rtgwg S. Hu Internet-Draft China Mobile Intended status: Informational M. Wang, Ed. Expires: January 3, 2019 Huawei V. Lopez Telefonica F. Qin Z. Li China Mobile T. Chua Singapore Telecommunications Limited July 2, 2018 Information Model of Control-Plane and User-Plane separation BNG draft-cuspdt-rtgwg-cu-separation-infor-model-02 Abstract To improve network resource utilization and reduce the operation expense, the Control-Plane and User-Plane separation conception is raised [TR-384]. This document describes the information model for the interface between Control-Plane and User-Plane separation BNG. This information model may involve both control channel interface and configuration channel interface. The interface for control channel allows the Control-Plane to send several flow tables to the User- Plane, such as user's information table, user's interface table, and user's QoS table, etc. And it also allows the User-Plane to report the resources and statistics information to the Control-Plane. The interface for configuration channel is in charge of the version negotiation of protocols between the Control-Plane and User-Plane, the configuration for devices of Control-Plane and User-Plane, and the reports of User-Plane's capabilities, etc. The information model defined in this document enables defining a standardized data model. Such a data model can be used to define an interface to the CU separation BNG. 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 https://datatracker.ietf.org/drafts/current/. Hu, et al. Expires January 3, 2019 [Page 1] Internet-Draft Infor Model for CU separation July 2018 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 3, 2019. Copyright Notice Copyright (c) 2018 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 (https://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 2. Concept and Terminology . . . . . . . . . . . . . . . . . . . 4 2.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 3. Control Plane and User Plane separation BNG Information Model Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3.1. Service Data Model Usage . . . . . . . . . . . . . . . . 6 4. Information Model . . . . . . . . . . . . . . . . . . . . . . 8 4.1. Information Model for Control-Plane . . . . . . . . . . . 9 4.1.1. User-Related Information . . . . . . . . . . . . . . 11 4.1.1.1. User Basic Information Model . . . . . . . . . . 11 4.1.1.2. IPv4 Information Model . . . . . . . . . . . . . 12 4.1.1.3. IPv6 Information Model . . . . . . . . . . . . . 13 4.1.1.4. QoS Information Model . . . . . . . . . . . . . . 14 4.1.2. Interface Related Information . . . . . . . . . . . . 15 4.1.2.1. Interface Information Model . . . . . . . . . . . 15 4.1.3. Device Related Information . . . . . . . . . . . . . 16 4.1.3.1. Address field distribute Table . . . . . . . . . 17 4.2. Information Model for User Plane . . . . . . . . . . . . 17 4.2.1. Port Resources of UP . . . . . . . . . . . . . . . . 18 4.2.2. Traffic Statistics Infor . . . . . . . . . . . . . . 19 5. Security Considerations . . . . . . . . . . . . . . . . . . . 20 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 7. Normative References . . . . . . . . . . . . . . . . . . . . 20 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 21 Hu, et al. Expires January 3, 2019 [Page 2] Internet-Draft Infor Model for CU separation July 2018 1. Introduction The rapid development of new services, such as 4K, IoT, etc, and increasing numbers of home broadband service users present some new challenges for BNGs such as: Low resource utilization: The traditional BNG acts as both a gateway for user access authentication and accounting and an IP network's Layer 3 edge. The mutually affecting nature of the tightly coupled control plane and forwarding plane makes it difficult to achieve the maximum performance of either plane. Complex management and maintenance: Due to the large numbers of traditional BNGs, a network must have each device configured one at a time when deploying global service policies. As the network expands and new services are introduced, this deployment mode will cease to be feasible as it is unable to manage services effectively and rectify faults rapidly. Slow service provisioning: The coupling of control plane and forwarding plane, in addition to a distributed network control mechanism, means that any new