Cross Stratum Optimization Research Group H. Yang Internet-Draft YL. Zhao Intended status: Informational J. Zhang Expires: May 12, 2016 Beijing University of Posts and Telecommunications Y. Lee Y. Lin FT. Zhang Huawei Technologies Co., Ltd. November 9, 2015 Cross Stratum Optimization Architecture for Optical as a Service draft-yangh-cso-oaas-09 Abstract Data centers based applications provide a wide variety of services such as cloud computing, video gaming, grid application and others. Currently application decisions are made with little information concerning underlying network used to deliver those services so that such decisions cannot be the most optimal from both network and application resource utilization and quality of service objectives. This document presents a novel architecture of Cross Stratum Optimization for application and network resource in dynamic optical networks. Several global load balancing strategies are proposed and demonstrated by experiments in Optical as a Service experimental environment. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on May 12, 2016. Yang, et al. Expires May 12, 2016 [Page 1] Internet-Draft CSO Architecture for OaaS November 2015 Copyright Notice Copyright (c) 2015 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Conventions Used in This Document . . . . . . . . . . . . 3 2. Terminologies . . . . . . . . . . . . . . . . . . . . . . . . 3 3. CSO Functional Architecture for OaaS . . . . . . . . . . . . 5 3.1. AC . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.2. SC . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 4. Advantage of CSO Architecture for OaaS . . . . . . . . . . . 8 5. CSO Procedure in CSO Architecture for OaaS . . . . . . . . . 8 6. Different Application Scenarios . . . . . . . . . . . . . . . 9 6.1. Network Resource Acquirement . . . . . . . . . . . . . . 9 6.2. Virtual Migration Request . . . . . . . . . . . . . . . . 9 6.3. Exception Handling . . . . . . . . . . . . . . . . . . . 10 7. Definition of New Interfaces in CSO Architecture for OaaS . . 10 7.1. Functional Requirement for UAI . . . . . . . . . . . . . 10 7.2. Functional Requirement for ASI . . . . . . . . . . . . . 10 7.3. Functional Requirement for SCI . . . . . . . . . . . . . 11 7.4. Functional Requirement for SMI . . . . . . . . . . . . . 11 8. CSO Strategies and Algorithms . . . . . . . . . . . . . . . . 11 9. CSO Experiment and Demonstration . . . . . . . . . . . . . . 13 9.1. CSO Experimental Environment . . . . . . . . . . . . . . 13 9.2. CSO Experimental Results . . . . . . . . . . . . . . . . 13 10. Security Considerations . . . . . . . . . . . . . . . . . . . 15 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15 12. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 12.1. Normative References . . . . . . . . . . . . . . . . . . 15 12.2. Informative References . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 Yang, et al. Expires May 12, 2016 [Page 2] Internet-Draft CSO Architecture for OaaS November 2015 1. Introduction With the emergence of cloud computing and high-bandwidth video applications such as live concerts, sporting events and remote medical surgery, various data center applications become more and more important, some Quality of Service related parameters of which have attracted much attention, such as jitter and latency. Therefore, there is a great need for a joint scheduling of network and application resources, the latter of which mainly refers to computing and storage resource, such as servers of various types and granularities (memory, disk, VMs). Many studies have been focused on traffic awareness in application resource [1], especially cross layer optimization in optical network [2]. However, few of them have been involved in global combined optimization of network and application resources. This document proposes a novel architecture based on Cross Stratum Optimization (CSO) [3] that enables a joint application/network resource optimization, responsiveness to quickly change demands from/ to application to/from network, enhanced service resilience (via cooperative recovery techniques between application and network) and quality of application experience (QoE) enhancement (via better use of current network and application resources). This architecture is intended to enable Optical as a Service (OaaS) by enabling large- bandwidth and multi-granularities applications based on Adaptive Multi-service Optical Networks (AMSON) with an increased resource utilization and resiliency across the application and network stratums. Four strategies including global load balancing (GLB), random based (RB), application resource based (AB) and network resource based (NB) strategies are proposed and validated in our experimental environment. Experimental results show that GLB in CSO architecture performs more effective compared with others. 1.1. Conventions Used in This Document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. 