DIFS and CW3.Each AC g
29、ets its own Transmission Opportunity(TXOP)4.Call Admission Control(CAC)with TSpecBRKEWN-203124How QoS Works in Wi-Fi6/6E(802.11ax)2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveSubcarriers(Resource Units RUs)can be assigned to different users for uplink transmissionsCan b
30、e combined with UL MU MIMOOFDMA(Orthogonal Frequency Division Multiple Access)BRKEWN-203126 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveOFDMA(Orthogonal Frequency Division Multiple Access)Multiple Stations Transmit in a scheduled TimeslotA Single Station Transmits in a
31、 Timeslot won by the contention algorithm(EDCA)BRKEWN-203127 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLive802.11ac allows for downlink MU-MIMO802.11ax adds uplink MU-MIMOAP checks which STAs can send together AP sends trigger frame and STAs respond all at the same time
32、802.11ax Uplink(UL)MU-MIMOSTAsTrigger frameSTAsSTAsSTAsBRKEWN-203128 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveBuffer Status Reports(BSRs)ACI BitmapDelta TIDACI HighScaling FactorQueue Size HighQueue Size AllAC_BEAC_BKAC_VIAC-VOHow much traffic is buffered in an Acce
33、ss CategoryBits:4 2 2 2 8 8STAs may send QoS information in the BSR Control subfield BSR Control subfield of any frameIdentify which ACFor a single ACFor multiple ACsBRKEWN-203129 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveBuffer Status Report Polling(BSRP)(Figuring o
34、ut how many RUs to Assign)STAsSTAsSTAsTrigger 1BSRPAIFSSIFSSTAsBSRBSRBSRBSRTrigger 2MU-RTSSIFSSIFSCTSCTSCTSCTSTrigger 3TriggerSIFSSIFSUL-PPDUUL-PPDUUL-PPDUUL-PPDUMulti-STA Block AckSIFSBRKEWN-203130 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveHow Does This Work in Mixe
35、d Environments?31BRKRST-25156GE spectrum is safe only 11ax clients can work in this spectrum!In the lower bands,the AP will need to contend with legacy clients to win the EDCA algorithm so it can perform OFDMA/Multi-User UplinkOver time,as legacy clients go away the medium will shift to a predominan
36、t OFDMA model(good)Vs.IOS-XE/Catalyst 9800 QoS Deployment 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveA Consistent QoS Strategy:Unifying Wired and Wireless QoSBRKEWN-203133Class 6Class 4Class 2Class 1Class 7Class nClass 3BackgroundBest EffortVideoVoiceEnterprise QoSEnt
37、erprise QoSWLAN QoSWLAN QoSClass 5PQ+CBWFQPQ+CBWFQ802.11 QoS802.11 QoSBy definition of IEEE 802.11e standard there are only 4 levels of service(Access Categories)The class-based QoS model should align with the four AC model in the wireless networkNeed to make sure the QoS markings are consistent end
38、-to-end through the network and the design is consistent 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveCatalyst 9800 Downstream QoS ModelWired Wired NetworkNetwork802.1Q Trunk802.1Q TrunkCAPWAP EncapsulatedCAPWAP EncapsulatedDSCPDSCP802.1q802.1qCAPWAPCAPWAPCAPWAP Encapsu
39、latedCAPWAP EncapsulatedDSCPDSCPUPUPDSCPDSCP PayloadPayloadUPUPDSCPDSCP PayloadPayload802.1q802.1qDSCPDSCP PayloadPayload1 1The client packet is received over an 802.1q trunk by the WLC.The WLC uses the DSCP value of the original IP packet and maps it to the outer DSCP of the CAPWAP tunnel(assuming
40、no ceiling value is applied via Metal QoS at the WLC).It also maps DSCP to UP and set it in the inner 802.11e header1 1Note:class of Service(CoS)tagging is not supported in 9800(supported but not recommended in AireOS)APAPWLCWLCBRKEWN-203134 2023 Cisco and/or its affiliates.All rights reserved.Cisco
41、 Public#CiscoLiveCAPWAP EncapsulatedCAPWAP EncapsulatedDSCPDSCPDSCPDSCP PayloadPayloadCAPWAP EncapsulatedCAPWAP EncapsulatedDSCPDSCP802.1q802.1qUPUPDSCPDSCP PayloadPayload802.1q802.1qDSCPDSCP PayloadPayloadCatalyst 9800 Downstream QoS ModelWired Wired NetworkNetworkUPUPDSCPDSCP PayloadPayload2 22 2T
42、he AP leverages the inner UP value received from the WLC for internal QoS processing and queuingThe 802.11e UP value is also copied in the egress wireless 802.11 frame to the client,over the airCAPWAPCAPWAP802.1Q Trunk802.1Q Trunk1 1The client packet is received over an 802.1q trunk by the WLC.The W