technology has to rely heavily on the existing network devices. To address these challenges, cloud-based BNG with CU separation conception is raised [TR-384], [I-D.cuspdt-rtgwg-cu-separation-bng-deployment]. The main idea of Control-Plane and User-Plane separation method is to extract and centralize the user management functions of multiple BNG devices, forming an unified and centralized control plane (CP). And the traditional router's Control Plane and Forwarding Plane are both preserved on BNG devices in the form of a user plane (UP). This document describes an information model for the interface between Control-Plane and User-Plane separation BNG. This information model may involve both control channel interface and configuration channel interface. The interface for control channel allows the Control-Plane to send several flow tables to the User- Plane, such as user's information table, user's interface table, and user's QoS table, etc. And it also allows User-Plane to report the resources and statistics information to the Control-Plane. The interface for configuration channel is in charge of the version negotiation of protocols between the Control-Plane and User-Plane, the configuration for the devices of Control-Plane and User-Plane, and the report of User-Plane's capabilities, etc. The information model defined in this document enables defining a standardized data model. Such a data model can be used to define an interface to the CU separation BNG. Hu, et al. Expires January 3, 2019 [Page 3] Internet-Draft Infor Model for CU separation July 2018 2. Concept and 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 [RFC2119]. 2.1. Terminology BNG: Broadband Network Gateway. A broadband remote access server (BRAS, B-RAS or BBRAS) routes traffic to and from broadband remote access devices such as digital subscriber line access multiplexers (DSLAM) on an Internet service provider's (ISP) network. BRAS can also be referred to as a Broadband Network Gateway (BNG). CP: Control Plane. CP is a user control management component which supports the management of UP's resources such as the user entry and forwarding policy UP: User Plane. UP is a network edge and user policy implementation component. The traditional router's Control Plane and Forwarding Plane are both preserved on BNG devices in the form of a user plane. 3. Control Plane and User Plane separation BNG Information Model Overview Briefly, a CU separation BNG is made up of a centralized CP and a set of UPs. The CP is a user control management component which supports to manage UP's resources such as the user entry and forwarding policy, for example, the access bandwidth and priority management. And the UP is a network edge and user policy implementation component. It can support the forwarding plane functions on traditional BNG devices, such as traffic forwarding, QoS, and traffic statistics collection, and it can also support the control plane functions on traditional BNG devices, such as routing, multicast, etc. The following figure describes the architecture of CU separation BNG Hu, et al. Expires January 3, 2019 [Page 4] Internet-Draft Infor Model for CU separation July 2018 +-----+ +-----+ +-----+ +-----+ |EMS | |DHCP | |AAA | |policy | | |server |server |server +----|+ +---|-+ +--|--+ +--|--+ | | | | | | | | | | | | | | | | +----|---------|---------|---------|----+ | +--|----+ +--|--+ +---|--+ +----|--+ | | |address| | sub | | AAA | |service| | | |mgt | | Mgt | | | |control| | | +-------+ +-----+ +------+ +-------+ | | | Control Plane | +--------------------------------+ | | | User plane management | | | | | | | +-------------|------------------+ | +-----------------|---------------------+ | | | |----------------|-----------------| | | | | | | +--------|-----+ +------|-------+ +------|------+ | +---------+ | | +---------+ | |+-----|----+ | | | routing | | | | routing | | || routing | | | | control | | | | control | | || control | | | +---------+ | | +---------+ | |+----------+ | | +----------+ | | +----------+ | |+----------+ | User Plane | |forwarding| | | |forwarding| | ||forwarding| | | |plane | | | |plane | | ||plane | | | +----------+ | | +----------+ | |+----------+ | +--------------+ +--------------+ +-------------+ The CU separated BNG is shown in above figure. The BNG Control Plane could be virtualized and centralized, which provides