2. Terminologies AB: Application resource Based. AC: Application Controller. AMSON: Adaptive Multi-service Optical Networks. ARAE: Application Resource Abstract Engine. Yang, et al. Expires May 12, 2016 [Page 3] Internet-Draft CSO Architecture for OaaS November 2015 ASI: Application-Service Interface. CSO: Cross Stratum Optimization. DB: Data Base. DBM: Data Base Management. DCN: Data Center Network. GLB: Global Load Balancing. GMPLS: General Multi-Protocol Label Switching. LSA: Link State Advertisement. MIB: Management Information Base. NB: Network resource Based. NRAA: Network Resource Abstraction Algorithm. NRAE: Network Resource Abstract Engine. NRDB: Network Resource Database. NMS: Network Management System. OaaS: Optical as a Service. OAM: Operation Administration and Maintenance. OSPF: Open Shortest Path First. PA: Protocol Agent. PCE: Path Computation Element. QoE: Quality of Experience. RB: Random Based. SA: Service Agent. SA-PCE: Service-Aware PCE enhancement algorithm. SC: Service Controller. Yang, et al. Expires May 12, 2016 [Page 4] Internet-Draft CSO Architecture for OaaS November 2015 SCI: Service-Control plane Interface. SMI: Service-Management Plane Interface. SSE: Server/VM Selection Engine. TED: Traffic Engineering Database. UA: User Agent. UAI: User-Application Interface. VM: Virtual Machine. 3. CSO Functional Architecture for OaaS The CSO functional architecture for OaaS is illustrated in Fig. 1 and Fig. 2. Yang, et al. Expires May 12, 2016 [Page 5] Internet-Draft CSO Architecture for OaaS November 2015 ------------------------------------- ---------- | ------- | | | | | SSE |\ | | | | / ------- \ ------ | | | | / | | DB | | ------------ | | | / | ------ |--| User Plane |--| | | / | / | ------------ | | | ------ / -------- / | | | | | UA |-----| ARAE | AC |------------------| | | ------ -------- | | | -----|------------------------------- | | | | | | | | -----|------------------ ------------------------- |Management| | ------ ------ | | ----------- | | Plane | || | | |--|--|--| Signaling | |--| | || SA |------| PA | | | ----------- | | | || |\ | |--|--|-- --------- | | | | ------ \ ------ | | | OSPF-TE | | | | | | \ | | | ---------Control Plane| | | | | \ | | ------------------------- | | | | \ | | | | | | -------- \ ------- | ------------------ | | | || NRAE |----| PCE |-|--| Other domain SCs | | | | | -------- ------- | ------------------ | | | | \ | | ----------------------- | | | \ | | | Transport Plane |----| | | \ ------- | ----------------------- | | | SC \| DBM |-|-------------------------------| | | ------- | | | ------------------------ ---------- Fig.1 CSO functional architecture for OaaS Yang, et al. Expires May 12, 2016 [Page 6] Internet-Draft CSO Architecture for OaaS November 2015 ------------------------------------------------------- | -------- ------------ --------- | | | DCNs |------| AC |-------| Users | | | -------- / ------------ \ --------- | | / | \ Application Stratum | |---------------/--------|---------\--------------------| | / | \ Network Stratum | | ------ ------ ------ | | | SC | | SC | | SC | | | ------ ------ ------ | | | | | | | | | | | | ------------ ------------ ------------ | | | | | | | | | | | domain A |--| domain B |--| domain C | | | | | | | | | | | ------------ ------------ ------------ | ------------------------------------------------------- Fig.2 CSO schematic for OaaS The application stratum plane, service stratum plane and user plane are introduced in the novel architecture of CSO besides traditional planes, i.e., control plane, management plane and transport plane. The responsibility for centralized application stratum plane is concerned with maintaining application resources in data centers, while service stratum plane provides to application stratum the network resource information abstracted from control plane with NRAA. In addition, GLB computation is implemented based on both the application stratum and network stratum resources, while service stratum will enforce SA-PCE. The responsibilities and interactions among these entities are provided below. 3.1. AC AC comprises UA, SSE, DB and ARAE. AC is responsible for interacting with user plane and obtaining network and application resource abstract information abstracted from SCs and DCNs. AC completes the GLB computation based on them. UA authenticates the user requests and maintains user information. With GLB computation, SSE chooses the optimal server or VM for users, allocates application resources, and determines the location of the distributed application or where to migrate virtual machines. ARAE provides to GLB computation the suited application resource abstract information obtained from DCNs, such as running state and idle resource of servers or VMs. Yang, et al. Expires May 12, 2016 [Page 7] Internet-Draft CSO Architecture for OaaS November 2015 3.2. SC SC is composed of SA, PA, PCE, NRAE and DBM. Three main functional requirements for SC in OaaS architecture