At the beginning of 2024, I looked at configuring a very basic SRv6 L3VPN service using VyOS. During that effort, I ran into a critical caveat in which CE traffic was not being forwarded until locally sourced traffic on each PE was transmitted.
Issue The trace below demonstrates a sequence of CE1 sourced ICMP echo packets destined for CE5. We can see that they were encapsulated in an SRv6 packet by noting the destination prefix as the End.
In a previous post, I wrote about my experiences with using FRR on Ubuntu to provide L3VPN services over Segment Routing on IPv6 (SRv6).
Since then a new major version of FRR has become available and I thought it may be time to revisit this configuration to see if I still experience the same issues.
Success TL;DR - I am happy to report that IPv4 and IPv6 L3VPN mostly works out of the box.
In this post we take a look at configuring Segment Routing IPv6 (SRv6) using VyOS. For those unfamiliar, VyOS is an open-source routing platform built on top of Debian Linux and features a commit-based configuration system similar to Juniper’s JUNOS. It originated as a fork of Vyatta Core in late 2013 after Brocade stopped development. If you are new to VyOS, it is recommended to read the quick start guide before continuing.
It is no secret that Segment Routing over MPLS offers a lot of promise and provides a simple path for network operators to migrate from existing LDP and RSVP-TE based networks. However, what if I told you that you could do even more with SR and not even run MPLS at all? What if then I told you that these nodes could be located anywhere with IPv6 access and physical adjacency is not even required?
In this lab we explore Segment Routing (SR) using Multiprotocol Label Switching as an encoding mechanism.
Segment Routing, also known as “Source Packet Routing in Networking” (SPRING), is a method of routing in which ingress routers prepend instructions to traffic that cause actions to be performed by transit nodes as it travels across a network. This is sometimes as simple as a list of routers a packet must traverse to reach its destination.
Jonathan Voss