Traffic Shaper for Control Data Traffic Industry

Transcription

1 Traffic Shaper for Conrol Daa Traffic Indusry IEEE 82 AVB Meeing San Diego Franz-Josef Göz, Siemens AG

2 Why an ADDITIONAL Shaper for CDT in Bridges? Reasons: Shaper wih less configuraion effor in bridges (only bandwidh no window size) Adap o differen link speeds wihin a nework Auomaically adapion o raffic flow For mashed neworks wih muliple alker Plugging of new componens may change bandwidh bu he ime schedule mus no adaped The shaper shall suppor periodic and even-based CDT (bandwidh limiaion) Robus for safey criical applicaions Emergency operaion feaures (fail operaional behavior) NEW Shaper has o fulfill he following requiremens: Guaraneed Low Laency for CTD Guaranee for maximum burs size for CTD Guaraneed bandwidh also for oher raffic classes Seie IEEE 82 Meeing San Diego

3 Conrol Daa Traffic Class (CDT) - Basics Traffic shaper for Conrol Daa Traffic in end saions and bridges Suppor periodic ime based ransmission of Conrol Daa Frames in end saions Transmission imesamp for window (burs) Transmission imesamp per frame Specify scheduler for Conrol Daa Traffic in bridges TABS Time Aware Blocking Shaper wih one and muliple windows BLSA Burs Limiing Shaper Algorihm for CDT (will be explained in his presenaion) Preempion for Conrol Daa Traffic Peer-o-Peer fragmenaion of legacy raffic and AV Sreams The preempion mechanism can be used for Periodic CDT Even-based CDT Transmission Inpus Transmission Oupus Bu mechanism like L2 Rouing for CDT (shores pah, muliple pah for seamless redundancy), Bandwidh reservaion for CDT and Scheduling of CDT o opimize laency, minimize make span and minimize resources in bridges for Conrol Daa Traffic are sill required! Seie IEEE 82 Meeing San Diego

4 Muliple Transmission Periods for CDT Typical Use Case : CDT high 125µ ransmission period CDT low 1 ms ransmission period Two CDT Classes wihin a funcional cell because no all physical values (e.g. emperaure) do change wih same speed Typical requiremen on laency: Max laency for CDT high < 6µs Max laency for CDT low < 5µs To minimize impac wo Class for CDT are helpful (one CDT Class mandaory, a second or.. opional) PLC PLC... PLC PLC PLC PLC: Programmable Logic Conroller for inpu/oupu daa DEV: Device for inpu / oupu daa (sensor / acuaor) Video Server... DEV PLC DEV communicaion relaion PLC PLC communicaion relaion Eherne DEV overlapping funcional cells for PLC <-> DEV conrol daa raffic communicaion Consrains for CDT Class: Minimum ransmission period (mintp): e.g. 31,25µs To simplify load balancing sraegy Seps of 2 N x mtp (31,25µs 1ms), N {1, 5} (odd-numbered shall be avoided -> bandwidh calculaion becomes much more difficuly) Only one common ransmission period wihin one funcional cell or overlapping funcional cells (leas common muliple) Typical CDT frame size in he range of 64 4Byes Moion Conrol Cell DEV DEV Machinery Cell DEV PRE-EMPTION Seie IEEE 82 Meeing San Diego

5 Mechanism o Guaranee Low Laency for CDT Aging for CDT Frames in CDT ransmi queue Add local ime samp when puing CDT Frame in x queue Drop CDT Frames when residence ime > MaxAge Bandwidh observaion for CDT on ingress por Bandwidh measuremen for CDT Inerval = x * TP Bandwidh limiaion and so called nework fuses o proec nework (e.g. babbling alker) Diagnosic concep Coun packe drop caused by aging Exceeding bandwidh on ingress por Bandwidh limiaion for CDT on egress por Bandwidh reservaion and limiing for CDT Limiing burs size for CDT Seie IEEE 82 Meeing San Diego

6 Proposal: Burs Limiing Shaper Algorihm for CDT SlopeSend SlopeSend While reserved bandwidh for Conrol Daa is available he queue for Conrol daa has highes prioriy (green area) While reserved bandwidh for Conrol Daa is consumed he queue for Conrol daa has lowes prioriy (blue area) o guaranee bandwidh for legacy raffic When Conrol Daa frames are ransmied in he green area hey can preemp ransmission of a legacy frame In he blue area Conrol Daa frames can only be ransmied when he queues for legacy raffic are empy Seie IEEE 82 Meeing San Diego