are described below. Firstly, SC provides network services to AC. According to the type of services, SC computes the paths and drives control plane to establish the paths so as to implement the concept of OaaS. Secondly, SC offers to AC the resources abstract information including the mapping of application and optical layer, logical topology of optical layer and the status of network transmission for AC decision. Finally, it provides to management plane the database interface so that network administrator can monitor it. SA communicates to AC with authentication and access control permission of transport network resources through ASI. SA also translates AC profile into connection and service parameters in transport network which contains bandwidth, delay, jitter and others. PA drives the GMPLS signaling of control plane and receives the routing information. PCE enforce SA-PCE while NRAE abstracted from control plane with NRAA. In addition, TED, NRDB, MIB and configuration are contained in DBM. 4. Advantage of CSO Architecture for OaaS CSO Architecture for OaaS is the spread of traditional three planes, i.e., control plane, management plane and transport plane. The decisions based on CSO architecture for OaaS can be the most optimal and have the least cost from both application and network resource utilization, while the quality of user experience can reach the highest in this architecture. According to various demands and expenses of different server providers, the operator can provide to them abstract topologies with NRAA so that this mechanism guarantees the security between operator and server provider or among server providers. Since the CSO architecture for OaaS is based on new strategies and algorithms, the spread of current network may be just software promotional and the architecture is provided with the higher expansibility and flexibility. 5. CSO Procedure in CSO Architecture for OaaS When the UA in AC receives the application request from user plane, it will forward this request to SSE after authenticating the user requests. The certified request is analyzed via SSE and transmitted to ARAE for the application resource information. SSE receives the network abstract information from SC via AC gateway upon request. ARAE responds to SSE the suited application resource abstract information obtained from DCNs, according to the analysis result from it. Upon completing the GLB computation based on application and Yang, et al. Expires May 12, 2016 [Page 8] Internet-Draft CSO Architecture for OaaS November 2015 network abstract resource, and SSE chooses the most optimal server or VM for users, allocates application resources, and determines the location of the distributed application or where to migrate virtual machines. According to service type, resources occupancy rate and QoE, UA performs accounting function and transmits the application requirements to SC via ASI. UA receives the responses to NRAE and returns to UA. Rating the service based on the distribution of resources and returning the feedback, UA provides to user stratum the resources at last. When SA receives the location of the server/VM and the service type, it will translate this profile into connection and service parameters in transport network which contains bandwidth, delay, jitter and others after authentication and access control permission to this requirement. SA also forwards the network resource profile to PCE at the same time. Completing SA-PCE computation that factors in the connection and service parameters constraints, SA-PCE provides the explicit route to PA. Then using the RSVP signaling protocol, PA drives control plane to establish the path through SCI. After the path is setup successfully, it will conserve the information of the path into DBM and return overall results including transport network resource to AC. After receiving the OSPF LSA from control plane, PA provides it to DBM for network resources synchronization. AC obtains application and network information periodically or based on event-based trigger. Meanwhile, NRAE interacts with network TE topology information base and DBM for abstracting network resource. NRAE provides abstract information to the authorized AC using NRAA. 6. Different Application Scenarios 6.1. Network Resource Acquirement SCs receive the OSPF LSA from control plane to obtain the completely TE topology information network and provide it to DBM for network resources synchronization. AC obtains application and network information periodically or based on event-based trigger. Based on NRAA, SCs computes the abstract topology and feedback to AC. 6.2. Virtual Migration Request Due to the insufficiency of network or servers/VMs resource, or the abrupt emergency to servers or network, or the requirement of saving energy consumption, Virtual migration request becomes significant in reality application. Virtual migration migrates to the destination server with multi-granularities and the choice of destination one follows the procedure of CSO in OaaS architecture. Yang, et al. Expires May 12, 2016 [Page 9] Internet-Draft CSO Architecture for OaaS November 2015 6.3. Exception Handling When unexpected error happens in the process of CSO, SC will receive GMPLS OAM from control plane and provide the alarm information to AC and saves into DBM. SC needs to route again as the service delivery process. 