SRv6-Enhanced BGP Signaling for EVPN SID Advertisement

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Solution Overview

Problem

Current packet switching technologies face challenges in efficiently routing packets through networks with increasing demand for speed and capacity, particularly in supporting Ethernet Virtual Private Networks (EVPN) using Segment Routing (SRv6) and enhanced Border Gateway Protocol (BGP) signaling, as they struggle to effectively advertise and utilize Segment Identifiers (SIDs) for EVPN functions across different underlay networks.

Innovation Solution

The implementation of SRv6-enhanced BGP signaling allows for the advertisement of SIDs in BGP route messages, enabling routers to perform EVPN end functions by encapsulating packets with SRHs containing SIDs, which include locators and function encodings for EVPN routers, facilitating EVPN functionality across SRv6 and MPLS-based networks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If packet switching technology is used to increase network speed and capacity, then network performance improves, but the ability to effectively advertise and utilize Segment Identifiers for EVPN functions across different underlay networks deteriorates

Engineering Contradiction:

Improvenetwork speed and capacityVSAvoidEVPN function support across underlay networks

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The patent applies universality by designing the SID structure to serve multiple functions simultaneously. The SID includes both a locator portion for routing and a function encoding portion for EVPN operations, allowing a single identifier to work across different underlay networks (SRv6 and MPLS) and support various EVPN functions without requiring separate mechanisms for each network type or function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent changes the parameter structure of the SID by encoding multiple pieces of information (locator, function type, EVPN instance identifier) within a single identifier. This parameter consolidation allows the network to maintain high-speed packet switching while embedding sufficient information to perform EVPN functions across different underlay networks without requiring additional signaling or multiple identifiers.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If Segment Identifiers include detailed function encodings for EVPN routers, then EVPN functionality is enhanced, but the complexity of routing protocol messages increases

Engineering Contradiction:

ImproveEVPN end function capabilityVSAvoidBGP route message structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the SID into distinct functional portions: a locator portion for network routing and a function encoding portion for EVPN operations. This segmentation allows BGP route messages to carry detailed EVPN function information in a structured, organized manner that reduces processing complexity compared to carrying unstructured or scattered function indicators throughout the message.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent adds a new dimension to the SID by incorporating function encoding that operates alongside the traditional locator function. This dimensional expansion allows the same BGP message structure to convey both routing information and EVPN function specifications without requiring separate message types or additional protocol fields, thereby enhancing functionality while maintaining message structure efficiency.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If routers perform EVPN end functions by processing SIDs with function encodings, then network flexibility is improved, but the processing overhead at each router increases

Engineering Contradiction:

Improvenetwork flexibility for EVPN servicesVSAvoidrouter processing requirements

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-encoding the EVPN function requirements directly into the SID within the BGP route advertisement messages. This allows receiving routers to perform simple lookup operations based on the pre-encoded function identifiers rather than requiring complex real-time analysis of EVPN requirements, thereby maintaining network flexibility while reducing per-packet processing overhead at each router.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12255976B2Ethernet virtual private network using segment routing

Publication Date: 2025.03.18 CISCO TECHNOLOGY INC

AI summary

In one embodiment, Ethernet Virtual Private Network (EVPN) is implemented using Internet Protocol Version 6 (IPv6) Segment Routing (SRv6) underlay network and SRv6-enhanced Border Gateway Protocol (BGP) signaling. A particular route associated with a particular Internet Protocol Version 6 (IPv6) Segment Routing (SRv6) Segment Identifier (SID) is advertised in a particular route advertisement message of a routing protocol (e.g., BGP). The SID includes encoding representing a particular Ethernet Virtual Private Network (EVPN) Layer 2 (L2) flooding Segment Routing end function of the particular router and a particular Ethernet Segment Identifier (ESI), with the particular SID including a routable prefix to the particular router. The particular router receives a particular packet including the particular SID; and in response, the particular router performs the particular EVPN end function on the particular packet.