significant benefits such as centralized session management, flexible address allocation, high scalability for subscriber management capacity, and cost-efficient redundancy, etc. The functional components inside the BNG Service Control Plane can be implemented as VNFs and hosted in a NFVI. The User Plane Management module in the BNG control plane centrally manages the distributed BNG User Planes (e.g. load balancing), as well as the setup, deletion, maintenance of channels between Control Hu, et al. Expires January 3, 2019 [Page 5] Internet-Draft Infor Model for CU separation July 2018 Planes and User Planes. Other modules in the BNG control plane, such as address management, AAA, and etc., are responsible for the connection with outside subsystems in order to fulfill the service. The routing control and forwarding Plane in the BNG User Plane (local) could be distributed across the infrastructure. 3.1. Service Data Model Usage The idea of the information model is to propose a set of generic and abstract information models. The models are intended to be used in both Control Plane and User Planes. A typical scenario would be that this model can be used as a compendium for the interface between Control Plane and User Planes of CU separation BNG, that corresponding data model or TLVs can be defined to realize the communication between the Control Plane and User Planes. Hu, et al. Expires January 3, 2019 [Page 6] Internet-Draft Infor Model for CU separation July 2018 ----------------- //// \\\\ //// \\\\ // Cloud \\ | | | | | | | | | +-----------------+ | | | Control Plane | | \\ | | // \\\\ +---------+-------+ //// \\\\ | //// ------------------ | +------------------+-----------+-----+ | | | | User's information IP address QoS: ....... May Including: ...... CIR; | User ID; | PIR; | User MAC; | CBS; | Access method(PPPoE, | PBS; | IPoE, etc) ...... | ...... | | | | | +------------------V-----------+-----+ | +----+ | ------- | /// \\\ +------+ +-------v---------+ +--------+ | | | OTL | | User Plane | | Core | | Internet | | +-------+ +-------+ Routing|-----| | +------+ +-----------------+ +--------+ \\\ /// ------- CU Separation BNG As shown in above figure, when users access to the BNG network, the control plane solicits these users' information (such as user's ID, user's MAC, user's access methods, for example via PPPoE/IPoE), associates them with available bandwidth which are reported by User planes, and based on the service's requirement to generate a set of tables, which may include user's information, user's IP address, and QoS, etc. Then the control plane can transmit these tables to the User planes. User planes receive these tables, parses it, matches these rules, and then performs corresponding actions. Hu, et al. Expires January 3, 2019 [Page 7] Internet-Draft Infor Model for CU separation July 2018 4. Information Model This section specifies the information model in Routing Backus-Naur Form [RFC5511]. This grammar intends to help readers better understand the English text description in order to derive a data model. However it may not provide all the details provided by the English text. When there is a lack of clarity in grammar the English text will take precedence. This section describes information model that represents the concept of the interface of CU separation BNG which is languages and protocols neutral. The following figure describes the Overview of Information Model for CU separation BNG. ::= ::= ::= []|[] [] :: = [][] [][] ::= ::=( )|() ::= () [] ::= ::= Hu, et al. Expires January 3, 2019 [Page 8] Internet-Draft Infor Model for CU separation July 2018 ::= ::= ::= ::= ::= ::= 4.1. Information Model for Control-Plane This section describes information model for the Control-Plane (CP). As mentioned in section 3, the Control Plane is a user control management component which manages the user's information, User- Plane's resources and forwarding policy, etc. The control plane can generate several tables which contain a set of rules based on the resources and specific requirements of user's service. After that, the control plane sends the tables to User Planes, and User planes receive the tables, parse them, match the rules, and then perform corresponding actions. The Routing Backus-Naur Form grammar below illustrates the Information model for Control-Plane: Hu, et al. Expires