7. Definition of New Interfaces in CSO Architecture for OaaS Due to additional planes in OaaS architecture, new interfaces between themselves, which contain ASI, UAI, and which between them and traditional planes in GMPLS containing SCI, SMI is to be defined in this section. Nevertheless, only functional requirement will be demonstrated for each of above-mentioned interfaces, by which service of OaaS and Cross Stratum Optimization could work well. 7.1. Functional Requirement for UAI UAI is the interface between user plane and application plane, which conveys the user's application request from user plane to application plane and the reply information. Such user denotes the general users who apply for the application, not only includes the particular clients asking for video service, but also revolves the service provider managing the application resource such as virtual migration. In other words, managers of the service provider access the application Plane by the same interface, even if the permission will differ common users. Whatever kinds of application request is submitted, UAI should transmit the request information transparently, which consists of the user identity, request type, specified information. 7.2. Functional Requirement for ASI ASI is the interface between service plane and application plane, which conveys the request for optical service of all application, containing path establishment request and network resource abstract request. The latter is foundation to CSO, because the replied abstract information will be referred to for application plane to make a judgment, such as selecting a proper datacenter for a user or to which migrating virtual machines. Therefore, the interface from SC to AC should convey the whole abstraction information, which is abstracted and packed by abstracting module in SC, as well as optical service reply. As to the common request for optical service, the request information must include the service style, such as VOD and virtual migration, and the source and destination node in optical layer of this service. Yang, et al. Expires May 12, 2016 [Page 10] Internet-Draft CSO Architecture for OaaS November 2015 The reply of which also contains the path establishment result and if it is failure, the reason should be given. 7.3. Functional Requirement for SCI SCI is the interface between service plane and control plane. The message transmitted through this interface is standard GMPLS including OSPF and RSVP messages, which is easily compatible to GMPLS control plane. 7.4. Functional Requirement for SMI SMI is the interface between service plane and management plane. The database of the network information maintained by SC, could supply some detailed network operating condition for management plane to make decision, and management plane also can issue OAM commands to SC. Both state information and OAM message will be defined by SMI. 8. CSO Strategies and Algorithms Based on functional architecture of CSO-OaaS described above, we propose four strategies including GLB strategy based on CSO, RB, AB and NB strategies. These strategies and related algorithms are described in detail below. With RB strategy, the destination node of data center server is randomly selected by control plane when the application request comes. With AB strategy, according to the CPU, memory, disk utilization and I/O scheduling, control plane chooses the server node having the minimum application utilization as the destination. NB strategy selects the node which has the path of the minimum network hop from the source to the destination. With GLB strategy, as described in previous sections, AC selects the server node and the DC location based on the application status collected from data center networks and the network condition provided by SCs dynamically. We define alpha as the joint optimization factor to measure the balance between the network and application resources, which contains the application and network parameters. Three application parameters, current memory utilization Ur which models RAM, CPU usage Uc and the utilization of I/O scheduling Us describe the current usage of data center application resource. The network parameters are comprised of the TE weight Bl and delay tl which is related to traffic cost and delay of the current link and the hop Hp of the candidate path. These parameters are normalized to meet the linear relationship between them. The application function with application parameters of current each node is expressed as dimensionless overall