Assessing the Performance of Multi- Layer Path Computation - PowerPoint PPT Presentation

Assessing the Performance of Multi- Layer Path Computation Algorithms for different PCE Architectures, Anaheim, 2013, March 20 th , S. Martinez, V. López, M. Chamania, Ó. González de Dios, A. Jukan and J. P. Fernández-Palacios 0 Telefónica Servicios Audiovisuales S.A. / Telefónica España S.A. TELEFÓNICA I+D Título de la ponencia / Otros datos de interés / 26-01-2010 Telefónica I+D 0

Assessing the Performance of Multi- Layer Path Computation Algorithms for different PCE Architectures, S. Martinez, V. López, M. Chamania, Ó. González de Dios, A. Jukan and J. P. Fernández-Palacios Anaheim, 2013, March 20 th 1 Telefónica Servicios Audiovisuales S.A. / Telefónica España S.A. TELEFÓNICA I+D Título de la ponencia / Otros datos de interés / 26-01-2010 Telefónica I+D 1

Index 01 Introduction 02 Implemented ML Algorithms 03 Results 04 Conclusions and Next Steps Telefónica I+D 2

01 Introduction Telefónica I+D Telefónica I+D 3

Introduction § A typical core network is based on an IP/MPLS network designed over a transport network (e.g. Wavelength-Switched Optical Network). § Multi-layer interworking is considered to increase efficiency. § Joint computation (IP/MPLS+WSON) is key. § Path Computation Element: standard approach to solve the computation § Two PCE-based schemes proposed to compute multi-layer paths: • Coordinated (multiple) PCEs solution: each layer has its own PCE. • Integrated(single) multi-layer PCE where a unique PCE has the complete multi-layer topology information. § We have implemented PCE-based schemes and several algorithms. § Performance is assessed in terms of blocking and computation delay Telefónica I+D 4

Cooperating PCEs scheme Telefónica I+D 5

Multilayer PCE scheme § Single multilayer graph to compute all the requests. Telefónica I+D 6

Multi-layer Paths § ERO: Standard representation of a path. § Multi-layer Path includes path in upper layer and paths in lower layer § Multi-layer ERO: standard RSVP ERO subobjects and use the SERVER_LAYER_INFO sub-object to indicate a layer change. § Virtual Network Topology Manager (VNTM) takes care of the establishment of lower layer paths § ERO inside a TE-Link Suggestion message is sent to VNTM. Telefónica I+D 7

Emulated Setup § Multi-layer PCE emulates the 2 modes (integrated and cooperation). § Cooperation between PCEs demonstrated in Chamania et al . ICC 2012. Telefónica I+D 8

Message Exchange VNTM NMS ¡(Client ¡PCC) ML-­‑PCE The ¡NMS ¡starts ¡the ¡PCEP ¡ N E P O session ¡with ¡the ¡ML-­‑PCE O P E N e v i l a p e e K K e e p a l i v e The ¡NMS ¡Sends ¡a ¡ R e q u e s t ¡ request ¡to ¡the ¡ML-­‑PCE ( B W ) ERO ¡ e ¡ s n o p computation ¡ s The ¡NMS ¡detects ¡that ¡it ¡is ¡a ¡ e R A ) O R time ¡(ms) E -­‑ L ML-­‑Response ¡and ¡suggest ¡the ¡ M ( links ¡to ¡the ¡VNTM N O I T S E G G U ) S d _ e K d N u I l L c _ n E ¡ i T O R E -­‑ L M ( LSP ¡ A establishment ¡ time ¡(ms) TE_LINK_CONFIRMATION OSPF ¡Link ¡Notification (ML ¡ERO ¡included) (Update ¡Optical ¡TEDB/Graph) OSPF ¡Link ¡Notification (Update ¡Optical ¡TEDB/graph) Telefónica I+D 9

