EVPN SRv6 Route Advertisement for L2VPN Pseudo-Wire Migration
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Solution Overview
Problem
The challenge lies in evolving an MPLS forwarding-based L2VPN VPWS into an SRv6 forwarding-based EVPN VPWS, as existing methods fail to enable seamless transition due to the inability to process established L2VPN pseudo-wires during the network evolution from MPLS to SRv6, leading to forwarding errors and resource inefficiencies.
Innovation Solution
The proposed solution involves extending the EVPN SRv6 route advertisement packet to include pseudo-wire identification information, allowing network devices to identify and process existing L2VPN pseudo-wires, thereby enabling the transition by disabling or adjusting priorities of L2VPN pseudo-wires and establishing SRv6 pseudo-wires, ensuring smooth evolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the EVPN SRv6 route advertisement packet is extended to carry pseudo-wire identification information, then the ability to identify and process existing L2VPN pseudo-wires during network evolution is improved, but the complexity of the route advertisement packet structure increases
Solution Approach 1:
The pseudo-wire identification information is nested within the existing EVPN route advertisement packet structure by utilizing the unused bits in the Extended Community attribute field. This allows the packet to carry both original EVPN routing information and additional pseudo-wire identification data without creating a completely new packet structure, thereby improving adaptability while controlling complexity.
Solution Approach 2:
The Extended Community attribute field in the EVPN route advertisement packet is made multi-functional by using it to carry both traditional EVPN routing attributes and pseudo-wire identification information. This universal approach allows the same packet structure to serve multiple purposes during network evolution, improving versatility without significantly increasing structural complexity.
2Reliability
If the L2VPN PW is disabled during network evolution to L2VPN VPWS, then forwarding errors are reduced, but the loss of existing connectivity occurs during transition
Solution Approach 1:
The pseudo-wire identification information is embedded in the route advertisement packet before the L2VPN PW is disabled. This preliminary action allows the receiving device to prepare for the transition by identifying the pseudo-wire that will be disabled, ensuring seamless connectivity handover and minimizing interruption time while maintaining forwarding accuracy.
Solution Approach 2:
The route advertisement packet with pseudo-wire identification information provides feedback to the receiving device about the upcoming network evolution. This feedback mechanism enables the receiving device to proactively adjust its forwarding state, reducing forwarding errors while minimizing connectivity interruption by coordinating the disablement timing.
3Adaptability or versatility
If both L2VPN VPWS and EVPN VPWS services are supported on the same PE, then service versatility is improved, but the difficulty of managing and evolving between the two services increases
Solution Approach 1:
The pseudo-wire identification information is added locally to the route advertisement packets exchanged between PEs, allowing each PE to independently identify and manage its local L2VPN pseudo-wires during evolution to EVPN VPWS. This localized approach enables service versatility while keeping management complexity controllable by avoiding global reconfiguration.
Data Source
AI summary
A route advertisement method, a network device, and a computer storage medium are provided, and pertain to the field of communication technologies. According to this application, an EVPN SRv6 route advertisement packet is extended to carry pseudo-wire identification information of an L2VPN PW between a first network device and a second network device, to help find, based on the pseudo-wire identification information, a forwarding entry associated with the L2VPN PW, and further process the forwarding entry associated with the L2VPN PW, thereby evolving an MPLS forwarding-based L2VPN VPWS into an SRv6 forwarding-based EVPN VPWS, or evolving an MPLS forwarding-based L2VPN VPLS into an SRv6 forwarding-based EVPN VPLS. In addition, the MPLS forwarding-based L2VPN VPWS or VPLS can be evolved into another type of EVPN SRv6 network.