function fac(Ur,Uc,Us,k) = kc*Uc+kr*Ur+ks*Us, kc+kr+ks=1, kc>=0, Yang, et al. Expires May 12, 2016 [Page 11] Internet-Draft CSO Architecture for OaaS November 2015 kr>=0, ks>=0, where kc,kr,ks are adjustable evaluation rank rate among CPU, RAM utilization and I/O scheduling. Initially, the evaluation rank of CPU is the highest of all, while the rank of RAM is higher than I/O scheduling. At this point, evaluation ranks satisfy the expressions as follows: kc=Ra, kr=Rb, ks=Rc, Ra+Rb+Rc=1, Ra>=Rb>=Rc, where Ra,Rb,Rc are constants and their priorities decrease increasingly. That means the higher utilization corresponds to higher priority. Once Ur or Us exceeds Uc, for instance Ur>=Uc>=Us, the evaluation rank of them will adjust according to this change as follows: kc=Rb, kr=Ra, ks=Rc. By parity of reasoning, kc,kr,ks will modify dynamically based on the feedback of utilization variation. In addition, network function with parameters of current each node is expressed as dimensionless overall function fbc(Bl,Hp,tl) = kB*(B1+B2+...+Bl+...+BHp)/B*Hp+kt*(t1+t2+...+tl+...+tHp)/t*Hp, which the candidate path is calculated by the network stratum resources with candidate server destination nodes chosen by AC. fa1, fa2,...,fak are the application functions with parameters among the K candidate server nodes and fb1, fb2,...,fbk are the network functions with parameters associated with the K candidate paths. So the joint optimization factor alpha meets the formula as follows. In this formula, beta is the dynamic weight between the network and application parameter, which associates with the variance of application parameters from each server node. The variance is related to DC load balancing degree, while the larger variance represents balancing degree becomes worse in DCs. Based on the formula described below, the application utilization weight changes dynamically according to the feedback of load balancing degree. At first, the weight of application utilization is relatively smaller due to the lower application parameters variance. With the increasing of application parameters variance, the application utilization weight turns into higher, which miu is normalizing factor of beta. The formula is alpha = [fac(Ur,Uc,Us,k)/max(fa1,fa2,...,fak)]*beta + [fbc(Bl,Hp,tl)/max(fb1,fb2,...,fbk)]*(1-beta), beta = miu*sqrt{var(fa)/max[ var(fa1),var(fa2),...,var(fak)]}. According to application utilization, AC first chooses the K candidate server nodes in application stratum, which can provide this type of application. In network stratum, the node with minimum alpha value based on the joint optimization factor will be selected from the K candidates. In all schemes, the path will be reserved and setup through signalling protocol between the source and destination node after the choice of the node. Yang, et al. Expires May 12, 2016 [Page 12] Internet-Draft CSO Architecture for OaaS November 2015 9. CSO Experiment and Demonstration 9.1. CSO Experimental Environment Experimental environment is built to support the architecture of CSO and deployed in five servers, while each server mounts virtual machines created by VMware software running at servers. Since each virtual machine has the operation system and its own computation resource, the virtual OS technology makes it easy to set up experiment topology based upon NSFNET with 14 control plane nodes. In addition, Network Management System (NMS) is placed to monitor and initialize the transport plane elements, while NMS is an inseparable management system which manages the overall network.[4] The service application usage is selected randomly from 1% to 0.1% for each application demand and network bandwidth required for each application is assumed one wavelength equivalent. Each node supports 40 wavelengths with no wavelength conversion or 3R regeneration capability. 9.2. CSO Experimental Results Based on CSO functional architecture described above, GLB strategy based on the cross-stratum optimization is implemented and experimentally compared with RB, AB and NB strategies in CSO Experimental environment. The experimental results are shown in Tab. 1-4. Tab. 1 illustrates load balancing degree resulting from RB, AB, NB and GLB strategy. The load balancing degree is defined as the variance of application utilization in each data center server. The higher load balancing degree is, the worse the effect of load balancing is. As shown, GLB strategy leads to much lower load balancing degree than RB and NB strategy, but higher than AB strategy. In fact, AB strategy computes the node only considered application utilization, the path may not be able to setup because it does not have enough wavelength resource. In Tab. 2, GLB has less network blocking probability than RB and AB strategies. Tab. 3 shows that GLB approach has less average hop than RB and AB strategies obviously, for it factors the latency. With the increase of offered load, the curve of GLB scheme gets closer to NB. In