BGP Override AS-path split-horizon

graph LR
    subgraph ATE ["Automated Test Equipment (ATE)"]
        direction TB
        Port1_ATE["ATE Port 1<br/>(AS 65502)"]
        Port2_ATE["ATE Port 2<br/>(AS 65503)"]
    end

    subgraph DUT ["Device Under Test (DUT)"]
        direction TB
        Port1_DUT["DUT Port 1<br/>(AS 65501)"]
        Port2_DUT["DUT Port 2<br/>(AS 64513)"]
    end

    %% Peering Connections
    Port1_ATE <-->|eBGP| Port1_DUT
    Port2_ATE <-->|eBGP| Port2_DUT

    %% Styling
    classDef ateStyle fill:#f8f9fa,stroke:#3c4043,stroke-width:2px,rx:10,ry:10;
    classDef dutStyle fill:#e8f0fe,stroke:#1a73e8,stroke-width:2px,rx:10,ry:10;
    classDef nodeStyle font-family:sans-serif,font-size:12px;

    class ATE ateStyle;
    class DUT dutStyle;
    class Port1_ATE,Port2_ATE,Port1_DUT,Port2_DUT nodeStyle;

• Establish BGP Session: Configure and establish an eBGP session between the DUT (Port1) and the ATE (Port1).

• Baseline Test (No "allow-own-in"):
  • Advertise a prefix from the ATE (e.g., 192.168.1.0/24) with an AS-path that includes AS 65501 (DUT's AS) in the middle (e.g., AS-path: 65502 65500 65501 65499).
  • Verify that the ATE Port2 doesn't receive the route. due to the presence of its own AS in the path.
  • Validate session state and capabilities received on DUT using telemetry.

• Test "allow-own-as 1":
  • Enable "allow-own-as 1" on the DUT.
    • Re-advertise the prefix from the ATE with the same AS-path.
    • Verify that the DUT accepts the route.
    • Verify that the ATE Port2 receives the route.
    • Validate session state and capabilities received on DUT using telemetry.

• Test "allow-own-as 3":
  • Change the DUT's configuration to "allow-own-as 3".
  • Test with the following AS-path occurrences:
    • 1 Occurrence: 65502 65500 65501 65499
    • 3 Occurrences: 65502 65501 65501 65501 65499
    • 4 Occurrences: 65502 65501 65501 65501 65501 65499 (Should be rejected)
  • Verify that the ATE Port2 receives the route with 1 and 3 occurrences of AS 65501 but rejects it with 4 occurrences.
  • Validate session state and capabilities received on DUT using telemetry.

• Test "allow-own-as 4:
  • Change the DUT's configuration to "allow-own-as 4".
  • Test with the following AS-path occurrences:
    • 1 Occurrence: 65502 65500 65501 65499
    • 3 Occurrences: 65502 65501 65501 65501 65499
    • 4 Occurrences: 65502 65501 65501 65501 65501 65499
  • Verify that the ATE Port2 receives the route with 1, 3 and 4 occurrences of AS 65501.
  • Validate session state and capabilities received on DUT using telemetry.

• Test "allow-own-as 1":
  • Change the DUT's configuration to "allow-own-as 1".
  • Test with the following AS-path occurrence:
    • Occurrence: 65502 65500 65499 65501
  • Verify that the ATE Port2 receives the route of AS 65501.
  • Validate session state and capabilities received on DUT using telemetry.

{
  "network-instances": {
    "network-instance": [
      {
        "name": "DEFAULT",
        "config": {
          "name": "DEFAULT"
        },
        "protocols": {
          "protocol": [
            {
              "identifier": "BGP",
              "name": "BGP",
              "config": {
                "identifier": "BGP",
                "name": "BGP"
              },
              "bgp": {
                "peer-groups": {
                  "peer-group": [
                    {
                      "peer-group-name": "BGP-PEER-GROUP1",
                      "config": {
                        "peer-group-name": "BGP-PEER-GROUP1"
                      },
                      "as-path-options": {
                        "config": {
                          "allow-own-as": 1
                        }
                      }
                    }
                  ]
                }
              }
            }
          ]
        }
      }
    ]
  }
}

paths:
  ## Config paths
  /network-instances/network-instance/protocols/protocol/bgp/peer-groups/peer-group/as-path-options/config/allow-own-as:
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/as-path-options/config/allow-own-as:

  ## State paths
  /network-instances/network-instance/protocols/protocol/bgp/peer-groups/peer-group/as-path-options/state/allow-own-as:
  /network-instances/network-instance/protocols/protocol/bgp/neighbors/neighbor/as-path-options/state/allow-own-as:

rpcs:
  gnmi:
    gNMI.Set:
    gNMI.Subscribe:

• MFF - A modular form factor device containing LINECARDs, FABRIC and redundant CONTROLLER_CARD components
• FFF - fixed form factor