January 3, 2019 [Page 9] Internet-Draft Infor Model for CU separation July 2018 ::= ::= []|[] [] :: = [][] [][] ::= ::=( )|() ::= () [] ::= ::= ::= ::= ::= user-related-infor-model: present the attributes which can describe the user's profile, such as user's basic information, qos, and IP address, etc. interface-related-infor-model: present the attributes which relate to some physical/virtual interface. This model can be used to indicate which kinds of service can be supported by interfaces. Hu, et al. Expires January 3, 2019 [Page 10] Internet-Draft Infor Model for CU separation July 2018 device-related-infor-model: present the attributes which relate to specific device. For example the control plane can manage and distribute the users, which belong to same subnet, to some specific devices. And the user plane's devices provide corresponding service for these users. 4.1.1. User-Related Information The user related information are a bunch of attributes which may bind to specific users. For example, the control plane can use a unified ID to distinguish different users and distribute the IP address and QoS rules to a specific user. In this section, the user related information models are presented. The user related information models include the user information model, IPv4/IPv6 information model, QoS information model, etc. The Routing Backus-Naur Form grammar below illustrates the user related information model: ::= []|[] [] :: = [][] [][] ::= ::=( )|() ::= () [] 4.1.1.1. User Basic Information Model The User Basic Information model contains a set of attributes to describe the basic information of a specific user, such as user's mac address, access type (via PPPoE, IPoE, etc), inner vlan ID, outer vlan ID, etc. Hu, et al. Expires January 3, 2019 [Page 11] Internet-Draft Infor Model for CU separation July 2018 The Routing Backus-Naur Form grammar below illustrates the user basic information model: :: = [][] [][] USER_ID (4 bytes): is the identifier of user. This parameter is a unique and mandatory, it can be used to distinguish different users. MAC_ADDRESS (6 bytes): is the MAC address of the user. ACCESS_TYPE (2 bytes): This attribute is an optional parameter. It can be used to indicate the protocol be used for user's accessing, such as PPPoE, IPoE, etc. SESSION_ID (4 bytes): This attribute is an optional parameter. It can be used as the identifier of PPPoE session. INNER_VLAN-ID (2 bytes): The identifier of user's inner VLAN. OUTER_VLAN_ID (2 bytes): The identifier of user's outer VLAN. USER_INTERFACE (4 bytes): This attribute specifies the binding interface of a specific user. The ifIndex of the interface MAY be included. This is the 32-bit ifIndex assigned to the interface by the device as specified by the Interfaces Group MIB [RFC2863]. The ifIndex can be utilized within a management domain to map to an actual interface, but it is also valuable in public applications [RFC5837]. The ifIndex can be used as an opaque token to discern which interface of User-Plane is providing corresponding service for specific user. 4.1.1.2. IPv4 Information Model The IPv4 information model presents the user's IPv4 parameters. It is an optional constructs. The Routing Backus-Naur Form grammar below illustrates the user's IPv4 information model: ::= USER_ID (4 bytes): is the identifier of user. This parameter is unique and mandatory. This attribute is used to distinguish different users. And it collaborates with other IPv4 parameters to present the user's IPv4 information. Hu, et al. Expires January 3, 2019 [Page 12] Internet-Draft Infor Model for CU separation July 2018 USER_IPV4 (4 bytes): This attribute specifies the user's IPv4 address, and it's usually used in user plane discovery and ARP reply message. MASK_LENGTH (4 bytes): This attribute specifies the user's subnet masks lengths which can identify a range of IP addresses that are on the same network. GATEWAY (4 bytes): This attribute specifies the user's gateway, and it's usually used in User Plane discovery and ARP reply message. VRF (4 bytes): is the identifier of VRF instance. 