ALTO Working Group M. Chen Internet-Draft X. Wang Intended status: Standards Track Tongji University Expires: January 10, 2017 July 9, 2016 ALTO in Ethernet and Optical Converged Networks draft-chen-alto-ethernet-optical-converged-network-00 Abstract In conventional enterprise data centers, there are at least two networks: Ethernet that allows users to access their applications on servers, optical networks which built on Fiber Channel, that enables those servers to access big data on storage network. Because of their specialized hardware, they have vastly different management tools and require completely different skill sets to build and maintain. The Application-Layer Traffic Optimization (ALTO) protocol is designed to provide network related information to client applications. It has developed a lot in Ethernet, and now we consider to build a central control in a basic Ethernet and Optical converged networks. Follow the concept of ALTO implementing in Ethernet networks, an ALTO server can get the necessary information from underlining Ethernet and Optical converged networks. After abstracting the network information, ALTO server can achieve a central resource allocation and organize them into a standard format so as to provide useful information to ALTO clients. This document designs a basic way of applying ALTO in converged networks. 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 January 10, 2017. Chen & Wang Expires January 10, 2017 [Page 1] Internet-Draft ALTO Optical July 2016 Copyright Notice Copyright (c) 2016 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 . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.2. Requirements Language . . . . . . . . . . . . . . . . . . 3 1.3. Changes Since Version -00 . . . . . . . . . . . . . . . . 4 2. ALTO Architecture in Converged Networks . . . . . . . . . . . 4 3. Ethernet and Optical Converged Networks Model . . . . . . . . 5 4. Optical Resource Abstraction and Allocation . . . . . . . . . 5 4.1. Optical Resource Abstraction . . . . . . . . . . . . . . 5 4.2. Optical Resource Allocation . . . . . . . . . . . . . . . 6 5. ALTO Standardized Converged Networks Information Construction 8 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 7. Privacy And Security Considerations . . . . . . . . . . . . . 9 8. Normative References . . . . . . . . . . . . . . . . . . . . 9 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 1. Introduction Reliability and Effectiveness are key metrics of the network qualities. When facing multiple services, performance of networks varies a lot. It seems that just one network would be more cost- efficient. However, as a result of big data and cloud computing, optical networks play an important role in meeting high speed demand. Due to different mechanisms of packet and circuit networks' control, management and transport technology, a unified control of the two networks develops slowly. One highly scalable, high-performance network with consistent management tools handling both Ethernet and storage traffic is a promise of converged networking. The initialize of converged networks was because 1Gbps Ethernet couldn't handle the loads that enterprises throw at their 4Gbps and 8Gbps Fiber Channel-based storage networks. After that, Ethernet Chen & Wang Expires January 10, 2017 [Page 2] Internet-Draft ALTO Optical July 2016 capability has increased but Fiber Channel still wins in an assured delivery protocol. Using high-level protocols in Ethernet to implement flow control and error correction is both complex and expensive from a latency perspective. ALTO is aimed at application layer optimization and it standardizes the interaction between ALTO server and ALTO clients. How to extract information from underlining networks and abstract them properly are crucial. In practical, loading network information by an Agent, as well as getting available information with OpenFlow protocol by building an ALTO server on a SDN controller are both viable ways. Here we point out a basic thread on how to achieve optical resource abstraction and allocation based on OpenFlow extension. After that, we use necessary information to reflect basic standard information of ALTO server. In this case, bandwidth achievement is the significant difference comparing with Ethernet, and other metrics like hop count, cost can follow the Ethernet conception. Here we put optical transport network (OTN) devices as the optical network elements and discuss electrical switching, and the optical switching is out of scope of this document. This document is organized as follows. Section 2 proposal an ALTO Architecture in Converged Networks. Based on it, Section 3 forward a simple Ethernet and optical converged networks model. In the Optical Networks Resource Abstraction module shown in Figure 1. Section 4 aims to illustrate it by explain optical resource abstraction and allocation. In detail, Section 4.1 analyze the southbound interface design based on OTN physical features. Section 4.2 illustrate a simple rule on allocate the optical bandwidth resource and configurations. At last, Section 5 discuss the central aspect from ALTO server of Ethernet and optical converged networks and future thinking. 1.1. Terminology This document uses terms defined as follows: o {1.2.3}: References of this form are to sections in the ALTO protocol specification [RFC7285]. o And other terms defined in {8.2} of [RFC7285]. 1.2. 