VMware validated design for BGP peering between NSX Edges and PE

Products

• VMware NSX

Issue/Introduction

The core issue identified with the "Design1" is the introduction of unnecessary complexity at the physical layer by cross-connecting both VLAN 100 and VLAN 200 to both Provider Edge (PE) routers. While the design achieves required redundancy, the complexity makes troubleshooting difficult and potentially requires more intricate routing policies (route maps) on the physical routers to ensure deterministic traffic paths.

Cause

The cause stems from the "Design1" philosophy of having both PE1 and PE2 terminate both VLAN 1 and VLAN 2 connections.

• This approach complicates BGP session management and traffic path assurance due to overlapping VLANs across both PEs.
• It requires more complex configurations on the physical switches and routers, such as additional Switched Virtual Interfaces (SVIs), which increases the potential for configuration errors and management overhead.

Resolution

The "VMware Design" provides the resolution by simplifying the physical network implementation while maintaining the same high availability and Equal-Cost Multi-Path (ECMP) benefits.

• Simplified Physical Layer: Each physical router (PE1 and PE2) only needs to be aware of one specific VLAN on its link to the Edge cluster (VLAN 100 to PE1, VLAN 200 to PE2).
• Cleaner Alignment: This setup naturally aligns with the NSX operational model for Active-Active T0 gateways, making the design cleaner and easier to troubleshoot.

 

Functional Differences and Preference

• Functional Differences: Both designs provide high availability and ECMP routing. However, the "Design1" introduces significant complexity at the physical and routing policy layers compared to the "VMware Design". The "VMware Design" simplifies physical switch configurations and reduces the number of required SVIs.
• Preference: The "VMware Design" is preferred because it offers a much cleaner, more standard, and less complex physical network implementation while delivering the same benefits. This results in easier management, troubleshooting, and better alignment with the intended operational model

Additional Information

Reference doc: NSX Edge Networking Setup