4.1.1.3. IPv6 Information Model The IPv6 information model presents the user's IPv6 parameters. It is an optional constructs. The Routing Backus-Naur Form grammar below illustrates the user's IPv6 information model: ::=( )|() USER_ID (4 bytes): is the identifier of user. This parameter is unique and mandatory. This attribute is used to distinguish different users. And it collaborates with other IPv6 parameters to present the user's IPv4 information. USER_IPV6 (2 bytes): This attribute specifies the user's IPv6 address, and it usually be used in neighbor discovery (ND discovery). PREFIX_LEN (4 bytes): This attribute specifies the user's subnet prefix lengths which can identify a range of IP addresses that are on the same network. PD_ADDRESS (4 bytes): In IPv6 networking, DHCPv6 prefix delegation is used to assign a network address prefix and automate configuration and provisioning of the public routable addresses for the network. This attribute specifies the user's DHCPv6 prefix delegation address, and it's usually used in neighbor discovery (ND discovery). PD_PREFIX_LEN (4 bytes): This attribute specifies the user's DHCPv6 delegation prefix length, and it's usually used in neighbor discovery (ND discovery). VRF (4 bytes): is the identifier of VRF instance Hu, et al. Expires January 3, 2019 [Page 13] Internet-Draft Infor Model for CU separation July 2018 4.1.1.4. QoS Information Model In CU separation BNG, the Control-Plane (CP) generates the QoS table base on UP's bandwidth resources and specific QoS requirements of user's services. This table contains a set of QoS matching rules such as user's committed information rate, peak information rate, committed burst size, etc. And it is an optional constructs. The Routing Backus-Naur Form grammar below illustrates the user's qos information model: ::= () [] USER_ID (4 bytes): is the identifier of user. This parameter is unique and mandatory. This attribute is used to distinguish different users. And it collaborates with other qos parameters to present the user's qos information. CIR (4 bytes): In BNG network, the Committed Information Rate (CIR) is the bandwidth for a user guaranteed by an internet service provider to work under normal conditions. This attribute is used to indicate the user's committed information rate, and it usually collaborates with other qos attributes (such as PIR, CBS, PBS, etc) to present the user's QoS profile. PIR (4 bytes): Peak Information Rate (PIR) is a burstable rate set on routers and/or switches that allows throughput overhead. This attribute is used to indicate the user's peak information rate, and it usually collaborate with other QoS attributes (such as CIR, CBS, PBS, etc) to present the user's QoS profile. CBS (4 bytes): The Committed Burst Size (CBS) specifies the relative amount of reserved buffers for a specific ingress network's forwarding class queue or egress network's forwarding class queue. This attribute is used to indicate the user's committed burst size, and it usually collaborates with other qos attributes (such as CIR, PIR, PBS, etc) to present the user's QoS profile. PBS (4 bytes): The Peak Burst Size (PBS) sepcifies the maximum size of the first token bucket. This attribute is used to indicate the user's peak burst size, and it usually collaborate with other qos attributes (such as CIR, PIR, CBS, etc) to present the user's QoS profile. QOS_PROFILE (4 bytes): This attribute specifies the standard profile provided by the operator. It can be used as a QoS template which is Hu, et al. Expires January 3, 2019 [Page 14] Internet-Draft Infor Model for CU separation July 2018 defined as a list of classes of services and associated properties. The properties may include: o Rate-limit: used to rate-limit the class of service. The value is expressed as a percentage of the global service bandwidth. o latency: used to define the latency constraint of the class. The latency constraint can be expressed as the lowest possible latency or a latency boundary expressed in milliseconds. o jitter: used to define the jitter constraint of the class. The jitter constraint can be expressed as the lowest possible jitter or a jitter boundary expressed in microseconds. o bandwidth: used to define a guaranteed amount of bandwidth for the class of service. It is expressed as a percentage. 