Turning the Network: Lessons learned from redeploying an ISP's network

This talk will go through the process Cox Business went through to upgrade our internal network. At the beginning of the project, the network consisted of a number …

This talk will go through the process Cox Business went through to upgrade our internal network. At the beginning of the project, the network consisted of a number of separate islands, with separate OSPF area 0s, different metrics, different BGP policies, and utilizing basic point-to-point pseudowires between specially configured nodes to manage cross-market functionality. The end product is a cohesive nationwide multi-instance multi-topology IS-IS domain, with IPv4 and IPv6 routing capabilities, consistent BGP topologies supporting L2VPNs, L3VPNs, and SDN, and a defense-in-depth security model applied. This talk will go through the phases of the project, from initial concept to our final deployments, with focuses on not only the technology deployed, but also a lot of the “lessons learned” from the work. The different phases included initial project scoping, an initial high level design, consulting with other engineers both internally and externally, and numerous revisions to the HLD, low-level design, testing, and deployment. The large amount of time spent on the HLD and corresponding low-level design and testing resulted in a deployment that had no impact to end customers, and only one minor issue that arose during the work. The presentation is aiming to talk more about the “whys”, as opposed to straight configuration examples. While some configurations will be shown, they are presented in the context of highlight where issues were buried, or other neat tricks utilized to work around issues. The final section will include both “Why We Did” and “Why We Didn’t” sections, diving more into the thinking that led to the decisions made.