02 Implemented ML Algorithms Telefónica I+D Telefónica I+D 10

Implemented Algorithms: Two TEDBs Architecture § Multi-layer path computation for a request in the client network can be reduced to a combination of one or more of four different operations: • Operation 1: Route the traffic onto an existing light-path directly connecting the source and the destination . • Operation 2: Route the traffic through multiple existing light-paths. • Operation 3: Set up a new light-path directly between the source and the destination and route the traffic onto this light-path. • Operation 4: Set up one or more light-paths that do not directly connect the source and the destination , and route the traffic onto these light-paths and/ or some existing light-paths. H. Zhu, et al , “A novel generic graph model for traffic grooming in heterogeneous WDM mesh networks,” IEEE/ACM Trans. , 2003. Telefónica I+D 11

Implemented Algorithms : Two TEDBs Architecture § The combination of the four operations leads us to the following algorithms for multilayer routing: • Minimizing the Number of Traffic Hops (MinTH) . • Minimizing the Number of Light-paths (MinLP) . • Minimizing the Number of Wavelength-Links (MinWL). Telefónica I+D 12

Algorithms Implemented: One TEDBs Architecture § Multilayer auxiliary graph § Different weights to the edges in order to reach the different grooming policies by applying K-shortest-paths to this graph. Telefónica I+D 13

03 Results Telefónica I+D Telefónica I+D 14

Validation scenario § Telefonica core Network Scenario: • Client Layer: MPLS (PSC). • Transport Layer: Optical/Lambdas (LSC). § 80 lambdas/fiber. § Bandwidth requests: § 1-10 Gbps at MPLS layer. § Sequential requests. § Random order. Telefónica I+D 15

Evaluation of ML algorithms 962 ¡con. 1101 ¡con. 889 con. 1362 ¡con. Telefónica I+D 16

Evaluation of ML algorithms (II) § MinTH policy can improve total capacity allocation by 13.91% when using a single PCE as compared to multiple PCEs while the increase in the MinLP policy is 9,97%. Telefónica I+D 17

Computation time Evaluation § Mean Computation time on Single ML PCE: • 54.32 ms MinLP, 53.57 ms MinTH § Multiple PCE solution: • 29.15 ms MinLP, 27.19 ms MinTH • Additionally, delay between PCEs per each query (0 in this setup) § Multi-layer PCE solution computation time bigger due to size of graph. • the PCE is running KSP in a large graph with N+1 layers (81 in this case). • KSP complexity increases linearly with number of arcs and nodes the computation time for this algorithm is much higher than in the case of § Multiple PCE • Each PCEs runs their own KSP+First Fit. Telefónica I+D 18

Number of operations Number Operations 2 TEDB Number Operations 1 TEDB 1400 1400 # Operation 1 # Operation 1 # Operation 2 1200 1200 # Operation 2 # Operation 3 # Operation 3 # Operation 4 1000 1000 # Operation 4 800 800 600 600 400 400 200 200 0 0 MinTH MinLP MinWL MinTH MinLP MinWL § In two TEDB case, interactions between PCEs is limited to one. Telefónica I+D 19

05 Conclusions and Next Steps Telefónica I+D Telefónica I+D 20

Conclusions § Multi-layer coordination is becoming an important requirement in network operators, due to its potential to reduce carrier’s investments, network interventions and thus cost of operations. § Multi-layer PCE is a key technology for multi-layer coordination and interworking. § This work shows the performance achieved with full topological information or with partial information. § Results show that integrated TED PCE can increase 13,91% bandwidth utilization in Spanish topology, but its computational time increases 49,24% in comparison with two coordinated TEDs per layer. Telefónica I+D 21

Algorithms Evaluation § Use of resources in the network for the different algorithms in a non blocking static scenario (results for 400 requests): Resource use 1 TEDB Resource use 2 TEDB 1400 1400 # LP # LP # WL # WL 1200 1200 # Hops x 100 # Hops x 100 1000 1000 800 800 600 600 400 400 200 200 0 0 MinLP MinTH MinWL MinLP MinTH MinWL Telefónica I+D 22