Tab. 4, global blocking probability measures both the network and application blocking situation measured by CPU and memory overflow. Though AB approach has lower load balancing degree and similar average hop is computed through NB scheme, GLB strategy has significantly lower integrated blocking probability than all other approaches. Yang, et al. Expires May 12, 2016 [Page 13] Internet-Draft CSO Architecture for OaaS November 2015 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | Load balancing degree | | Traffic load +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | RB | AB | NB | GLB | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 100 |0.00594 |7.65E-5 |0.05639 |0.00333 | | 200 |0.00951 |7.77E-5 |0.10181 |0.00361 | | 300 |0.01286 |7.85E-5 |0.12019 |0.0036 | | 400 |0.01409 |7.49E-5 |0.12352 |0.00334 | | 500 |0.01198 |7.8E-5 |0.12043 |0.00303 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Tab.1 Load balance factor of four strategies +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | Network blocking probability | | Traffic load +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | RB | AB | NB | GLB | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 100 |0.00002 |6.5E-4 |7.6E-4 |5E-5 | | 200 |0.01902 |0.01866 |0.02152 |5.2E-4 | | 300 |0.08462 |0.09368 |0.05992 |0.03628 | | 400 |0.15036 |0.17944 |0.08968 |0.12418 | | 500 |0.19862 |0.25528 |0.10462 |0.18104 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Tab.2 Network blocking probability of four strategies +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | Average hop | | Traffic load +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | RB | AB | NB | GLB | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 100 |5.50661 |5.5058 |3.604 |4.2668 | | 200 |5.48937 |5.4813 |3.59706 |4.25557 | | 300 |5.42255 |5.40668 |3.56946 |4.23117 | | 400 |5.34908 |5.31895 |3.5374 |4.1668 | | 500 |5.28607 |5.21635 |3.50851 |4.0981 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Tab.3 Average hop of four strategies Yang, et al. Expires May 12, 2016 [Page 14] Internet-Draft CSO Architecture for OaaS November 2015 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | Global blocking probability | | Traffic load +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | RB | AB | NB | GLB | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 100 |2E-5 |6.5E-4 |0.00162 |5E-5 | | 200 |0.02902 |0.01866 |0.06412 |5.2E-4 | | 300 |0.0975 |0.09368 |0.1776 |0.03628 | | 400 |0.18458 |0.17944 |0.2843 |0.12864 | | 500 |0.27046 |0.25528 |0.36988 |0.19704 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Tab.4 Global blocking probability of four strategies 10. Security Considerations TBD 11. Acknowledgments The RFC text was produced using Marshall Rose's xml2rfc tool. 12. References 12.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFC's to Indicate Requirement Levels", RFC 2119, March 1997. 12.2. Informative References [Ref1] Meng, Xiaoqiao., Pappas, V., and Li. Zhang, "Improving the Scalability of Data Center Networks with Traffic-aware Virtual Machine Placement", May 2010. [Ref2] Christodoulopoulos, K., Manousakis, K., and E. Varvarigos, "Cross Layer Optimization of Static Lightpath Demands in Transparent WDM Optical Networks", July 2009. [Ref3] Lee, Young., Bernstein, Greg., So, Ning., Kim, Tae., Shiomoto, Kohei., and Oscar. Dios, "draft-lee-cross- stratum-optimization-datacenter-00", March 2011. [Ref4] Zhang, Jie., Chen, Xue., and Yuefeng. Ji, "Experimental Demonstration of a DREAM-based Optical Transport Network with 1000 Control Plane Nodes, ECOC2011", September 2011. Yang, et al. Expires May 12, 2016 [Page 15] Internet-Draft CSO Architecture for OaaS November 2015 Authors' Addresses Hui Yang Beijing University of Posts and Telecommunications No.10,Xitucheng Road,Haidian District Beijing 100876 P.R.China Phone: +8613466774108 Email: yang.hui.y@126.com URI: http://www.bupt.edu.cn/ Yongli Zhao Beijing University of Posts and Telecommunications No.10,Xitucheng Road,Haidian District Beijing 100876 P.R.China Phone: +8613811761857 Email: yonglizhao@bupt.edu.cn URI: http://www.bupt.edu.cn/ Jie Zhang Beijing University of Posts and Telecommunications No.10,Xitucheng Road,Haidian District Beijing 100876 P.R.China Phone: +8613911060930 Email: lgr24@bupt.edu.cn URI: http://www.bupt.edu.cn/ Young Lee Huawei Technologies Co., Ltd. Huawei Base,Bantian,Longgang District,Shenzhen Shenzhen 518129 P.R.China Email: leeyoung@huawei.com URI: http://www.huawei.com/ Yang, et al. Expires May 12, 2016 [Page 16] Internet-Draft CSO Architecture for OaaS November 2015 Yi Lin Huawei Technologies Co., Ltd. Huawei Base,Bantian,Longgang District,Shenzhen Shenzhen 518129 P.R.China Email: yi.lin@huawei.com URI: http://www.huawei.com/ Fatai Zhang Huawei Technologies Co., Ltd. Huawei Base,Bantian,Longgang District,Shenzhen Shenzhen 518129 P.R.China Email: zhangfatai@huawei.com URI: http://www.huawei.com/ Yang, et al. Expires May 12, 2016 [Page 17]