Cilium Feature Proposal

Describe the feature you'd like

VXLAN is used in the context of egress gateway (possibly in other contexts as well but I'm not aware of that). If Hubble included some info from VXLAN headers into a flow, we would be able to distinguish between egress gateway traffic and other VXLAN traffic.

(Optional) Describe your proposed solution

I don't think Cilium currently emits VXLAN packets today. If it doesn't, then the initial step to take is to add VXLAN headers to monitor events. The next step is to implement a VXLAN header parser in Hubble. At a minimum, we probably want to extract the VNI and the outer IP header.