Validate continuous and event-driven OpenConfig gNMI streaming telemetry for BGP operational state on the DUT. Verify telemetry accuracy and subscription latency for session transitions (ESTABLISHED, IDLE), prefix telemetry counters (received, sent, installed), max-prefix warning/teardown events, and multiprotocol L3VPN state exports for streaming telemetry collectors.

• TESTBED_DUT_ATE_2LINKS (ATE Port 1 simulating Customer CE peer; ATE Port 2 simulating Core iBGP peer).

graph LR;
  ate1[ATE Port 1: Customer CE] -- "eBGP Session" --> dut1[DUT Port 1: Tenant VRF]
  dut2[DUT Port 2: Core Transit] -- "iBGP Session" --> ate2[ATE Port 2: Core Route Reflector RR]
  dut1 -- "gNMI Subscribe STREAM" --> collector[Collector / Telemetry Client]

1. Configure tenant VRF ce1 and establish eBGP session on DUT Port 1 (192.0.2.1/30) with ATE Port 1 (192.0.2.2, AS 65001).
2. Configure max-prefix limit on DUT for ATE CE: max-prefixes 100, warning-threshold-pct 80 (80 prefixes).
3. Establish gNMI Subscribe session in STREAM mode with SAMPLE and ON_CHANGE subscription modes targeting:
   • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/state/
   • /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/afi-safis/afi-safi/state/prefixes/

• Step 1: Establish BGP session with ATE CE.
• Step 2: Subscribe to /network-instances/network-instance[name=ce1]/protocols/protocol[identifier=openconfig-policy-types:BGP][name=BGP]/bgp/neighbors/neighbor[neighbor-address=192.0.2.2]/state/session-state.
• Step 3: Verify initial stream update reports ESTABLISHED.
• Step 4: Simulate peer flap by administrative shutdown on ATE CE.
• Step 5: Verify event-driven ON_CHANGE gNMI update is streamed with session-state: IDLE in less than 10 seconds.
• Step 6: Verify established-transitions and last-established timestamps update accurately.

• Step 1: ATE CE advertises 50 IPv4 routes (198.51.100.0/24 block) and 25 IPv6 routes (2001:db8:100::/48 block), while DUT advertises 10 IPv4 routes (203.0.113.0/24 block) to ATE CE.
• Step 2: Subscribe to /network-instances/network-instance[name=ce1]/protocols/protocol[identifier=openconfig-policy-types:BGP][name=BGP]/bgp/neighbors/neighbor[neighbor-address=192.0.2.2]/afi-safis/afi-safi[afi-safi-name=openconfig-bgp-types:IPV4_UNICAST]/state/prefixes/received, .../state/prefixes/sent, and .../state/prefixes/installed.
• Step 3: Verify telemetry reports received: 50, installed: 50, and sent: 10.
• Step 4: ATE CE advertises 20 additional IPv4 routes (total 70 routes).
• Step 5: Verify telemetry stream updates promptly to received: 70 and installed: 70.

• Step 1: ATE CE advertises 15 additional routes (total 85 routes, exceeding the 80% warning threshold).
• Step 2: Verify the BGP session remains ESTABLISHED.
• Step 3: Verify telemetry state leaf /network-instances/network-instance[name=ce1]/protocols/protocol[identifier=openconfig-policy-types:BGP][name=BGP]/bgp/neighbors/neighbor[neighbor-address=192.0.2.2]/afi-safis/afi-safi[afi-safi-name=openconfig-bgp-types:IPV4_UNICAST]/ipv4-unicast/prefix-limit/state/prefix-limit-exceeded or vendor warning event is streamed to telemetry client.

• Step 1: ATE CE advertises 20 additional routes (total 105 routes, exceeding the hard limit of 100).
• Step 2: Verify the DUT tears down the BGP session and sends a Notification (Cease / Maximum Number of Prefixes Reached).
• Step 3: Verify telemetry stream emits session-state: IDLE and /network-instances/network-instance[name=ce1]/protocols/protocol[identifier=openconfig-policy-types:BGP][name=BGP]/bgp/neighbors/neighbor[neighbor-address=192.0.2.2]/state/last-prefix-limit-exceeded timestamp updates to indicate max-prefix limit violation.

{
  "network-instances": {
    "network-instance": [
      {
        "name": "ce1",
        "protocols": {
          "protocol": [
            {
              "identifier": "openconfig-policy-types:BGP",
              "name": "BGP",
              "bgp": {
                "neighbors": {
                  "neighbor": [
                    {
                      "neighbor-address": "192.0.2.2",
                      "afi-safis": {
                        "afi-safi": [
                          {
                            "afi-safi-name": "openconfig-bgp-types:IPV4_UNICAST",
                            "ipv4-unicast": {
                              "prefix-limit": {
                                "config": {
                                  "max-prefixes": 100,
                                  "warning-threshold-pct": 80
                                }
                              }
                            }
                          }
                        ]
                      }
                    }
                  ]
                }
              }
            }
          ]
        }
      }
    ]
  }
}

paths:
  # Operational State
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/state/session-state:
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/state/last-established:
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/state/established-transitions:
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/state/last-prefix-limit-exceeded:
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/afi-safis/afi-safi/ipv4-unicast/prefix-limit/state/prefix-limit-exceeded:
  # Prefix Counters
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/afi-safis/afi-safi/state/prefixes/received:
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/afi-safis/afi-safi/state/prefixes/sent:
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/afi-safis/afi-safi/state/prefixes/installed:

rpcs:
  gnmi:
    gNMI.Subscribe:

• FFF