What we learned after implementing SRv6 in modern networks, and how you can use it tomorrow.
Have you ever wished you could just “program” your network? Imagine a world where you could tell your packets exactly where to go, what to do, and how to behave—all from the source router. That’s exactly what Segment Routing over IPv6 (SRv6) offers: the power to shape traffic flows with precision, all while eliminating the complex, error-prone processes of traditional tunneling and per-flow states.
What most teams do today?
Network teams often struggle with traditional tunneling protocols like MPLS, which require maintaining complex per-flow states in each router. These methods are hard to scale and lack the flexibility that modern networks demand. Service chaining requires manual stitching of middleboxes, and the whole process often ends up being inefficient and costly.
Why it fails?
As modern networks scale and evolve with the growth of cloud applications, 5G, and IoT, legacy network configurations become too complex. Multiple protocols, manual configuration of service chains, and per-flow state management slow down the network. Additionally, relying on separate tunneling protocols and middleboxes adds more layers of complexity that are hard to maintain and troubleshoot.
Framework / Approach
Step 1: Define
SRv6 provides a modern solution by leveraging IPv6 and Segment Identifiers (SIDs). The concept is simple: each packet carries an embedded list of SIDs that guide its journey through the network, removing the need for per-flow state or complex tunneling.
Step 2: Diagnose
The problem with traditional networks is the reliance on protocols that require constant updates and per-flow configurations. This becomes unsustainable at scale. SRv6 simplifies this by treating the network as a programmable fabric, where the path of the packet is explicitly defined by the source router, and core routers need only read and forward the active SID.
Step 3: Decide
SRv6 integrates seamlessly into existing IPv6 networks, making it the ideal choice for modern service provider networks and data centers. It enables precise traffic steering, service chaining, and failover mechanisms without additional protocols.
Step 4: Deliver
With SRv6, engineers can:
- Create custom service chains with just a list of SIDs.
- Instantly reroute traffic in the event of failures, providing near-zero downtime.
- Program the path and behavior of network packets dynamically.
Case Study: Scaling a Global Network
A service provider struggled with manually managing service chains and maintaining stateful protocols like MPLS. This led to inefficiencies, particularly in their metro and core networks, affecting service delivery and scalability.
Actions taken
- Implemented SRv6 to replace MPLS and reduce protocol complexity.
- Designed a custom SID list to automate the service chain, allowing packets to traverse firewalls, load balancers, and application servers in sequence.
- Set up fast reroute (FRR) to quickly handle network failures, ensuring minimal disruption.
Results (numbers + timeline)
- The provider saw a 40% reduction in network overhead and complexity.
- Service provisioning time decreased by 30%, enabling faster service delivery.
- Failover times were reduced to sub-50ms, increasing overall network resilience.
What didn’t work (one candid lesson)
One of the challenges was planning the SID address space correctly. In the beginning, there was some confusion about how to assign SIDs without causing overlaps. However, once the addressing scheme was clarified and documented, the process ran much smoother.
Playbook / Checklist
- SID Address Planning: Carefully plan your SID address space to ensure consistency and avoid collisions.
- Fast Reroute Testing: Set up TI-LFA (Fast Reroute) to guarantee that backup paths are ready in case of failures.
- Automate Configuration: Use SDN platforms to automate SID assignment and policy deployment to streamline operations.
How to start in 30 minutes
- Set up SRv6 on a router that supports IPv6 extension headers.
- Plan and allocate your SID space.
- Configure basic service chaining by adding SIDs to the IPv6 header.
Conclusion & Next Step
SRv6 represents the future of network routing, offering unparalleled flexibility, scalability, and simplicity. By adopting SRv6, you can build networks that are easier to manage, more resilient, and better equipped to handle modern traffic demands. To get started, experiment with SRv6 in a test environment and start leveraging its benefits in your production network.
At TelenceSolutions
We continue to help professionals build scalable, intelligent networks through real-world, hands-on learning — from OSPF and IS-IS fundamentals to BGP, SD-WAN, and AI-driven automation.