OPSAWG J. Zhao Internet Draft Fudan University Intended status: Informational X. Song Expires: May 2015 Oriental Cable Network J. Li B-STAR November 24, 2014 A Reference Model for OAM in Ethernet over Coaxial Access Network draft-zhao-opsawg-eoc-oam-model-00.txt 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), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html This Internet-Draft will expire on May 24, 2009. Copyright Notice Copyright (c) 2014 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. Zhao et al. Expires May 24, 2015 [Page 1] Internet-Draft Reference Model for EoC OAM November 2014 Abstract This document describes an architectural and functional reference model for the Operations, Administration and Maintenance (OAM) of Ethernet over coaxial access network. This model applies to the protocol between Coax Line Terminal and Coax Network Unit in the access network. Table of Contents 1. Introduction ................................................. 2 2. Terminology .................................................. 3 3. Network OAM Framework ........................................ 3 4. Reference Model for Interoperability ......................... 5 4.1. Basic Functionality Interoperability .................... 5 4.2. Service Interoperability ................................ 5 5. Protocol for Interoperability ................................ 5 6. Security Considerations ...................................... 7 7. IANA Considerations .......................................... 8 8. References ................................................... 8 8.1. Normative References .................................... 8 8.2. Informative References .................................. 8 1. Introduction Ethernet over coaxial (EoC)provides a cost-effective way for Internet service providers to ensure a high quality Internetaccess for their subscribers with hybrid fiber coaxial network, while accelerating the deployment of digital video service and the ability to connect multiple devicesto the same coaxial cable. For managing and controlling such an access network, a network operator will prefer to have a unified scheduling, management, and quality-of-service (QoS) environment that includes coaxial portions of the hybrid fiber coaxial network. This can be achieved by designing the Operations, Administration and Maintenance (OAM)[1] functionalities, and by having a centralized OAM framework from the cable head-end to the end-users' premises. The document defines a reference model and associated protocol that introduces requirements on an EoC system to support the configuration and transport of a class of service between a coax line terminal(CLT) and the coax network unit(CNU). Zhao et al. Expires May 24, 2015 [Page 2] Internet-Draft Reference Model for EoC OAM November 2014 The approach of the document is to outline the functionalities and potential mechanisms for providing the OAM for EoC access network, as well as illustrating interoperability protocol by example. 2. Terminology 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 [2]. ACS Automatic Configuration Server CLT CoaxialLine Terminal CNU Coax Network Unit EoC Ethernet over Coaxial MAC Media Access Control MDIO Management Data Input/Output MME Management Message Entity SNI Service Node Interface OAM Operations, Administration and Maintenance UNI User Network Interface 3. Network OAM Framework The OAM reference architecture, as shown in figure 1,identifies the elements that an EoC network minimally requires to perform and communicate properly between the functional subsystems of the EoC system. According to the need for service and device management in EoC system, the OAM framework includes: o EoC functionality Management Functionality management is a common tool for setting the parameters of Ethernet signal over coaxial, e.g. radio frequency and modulation. o Service Management Service management is responsible for setting Ethernet profiles, e.g. VLAN, multicast, frame filtering, bandwidth, QoS, broadcast flood, UNI port. o Performance Management Performance management is a key tool that allows users to discover the performance of CLT port, CNU port and UNI by measuring the metrics of Ethernet service and RF. Zhao et al. Expires May 24, 2015 [Page 3] Internet-Draft Reference Model for EoC OAM November 2014 o Failure Management Failure management supports detecting and monitoring the state of CLT and CNU continuously or at intervals. If failure occurs, it will result in warning, or loopback detection, etc. o Security Management Security management defines the security measures for accessing CNU, e.g. user and password authentication, privilege authorization, and key management. o System Management System management describes the functionalities of software and hardware maintenance, e.g. CNU remote boot, firmware update. +------------------------------------------------------------+ | | | +-----------+ +------------+ +------------+ | | | Function- | | Service | | Performance| | | | ality | | | | | | | | Management| | Management | | Management | | | +-----------+ +------------+ +------------+ | | ^ ^ ^ | | | | | | | V V V | |------------------------------------------------------------| | | | Network Operations, Administration and Maintenance | | | |------------------------------------------------------------| | ^ ^ ^ | | | | | | | V V V | | +-----------+ +------------+ +------------+ | | | Failure | | Security | | System | | | | | | | | | | | | Management| | Management | | Management | | | +-----------+ +------------+ +------------+ | +------------------------------------------------------------+ Figure 1 OAM framework Zhao et al. Expires May 24, 2015 [Page 4] Internet-Draft Reference Model for EoC OAM November 2014 4. Reference Model for Interoperability In the EoC system, the interoperability model includes basic functionality interoperability and service interoperability. 4.1. Basic Functionality Interoperability The basic functionality, which is specify by various EoC standards, such as IEEE 1901-2010 [3], refers to the interoperability of physical layer and the MAC layer implementation from different manufacturers between CLT and CNU Ethernet services. The physical layer interoperability includes the consistency of working frequency and the modulation parameters of CLT and CNU. The MAC layer interoperability includes the mechanism of CSMA / CA, TDMA, and clock synchronization between CLT and CNU. 4.2. Service Interoperability Service interoperability refers to the ability of proper service operation and management between different CLT and CNU vendors. The consistency includes user port related operation at terminals, multicast operations, VLAN operations, QoS-related operations, bandwidth-limiting operations. In addition, service interoperability also includes all the management operations associated with the EoC basic functionality (mainly the EoC system configuration and management), as well as partially the service carrying operations (mainly the configuration of service carrying). Other management operations other than the specifiedabove,can be defined as well, but it's not in the scope of this document. 