43、LC uses the DSCP value of the original IP packet and maps it to the outer DSCP of the CAPWAP tunnel(assuming no ceiling value is applied via Metal QoS at the WLC).It also maps DSCP to UP and set it in the inner 802.11e headerWLCWLC1 1UPUPBRKEWN-203135 2023 Cisco and/or its affiliates.All rights rese
44、rved.Cisco Public#CiscoLiveUPDSCP PayloadCatalyst 9800 Upstream QoS ModelWired Network802.1Q Trunk802.1p23 1The client 802.11e frame is received by the AP.The AP utilizes the DSCP value in the original packet for internal QoS processing and then maps it to the outer CAPWAP IP header,(assuming no cei
45、ling value is applied via Metal QoS at the WLC)(*)CAPWAPTrust DSCPCAPWAP EncapsulatedCAPWAP EncapsulatedDSCPDSCP802.1q802.1qDSCPDSCPPayloadPayload802.1q802.1qDSCPDSCP PayloadPayloadCAPWAP EncapsulatedCAPWAP EncapsulatedDSCPDSCPDSCPDSCP PayloadPayload3 1This allow preservation of the DSCP value from
46、the client all the way through the network,emerging untouched from the WLC(assuming no Metal QoS or AVC policy is applied to remark DSCP)2 2BRKEWN-203136 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveDownstream QoS Variant:Flex Local SwitchingWired Wired NetworkNetworkUP
47、UPDSCPDSCPPayloadPayload1 1Once the Ethernet frame is received,the AP takes the DSCP value of the IP packet,process any QoS policy(e.g.,AVC policy),maps it to the 802.11e UP value on the wireless frame and queue the frame accordingly.The frame is then sent to the client.1 1CAPWAP controlCAPWAP contr
48、ol802.1Q Trunk802.1Q Trunk802.1q802.1qDSCPDSCPPayloadPayloadBRKEWN-203137 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveUpstream QoS Variant:Flex Local Switching802.1p3 1The client 802.11e frame is received by the AP.The AP looks at the original packet DSCP to apply any
49、QoS policy before sending the packet onto the wireCAPWAP controlTrust DSCPWired Wired NetworkNetwork802.1Q Trunk802.1Q TrunkUPUPDSCPDSCP PayloadPayload1 1802.1q802.1qDSCPDSCP PayloadPayloadBRKEWN-203138 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveUPDSCP PayloadUpstream
50、 QoS Variant 2:SDA Fabric802.1pThis allow preservation of the DSCP value from the client all the way through the network,emerging untouched from the Border(assuming no Metal QoS or AVC policy is applied to remark DSCP)23 1The client 802.11e frame is received by the AP.The AP utilizes the DSCP value
51、in the original IP packet for internal QoS processing and then maps it to the outer VXLAN header(*)2Trust DSCP(*)Before release 17.4,you need to explicitly configure“qos-map trust-dscp-upstream”under the AP join profile.If this setting is not there,the AP will use the UP value in the received frame
52、to derive the outer DSCP value of the VXLAN headerVXLANVXLANFabric EdgeFabric BorderSDAVXLAN EncapsulatedVXLAN EncapsulatedDSCPDSCPIPIPDSCPDSCP PayloadPayloadIPVXLAN EncapsulatedVXLAN EncapsulatedDSCPDSCPIPIPIPIPDSCPDSCPPayloadPayloadIPIPDSCPDSCP PayloadPayload3 1BRKEWN-203139 2023 Cisco and/or its
53、affiliates.All rights reserved.Cisco Public#CiscoLiveUnder the Hood:Catalyst 9800 IOS-XE is Based on Modular QoSCatalyst QoS model is based on Modular Modular QoS CLI(MQC)QoS CLI(MQC)In IOS-XE,MQC MQC is used to implement the Differentiated Service model QoSThe main MQC constructs:ClassClass-map:map
54、:to classify trafficPolicyPolicy-map:map:to bind traffic class to actionsServiceService-policy:policy:to attach policy-map to target/directionip access-list extended AutoQos-4.0-Output-Acl-CAPWAP-C10 permit udp any eq 5246 16666 anyclass-map match-any AutoQos-4.0-Output-CAPWAP-C-Classmatch access-gr
55、oup name AutoQos-4.0-Output-Acl-CAPWAP-Cclass-map match-any AutoQos-4.0-Output-Voice-Classmatch dscp efpolicy-map AutoQos-4.0-wlan-Port-Output-Policyclass AutoQos-4.0-Output-CAPWAP-C-Classpriority level 1class AutoQos-4.0-Output-Voice-Classpriority level 2class class-defaultinterface TenGigabitEther
56、net0/0/0service-policy output AutoQos-4.0-wlan-Port-Output-PolicyClassification ACLClass-map definitionPolicy-map definitionService-policy attachmentBRKEWN-203140 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveController Hierarchical Wireless QoSClient Based PolicyVOICEGu
57、estCorpGi 0/1Service LevelVOICEBUSINESSBUSINESSDEFAULTDEFAULTSSID Based PolicyRadio Default Shaper(non-configurable)Port Queueing PolicyBRKEWN-203141 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveConfiguring QoS on the Catalyst 9800 ControllerBegin by Navigating to Servi
