QoS of Optical Packet Metro Networks

Transcription

1 QoS of Optical Packet Metro Networks Annie Gravey, Philippe Gravey, Michel Morvan, Bogdan Uscumlic, Lida Sadeghioon OFC 2014, March 12 th, 2014

2 Outline of the presentation 1. POADM multi-ring metro network operation 2. Transfer plane QoS for POADM rings 3. Label-based MAC : operation and node configuration 4. Protecting traffic in POADM networks 5. Dimensioning POADM rings for QoS 6. Conclusion - 2 -

3 WDM metro rings Internet Electronic Switch/router CO IP/MPLS backbone Op4cal Packet/Circuit switch Electronic aggrega4on in access by electronic packet switches or long reach PONs λ and sub- λ transparent virtual circuits (aggrega4on threshold) PoP Primary Ring LR PON - 3-3

4 POADM WDM rings (Alcatel 2007) POADM ring Optically Transparent Transit Optically Opaque Switching mul4ple (shared) data channels (e.g. 40 channels, each channel 10Gbs) a tunable transmiler per node mul4ple fixed receiver per node synchronized opera4on (e.g. 20µs slots) a single (shared) control channel to control inser4on/extrac4on Single Control Channel Multiple Data channels λc λ1 λ2 λ3 λ4-4 -

5 Transfer plane QoS for POADM rings Electronic layer Optical layer Loss buffer congestion at insertion or reception NA Delay Grooming electronic packets into optical packets Receiving several optical packets per time slot Insertion delay Propagation delay Loss in the electronic layer : avoided thanks to appropriate dimensioning Loss in the optical layer : none by design, optical transparency for packets in transit Grooming delay : trade-off between flow granularity, flow rate and latency Propagation delay : upper bounded by ring circumference (5µs/km) Insertion delay : MAC operation dependent Receiver delay : MAC operation dependent - 5 -

6 MAC operation for insertion and extraction Opportunistic insertion process NO RESERVATION A node inserts an optical packet per time slot, if an appropriate combination (destination, channel) is available Multiple queues to serve depending on destination and requested QoS : scheduling issue Exhaustive extraction process A node may receive several packets per time slot SPATIAL REUSE Queueing process at egress of POADM system - 6 -

7 MAC related delays Insertion latency (in µs) vs offered load Insertion jitter (in µs) vs offered load A few slot times! Bernoulli traffic assump4on (a node aggregates several thousands of clients) A simple Geo/Geo/1 models the inser4on delay A simple ngeo/d/1 models the extrac4on delay - 7 -

8 POADM performance Objective : carrier-grade performance (loss, latency, jitter) as long as the network is properly dimensioned This would be similar to classical electronic packet switched network BUT : optical transparency Improves transfer plane performance Degrades dimensioning efficiency POADM is not work-conserving - 8 -

9 Stability issue illustrated E A Λ 1 Λ 2 D B C Number of queued packets Simulation time (seconds) Traffic matrix The load on each Λ is less than 1 but station A is congested! - 9 -

10 Stability issue Is conges4on possible? Is Transit Traffic queued With OEO (e.g. Resilient Packet Ring) yes yes yes no Work conserving yes no Without OEO (POADM) Randomness of Insertion process (e.g. Geo/Geo/1 queue) Dimensioning a POADM ring requires stability conditions! Stability conditions depend on scheduling

11 POADM Multiservice support Multiple client layers with different QoS requirements Delay and jitter Availability QoS differentiation is applied with policies Grooming electronic packets into optical packets Scheduling optical packets insertion Protecting selected sets of optical packet flows Flow differentiation is mandatory!

12 A label-based MAC for POADM networks Different flows are recognized thanks to labels at SDU and PDU levels PDU crea4on according to client layer QoS Guaranteed transport of PDUs per flow protec4on mechanisms With a label- based MAC, POADM carries virtual circuits and is connechon oriented

13 Per-flow POADM operation OperaHons Receive/Pass/Erase/Insert Working/Backup Local Database Flow Specifications Type, ID, QoS, Labels, Paths Switching Information Protection Information Switching Information Table (SIT) Protection Information Table (PIT) Each flow is a Virtual Circuit iden4fied by its label With the SIT: a node only handles those flows that it has to insert and/or receive The SIT can be Sta4c or dynamic POADM configurahon is SDN compliant

14 Multicast support in POADM networks Each mul4cast flow is a labeled virtual circuit The correspondence table is periodically broadcast Each Node is IGMP- Proxy L1 L2 The SIT is dynamically updated depending on requested flows P1 P2 L1 L2 Specific extrac4on process for mul4cast flows Multicast Service Point (MSP)

15 Protection Methods Regular (1:1) protec4on Premium (1+1) protec4on S S D D

16 Per-flow POADM protection Local Database S Flow Specifications Type, ID, QoS, Labels, Paths Switching Information Protection Information Switching Information Table (SIT) Protection Information Table (PIT) D Failure detection (absence of control message) Global OAM message Identification of affected flows (PIT) Reconfiguration of insertion/ extraction (SIT) Adjacent to failure Distribution on ring within each node

17 Performance of Failure Recovery N0( SRC) Ni(Des) N0(SRC) T Loss T notify x x t f Loss t repaired x x T disorde r Disordering

18 Configuration of POADM networks Design Configuration According to long term traffic predictions, client layers SLAs, metrics to optimize. According to client traffic matrices Select rings Provision data channels and associated control channels Map client flows on labelled PDU flows Configure FIT and PIT in each node

