SAP Networking and Connectivity on AWS

Let's start with the most basic idea: a network is simply a way for computers to talk to each other. AWS provides a virtual network called a VPC (Virtual Private Cloud). Think of a VPC as a private, fenced-off piece of the AWS cloud that only you can access. Inside this VPC, you launch servers (Amazon EC2 instances) that run SAP applications like SAP S/4HANA or SAP NetWeaver.

For SAP systems to function, they must communicate with each other. For example, an SAP application server needs to query an SAP HANA database. This internal traffic stays inside the VPC. But the real world is more complex. Your company headquarters, branch offices, and external partners also need to reach the SAP system. That's where connectivity comes in.

AWS offers three primary ways to connect external networks to your VPC: VPN (Virtual Private Network), Direct Connect, and Transit Gateway. Let's define each.

A VPN creates an encrypted tunnel over the public internet. Imagine sending a letter inside a locked briefcase through the postal service. The briefcase is the encryption; the postal service is the internet. VPNs are simple to set up and use existing internet connections, but they suffer from internet congestion and latency (delay). A Direct Connect is a physical, private cable that goes from your data centre or office directly into an AWS facility. It bypasses the public internet entirely, offering consistent speeds and lower latency. This is critical for SAP because SAP HANA replication and real-time data processing demand very low jitter (variation in delay).

AWS Transit Gateway acts as a central hub that connects all your VPCs and on-premises networks together. Without Transit Gateway, you would need to create dozens of individual connections, like stringing phone lines between every pair of offices. Transit Gateway is a single router that simplifies management and reduces complexity.

Every VPC has subnets - smaller segments of the IP address range. You can place SAP application servers in one subnet and database servers in another. To control who can talk to whom, you use Security Groups (stateful firewalls attached to individual servers) and Network Access Control Lists (NACLs), which are stateless firewalls at the subnet boundary. For SAP, you might allow only the application server subnet to talk to the database subnet on port 3$01$ for SAP HANA.

Routing is how data knows where to go. Each subnet has a route table that says: 'All traffic destined for the internet goes through the Internet Gateway' or 'Traffic for the corporate network goes through the Transit Gateway.' If you misconfigure routing, data gets lost, and your SAP system breaks.

High availability means making the network resilient. You can set up VPN connections in two different AWS regions or use two Direct Connect circuits from different providers. If one link fails, traffic automatically fails over to the other. This is called a redundant connection. SAP systems cannot afford downtime - a network outage means halted production lines in a factory or frozen financial closings.

Finally, bandwidth must be sized correctly. SAP HANA systems can generate gigabytes of data per hour. If you provision a 1 Gbps Direct Connect link but your replication actually needs 10 Gbps, the network becomes a bottleneck. The exam tests your ability to calculate required bandwidth and recommend the appropriate connection type.

An IT professional (let's call her Priya) works for a global manufacturing company deploying SAP S/4HANA on AWS. Her first task is to connect the company headquarters in London to the AWS environment so the finance team can access the SAP system.

Priya begins by assessing the company's traffic. The finance team runs daily reports that push 500 MB of data to the cloud. The HR team synchronises employee records using SAP Cloud Platform Integration, which adds another 200 MB daily. For this volume, a VPN connection over the internet would work, but the company's leadership demands consistent performance because month-end closing is non-negotiable. Priya selects Direct Connect as the primary connection.

She works with a Direct Connect Partner to order a 1 Gbps Direct Connect circuit from the London office to the nearest AWS Direct Connect location (in London). The circuit is physically installed. Priya then creates a Virtual Private Gateway in her AWS account and attaches it to her VPC. She configures a VLAN (Virtual Local Area Network) interface on the Direct Connect to carry traffic to the VPC. This is called a private virtual interface.

Next, Priya sets up a second Direct Connect circuit from a different provider for redundancy. She creates a VPN connection as a backup in case both Direct Connect circuits fail. She uses AWS Transit Gateway to connect the London VPC to a second VPC in Frankfurt that runs SAP BW (Business Warehouse). The Transit Gateway automatically routes traffic between the two VPCs without needing VPC peering.

To secure traffic, Priya creates Security Groups: one for SAP application servers (allowing TCP 3200, 3300 from the corporate network) and one for the HANA database (allowing only the application servers on TCP 3001$). She adds NACLs as a second layer, blocking all ports except those needed for SAP.

Throughout the process, she monitors network performance using Amazon CloudWatch metrics. She sets up alarms if latency exceeds 10 milliseconds or if throughput drops below 900 Mbps. At month-end, when the finance team processes closing, the Direct Connect link shows stable 950 Mbps utilisation with zero packet loss.

When a new factory opens in Madrid, Priya extends the network by ordering a smaller 500 Mbps Direct Connect circuit for that site and routing it through the existing Transit Gateway. The entire expansion takes two weeks, compared to months if she had to manage dedicated physical lines for each office.