58、ces QoS and Add a new policyBRKEWN-203142 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveQoS Policy WorkflowName your policy,add applications(Class-maps)BRKEWN-203143 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveMaking Things Easy with Auto Q
59、oSNoneGuest EnterpriseVoiceFastlaneBRKEWN-203144 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveCatalyst 9800 Auto QoS explainedVoiceVoice:sets the recommended QoS policy to correctly mark and prioritize voice at the SSID level and enables CAC.GuestGuest:sets the recommen
60、ded QoS policy at SSID level to mark everything to Best EffortEnterpriseEnterprise:sets the recommended QoS policy at SSID level to mark VoIP Data,and Signaling,Multimedia,Transaction,Bulk-Data and Scavenger trafficFastlaneFastlane:sets the specific EDCA parameters.Fastlane also sets clients specifi
61、c policies only for Apple clients.With All options queuing is configured on the C9800 egress port for prioritizing voice and CAPWAP trafficOnce Auto-QoS profile is applied on the policy profile,you can view the policies via the“show policy mapshow policy map”command and show the configuration via“sh
62、ow run”BRKEWN-203145 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveRemember this?AireOS Precious Metal QoS MethodBRKEWN-203146 The main purpose of the QoS profile is to limit the maximum DSCP allowed on a CAPWAP tunnel,and thus limit the 802.11 UP value QoS profiles may
63、be used and applied to each WLAN(SSID)DSCP 10DSCP 34DSCP 46DSCP 0 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveCatalyst 9800 Improving Metal QoS ProfilesBRKEWN-203147QoS Metal Profiles in C9800:For C9800 you can apply Metal QOS on Egress and Ingress direction separately
64、On the GUI,you can only set the Metal QoS per SSID.On CLI you can also configure it on client targetFor each profile,a max DCSP setting is used to remark any traffic in excess of the DSCP limit Qos ProfileMax DSCPBronzeBronze8SilverSilver0GoldGold34PlatinumPlatinum46 2023 Cisco and/or its affiliates
65、.All rights reserved.Cisco Public#CiscoLiveAVC QoS WorkflowAdd applications and assign a policyYou can also choose User Defined and input application portsChoose ProtocolSelect“AVC”ModeSelect a number of applicationsAssign a policyBRKEWN-203148 2023 Cisco and/or its affiliates.All rights reserved.Ci
66、sco Public#CiscoLiveCat 9800 Custom AVC CapabiliitesCustom apps and attributes can be defined by the userCustom IP,Port,DSCPCustom HTTP Host and URLC9800(config)#ip nbar custom my_http http url“latest/whatsnew.html”C9800(config)#ip nbar custom my_http http host“”C9800(config)#ip nbar custom my_http
67、http url“latest/whatsnew”host“”The URL or host specification strings can take the form of a regular expressionsExample:C9800(config)#ip nbar custom my_app transport udpC9800(config-custom)#ip address 9.9.71.50 9.9.71.11 9.9.71.14C9800(config-custom)#port 1111C9800(config-custom)#dscp 0C9800(config-c
68、ustom)#direction anyBRKEWN-203149 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveImproved AVC Visualization and ReportingSOURCE TYPE and SOURCE SSIDGlobal and per-SSID stats monitoringSOURCE TYPE and SOURCE SSIDIngress vs Egress DirectionHISTORICAL DATA2 hours,24 hours,48
69、 hours APP VISIBILITY TIMELINEHistorical View of Application behavior BRKEWN-203150Looking to the Future:IEEE 802.11be and Beyond 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveUltra Reliable and Deterministic Wireless5G Release 16 introduced Ultra-Reliable Low Latency Co
70、mmunication(URLLC)for fast moving vehicles and seamless roamingCisco CURWB(Fluidmesh)supports this todayWi-Fi will follow soon with 802.11be(Wi-Fi7)BRKEWN-203152 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveMulti-Link Operations(MLO)Ability to Tx and Rx on multiple chan
71、nelsAbility to Tx and Rx on multiple channels QoSQoS-basedbased link selection/steeringMAPC Time and space scheduling across multiple APsWireless Time Sensitive Networking(TSN)Enhanced QoS Capabilities SLASLA-basedbased KPI delivery(latency,jitter,etc.)NetworkNetwork and client-side supportIEEE 802.