19 Dimensioning a POADM ring (1/2) Knowing (predicting!) the traffic matrix at client level... The routing process (is intra-ring traffic allowed?) the protection requirements (flows to protect, protection schemes ) Allows the derivation of the traffic matrix at network level P2P client level matrix 0 a a a a 0 a a a a 0 a a a a 0 concentration-distribution any-to-any 0 3a 3a 3a 3a a a Network level traffic matrix 0 a a a a 0 a a a a 0 a a a a

20 Dimensioning a POADM ring (2/2) Network cost = wavelength cost (Cw) + receiver cost (Cr) Trade-off between the number of data channels and the total number of receivers A B A B A B C D A B C D Ch 5 Rx 3 Ch 4 Rx Traffic matrix D C D C Optimizing the network cost Linear programming to obtain the optimal design (small networks) Heuristics (large networks)

21 Impact of stability on dimensioning cost Single ring Uniform traffic Dominant wavelength cost (Cw>>Cr) 22% Cost increase 33% Number of Wavelengths increase

22 Efficiency of optimal dimensioning Single ring, single POP Dominant wavelength cost (Cw>>Cr) Θ =0 (AggregaHon/DistribuHon), Θ =100 (uniform) Wavelength occupancy may be large, even with stable design! Average (80%) maximum (95%)

23 Impact of protection on dimensioning cost Bidirectional ring Dominant wavelength cost (Cw>>Cr) Uniform traffic Dual premium Dual regular Single unprotected Dual unprotected A regular protected dual ring requires the same number of channels than a single unprotected ring (not always true!)

24 POADM : an alternative for metro networks Optical Packet Switching Electronic Packet Switching Optical Circuit Switching

25 Conclusion POADM provides sub-wavelength multiplexing granularity with ringbased optical transparency Carrier grade transfer layer performance : no loss, low latency (propagation delay), limited jitter, under stability conditions Versatile, modular and SDN compliant label-based control plane Video ready Unicast and Multicast support A separate control channel to support fine grained OAM procedures Flow based protection schemes support differentiated protection levels

26 QUESTIONS?

27 Stability condition for max weight schedulers Stability condition for max-weight scheduling policies including Longest queue first Longest delay first BUT neither priority queuing, nor round robin!

28 Stability issue illustrated E A Λ 1 Λ 2 D B C Number of queued packets Simulation time (seconds) λ 1 + λ2 = 0.53, µ 1 = 0.3, µ 2 = 0. 4 λ + λ > µ µ 2 µ µ 1 2 Traffic matrix

29 Relevant publications 1 USCUMLIC Bogdan, GRAVEY Annie, MORVAN Michel, GRAVEY Philippe, Impact of peer-to-peer traffic on the efficiency of optical packet rings. WOBS'2008 : international Workshop on Optical Burst/Packet Switching, september 8-11, London, UK, SADEGHIOON Lida, GRAVEY Annie, GRAVEY Philippe, A label based MAC for OPS multi-rings. ONDM 2011 : 15th International Conference on Optical Network Design and Modeling, february 2011, Torino, Italy, POINTURIER Yvan, USCUMLIC Bogdan, CERUTTI Isabella, GRAVEY Annie, ANTONA Jean-Christophe, Dimensioning and energy efficiency of optical metro rings. ONDM 2012 : 16th International Conference on Optical Networking Design and Modeling, april 2012, Colchester, United Kingdom, SADEGHIOON Lida, GRAVEY Annie, GRAVEY Philippe, Rapid Protection Schemes in an All-Optical Packet Metro Ring. NOC 2012: 17th European Conference on Network and Optical Communications, june 2012, Vilanova I La Geltru, Spain, 2012, ISBN USCUMLIC Bogdan, MATAVULJ Petar, GRAVEY Annie, GRAVEY Philippe, MORVAN Michel, WDM Optial Packet Ring Performance Insights: Scheduling and Capacity. ISCC '12: 17th IEEE Symposium on Computers and Communication, IEEE, july 2012, Cappadocia, Turkey, 2012, ISBN SADEGHIOON Lida, GRAVEY Philippe, GRAVEY Annie, Resilience in Transparent OPS Multi-Rings. PS 2012: Photonics in Switching 2012, september 2012, Ajaccio, France, SADEGHIOON Lida, USCUMLIC Bogdan, GRAVEY Philippe, GRAVEY Annie, Fully transparent design of a hybrid optical packet/circuit metropolitan area network. ONDM 2013 : the 17th International Conference on Optical Network Design and Modeling, april 2013, Brest, France, USCUMLIC Bogdan, GRAVEY Annie, CERUTTI Isabella, GRAVEY Philippe, MORVAN Michel, Stable Optimal Design of an Optical Packet Ring with Tunable Transmitters and Fixed Receivers. ONDM 2013 : the 17th International Conference on Optical Network Design and Modeling, april 2013, Brest, France, USCUMLIC Bogdan, SADEGHIOON Lida, GRAVEY Annie, GRAVEY Philippe, The Cost of Traffic Protection in Bidirectional Optical Packet Switching Rings. ISCC 2013 : 18th IEEE Symposium on Computers and Communications, july 2013, Split, Croatia,

30 Thank you for your attention! The research leading to these results has received funding - from the European Community Seventh Framework Program FP7/ under grant agreement no COMBO project; - From the French Minister for the Economy, Industry and Digital Affairs in the framework of the CELTIC-Plus project SASER-SaveNet