Introduction
Understanding the nuances of SR-MPLS vs. SRv6 is crucial for network architects and engineers to make informed decisions when designing and implementing their network infrastructures. In the realm of networking, two prominent protocols, SR-MPLS and SRv6, stand at the forefront, each offering unique advantages and functionalities. SR-MPLS, an acronym for Segment Routing over Multiprotocol Label Switching, relies on IPv4/IPv6 IGP/BGP for its control plane and MPLS for its data plane. On the other hand, SRv6, also known as Segment Routing with IPv6 data plane, employs IPv6 IGP/BGP for its control plane and IPv6 for its data plane. These two protocols present distinctive attributes in terms of network simplification, programmability, cloud-network synergy, terminal collaboration, cross-AS deployment, large-scale deployment, service provisioning, reliability, and forwarding efficiency. Let’s dive deeper into this comparative analysis to unravel the complexities and advantages each protocol brings to the networking landscape.
Network Protocol Simplification:
- SRv6 relies on IPv6 IGP/BGP for its control plane and IPv6 for its data plane.
- On the other hand, SR-MPLS employs IPv4/IPv6 IGP/BGP for its control plane and MPLS for its data plane.
Programmability:
- SRv6 offers remarkable flexibility, empowering service orchestrators and various applications to specify networks and service chains based on SLAs and service requirements. This enables a high degree of programmability and adaptability.
- In contrast, SR-MPLS demonstrates poor programmability, limiting the versatility in terms of specifying networks and service chains.
Cloud-Network Synergy:
- SRv6 seamlessly integrates with Data Centre Networks (DCNs), making it easy for them to support IPv6. Furthermore, carrier networks can be extended to user terminals using SRv6 technology, showcasing its effortless integration capabilities.
- Conversely, SR-MPLS faces challenges in DCNs, including virtual machines, where supporting MPLS proves difficult.
Terminal Collaboration:
- SRv6 enjoys strong support from terminals, including compatibility with Linux 4.10 and later versions. Notably, Linux 4.14 supports most SRv6 functions, simplifying deployment with its Function field expressions.
- In contrast, terminals encounter difficulties in supporting MPLS, posing obstacles in this regard.
Cross-AS Deployment:
- SRv6 excels in cross-AS deployment, benefiting from IPv6 reachability that simplifies its implementation across ASs. The need for flooding host routes across ASs is minimized, resulting in a reduced number of routes and simplified routing policies.
- SR-MPLS, however, presents complexity in cross-AS deployment, limiting its use to SR-MPLS TE only. Inter-AS controllers are required, and the local PE necessitates the loopback host routes of remote PEs, adding intricacy to the process.
Large-Scale Deployment:
- SRv6 proves ideal for large-scale network planning, as SIDs (Segment IDs) leverage the expansive IPv6 address space.
- On the other hand, SR-MPLS faces challenges due to the limited SID (MPLS label) space, making unified planning and maintenance of device SIDs a complex endeavor.
Service Provisioning Difficulty:
- SRv6 offers agile service provisioning, supporting coexistence with common IPv6 devices as long as the ingress and egress support SRv6.
- In contrast, SR-MPLS demands upgrading all devices in an AS to support it, leading to complex service provisioning.
Reliability:
- Both SRv6 and SR-MPLS benefit from Topology-Independent Loop-Free Alternate (TI-LFA) for enhanced reliability.
Forwarding Efficiency:
- When considering L3VPN encapsulation, SRv6 requires an IPv6 header of at least 40 bytes, with an additional 16 bytes added each time a SID is incorporated into an SRv6 SRH.
- In contrast, SR-MPLS boasts smaller encapsulation headers, such as at least two MPLS labels (4 bytes each) required for L3VPN encapsulation, with only 4 bytes added each time a SID is appended to the SR-MPLS label stack. This results in higher forwarding efficiency.
Conclusion
In conclusion, SRv6 and SR-MPLS present distinctive attributes in terms of network protocol simplification, programmability, cloud-network synergy, terminal collaboration, cross-AS deployment, large-scale deployment, service provisioning, reliability, and forwarding efficiency. Understanding these nuances enables network architects and engineers to make informed decisions when designing and implementing their network infrastructures.