How To Create Your Hybrid Network

By R. Leigh Hennig | October 29, 2020

How To Create Your Hybrid Network

Over the past decade of cloud migration, organizations have learned that the “one cloud fits all” mentality rarely suits the operational and budget requirements of the modern enterprise. While we’ve seen many companies accelerate their cloud adoption to support remote work initiatives, it’s important to keep in mind that many companies still choose to operate applications in the data center as well.

While the cloud certainly has its benefits, only specific use cases are best suited for 100 percent cloud deployment. Oftentimes, those use cases apply to very small companies that are software-driven, leaving the majority of organizations left to find the best solution to connect their on-premise data centers with cloud resources. 

Applications no longer reside exclusively in the data center, and workloads no longer reside exclusively in one specific cloud. Hybrid networks are becoming more prevalent, as they can address security and compliance concerns while also simplifying IT infrastructure management.

Managing and creating a hybrid network is no easy task. Below are a few things to keep in mind when planning your hybrid network.

Don’t Become Overwhelmed with BGP

Border Gateway Protocol (BGP) is the protocol underlying the global routing system of the Internet. It is designed to exchange routing and reachability information between autonomous systems. While traditionally only service providers have had to use it, BGP is becoming increasingly prevalent inside the data center. For example, more and more, we’re seeing BGP used as an overlay routing protocol in spine-leaf Clos fabrics.

BGP allows you to connect with AWS Direct ConnectMicrosoft Azure ExpressRoute, or Google Connect. For connecting to these services -- and others like them -- it’s also a requirement. While the potential complexity of BGP might seem overwhelming, you can simplify your deployment to get your hybrid network off the ground, and focus on two path selection knobs: local preference (to influence outbound routing to the cloud from your on-prem), and AS path (to influence routing to your on-prem from the cloud).

Choose Your Connection Method

There are multiple ways to connect your hybrid on-prem and cloud environments. Some of the most common include direct fiber attachment with a single leg, direct fiber attachment with multiple legs, single VPN tunnel, multiple VPN tunnels, and direct fiber attachment with VPN failover.

When deciding between options, it’s important to consider how each differs with respect to price, latency, availability, and throughput. Direct fiber attachments provide low latency and high speed, but take longer to deploy than setting up VPN tunnels over existing WAN connections, and are more expensive. VPNs are faster to deploy and more cost-effective, but depend heavily on the Internet weather, often subject to unpredictable latency and constrained throughput. 

Regardless of which method you choose, it’s important to plan your traffic flow accordingly.

Plan Your BGP Path Selection

BGP follows a set of rules when deciding which path to take across a network, and order is important. BGP will either choose the path with the highest preference, the path that was locally originated instead of the one learned externally, or the destination that has the shortest AS path, to name a few.

Key Considerations

In addition to the knobs BGP provides you, consider as well the community tags your provider supports. These influence how the recipient will treat your traffic.

Don’t forget to consider how BGP interacts with internal routing protocols, and consider how you’re going to redistribute routes to or from BGP to your IGP running on-prem, such as OSPF or EIGRP.

Once you’ve validated your configuration, test it out! Do alternate paths fail over as expected? Are you certain you’re able to control inbound and outbound traffic both during a planned maintenance, and during an emergent event?

A hybrid network provides the reliability and security of a private network, with the scalability and cost-effectiveness of the public Internet. Hybrid networks can help your organization remain agile, support business growth, optimize cloud deployment, and enable innovation.

To learn how Markley can help support you to create your hybrid network, please reach out to our team:

For more detail on hybrid networks, read the full guide: