CORE Connecting to Multiple COREs at an IXP

In this example, configure the CORE appliance of ISP 1 to connect to two other CORE appliances of ISP 2 and ISP 3 using two SCION links. The SCION links use the physical network of the IXP as the underlay network and thus have the same IP address, but different UDP ports as shown in the figure below.

We need to configure the following:

1. The physical network interface that is used to connect to the IXP’s network in the interfaces section of the appliance configuration.

2. The CORE SCION links to ISP 2 and ISP 3 in the scion/ases/neighbors section of the appliance configuration.

The relevant parts of the configuration for the CORE appliance of ISP 1 are shown below.

Network Interface

{
  "interfaces": {
    "ethernets": [
      {
        "name": "eth0",
        "addresses": ["192.168.1.10/24"],
      },
    ]
  }
}

SCION Links

{
  "scion": {
    "ases": [
      {
        "isd_as": "1-ff00:0:1",
        "neighbors": [
          {
            "neighbor_isd_as": "1-ff00:1:1",
            "relationship": "CORE",
            "interfaces": [
              {
                "address": "192.168.1.10:31000",
                "administrative_state": "UP",
                "interface_id": 10,
                "scion_mtu": 1472,
                "remote": {
                  "address": "192.168.1.20:31000",
                  "interface_id": 100
                }
              }
            ]
          },
          {
            "neighbor_isd_as": "1-ff00:2:1",
            "relationship": "CORE",
            "interfaces": [
              {
                "address": "192.168.1.10:31001",
                "administrative_state": "UP",
                "interface_id": 20,
                "scion_mtu": 1472,
                "remote": {
                  "address": "192.168.1.30:31000",
                  "interface_id": 15
                }
              }
            ]
          }
        ]
      }
    ]
  }
}