72、11be key capabilitiesMLO&MLDseamlessWTSNdeterministicBRKEWN-203153 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveMulti-Link Operation(MLO)A MLOMLO-capablecapable device is called a Multi-Link Device(MLDMLD)The MLD can be associated to both/all radios of an AP using both
73、or all of its radiosMLDs have more than one affiliated Stations(STAs),but generally ONEONE MAC Service Access Point(SAP)connected to the LLCThe SAP is tasked with aggregating data from multiple linksMLD 1MLD 1MACMAC-SAP 1SAP 1STA 1-1STA 1-2MLD 2MLD 2MACMAC-SAP 2SAP 2STA 2-1STA 2-22.4 GHz5 GHz6GHzBRK
74、EWN-203154 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveMulti-Link Operation(MLO)Enables new CapabilitiesMLD 1MLD 1MACMAC-SAP 1SAP 1STA 1-1STA 1-2MLD 2MLD 2MACMAC-SAP 2SAP 2STA 2-1STA 2-22.4 GHz5 GHz6GHzMLD 1MLD 1MACMAC-SAP 1SAP 1STA 1-1STA 1-2MLD 2MLD 2MACMAC-SAP 2SAP
75、2STA 2-1STA 2-2STR Mode(Simultaneous Tx and Rx)Essentially Full-DuplexNSTR Mode(Non-Simultaneous Tx and Rx)Load balanced traffic across multiple linksTransmitReceiveTx&RxTx&RxBRKEWN-203155BEBKVIVOLegendVIVOBEBK 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveSCS(Stream Cla
76、ssification Service)specifies traffic flows using an SCS request frame(a QoS Information Element/IEInformation Element/IE)The AP derives QoS rules by monitoring the corresponding uplink flowsAllows the STA to explicitly provide traffic classifiers and priority for each downlink flowA New QoS Paradig
77、m:802.11aa Stream Classification Service(SCS)SCS Request to the APDownstream traffic is managed according to the requested SCSSCS Rules ActivatedBRKEWN-203156 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveTraffic Identifiers(TIDs)TIDs TIDs are a 4-bit QoS field in 802.11
78、 header(the first 3 bits are where the UP value comes from)which are communicated in the SCS request With 802.11be TIDs may be used to select optimal links(5GHz vs.6GHz,etc.)TID to radio link mapping E.g.“Lets send all low-latency HD video on 6GHz,but everything else on 5GHz”The SCS QoS IE specifies
79、 traffic characteristics&requirementstraffic characteristics&requirements Inter-arrival-time/periodicity(max/min scheduling interval)Delay,reliability(delivery ratio)&jitter(indirectly)requirements Burst characteristics(size and window)Exact alignment(e.g.TSN 802.1Qbv)via service-start-time(SST)802.
80、11be/Wi-Fi7 QoSBRKEWN-203157 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveEnhanced QoS:802.11be SCS Enables Determinism0 00.10.10.20.20.30.30.40.40.50.50.60.60.70.70.80.80.90.91 10-1ms0-1ms1-10ms1-10ms10-25ms10-25ms25-100ms25-100ms+100ms+100msWi-Fi5Wi-Fi5Wi-Fi6/6EWi-Fi6
81、/6EWi-Fi6/6E w/Fastlane+Wi-Fi6/6E w/Fastlane+Wi-Fi7(SCS)Wi-Fi7(SCS)Wi-Fi7(SCS+802.1Qbv gates)Wi-Fi7(SCS+802.1Qbv gates)Probability(latency x)Latency performance improvements in highLatency performance improvements in high-traffic scenarios traffic scenarios Source:https:/mentor.ieee.org/802.11/dcn/2
82、2/11-22-0634-00-00be-802-11be-enhancements-for-tsn-time-aware-scheduling-and-network-management-considerations.pptxBRKEWN-203158Summary 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveConclusions Understanding the function of wireless QoS is foundational to any good deploy
83、ment especially the differences between EDCA and Wi-Fi6Think about how you will adapt a multi-class policy to wireless,which has only 4 classesBe aware of how Wi-Fi handles QoS mappings and markings,end-to-endIOS-XE improves on capabilities of AireOS,including the precious metal QoS model,extending
84、AVC flexibility,and much more802.11be QoS Innovations are coming in Wi-Fi to support new use cases60BRKEWN-2031 2023 Cisco and/or its affiliates.All rights reserved.Cisco Public#CiscoLiveFill out your session surveys!Attendees who fill out a minimum of four session surveys and the overall event surv
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87、sco and/or its affiliates.All rights reserved.Cisco Public#CiscoLive64Gamify your Cisco Live experience!Get points Get points for attending this session!for attending this session!Open the Cisco Events App.Click on Cisco Live Challenge in the side menu.Click on View Your Badges at the top.Click the+at the bottom of the screen and scan the QR code:How:123464 2023 Cisco and/or its affiliates.All rights reserved.Cisco PublicBRKEWN-2031#CiscoLive