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 RFC 2119 [RFC2119]. Chen & Wang Expires January 10, 2017 [Page 3] Internet-Draft ALTO Optical July 2016 1.3. Changes Since Version -00 o Change the format of API for clients' request. This design is more concise and has better compatibility. It does not modify the IRD of ECS. Section 3.1 introduces a new abstraction for Endpoint which defines the ConnectionURI to represent an endpoint. And a specific flow can be determined by a pair of ConnectionURI. o Add some design principles in section 4. o Give two strategies to solve the multi-path problem and handle fine-grained path error in section 6. One option is to introduce feedback mechanism, the other option is to implement exploring. 2. ALTO Architecture in Converged Networks As we introduce optical network resource into the underlining network environment. Some modules should addict to the ALTO server reasonably. Here is a ALTO Architecture in Ethernet and optical converged networks in Figure 1. In this architecture, we describe the underlining converged networks and Optical Networks Resource Abstraction further more in Section 3 and Section 4. Over the Ethernet Network Resource Extraction and Optical Networks Resource Abstraction modules, there is a Converged Network Resource Integration module which we may infer some aspects from it in the following. +---------------+ +---------------+ | ALTO Client A | | ALTO Client B | +-------^-------+ +-------^-------+ +----------------------------------------------+ | ALTO Server | | +----------------------------------------+ | | |Converged Network Resource Integration | | | +----------------------------------------+ | | +----------------------------------------+ | | |Ethernet |Optical Networks | | | |Resource Extraction|Resource Abstraction| | | +-------^----------------------^---------+ | +----------------------------------------------+ +---------------------+ +----------------------+ | Ethernet | |Optical Networks | | | | | +---------------------+ +----------------------+ Figure 1: ALTO architecture in converged networks. Chen & Wang Expires January 10, 2017 [Page 4] Internet-Draft ALTO Optical July 2016 3. Ethernet and Optical Converged Networks Model The variety of services requires controllable and flexible mechanism of networks in a certain degree. Dynamic scheduling service depending on specific situation can improve source utilization. And reasonably intelligent network control does not only save costs of network operation and maintenance, but also cater to the needs of various services much more. We proposed a simple Ethernet and optical converged networks model which has considered the physical characteristics of optical transport networks. The switching granularity is at time slot level, or optical fiber. In the model. Optical networks bear the large transmission tasks and locate in the core position. At the edge of the network model, Ethernet plays an access role of the network environment and face the applications directly. Consider the electrical switch character and separation design between control plane and data plane of optical networks, it seems to be less significant in applying ALTO to optical networks as the origin design can achieve the same effect as ALTO. But ALTO in Ethernet and optical converged network is of value to provide a better service for ALTO clients due to the converged network resource integration. Imagine that, ALTO server obtain a global view both on Ethernet and optical networks, the schedule and false detection will be more direct. 4. Optical Resource Abstraction and Allocation The feasible proposed architecture has to consider the programmability of network configuration based on physical device and application. Switching in optical NE can be supported in both electrical and optical domains. For time division multiplexing (TDM) circuits with guaranteed bandwidths, electrical switching is at tributary slot level. Generally, TDM is defined by the OTN optical data unit (ODUk) standards with a rigid bandwidth hierarchy, and provides fixed and guaranteed bandwidth for client ports. Networks can make an appropriate combination of electrical and optical switching based on the application requirements. 4.1. Optical Resource Abstraction Figure 2 illustrates OTN device abstraction and information mapping. Software defined networking principles can be applied to many different optical transport network architectures. So we leave a field to express feature type. In this case, we set it as OTN Layer Stack, and then list OTN layer entries. Each of layer entries' information refines layer class, signal type, adaptation. Layer class and signal type, as the most important optical port Chen & Wang Expires January 10, 2017 [Page 5] Internet-Draft ALTO Optical July 2016 information, will reflect some certain performance of optical networks. ODU client (ODUCLT) Layer represents client-side information and it is always Ethernet signal type. ODU Layer influences the length and allocation of tributary slot, it represents the switching granularity. The signal type of optical transform unit (OTU) Layer indicates a certain bandwidth. Optical Channel (OCh) Layer corresponds to the optical signal type. Here we discuss electrical switching only. +-----+ . +-----+ +-----+ . +-----+ . +-----+ |Eth | ---- | | | | . | | . | | |If | . | | | | . | | . | | +-----+ . | | |ODUk | . |OTUk | . |OCh | . | | ---- | | ---- | | ---- | | ---- +-----+ . |ODUk | |Sw | . |Proc | . |Sw | |OTUk | ---- | | | | . | | . +-----+ |If | . |Proc | | | . | | . +-----+ . | | | | . | | . . | | | | . | | . +-----+ . | | +-----+ . | | . |Other| ---- | | . | | . |If | . | | ----------------- | | ----------------- +-----+ . +-----+ . +-----+ . . . . | | | | | | | | +--|-----------------|--------------------|-----------|--------+ | | | OTN Layer Stack | | | | V V V V | +--------------+---------------+---------------+---------------+ |ODUCLT-Layer | ODU_Layer | OTU_Layer | OCh_Layer | +--------------+---------------+---------------+---------------+ |Layer-|Signal-|Layer-|Signal- |Layer-|Signal- |Layer-|Signal- | |Class |Type |Class |Type |Class |Type |Class |Type | +--------------+---------------+---------------+---------------+ Figure 2: Resource abstraction on optical NE. 4.2. Optical Resource Allocation Configuring tables of network element (NE) is another challenge. Based on signal types of NE, ODUx is a good candidate to become a match principle. Besides allocation tributary slot according to ODUx, we should also consider Ethernet signal types. A simple simulation scene presents two kind of services implementation based on bandwidth demand. Besides the specific technical realisation of optical NE table configuration. We would like to show an example of the service based clients use case in converged networks. Chen & Wang Expires January 10, 2017 [Page 6] Internet-Draft ALTO Optical July 2016 Tributary slot allocation plays an important role in electrical switching. As a direct influence factor of granularity, ODUx leads ways for matching flow entries namely resource allocation. In Figure 3, suppose electrical switching granularity of an optical NE is ODU0 which represents 1.25GE bandwidth. ODU0 presents a match principle of match field, i.e., ODU_SIGTYPE. And ODU_SIGID manages output ways as an action principle. Similarly, OTU Layer signal type OTU2 indicates a given bandwidth 10GE. Conclusively, bandwidth reflexed by OTUx and ODUx indicates numbers of tributary slot (TSLEN) gotten by OTUx's dividing by ODUx's, so we get a value of TSLEN: 8 to provide services in this case. In figure 3, suppose an client A requires 1GE bandwidth accesses Port 1 of Optical NE:1 (NE:1:1) . From above we can deduce that one tributary slot is occupied by the service namely tributary port number (TPN) equals 1. It should be noticed that tributary slot map (TSMAP) is presented by binary array. So the value of it is a result of transform from binary value to decimal value. In this situation, suppose client A is routed from NE:1:4 to NE:2:2. Apparently, the action principle of service in NE:1 turns to be match principle of NE:2 to a large extent. A small difference may be presented in TSMAP allocation. Referred to the action principle of NE:2, the output field is NE:2:4. Chen & Wang Expires January 10, 2017 [Page 7] Internet-Draft ALTO Optical July 2016 NE:1 +----------+------------------------+ |Sig-Type: | |Sig-Type: | |OTU2 | |ODUCLT | +-----------------------------------+ | 1 | +------+ 1 |----- Client A +----------+ | +----------+ 1GE | 2 | | | 2 | +----------+ | +----------+ | 3 | | | 3 | +----------+ | +----------+ +-----+ 4 |------+ | 4 | | +----------+-------------+----------+ | | | NE:2 | +----------+------------------------+ | |Sig-Type: | |Sig-Type: | | |OTU2 | |ODUCLT | | +-----------------------------------+ | | 1 | | 1 | | +----------+ +----------+ +---->| 2 |------+ | 2 | +----------+ | +----------+ | 3 | | | 3 | +----------+ | +----------+ | 4 | +----->| 4 |----- Client B +------------------------+----------+ 1GE Figure 3: Route configuration based on bandwidth. 5. ALTO Standardized Converged Networks Information Construction For OTN device, we know that the numbers of unused tributary slot can deduce to the remaining bandwidth resource. From the aspect of ALTO Clients, there is no need for them to know the underlining networks but just the remaining network resource and other parameters on transport. As we mentioned at the beginning, we can extract the optical networks information by extending OpenFlow protocol and abstract the information into useful resource. We can get the tributary slot information by changing a little bit on the port reply message of OpenFlow. This document put forward a possibility on integrating the Ethernet and optical converged networks by deploying an ALTO server. In the future, we will combine optical network resource with ALTO in protocol level. Chen & Wang Expires January 10, 2017 [Page 8] Internet-Draft ALTO Optical July 2016 6. IANA Considerations This document does not define any new media type or introduce any new IANA consideration. 7. Privacy And Security Considerations This document does not introduce any privacy or security issue not already present in the ALTO protocol. 8. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC7285] Alimi, R., Ed., Penno, R., Ed., Yang, Y., Ed., Kiesel, S., Previdi, S., Roome, W., Shalunov, S., and R. Woundy, "Application-Layer Traffic Optimization (ALTO) Protocol", RFC 7285, DOI 10.17487/RFC7285, September 2014, . Authors' Addresses Mingming Chen Tongji University 4800 Cao'an Road, Jiading District Shanghai China Email: mingmingminne@126.com Xin Tony Wang Tongji University 4800 Cao'an Road, Jiading District Shanghai China Email: xinwang2014@hotmail.com Chen & Wang Expires January 10, 2017 [Page 9]