{"id":4291,"date":"2022-04-01T13:58:00","date_gmt":"2022-04-01T11:58:00","guid":{"rendered":"https:\/\/blog.besharp.it\/?p=4291"},"modified":"2022-04-01T14:46:53","modified_gmt":"2022-04-01T12:46:53","slug":"hybrid-cloud-networking-backup-aws-direct-connect-network-connection-with-aws-site-to-site-vpn","status":"publish","type":"post","link":"https:\/\/blog.besharp.it\/hybrid-cloud-networking-backup-aws-direct-connect-network-connection-with-aws-site-to-site-vpn\/","title":{"rendered":"AWS Direct Connect with AWS Site-To-Site VPN as a failover"},"content":{"rendered":"\n

Introduction<\/h2>\n\n\n\n

Today, many solutions require approaches that implement a joint use of public cloud providers and their own on-prem resources. In this series of articles, we provide an overview of useful AWS services to build a hybrid network that seamlessly extends workloads from local installations to the public cloud according to business needs. <\/p>\n\n\n\n


In some scenarios, hybrid cloud networks rely on AWS Direct Connect (DX)<\/strong>. This service provides another option rather than the public internet to connect to AWS by delivering data through a private network connection<\/strong> between<\/strong> the on-premise facility<\/strong> and the AWS cloud<\/strong>. <\/p>\n\n\n\n

If you like to know more about Direct Connect, please check our previous blog post<\/a>. It explains what it is and how to choose it regarding some specific needs.<\/p>\n\n\n\n

In some cases, this connection alone is not enough. It is always better to guarantee a fallback connection<\/strong> as the backup of DX. There are several options, but implementing it with an AWS Site-To-Site VPN<\/strong> is a real cost-effective solution that can be exploited to reduce costs or, in the meantime, wait for the setup of a second DX.<\/p>\n\n\n\n

Please bear in mind that this solution does not ensure an SLA, and it is impossible to obtain it with a connection over the public internet. <\/p>\n\n\n\n

High-Level Architecture<\/h1>\n\n\n\n

This article will progress on what has already been put in place in the previous article (Hybrid Cloud Networking: centralized NAT Gateway through AWS Transit Gateway)<\/a>. We presented how to set up a Transit Gateway and share network appliances between AWS Accounts. So, please, it might be helpful to read it first to fully understand what will be explained here. <\/p>\n\n\n\n

Let’s assume that a fictitious company currently wants to connect its own on-premises facilities with the AWS Accounts directly to a DX connection by using a VPN Site-To-Site as a backup.<\/p>\n\n\n\n

Before proceeding, it is required that a Direct Connect has been already requested and ordered. Plus, the whole AWS networking has been centralized through Transit Gateway.<\/p>\n\n\n\n

As shown below, the connection between the local facility and AWS through the Direct Connect private connection can be configured by directly attaching the DX to the AWS Transit Gateway.<\/p>\n\n\n\n

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Let’s dive in: <\/strong><\/p>\n\n\n\n

Direct Connect offers a location over a standard Ethernet fiber-optic cable. One end is connected to the on-prem router, and the other to the AWS DX router. A user can associate it directly with the Transit Gateway through the Transit Virtual Interface (VIF)<\/strong>. This specific interface is different from the private\/public interface because it is linked directly with the Transit Gateway. This enables connectivity to all VPCs that share an attachment. <\/p>\n\n\n\n

Be careful! Please note that it is possible to attach only 1 transit virtual interface for DX dedicated connection. This limit cannot be increased. <\/a><\/p>\n\n\n\n

After the setup has been done, the company wants to use the site-to-site VPN <\/strong>as a backup. It consists of an encrypted link, called VPN tunnel, that connects the on-prem site with AWS. Each VPN connection includes two VPN tunnels which can simultaneously be used for high availability<\/em>. <\/p>\n\n\n\n

In our case, the two endpoints will be the Customer Gateway (CGW) for the on-prem side and the Transit Gateway for the AWS one.<\/p>\n\n\n\n

Please note that VPN has a couple of limits that must be taken into account in this design:<\/p>\n\n\n\n