Virtual TLOC for SD-WAN and Segment Routing Inter-working
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Solution Overview
Problem
Existing approaches fail to achieve end-to-end path control between a Software-Defined WAN (SD-WAN) domain and a Segment Routing (SR) domain when the remote domain is not an SD-WAN domain, limiting the ability to form an end-to-end SD-WAN session and exercise end-to-end control.
Innovation Solution
The introduction of a virtual Transport Locator (TLOC) in the SD-WAN border edge node, leveraging the SD-WAN overlay management protocol to redistribute VPN routes and create a virtual remote TLOC, allowing for end-to-end path control by associating a virtual TLOC with a node in the SR domain and publishing it within the SD-WAN domain, enabling communication across both domains without requiring both ends to be in the SD-WAN domain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional WAN or SD-WAN approaches are used to connect enterprise to data center, then dedicated circuits and routing management are provided, but end-to-end path control is not achieved when remote domain is not SD-WAN domain
Solution Approach 1:
The patent introduces a virtual TLOC as an intermediary entity that enables communication between SD-WAN and non-SD-WAN domains. The virtual TLOC acts as a mediator that translates SD-WAN routing requirements into formats compatible with traditional WAN or SR domains, allowing end-to-end path control without requiring both domains to be SD-WAN domains.
Solution Approach 2:
The patent changes the routing parameter representation by introducing virtual TLOC identifiers that map SD-WAN routing parameters to traditional WAN or SR domain parameters. This parameter transformation enables path control across domain boundaries by translating between different routing protocols and address schemes.
2Loss of information
If SD-WAN overlay management protocol redistributes VPN routes, then routing information is shared across domains, but additional destination lookups are required reducing efficiency
Solution Approach 1:
The patent performs preliminary route installation by pre-configuring routing entries in the forwarding plane based on VPN route redistribution. This preliminary action caches routing information in advance, eliminating the need for real-time destination lookups during packet forwarding and thus improving forwarding efficiency while maintaining complete routing information distribution.
3Reliability
If both ends must be in SD-WAN domain for end-to-end session, then proper path control is achieved, but adaptability to hybrid networks is limited
Solution Approach 1:
The patent creates a universal interface (virtual TLOC) that enables SD-WAN border edge nodes to function in multiple roles: both as native SD-WAN participants and as gateways to non-SD-WAN domains. This multi-functionality allows the system to maintain end-to-end session control while adapting to hybrid network environments where not all domains are SD-WAN domains.
Data Source
AI summary
According to an embodiment, a node comprises one or more processors operable to execute instructions to cause the node to perform operations that comprise receiving a packet from a first node associated with an SD-WAN domain. The packet comprises a header indicating a TLOC associated with a second node to send the packet, the second node associated with an SR domain. The operations comprise determining that the TLOC corresponds to a virtual TLOC used in the SD-WAN domain to identify the second node that is in the SR domain and, in response, determining a second node identifier used in the SR domain to identify the second node. The operations further comprise preparing the packet to be communicated via the SR domain. Preparing the packet comprises including the second node identifier in the packet. The operations further comprise sending the packet comprising the second node identifier to the second node.