Bright future of SRv6
As the demand for high-speed connectivity continues to grow, advanced networking technologies like Segment Routing over IPv6 (SRv6) are becoming more and more important. I've been following the progress of SRv6 in the service providers’ access network, and I'm convinced that it's going to change the game for everyone involved.
Let me give you a bit of background: traditionally, service providers have relied on Provider Edge (PE) routers in the first or second aggregation layer to provide connectivity to the cell site. While this has worked in the past, it's becoming clear that these devices may no longer have the granular view of the network traffic needed to support edge devices, advanced routing, and traffic engineering solutions.
The good news is that having SRv6 devices as PE routers on the cell site can offer a more efficient and flexible way to deliver services to the RAN nodes and edge devices. Not only does it reduce network complexity, but it also improves network scalability.
Traffic Separation (L3VPN), Inter-domain end-to-end Traffic Engineering, Network Slicing, SLA enforcement, and sub-50ms path restoration in any topology (TI-LFA) are all capabilities of SRv6 which makes it the protocol of choice for backhaul networks for 5G and beyond. The application of EVPN on top of SRv6 leverages the same routing infrastructure to provide L2VPN services.
So, what are the advantages of SRv6?
For one, SRv6 only requires IPv6 connectivity from the current IGP (Interior Gateway Protocol, usually IS-IS or OSPF). This means that legacy protocols for label signaling (like LDP and RSVP) are no longer needed and can be phased out of the network.
Additionally, SRv6 dramatically reduces inter-domain host routes in the network, enabling any-to-any traffic capability without requiring the routers' control plane to grow to an uneconomic scale.
One of the more important advantages of Segment Routing is the ability to implement network features across multiple domains. We can apply service termination, TE (Traffic Engineering), across routing domains without the need for the border routers to redistribute additional routing information.
Another advantage of SRv6 is its better integration with cloud services than (SR-)MPLS. It can be used to implement network functions directly in the cloud and mobile core, stretching the L2/L3VPN to the end node. This makes it easier to deploy and manage cloud-based services and can help reduce costs by eliminating the need for specialized hardware and complex service termination on the DCGW (Data Center Gateway).
At Ericsson, we've been working hard on developing a complete router portfolio that implements SRv6 natively without any performance degradation. These products implement the latest generation merchant ASIC chipsets for cell site (C-RAN and D-RAN), pre-aggregation, aggregation, DC gateway, and Cloud RAN use cases.
We've also been participating in industry events and working with our IP routing partners to develop migration- and interworking solutions.
From the end of 2022, we have progressively introduced support for SRv6 on the latest members of the Router 6000 family – Router 6673 and Router 6273. Two new routers (Router 6676 and Router 6678), as announced at Mobile World Congress, will also support SRv6 natively.
These SRv6-capable Router 6000 variants provide a greater degree of future-proofing for CSPs compared to previous-generation merchant silicon that does not have official support for SRv6.
As standards for SRv6 are solidifying, in Ericsson Solution Engineering, we are developing and testing migration- and interworking solutions with core IP leading vendors in the industry. Participation at EANTC multivendor interop testing event with SRv6 is one example of Ericsson’s dedication to SRv6.
While both SR-MPLS and SRv6 have their strengths and weaknesses, I believe SRv6 will evolve to be the protocol of choice for future backhaul networks. SRv6 is simpler, more scalable, and more flexible, provides native support for network functions, and has better integration with cloud services. As such, I expect network operators will consider deploying SRv6 in their networks to optimize their performance, reduce costs, and provide better services to their customers.
“Superior RAN implies a superior transport network”
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