Network Working Group Y. Cheng Internet-Draft China Unicom Intended status: Informational JF. Tremblay Expires: August 10, 2015 Viagenie J. Bi Tsinghua University February 6, 2015 Use Case for Distributed Data Center in SUPA draft-cheng-supa-ddc-use-cases-05 Abstract Large scale DCs can provide various services and usually have a lot of internal and external links, and these links are usually VPNs. The Service provisioning and network connectivity configurations are complex and sometimes dynamic, for which manual configuration is not suitable. This draft analyzes the use case in Distributed Data Centers (DDC), in which some VPN scenarios are covered, and the applicability of SUPA data models which can be used for better resource usage and easy service/network configuration. 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 August 10, 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 Cheng, et al. Expires August 10, 2015 [Page 1] Internet-Draft Use cases for DDC Applications in SUPA February 2015 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 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 3 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Challenges Faced by Data Center ISPs . . . . . . . . . . . . . 4 5. SUPA Benefits . . . . . . . . . . . . . . . . . . . . . . . . 4 6. Scenarios . . . . . . . . . . . . . . . . . . . . . . . . . . 5 6.1. Scenario - Inter DC Connectivity . . . . . . . . . . . . . 6 6.2. Scenario - vDC Connectivity . . . . . . . . . . . . . . . 7 6.3. Scenario - Dynamic Link Configuration for DC . . . . . . . 8 6.4. Scenario - VPC to DC Connectivity . . . . . . . . . . . . 8 7. Security Considerations . . . . . . . . . . . . . . . . . . . 9 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 9 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10 10.1. Normative References . . . . . . . . . . . . . . . . . . . 10 10.2. informative References . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10 Cheng, et al. Expires August 10, 2015 [Page 2] Internet-Draft Use cases for DDC Applications in SUPA February 2015 1. Introduction The SUPA (Simplified Use of Policy Abstractions) work aims at providing data models, including topology data models, network service specific data models, policy data models, to easily, accurately, and efficiently select and use the available communication network capabilities. An example of the data model can be found in [I-D.zaalouk-supa-configuration-model]. Service Management (SM) is used by an a communications service provider and/or operator to deploy and manage a communication network. An example of SM is a set of applications used by an Operational Support System (OSS) entity to perform network configuration. Several SUPA use cases have been introduced in the problem statement document. This document reviews various scenarios for Distributed Data Center (DDC) use case. Take a large-scale Internet Data Center (IDC) operator as an example, it provides server hosting, leased line, value-added services to enterprises and ISPs, and has more than 10 data centers using over one Tbps of bandwidth in a capital city. In this IDC network, traffic at each site is routed via configuring policy routes and adjusting routes prioritization to choose an outgoing link. This type of static provisioning comes with high costs and poor operability. Furthermore, the link bandwidth resources in the data centers are not efficiently utilized. In quite some of the scenarios, the links between DCs are VPNs, including L2VPN, L3VPN, etc. SUPA will be mainly used for those VPN configurations. Althouth there may be some cases where physical links are used, but those are out of the scope of this draft. DC and network may belong to different operators. If a DC operator needs to configure network connecivity for DCs, they may need to coperate with network oprators. Network operators can define and provide data models to enable this. This document illustrates several distributed datacenter (DDC) applications and explains how an operator could use SUPA to provide these applications. 2. Requirements Language 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]. Cheng, et al. Expires August 10, 2015 [Page 3] Internet-Draft Use cases for DDC Applications in SUPA February 2015 3. Terminology The terminology used in the SUPA problem statement draft [I-D.zhou-supa-framework] and [I-D.karagiannis-supa-problem-statement] apply also to this draft. DDC Distributed Data Center IDC Internet Data Center NM/NC Network Manager / Controller SM Service Management vDC virtual Data Center VPC Virtual Private Cloud (PC) 4. Challenges Faced by Data Center ISPs There are many challenges in traditional data centers: 1) infrastructure and network link is usually leased, depending on manual planning and design, which leads to low resource usage and high cost; 2) Service expansion is limited in a single physical DC. Each DC resource is isolated, so service and resource can only be deployed in one single DC; 3) VAS (Value Added Service) is provisioned via static configuration, which brings complex training, long service TTM time and poor flexibility. This could not meet the requirements of complex use cases, e.g., lot of VAS devices, significant differences between various services. 