4.1.2. Interface Related Information This model contains the necessary information for the interface. It is used to indicate which kind of service can be supported by this interface. The Routing Backus-Naur Form grammar below illustrates the interface related information model: ::= ::= ::= 4.1.2.1. Interface Information Model The interface model mentioned here is a logical construct that identifies a specific process or a type of network service. In CU separation BNG network, the Control-Plane (CP) generates the Interface-Infor table based on the available resources, which are received from the User-Plane (UP), and the specific requirements of user's services. The Routing Backus-Naur Form grammar below illustrates the interface information model: Hu, et al. Expires January 3, 2019 [Page 15] Internet-Draft Infor Model for CU separation July 2018 ::= ::= IFINDEX (4 bytes): The IfIndex is the 32-bit index assigned to the interface by the device as specified by the Interfaces Group MIB [RFC2863]. The ifIndex can be utilized within a management domain to map to an actual interface, but it is also valuable in public applications. The ifIndex can be used as an opaque token to discern which interface of User-Plane is providing corresponding service for specific user. BAS_ENABLE (2 bytes): This is a flag, and if it is TRUE, the BRAS is enabled on this interface. PPP_Only (2 bytes): This is a flag, and if it is TRUE, the interface only supports PPP user. IPV4_TRIG (2 bytes): This is a flag, and if it is TRUE, the interface supports that the user can be triggered to connect the internet by using IPv4 message. IPV6_TRIG (2 bytes): This is a flag, and if it is TRUE, the interface supports that the user can be triggered to connect the internet by using IPv6 message. ND-TRIG (2 bytes): This is a flag, and if it is TRUE, the interface supports that the user can be triggered to connect the internet by using neighbor discovery message. ARP_PROXY (2 bytes): This is a flag, and if it is TRUE, the ARP PROXY is enabled on this interface. 4.1.3. Device Related Information The device related information model presents the attributes which related to specific device. For example the control plane can manage and distribute the users, who belong to same subnet, to some specific devices. And then the user plane's devices can provide corresponding service for these users. The Routing Backus-Naur Form grammar below illustrates the device related information model: Hu, et al. Expires January 3, 2019 [Page 16] Internet-Draft Infor Model for CU separation July 2018 ::= ::= 4.1.3.1. Address field distribute Table In CU separation BNG information model, the Control-Plane (CP) generates and sends this Address field distribute table to UP. Based on this table, the user-plane's devices can be divided into several blocks, and each block is in charge of working for users with the same subnet. The Routing Backus-Naur Form grammar below illustrates the address field distribute information model: ::= 4.2. Information Model for User Plane This section describes information model for the interface of User Plane (UP). As mentioned in section 3, the UP is a network edge and user policy implementation component. It supports: Forwarding plane functions on traditional BNG devices, including traffic forwarding, QoS, and traffic statistics collection and Control plane functions on traditional BNG devices, including routing, multicast, and MPLS. In CU separation BNG information model, the CP generates tables and provides the rules. The UP plays two roles: 1. It receives these tables, parses it, and matches these rules, then performs corresponding actions. 2. It also generates several tables to report the available resources (such as usable interfaces, etc) and statistical information to CP. The Routing Backus-Naur Form grammar below illustrates the User Plane information model: Hu, et al. Expires January 3, 2019 [Page 17] Internet-Draft Infor Model for CU separation July 2018 ::= port-resource-information>::= ::= 4.2.1. Port Resources of UP The User Plane can generate the network resource table, which contains a bunch of attributes to present the available network resources, for example the usable interfaces. The Figure below illustrates the Port Resources Information Table of User-Plane: :: IFINDEX (4 bytes): IfIndex is the 32-bit index assigned to the interface by the device as specified by the Interfaces Group MIB [RFC2863]. The ifIndex can be utilized within a management domain to map to an actual interface, but it is also valuable in public applications. The ifIndex can be used as an opaque token to discern which interface of User-Plane is available. IF_NAME (64 