5. Protocol for Interoperability The service interoperability of EoC system includes two aspects: 1) protocol for interaction between CLT and CNU, which is implemented via the management message exchange; 2) an Interoperability Management Module(IMM) at CNU, which handles management message and transforms the message into specific format. For conventional CNU, the IMM need transform Management Message Entity(MME)into MDIO signals for layer 2 switching. For CNU with home gateway functions, IMM just forwards the MME to gateway transparently. The protocol for service interoperability defines the procedure for setting / reading the profile attributes, handling OAM requests and responses, and performing version management. Zhao et al. Expires May 24, 2015 [Page 5] Internet-Draft Reference Model for EoC OAM November 2014 The CNU which works as a home gateway, implements the management functionalities by forwarding messages via Interoperability Management Module. For the extended MME destined for home gateway, Interoperability Management Module change the destination MAC address as the MAC address of the home gateway, and forwards it to home gateway. For the extended MME destined for CLT, Interoperability Management Module change the destination MAC address as the MAC address of EoC module, and forwarded it to CLT. +-------------CNU----------------+ +----+ | +----+ +-----+ +-----+ | |CLT | | | | | | | | | | |<----------->| | | MME | | MME | HG | | | | MME | |EoC |<--->|IMM |<--->| | | | | | | | | |MDIO | SW | | | | | | | | | | | | +----+ | +----+ +-----+ +-----+ | +--------------------------------+ HG: Home Gateway, SW: Switch, MME: Management Message Entity IMM: Interoperability Management Module Figure 2 Interoperability between CLT and CNU The typical interaction between the CLT and CNU can be illustrated using an example. After CNU gets online, the configuration management is performed by BOSS and NMS automatically through the management channel. The procedure works as follows. 1. After CNU start, Interoperability Management Module reads the functional attributes of CNU; 2. CNU Interoperability Management Module registers extended MME at EoC module. After the registration, all registered extended MME will be forwarded to Interoperability Management Module for processing. 3. After receiving online message from CNU, CLT sends the extended MME to query the attribute the CNU. 1. Interoperability Management Module reply the attributes, including the MAC address of the home gateway using extended MME. 2. CLT sends the CNU's online authentication information to NMS. The authentication information includes the MAC addresses of EoC module and the home gateway. Zhao et al. Expires May 24, 2015 [Page 6] Internet-Draft Reference Model for EoC OAM November 2014 3. NMS and BOSS handle CNU authentication. If authenticated, the VLAN and IP information (Note: Including the subnet mask, IP gateway, ACS URL, DNS IP) will be sent to CLT using configuration profile. 4. After the receipt of the configuration profile, CLT first parses the configuration parameters and encapsulates the parameters of home gateway with extend MME, and then send it to CNU. If CLT does not receive any profile, it will send CNU online authentication information to the NMS periodically. 5. After Interoperability Management Module received extended MME, it will set the destination as the MAC address of home gateway, and the source as the MAC address of EoC module. Then it sends the modified MME to the home gateway. 6. Upon receiving the extended MME, the home gateway will configure its VLAN IP information (Note: Including the subnet mask, IP gateways, ACS URL, DNS IP) and sends the results back to CLT. 7. After received the MME from home gateway, Interoperability Management Module will set the source of the extended MME as the EoC MAC address. 8. After CLT received home gateway's MME on its successful configuration, it will establish the relationship between the home gateway and CNU locally. The configuration information of home gateway will be stored as well. 9. Home gateway will establish TR069 connection with ACS after it received the configuration management profile of VLAN and IP(note: including the subnet mask, IP gateway, ACS URL). Other OAM operations can be illustrated in a similar way. The interaction between CLT and CNU extended MME message. 6. Security Considerations This document discusses a reference model for implementing OAM in Ethernet over Coaxial access network. The solution to some of the problems discussed can have security implications, such as when a malicious client's attack on a protocol can create a false illusion of failures, or prevent the detection of actual ones. Malicious client should not be able to use non-EoC interfaces to insert EoC-specific OAM transactions. Providing a secure mechanism for EoC OAM is required if EoC-specific protocols are to be used Zhao et al. Expires May 24, 2015 [Page 7] Internet-Draft Reference Model for EoC OAM November 2014 successfully. Therefore, authentication and authorization for OAM MUST be considered when designing OAM-related mechanisms, which satisfy the reference model presented in this document. 7. IANA Considerations This memo does not have any IANA considerations. 8. References 8.1. Normative References [1] Andersson, L., Van Helvoort, H., Bonica, R., Romascanu, D., Mansfield, S., "Guidelines for the use the OAM acronym in the IETF ", RFC 6291, June 2011. [2] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. 8.2. Informative References [3] IEEE 1901-2010, "IEEE Standard for Broadband over Power Line Networks: Medium Access Control and Physical Layer Specifications" December 2010. Zhao et al. Expires May 24, 2015 [Page 8] Internet-Draft Reference Model for EoC OAM November 2014 Authors' Addresses Jin Zhao Fudan University 825 Zhangheng Rd., Shanghai 201203, China Email: jzhao@fudan.edu.cn Xuhong Song Oriental Cable Network 2860 Jinke Rd., Shanghai 201203, China Email: songxh@scn.com.cn Jin Li B-STAR 1158 Xiehe Rd., Shanghai 200335, China Email: jli@b-star.cn Zhao et al. Expires May 24, 2015 [Page 9]