F5 Virtual IP (VIP) and Floating IP Discovery Failure in Mobility Optimized Networking (MON)

Products

• VMware HCX

Issue/Introduction

When Mobility Optimized Networking (MON) is enabled for F5 BIG-IP virtual machines on a VMware HCX extended network, the F5 Virtual IP (VIP) and floating IP addresses are not discovered by HCX. This discovery failure prevents the system from programming the necessary host routes on the Tier-1 gateway. As a result, the VIP becomes unreachable from the extended network, even when connectivity to the backend servers and the F5 Self-IP remains functional.

• Connectivity to the F5 Virtual IP (VIP) or floating IP fails when MON is enabled on the extended segment.
• The F5 virtual machine (Self-IP) remains reachable.
• Backend servers attached to the same segment maintain connectivity.
• HCX Manager does not list the VIP or floating IP addresses in the MON configuration view for the virtual machine.

Environment

VMware HCX

Cause

HCX Mobility Optimized Networking (MON) relies on VMware Tools to identify IP addresses assigned to virtual machines. VMware Tools retrieves this information from the guest operating system's network interface configurations.

In F5 BIG-IP architectures, VIPs and floating IPs are managed by the F5 Traffic Management Microkernel (TMM) and are not bound to standard network interfaces (vNICs) in a way that the guest OS reports via standard networking commands (such as ifconfig or ip a).

Because these IPs are only visible through F5-specific management tools (e.g., tmsh), VMware Tools cannot detect them, and HCX is unable to automatically configure the required /32 host routes.

Resolution

The implementation of F5 VIPs and floating IPs is currently not a supported use case for Mobility Optimized Networking (MON).

HCX requires that all IPs intended for optimized routing be visible to VMware Tools and associated with a guest OS network interface on the extended segment.

 

 

Additional Information

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