bytes): the textual name of the interface. The value of this object should be the name of the interface as assigned by the local device and should be suitable for use in commands entered at the device's `console'. This might be a text name, such as `le0' or a simple port number, such as `1', depending on the interface naming syntax of the device. If several entries in the ifTable together represent a single interface as named by the device, then each will have the same value of ifName. IF_TYPE (4 bytes): the type of interface, such as Ethernet, GE, Eth- Trunk, etc. Hu, et al. Expires January 3, 2019 [Page 18] Internet-Draft Infor Model for CU separation July 2018 LINK_TYPE (4 bytes): This attribute specifies the type of link, such as point-to-point, broadcast, multipoint, point-to-multipoint, private and public (accessibility and ownership), etc. MAC_ADDRESS (6 bytes): This attribute specifies the available interface's MAC address. IF_PHY_STATE (1 bytes): The current operational state of the interface. This is an enumeration type node: 1- Up: ready to pass packets; 2- Down 3- Testing: in some test mode; 4- Unknow: status cannot be determined for some reason; 5- Dormant; 6- Not present: some component is missing. MTU: This attribute specifies the available interface's MTU (Maximum Transmission Unit). 4.2.2. Traffic Statistics Infor The user-plane also generates the traffic statistics table to report the current traffic statistics. The Figure below illustrates the Traffic Statistics Infor model of User-Plane: ::= USER_ID (4 bytes): is the identifier of user. This parameter is unique and mandatory. This attribute is used to distinguish different users. And it collaborates with other statistics parameters such as ingress packets, egress packets, etc, to report the user's status profile. STATISTICS_TYPE (4 bytes): This attributes specifies the traffic type such as IPv4, IPv6, etc. Hu, et al. Expires January 3, 2019 [Page 19] Internet-Draft Infor Model for CU separation July 2018 INGRESS_STATIISTICS_PACKETS (8 bytes): This attribute specifies the Ingress Statistics Packets of specific user. INGRESS STATISTICS_BYTES (8 bytes): This attribute specifies the Ingress Statistics Bytes of specific user. EGRESS_STATISTICS_PACKETS (8 bytes): This attribute specifies the Egress Statistics Packets of specific user. EGRESS_STATISTICS_BYTES (8 bytes): This attribute specifies the Egress Statistics Bytes of specific user. 5. Security Considerations None. 6. IANA Considerations None. 7. Normative References [I-D.cuspdt-rtgwg-cu-separation-bng-deployment] Gu, R., Hu, S., and Z. Wang, "Deployment Model of Control Plane and User Plane Separation BNG", draft-cuspdt-rtgwg- cu-separation-bng-deployment-00 (work in progress), October 2017. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC2863] McCloghrie, K. and F. Kastenholz, "The Interfaces Group MIB", RFC 2863, DOI 10.17487/RFC2863, June 2000, . [RFC5511] Farrel, A., "Routing Backus-Naur Form (RBNF): A Syntax Used to Form Encoding Rules in Various Routing Protocol Specifications", RFC 5511, DOI 10.17487/RFC5511, April 2009, . [RFC5837] Atlas, A., Ed., Bonica, R., Ed., Pignataro, C., Ed., Shen, N., and JR. Rivers, "Extending ICMP for Interface and Next-Hop Identification", RFC 5837, DOI 10.17487/RFC5837, April 2010, . Hu, et al. Expires January 3, 2019 [Page 20] Internet-Draft Infor Model for CU separation July 2018 Authors' Addresses Shujun Hu China Mobile 32 Xuanwumen West Ave, Xicheng District Beijing, Beijing 100053 China Email: hushujun@chinamobile.com Michael Wang (editor) Huawei 101 Software Avenue, Yuhua District Nanjing, Jiangsu 210012 China Email: wangzitao@huawei.com Victor Lopez Telefonica Sur 3 building, 3rd floor, Ronda de la Comunicacion s/n Madrid 28050 Spain Email: victor.lopezalvarez@telefonica.com Fengwei Qin China Mobile 32 Xuanwumen West Ave, Xicheng District Beijing, Beijing 100053 China Email: qinfengwei@chinamobile.com Zhenqiang Li China Mobile 32 Xuanwumen West Ave, Xicheng District Beijing, Beijing 100053 China Email: lizhenqiang@chinamobile.com Hu, et al. Expires January 3, 2019 [Page 21] Internet-Draft Infor Model for CU separation July 2018 Tee Mong Chua Singapore Telecommunications Limited 31 Exeter Road, #05-04 Comcentre Podium Block Singapore City 239732 Singapore Email: teemong@singtel.com Hu, et al. Expires January 3, 2019 [Page 22]