YD/T 4531-2023
Interface requirements for virtualized broadband remote access servers based on separation of forwarding and control (English Version)

Standard No.: YD/T 4531-2023
Language: Chinese, Available in English version
Release Date: 2023
Published By: Professional Standard - Post and Telecommunication CN / YD
Latest: YD/T 4531-2023

Introduction

Standard Technology Background and Evolution

With the maturity of SDN/NFV technology, the decoupling of the control plane and forwarding plane of traditional BRAS equipment has become an inevitable trend. This specification defines the standardized interface protocol of virtualized vBRAS in the control-forwarding separation architecture, and realizes:

Virtualized cloud deployment of the control plane
Distributed deployment of high-performance hardware on the forwarding plane
Standardized interaction through the CUSP protocol

Core Architecture Analysis

Application Layer: CUSP Transport Layer: TCP Network Layer: IP Link Layer: Ethernet

7.3 Message Type Definition

Components	Traditional BRAS	vBRAS with control-forwarding separation
Control plane	Tightly coupled with the forwarding plane	Centralized deployment of virtualization
Forwarding plane	Single device integration

Contains 23 fields such as MAC address, VLAN tag, and Access type, including:

AccessType: defines 6 access methods such as PPPoE/IPoE
DetectTimes: number of detection timeouts (0 means no detection)

8.6 Routing table definition

Message Type	Function Description
1-6	Control Channel Maintenance Class (Heartbeat/Synchronization, etc.)

RouteType	Description
0	User host route
3	Gateway route
5	L2TP LNS-side user route

Implementation Suggestions

Deployment Notes

Protocol compatibility: Ensure that both CP and UP support CUSP protocol v1
Resource reporting period: It is recommended that the traffic statistics reporting interval is ≤ 5 minutes
Exception handling: When the UP board status is Abnormal, the active/standby switchover needs to be automatically triggered

YD/T 4531-2023 history

2023 YD/T 4531-2023 Interface requirements for virtualized broadband remote access servers based on separation of forwarding and control

Interface requirements for virtualized broadband remote access servers based on separation of forwarding and control

Standard and Specification

DS/EN 301005-1 V1.1.4:1999 V interfaces at the digital Service Node (SN) - Interfaces at the VB5.1 reference point for the support of broadband or combined narrowband and broadband Access DS/EN 301005-1 V1.1.4:1998 V interfaces at the digital Service Node (SN) Interfaces at the VB5.1 reference point for the support of broadband or combined narrowband and broadband Access IEEE P1904.2/D3.1, February 2021 IEEE Draft Standard for Control and Management of Virtual Links in Ethernet-based Subscriber Access Networks IEEE P1904.2/D3.0, February 2021 IEEE Draft Standard for Control and Management of Virtual Links in Ethernet-based Subscriber Access Networks IEEE P1904.2/D3.2, April 2021 IEEE Draft Standard for Control and Management of Virtual Links in Ethernet-based Subscriber Access Networks IEEE Std 1904.2-2021 IEEE Standard for Control and Management of Virtual Links in Ethernet-based Subscriber Access Networks DS/EN 301217-1 V1.2.2:2000 V interfaces at the digital Service Node (SN); Interfaces at the VB5.2 reference point for the support of broadband or combined narrowband and broadband Access DANSK DS/ISO/IEC 14543-5-104:2024 Information technology – Home electronic system (HES) architecture – Part 5-104: Intelligent grouping and resource sharing for HES Class 2 and Class 3 – RA ISO/IEC 14543-5-104:2024 Information technology — Home electronic systems (HES) architecture — Part 5-104: Intelligent grouping and resource sharing for HES Class 2 and Class 3 – RA IEEE 1904.2-2021 Control and Management of Virtual Links in Ethernet-based Subscriber Access Networks

YD/T 4531-2023Interface requirements for virtualized broadband remote access servers based on separation of forwarding and control (English Version)