Metering External Network Traffic with NSX-T

It is common for service providers to meter internet traffic consumption of their tenants. In NSX-V environment you could get any interface statistics of an Edge Service Gateway via NSX API or vCloud Director Networking API:
GET /api/4.0/edges/{edgeId}/statistics/interfaces

Let us explore the ways you can do similar metering in NSX-T environment.

We have three points where we can meter external traffic:

1. On Tier-0 or VRF uplink (if such object is dedicated to the tenant). The API to use is:
   
   GET https://{{host}}/policy/api/v1/infra/tier-0s/{tier-0 name}/locale-services/default/interfaces/{uplink-name}/statistics
   
   If the Tier-0/VRF is stretched across multiple Edge nodes you will need to aggregate the data across multiple uplinks.
   
2. On Tier-0/VRF router downlink to a specific Tier-1 GW. This is useful if the Tier-0 is shared across multiple tenants and their Tier-1 GWs. The API is not documented in the API docs.
   
   GET https://{{host}}/policy/api/v1/infra/tier-0s/{tier-0 name}/tier-1-interface/statistics/summary?tier1_path=/infra/tier-1s/{tier-1 name}
   
3. On CSP (Service Interface) of a Tier-1 (or Tier-0) GW for use cases where a particular VLAN is connected directly to tenant GW. The API to use is quite long and must include the enforcement point (edge node backing active Tier-1 GW)
   
   GET https://{{host}}/policy/api/v1/infra/tier-1s/{tier-1 name}/locale-services/{locale id}/interfaces/{CSP interface id}/statistics?enforcement_point_path=/infra/sites/default/enforcement-points/default&edge_path=/infra/sites/default/enforcement-points/default/edge-clusters/{edge-cluster-id}/edge-nodes/{edge-node-id}