Networking for SAP RISE

Networking for SAP RISE on Azure: A Comprehensive Guide

Introduction: The Backbone of SAP RISE

When organizations decide to transition their core business processes to SAP RISE, they are essentially outsourcing the management of their SAP environment to SAP. While SAP handles the application layer and the underlying operating system maintenance, the customer remains responsible for the connectivity between their corporate network and the SAP-managed Azure environment. Networking is the foundation upon which this entire relationship rests. If the network is improperly configured, users will experience latency, application timeouts, and, in the worst-case scenario, a complete inability to access critical business data.

This lesson explores the intricacies of networking for SAP RISE on Azure. We will move beyond simple connectivity concepts and dive into the architecture of virtual networks, the nuances of private versus public endpoints, and the critical importance of security and latency management. Whether you are an architect planning the migration or a network administrator tasked with maintaining the link, understanding how data flows between your on-premises infrastructure and the SAP-managed Azure subscription is vital for a successful deployment.

Understanding the SAP RISE Networking Model

SAP RISE on Azure is hosted within a dedicated Azure subscription managed by SAP. From a networking perspective, this creates a "split-brain" scenario where your resources live in your Azure tenant, and your SAP application lives in the SAP-managed tenant. To make these two environments communicate, we must establish a secure, private, and high-performance bridge.

The Connectivity Architecture

The most common approach for connecting your corporate network to the SAP RISE environment is through a combination of Azure ExpressRoute and Virtual Network (VNet) Peering. Because the SAP RISE workload sits in a separate subscription, you cannot simply perform a standard VNet peering as you would within your own environment. Instead, SAP utilizes a concept often referred to as "Managed Connectivity" or "Cross-Subscription Connectivity."

Callout: The Shared Responsibility Model in Networking It is important to distinguish between what SAP manages and what you manage. SAP is responsible for the VNet where the SAP application servers and database reside. They manage the Network Security Groups (NSGs) and routing tables within that specific VNet. You are responsible for your own on-premises connectivity, your local firewalls, and the VNet where your application integration or user-facing services reside. The "Handshake" happens at the peering point between your VNet and the SAP-managed VNet.

Key Components of the Network Path

1. On-Premises Data Center: This is the starting point for your traffic. It usually connects to Azure via a physical or virtual circuit.
2. Azure ExpressRoute: This provides a private, dedicated connection that bypasses the public internet. It is the industry standard for SAP workloads because it ensures consistent latency and higher security.
3. Azure Virtual Network (VNet): Your "landing zone" in Azure. This is where your integration services, reporting tools, and user access points live.
4. VNet Peering (Cross-Subscription): The logical link that connects your VNet to the SAP RISE VNet.
5. SAP RISE VNet: The destination environment where the SAP S/4HANA system is deployed.

Designing for Latency and Throughput

SAP applications are notoriously sensitive to network latency. A high round-trip time (RTT) between the user and the application server can lead to significant degradation in the user experience, while latency between the application server and the database can cause the application to crash or time out.

The 10ms Rule

Industry standards for SAP on Azure dictate that the latency between the application server and the database should ideally be under 1ms. For user interaction, the round-trip time between the user's browser or GUI and the SAP application server should generally be kept below 100ms. If your users are distributed globally, you must design your network to minimize the distance data must travel.

Optimizing the Path

To maintain these metrics, you should:

• Colocate Resources: Try to deploy your integration points in the same Azure region as the SAP RISE environment. If SAP is in "East US," your integration VNet should also be in "East US."
• Avoid Hairpinning: Do not route traffic through your on-premises firewall if it is not necessary. If a cloud-native service needs to talk to the SAP RISE environment, ensure that the traffic stays within the Azure backbone.
• Monitor with Azure Network Watcher: Use tools like Connection Monitor to track latency continuously. If you see spikes, investigate whether your ExpressRoute circuit is saturated or if there is a routing misconfiguration.

Note: Always perform a latency baseline test before the migration. If you cannot meet the required latency thresholds during the testing phase, you will likely struggle once the system goes live.

Implementing Cross-Subscription Connectivity

Connecting your environment to the SAP-managed subscription requires careful coordination with SAP. You cannot simply initiate a peering request; you must work through the SAP Service Request (SR) process.