5. SUPA Benefits To solve the above challenges for data center ISPs, SUPA could be applied in the following ways: o SUPA supports an open network architecture: Open architecture, unified architecture and unified planning, fast interconnection with third party cloud platform, support fast service innovation. o SUPA supports overall DC resource integration: Network resource virtualization, inter-DC resource integration, virtual DC (vDC) service provisioning, unified inter-DC service, which reduces OPEX. Cheng, et al. Expires August 10, 2015 [Page 4] Internet-Draft Use cases for DDC Applications in SUPA February 2015 o SUPA supports automatic E2E service delivery: Network (including virtual network), computing, inter-DC management of storage resource, automatic service delivery, which improves operation efficiency. o SUPA contributes to improve DDC network usage: Intelligent scheduling of DDC traffic, improving link usage. o SUPA supports VAS service on-demand provisioning automatically: Create or delete VAS nodes on-demand, based on various service requirements; network forwarding policy based on the VAS routing, to achieve automatic draining and automatic configuration of VAS device policy. The following sections will illustrate three typical cases in distributed data center which could benefit from SUPA architecture. 6. Scenarios Cheng, et al. Expires August 10, 2015 [Page 5] Internet-Draft Use cases for DDC Applications in SUPA February 2015 6.1. Scenario - Inter DC Connectivity +--------------------------+ | Service Management | +--------------------------+ ^ | Inter DC connectivity | and policy | data models v +--------------------------+ | Network | | Manager / Controller | +--------------------------+ / \ / \ +---------+ \ /| DC1 |\ \ / +---------+ \ +-----------+ | | d1 \___a1________| DC-A | | | | | | +---------+ +-----------+ d3 | | DC2 |\ | +---------+ \ +-----------+ | | d2 \___a2________| DC-B | | | ____a3________| | \ +---------+ / +-----------+ \| DC3 |/ +---------+ Figure 1: Scenario - Inter DC Connectivity There can be a lot of links between data centers. Configuration of these links is complex. As shown in Figure 1, connectivity data models and policy data models can be defined to automate the configuration procedures. The service data model for connectivity will specify attributes of links, e.g. the end points of links, bandwidth and QoS, etc. The policy model can specify some high level requirements to the links, like routing strategy and price/cost stragety. Inter DC connections can be classified into to types: connections within a single administrative domain and connections across multiple administrative domains. Links d1, d2 and d3 are within an administrative domain; and links a1, a2 and 3 are across domains. The difference between them is, connections across multiple administrative domain require extra negotiation and authentication/ Cheng, et al. Expires August 10, 2015 [Page 6] Internet-Draft Use cases for DDC Applications in SUPA February 2015 authorization, which can be achieved via communications between MAs. Data models for this purpose should also be defined. 6.2. Scenario - vDC Connectivity +--------------------------+ | Service Management | +--------------------------+ ^ | vDC connectivity | and policy | data models v +--------------------------+ | Network | | Manager / Controller | +--------------------------+ / \ / \ / \ +-------------------+ +-------------------+ | DC1 | | DC2 | | +---------------+ | vDC link | +---------------+ | | | Tenant1 (vDC) |<----------------->| Tenant1 (vDC) | | | +---------------+ | | +---------------+ | | | | | | +---------------+ | | +---------------+ | | | Tenantk (VDC) | | | | Tenantn (vDC) | | | +---------------+ | | +---------------+ | +-------------------+ +-------------------+ Figure 2: Scenario - vDC Connectivity A DC tenant may have resources, e.g. network, computing, storage, etc, in multiple physical DCs. DC operators will provide internal network connections for these distributed resources, and make it look like one seamless entity, which can be called as virtual DC (vDC). The internal links for vDC can be implemented via tunneling technologies, e.g. VPN or VxLAN, etc. As show in Figure 2, connectivity data model and policy can be defined to automate the links configuration for vDCs. A policy model may contain information like user's grade which will be use to derive service level parameters, including bandwidth, QoS, etc. The connectivity data model may provide the information about the resource location for tunnel setup. Cheng, et