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  • Pablo Camarillo, Technical Lead at Cisco
  • Clarence Filsfils, Cisco Fellow and Cisco
  • Ahmed Abdelsalam, Technical Lead at Cisco
  • Dennis Cai, Head of Network Infrastructure at Alibaba Cloud
  • Eddie Ruan, Director of Network System Software at Alibaba Cloud
  • Yuanchao Su, Director of Network Architecture & Planning at Alibaba Cloud

In the world of networking, collaboration between industry leaders is crucial to drive innovation and develop cutting-edge solutions to resolve critical biz problems. This blog post highlights the industry collaboration between Alibaba Cloud and Cisco in developing and deploying an SRv6 SONiC whitebox router to support Alibaba Cloud’s ‘Predictable Network’ vision, which supports all Alibaba Cloud services. We explore the value proposition of SRv6 as a unified protocol across different domains, the full-stack solution developed by the joint-forces of the community, and the results in deploying the solution in the production network of Alibaba.

As cloud becomes the new norm, cloud customers request more predictable network performance in terms of bandwidth, delay, jitter and packet loss etc., to support their LOB. For example, 1 second link flapping in the WAN may lead to a case raised by an online gaming customer on Alibaba Cloud, as their end customers would complain gaming experience impacted. The recent AI wave posts even more strict performance requirement on the underlying network. To resolve these new requirements, Alibaba Cloud initiates an open and high-performance network system called ‘Predictable Network’ in 2020. Alibaba Cloud and Cisco have joined forces to collaborate on the development of Predictable Network since then as both sides believe only SRv6 can provide the flexibility and scalability to support Alibaba’s future growth.

SRv6 is a novel architecture that provides a unified dataplane across all network domains (WAN, Metro, DC, Cloud, Host, Container), SRv6 uSID resolves the IPv6 header overhead issue by compressing the header very effectively. With proper IPv6 address schema planning, SRv6 eliminates the need for gateways at domain boundaries, simplifying operations and removing bottlenecks from the network. SRv6 uSID also offers less MTU overhead compared to alternatives, alongside with feature richness.

Built on top of IPv6, it benefits from IP summarization -thanks to IP longest prefix match- and load balancing -with the IPv6 Flow Label-. SRv6 uSID complements it enabling the creation of the various services, such as VPNs, Traffic Engineering, Network Slicing, and NFV policies, in a stateless and scalable manner. Alibaba has chosen SRv6 uSID for their Predictable Network design.

Alibaba Cloud is also willing to contribute SRv6 innovation to open source community. The appeal of an open-source network OS lies in its ability to be enhanced by the community and shared across different network equipment manufacturers, simplifying operations.

The SRv6 SONiC collaboration started in 2021 and quickly achieved the first milestone of an updated SAI header for SRv6. This joint effort introduced many SRv6 uSID features. The community development collaboration gained momentum, with major updates upstreamed by Alibaba Cloud and Cisco in the Nov 2022 releases of SONiC, which is largely deployed in Alibaba Cloud’s production network. In March 2023, the last building block of the solution was accomplished: FRR updates to support SRv6 uSID L3VPN services with BGP control-plane.

Today, we have a full-stack solution encompassing SAI, SONiC, and FRR, enabling seamless deployment and efficient operation of SRv6 uSID in whitebox routers. Alibaba has developed a custom SRv6 SONiC whitebox router in their production network to support critical biz, demonstrating the feasibility and effectiveness of running SONiC with SRv6 uSID in a whitebox

Announcement of the SONiC-based device in the APSARA 2022 conference.

As of now, this whitebox device with SONiC is actively routing live traffic in Alibaba’s network. The current implementation of FRR and SONiC supports an SRv6 uSID-based fabric with BGP services. However, the collaboration doesn’t stop here. Alibaba is looking to expand the SONiC device’s footprint, and development efforts in SAI, SONiC, and FRR continue. Notably, contributions have been made to enhance the routing capabilities(SONiC Routing WG is initiated by Alibaba Cloud), performance monitoring in the fabric including Path Tracing (Sept 2023 release of SAI). These efforts aim to drive further deployments of SONiC devices with SRv6 uSID worldwide.

In conclusion, the collaboration between Alibaba Cloud and Cisco has led to the development of an innovative SRv6 uSID whitebox router with SONiC. This unified protocol offers a powerful and efficient solution for network optimization and simplification across various domains. The full-stack solution, including SAI, SONiC, and FRR, enables seamless deployment and operation of SRv6 uSID. Alibaba Cloud has successfully deployed this solution in their production network and plans to expand the footprint of SONiC-based devices. The authors of this blog acknowledge and thank all the members of the SAI, SONiC, and FRR communities for their contributions in achieving this significant milestone.