Step-by-Step: Establishing the Connection

1. Gather VNet Details: Identify the VNet ID and the address space of your VNet. You must ensure there is no IP address overlap with the SAP RISE VNet.
2. Submit a Request to SAP: Use the SAP Launchpad or the designated support portal to request a VNet peering. You will need to provide your VNet details and the required access permissions.
3. Accept the Peering Request: Once SAP initiates the peering from their side, you will see a request in the Azure Portal under your VNet's "Peerings" blade. You must approve this request.
4. Configure Routing: Update your User Defined Routes (UDRs) to ensure that traffic destined for the SAP RISE IP ranges is directed toward the peering connection.

Code Snippet: Validating VNet Peering via Azure CLI

You can use the Azure CLI to verify that your peering connection is active and healthy. This is useful for automated health checks.

# Verify the status of the peering connection
az network vnet peering show \
  --resource-group MyResourceGroup \
  --vnet-name MyVNet \
  --name MyPeeringToSAP \
  --query "peeringState" \
  --output tsv

# Expected output: "Connected"

Explanation: This command queries the status of the peering. If the output is "Initiated," it means the request has been sent but not yet accepted or fully configured by the other side. "Connected" indicates that the tunnel is fully established.

Security and Traffic Filtering

Just because you are connected to the SAP RISE environment does not mean you should open all ports. Security is a shared responsibility, and you must protect your own VNet from potential lateral movement or unauthorized access.

Network Security Groups (NSGs)

NSGs act as a firewall for your VNet. You should implement a "least privilege" model. If you have an application that only needs to talk to the SAP system via OData services, only open port 443. Do not open the entire range of SAP GUI ports unless explicitly required.

Azure Firewall and NVA

For more complex scenarios, you might want to inspect traffic between your network and the SAP RISE network. You can deploy an Azure Firewall or a Network Virtual Appliance (NVA) in your VNet. All traffic destined for SAP would be routed through this firewall, allowing you to log and filter traffic according to your organization's security policy.

Warning: Be careful with routing traffic through an NVA. If the NVA becomes a bottleneck or goes down, your SAP connectivity will be severed. Always ensure your NVA deployment is highly available and sized appropriately for the expected traffic throughput.

Traffic Filtering Best Practices

• Use Service Tags: When configuring NSGs, use Azure Service Tags like VirtualNetwork or AzureCloud instead of hardcoding IP addresses where possible.
• Log Everything: Enable NSG flow logs. This allows you to audit who is talking to the SAP RISE environment and provides valuable data for troubleshooting connection issues.
• Restrict Inbound: Ensure that your SAP integration points are not exposed to the public internet. Use Private Links where possible to keep traffic on the Microsoft network.

Handling DNS and Name Resolution

One of the most common points of failure in SAP RISE migrations is DNS. Your local environment needs to resolve the hostnames of the SAP application servers, and the SAP environment may occasionally need to communicate with your internal services.

Private DNS Zones

The best way to handle this is through Azure Private DNS Zones. You can link your VNet to a Private DNS Zone that contains the records for the SAP RISE environment. This ensures that when your application tries to connect to s4hana.internal.sap, it resolves to the correct private IP address.

DNS Forwarding

If you have a complex on-premises DNS infrastructure, you might need to use an Azure DNS Private Resolver. This allows your on-premises servers to query the Azure DNS directly, bridging the gap between your local Active Directory and the cloud-based name resolution.

Troubleshooting Common Networking Issues

Even with a perfect design, issues will arise. Being prepared to troubleshoot is as important as the design itself.

The "Can't Connect" Checklist

When a user reports they cannot connect to the SAP system, follow this systematic approach:

1. Check the Peering Status: Is the VNet peering showing as "Connected"?
2. Test Connectivity: Use the tcpping utility or Test-NetConnection in PowerShell to test specific ports.
   • Example: Test-NetConnection -ComputerName <SAP_IP> -Port 3200
3. Verify Routing: Does your VNet routing table show the correct route to the SAP VNet? Check for conflicting UDRs.
4. Review NSG Logs: Check if a security rule is dropping the traffic.
5. Check ExpressRoute Health: If you are connecting from on-premises, is the circuit up? Use the ExpressRoute circuit monitoring tools in the Azure Portal.

Comparison Table: Connectivity Options

Best Practices for Long-Term Success

To ensure your SAP RISE network remains reliable, adhere to these industry-standard practices:

• IP Address Management (IPAM): Start by planning your IP address space carefully. Avoid address space overlaps at all costs, as they are notoriously difficult to fix after the fact.
• Automation: Use Infrastructure as Code (IaC) tools like Terraform or Bicep to manage your VNet and routing configurations. This ensures consistency and prevents manual configuration drift.
• Monitoring: Implement proactive monitoring. Don't wait for a user to report a slowdown. Set alerts for latency thresholds, ExpressRoute circuit errors, and high traffic volume on your peering connections.
• Documentation: Keep a detailed network diagram of your connectivity to the SAP RISE VNet. Include IP ranges, peering names, and the contact information for your SAP support liaison.

