中国移动-中国移动弹性SD-WAN技术白皮书（英文）-2020.12-23页_1mb

China Mobile Elastic SD-WAN Technology White Paper Summary

Core Content

This white paper introduces China Mobile's Elastic SD-WAN solution, which is designed to address the challenges of traditional enterprise WANs in the context of cloud migration and digital transformation. It emphasizes the integration of underlay and overlay networks through SRv6 technology to enhance network performance, scalability, and service customization.

Main Viewpoints

• Cloud Migration Imperative: Enterprises are increasingly migrating to the cloud, necessitating agile network connectivity and efficient use of WAN resources.
• SD-WAN Evolution: Traditional SD-WAN solutions, which rely on pure overlay networks, face limitations in performance and scalability. Elastic SD-WAN overcomes these by integrating underlay and overlay capabilities.
• SRv6 as a Core Technology: SRv6 provides enhanced scalability and programmability, enabling flexible network path control and efficient service function chaining.
• Elastic SD-WAN Architecture: It combines programmable underlay networks and cloud virtualization, offering a comprehensive solution for enterprise networking.
• Differentiated Services: Elastic SD-WAN supports granular application services with unique SLA guarantees and value-added services, maximizing the utilization of cloud and network resources.

Key Information

1. Overview of Traditional Enterprise WANs

• Traditional WANs use leased lines or self-run lines to connect enterprise sites.
• The rise of cloud computing and network virtualization has transformed enterprise networking needs, requiring more flexible and scalable solutions.
• The complexity of managing individual nodes and ensuring application experience and security has increased significantly.

2. Background of SD-WAN and SRv6

2.1 Overlay Technology

• Overlay technology virtualizes the network by building a virtual network on top of physical networks.
• It uses tunneling technologies like VxLAN, GRE, and IPSec, but these can introduce complexity and reduce forwarding efficiency.

2.2 SRv6 Technology

• SRv6 is a source routing technology based on IPv6, allowing for flexible path programming.
• It uses Segment IDs (SIDs) with a structure of Locator, Function, and Argument.
• SRv6 provides simplified control protocols, high scalability, programmability, and high reliability.
• It enhances the ability of SD-WAN to sense and control underlay networks, aligning with the future direction of SD-WAN evolution.

3. Technical Architecture of Elastic SD-WAN

• Vertical Architecture:

  • Cloud and Network Orchestration Layer: Coordinates underlay and data center resources based on SD-WAN service requests.
  • Underlay Control Layer: Manages underlay network resources such as metropolitan, provincial, and backbone networks.
  • Forwarding Layer: Divided into access, aggregation, and backbone segments.

• Horizontal Architecture:

  • Access Segment: Connects CPE and PoP GW, supporting multiple access types (Internet, leased lines, 4G/5G).
  • Aggregation Segment: Connects PoP GW to data center and backbone networks.
  • Backbone Segment: Supports underlay SRv6 functionality.

4. Elastic SD-WAN Solution Highlights

• Underlay Coordination Capability: Enables efficient use of underlay network resources.
• Native IPv6 Service Function Chaining: Supports flexible service chaining through SRv6.
• Telemetry: Provides real-time network performance monitoring.
• Application Awareness: Enables traffic prioritization based on application SLA requirements.

5. Application Scenarios

• Large Enterprise Scenarios:

  • Branch Interconnection: Uses SRv6 tunnels between CPEs and PoP GWs, with optional value-added services.
  • Cloud Migration: SRv6 tunnels from CPE to cloud VPC GW, supporting end-to-end cloud migration.
  • Enterprise Internet Access: Direct IPv6 connectivity from CPE to MAN, with optional traffic routing through PoP GW.

• SME Scenarios:

  • Branch Interconnection: SRv6 tunnel from CPE1 to PoP GW1, then to PoP GW2 and CPE2.
  • Cloud Migration: SRv6 tunnel from CPE to near-end VPC GW.
  • Enterprise Internet Access: Similar to large enterprises, but with shared control points and flexible routing.

• Mixed Enterprise Scenarios:

  • Enterprises can flexibly combine different bearer solutions based on their networking needs.
  • This flexibility allows for adapting to changing network demands.

6. Control and Forwarding Principles

• The SD-WAN controller calculates the end-to-end path and issues policies to CPEs.
• The path is divided into access, aggregation, and backbone segments.
• In large enterprise scenarios, traffic may or may not pass through a PoP GW.
• Traffic passing through PoP GW allows for value-added services and better QoS.
• Traffic not passing through PoP GW simplifies the path but still ensures service quality through SRv6 policy.

7. Solution Advantages

• Flexibility: Supports various access modes and service types.
• Scalability: SRv6 enables efficient path generation and resource allocation.
• Customization: Allows for tailored services based on application needs.
• Integration: Combines cloud and network resources, enabling a unified service delivery model.
• Security and SLA: Ensures secure and reliable connections with SLA guarantees for different applications.

Summary

China Mobile's Elastic SD-WAN is a next-generation solution that integrates SRv6 technology with cloud and network resources to provide more flexible, scalable, and secure enterprise networking. It addresses the limitations of traditional SD-WAN by enabling underlay-overlay coordination, application-aware routing, and service function chaining. The solution supports three main scenarios: large enterprises, SMEs, and mixed enterprises, offering differentiated services and value-added capabilities. Elastic SD-WAN enables centralized management, dynamic path selection, and precise traffic control, making it a key technology for future enterprise network evolution.