7 Burs Limiing Shaper Algorihm for CDT Calculaions for Burs Limiing Shaper Algorihm (BLSA): Link speed (linkspeed) Common ransmission period (CTP) Leaky Bucke Bandwidh Fracion (LB_BwF is reserverd bandwidh for Conrol Daa in %) Leake Rae for Conrol Daa Traffic: LeakRae = LB_BwF * linkspeed Mean Frame Size for Conrol Daa Frames in Bis: MeanCDFrameSize Send Slope for Conrol Daa in bis : Slope Send = (1 LB_BwF) * MeanCDFrameSize Idle Slope for Conrol Daa in bis: Slope Idle = LB_BwF * MeanCDFrameSize Maximum number of Bis (maximum burs size) per TP: MaxLevel = LeakRae * CTP + SafeyMargin Mean Conrol Daa Frames per ransmission period: mcdframestp = MaxLevel / Slope Send Re-prioriy level: ResumeLevel =.1 * MaxLevel Simple example for 1% of he available bandwidh for Conrol Daa Traffic, CTP = 125µs and mean frame size for Conrol Daa Frames: MeanCDFrameSize = 128 byes linkspeed = 1 Gbi/s LB_BwF =.1 (1%) LeakRae =.1 * 1 Gbi/s = 1Mbi/s Slope Send = (1 LB_BwF) * 8 * 128 byes = 922 bis Slope Idle = LB_BwF * 8 * 128 byes = -13 bis MaxLevel = 1 Mbis/s * 125µs + SafeyMargin = 125 bis + SafeyMargin 13 bis mcdframestp = > 13 bis / 922 bis 14 Conrol Daa frames ResumeLevel =.1 * 13 bis = 13 bis Seie IEEE 82 Meeing San Diego

8 Burs Limiing Shaper Algorihm for CDT number of queued conrol daa frames ULL_1 ULL-Queue Prioriy Legacy-Queue Prioriy ULL-Queue Prioriy < Legacy-Queue Prioriy ULL_6 ULL_4 ULL_5 ULL_6 ULL_7 ULL_8 number of queued legacy frames ransmied frames Leg_1 Leg_2 Leg_3 Leg_4 Bis ULL_1 (496 Bi) (372 Bi) ULL_SendBis = 9216 (248 Bi) Leg_1 (372 Bi) ULL_SendBis = ULL_IdleBis = ULL_IdleBis = 7168 ULL_4 (8192 Bi) ULL_5 (7168 Bi) ULL_6 (248 Bi) Leg_2 (248 Bi) Leg_3 (248 Bi) ULL_7 (248 Bi) ULL_SendBis: ULL_SendBis = 1536 ULL_SendBis = 248 ULL_SendBis = ULL_IdleBis = ULL_IdleBis = 496 ULL_IdleBis: ULL_IdleBis = 128 ULL_8 (248 Bi) ULL_SendBis: 248 ULL_IdleBis: MaxLevel ULL_1 ResumeLevel SlopeSend ULL_4 ULL_5 SlolpenSend SlopeSend ULL_6 SlolpIdle ULL_7 ULL_8 512 Resume_Level Seie IEEE 82 Meeing San Diego

9 Compare Burs Limiing Shaper Algorihm (CDT) wih Credi Based Shaper Algorihm (AV Sreams) number of queued conrol daa frames ULL_1 Burs Limiing Scheduler for Conrol Daa Traffic ULL_6 ULL_4 ULL_5 ULL_6 ULL_7 ULL_ MaxLevel ULL_5 ULL_ ULL_1 ResumeLevel SlopeSend ULL_4 SlopeSend SlopeSend ULL_7 ResumeLevel ULL_8 Credi hicredi Credi Based Scheduler for AV Sreams idleslope sendslope locredi number of queued frames Seie Fr A Fr B Fr D Fr C Fr D Fr C Fr D Fr E Fr E IEEE 82 Meeing San Diego

10 Nex Seps? Which PAR includes Specificaion for NEW Conrol Daa Traffic Class Suppored ransmission Periods Muliple ransmission periods... Burs Limiing Scheduler Algorihm (BLSA)??? Seie IEEE 82 Meeing San Diego