Callout: Why "Public" is the Enemy In the world of SAP RISE, the public internet is not your friend. While it is tempting to use public IP addresses for ease of setup, this exposes your critical business data to unnecessary risk. Always prioritize private connectivity (ExpressRoute) and private endpoints. If you find yourself needing to open a public port for an SAP service, stop and ask if a Private Link or a VPN tunnel could be used instead.

Common Pitfalls and How to Avoid Them

Pitfall 1: Overlapping IP Ranges

This is the most common issue. If your corporate network uses the 10.0.0.0/16 range and the SAP RISE VNet also uses 10.0.0.0/16, you will have an IP conflict that makes routing impossible.

• The Fix: Conduct a thorough IP audit before the project begins. Use non-overlapping RFC 1918 address spaces for all your Azure workloads.

Pitfall 2: Neglecting Routing Tables

Sometimes the peering is "Connected," but traffic still doesn't flow. This is usually because the routing table (UDR) is missing a route to the SAP VNet.

• The Fix: Ensure every subnet that needs to talk to SAP has an associated route table that explicitly points the SAP address range to the Peering connection.

Pitfall 3: Ignoring MTU Sizes

Large packets can sometimes be dropped if the Maximum Transmission Unit (MTU) size is not consistent across the network path.

• The Fix: Ensure your ExpressRoute and VNet configurations support standard MTU sizes. If you are using VPNs in conjunction with ExpressRoute, be aware of the overhead that encapsulation adds.

Pitfall 4: Lack of Redundancy

A single ExpressRoute circuit is a single point of failure. If the provider has an outage, your SAP system goes offline.

• The Fix: For critical production workloads, always deploy redundant ExpressRoute circuits, ideally from different providers or using different physical entry points (meet-me locations).

FAQ: Frequently Asked Questions

Q: Can I use a S2S VPN for SAP RISE production? A: While technically possible, it is strongly discouraged for production workloads due to latency and reliability concerns. ExpressRoute is the standard requirement.

Q: Does SAP RISE require a specific Azure region? A: SAP RISE is available in most Azure regions, but you must confirm availability for your specific geographic location and SAP version requirements.

Q: Who manages the firewalls inside the SAP RISE VNet? A: SAP manages the firewalls (NSGs) within their subscription to protect the SAP application. You have no control over these, nor do you need it.

Q: Can I connect my SAP RISE VNet to multiple on-premises locations? A: Yes, you can connect multiple ExpressRoute circuits or VPNs to your VNet, which then connects to the SAP RISE VNet. Ensure your routing is configured correctly to avoid asymmetric routing.

Q: What is the lead time for setting up this networking? A: The networking configuration itself is fast, but the coordination with SAP and the provisioning of circuits (if using ExpressRoute) can take weeks. Plan accordingly.

Key Takeaways

1. Foundation is Key: The network is the lifeblood of SAP RISE. A poorly designed network will result in a poor SAP experience, regardless of how well the application is configured.
2. Prioritize Private Connectivity: Always favor ExpressRoute over public internet-based connections to ensure low latency and high security.
3. Plan for IP Space: Never underestimate the difficulty of fixing overlapping IP ranges. Perform a comprehensive audit during the planning phase.
4. Shared Responsibility: Understand the boundary between your network responsibilities and SAP's responsibilities. You manage the bridge; they manage the destination.
5. Monitor and Alert: Proactive monitoring is essential. Use Azure tools to track latency and connection health so you can address issues before they become business-impacting outages.
6. Security First: Apply the principle of least privilege to your NSGs and firewalls. Keep traffic off the public internet by utilizing Private Links and private endpoints.
7. Redundancy Matters: For production workloads, build for failure. Redundant circuits and high-availability network designs are worth the investment for mission-critical SAP systems.

By following these guidelines and maintaining a structured, well-documented approach to your networking architecture, you can provide a stable and high-performing environment for your SAP RISE workloads. Remember that network engineering is an iterative process; as your business needs grow and change, your network architecture should evolve to match those demands. Keep your documentation updated, maintain your monitoring tools, and always prioritize the stability and security of the connection between your users and their data.