al. Expires August 10, 2015 [Page 7] Internet-Draft Use cases for DDC Applications in SUPA February 2015 6.3. Scenario - Dynamic Link Configuration for DC Static and over provisioning for DC links is not always a good solution. Sometimes dynamic configuration is necessary. One case is virtual machine migration and large amount of data transfer between DCs. But this kind of activity does not happen frequently. A dedicated link with constant bandwidth for this purpose is too expensive. The network operator should allow the DC operator to create a link on demand when necessary. This link may have large bandwidth but last for a limit time period. An alternative is to have a static link but with limited bandwidth; and the bandwidth can be increased on demand for a short period. Data models can help to automate these kind of configurations. These data models will help DC operators to add and remove links, change the attributes of links. 6.4. Scenario - VPC to DC Connectivity +--------------------------+ | Service Management | +--------------------------+ ^ | VPC to DC connectivity | and policy | data models v +--------------------------+ | Network | | Manager / Controller |______________ +--------------------------+ \ / \ \ / \ \ / \ | +-------------------+ +-------------------+ | | Cloud for VPCs | | | | | +---------------+ | VPC link | DC1 (Database) | | | | VPC1 |-----------------| | | | +---------------+ \ +-------------------+ | | +---------------+ |\ | | | VPC2 | | \ | | +---------------+ | \ +-------------------+ | | +---------------+ | \ VPC link | | / | | ...... | | \__________| DC2 (Storage) |/ | +---------------+ | | | +-------------------+ +-------------------+ Cheng, et al. Expires August 10, 2015 [Page 8] Internet-Draft Use cases for DDC Applications in SUPA February 2015 Figure 3: Scenario - VPC to DC Connectivity As virtualization technology becomes more and more popular, some organizations and companies now begin to use cloud platform to support their computer desktop, rather than using physical personal computers and workstations. The kind of cloud platform can be a commercial solution, e.g. Amazon's cloud platform. VPCs at cloud service providers' DC may keep on running for a long time even if no user is actually accessing it; but the cloud platform may bring VPCs into power saving mode when there is little or no load in it. The organizations and companies, e.g. a university, sometimes provide some internal services like database which is only available to the VPC but not available to users in the public network. These kind of services can be located in an cloud operator's DC. The VPC and the internal services sometimes are located in different DCs, or even provided by different vendors. VPNs are configured for the VPCs to provide connection to the DCs where services are hosted. As shown in Figure 3, connectivity data models and policy data models can be defined to automate the configurations of links between VPC and DC where service is located. In the data models, the location where internal service is located should be specified; a user/VPC's access rights can also be specified. 7. Security Considerations Security is a key aspect of any protocol that allows state installation and extracting of detailed configuration states. More investigation remains to fully define the security requirements, such as authorization and authentication levels. 8. IANA Considerations Not applicable. 9. Acknowledgements The authors of this draft would like to thank the following persons for the provided valuable feedback: Cathy Zhou, Georgios Karagiannis, Scott O. Bradner, James Huang. 10. References Cheng, et al. Expires August 10, 2015 [Page 9] Internet-Draft Use cases for DDC Applications in SUPA February 2015 10.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 10.2. informative References [I-D.karagiannis-supa-problem-statement] Karagiannis, G., Will, W., Tsou, T., Qiong, Q., Contreras, L., and P. Yegani, "Problem Statement for Shared Unified Policy Automation (SUPA)", draft-karagiannis-supa-problem-statement-02 (work in progress), October 2014. [I-D.zaalouk-supa-configuration-model] Zaalouk, A., Pentikousis, K., and W. Will, "YANG Data Model for Configuration of Shared Unified Policy Automation (SUPA)", draft-zaalouk-supa-configuration-model-01 (work in progress), October 2014. [I-D.zhou-supa-framework] Zhou, C., Contreras, L., Qiong, Q., and P. Yegani, "The Framework of Shared Unified Policy Automation (SUPA)", draft-zhou-supa-framework-00 (work in progress), January 2015. Authors' Addresses Ying Cheng China Unicom P.R. China Email: chengying10@chinaunicom.cn JF Tremblay Viagenie Email: jean-francois.tremblay@viagenie.ca Cheng, et al. Expires August 10, 2015 [Page 10] Internet-Draft Use cases for DDC Applications in SUPA February 2015 Jun Bi Tsinghua University Bei Jing China Email: junbi@cernet.edu.cn Cheng, et al. Expires August 10, 2015 [Page 11]