Creating a redundant GRE

Creating a redundant GRE in the UI

You can create a redundant GRE on an existing transit gateway, or when you create a transit gateway.

To create a redundant GRE, follow these steps:

1. Select one of the following choices:

   • To create a redundant GRE on an existing transit gateway:

     1. From your browser, open the IBM Cloud console and log in to your account.
     2. Select the Navigation Menu icon from the upper left, then click Interconnectivity > Transit Gateway.
     3. Click the name of the transit gateway where you want to add a connection.
     4. Click Add connection in the Connections tab.

   • To create a redundant GRE while creating a transit gateway:

     1. From your browser, open the IBM Cloud console and log in to your account.
     2. Select the Navigation Menu icon from the upper left, then click Interconnectivity.
     3. Click Transit Gateway from the left navigation window. Then, click Create transit gateway.
     4. Enter the transit gateway name, resource group, and location.

2. Select Redundant GRE as your network connection type.

3. Enter the connection name.

4. Select the base network type (Classic infrastructure or VPC) and whether this is a connection to a network in another account. If you select VPC as the base network, you can select the region and VPC that you want to target.

   Prefixes of the base network are not advertised to the transit gateway.

5. If this connection is to a network in another account, enter the account ID and the cloud resource name (CRN) of the VPC.

   For cross accounts, all tunnels in a redundant GRE target the same account. Cross-account approval is for the redundant GRE and all tunnels under the GRE will be accepted or rejected.

   To find the CRN, click Navigation Menu > Resource List from the IBM Cloud console. Expand the Networking section, then click the table row of the Virtual Private Cloud whose CRN you want to find. The VPC CRN is shown in the details on the Overview tab.

6. Add GRE tunnels for this connection. A minimum of two GRE tunnels are required. You can click Add tunnel to add more tunnels, but you cannot exceed two tunnels per zone.

   1. Select an availability zone in which to create the tunnels. When you select a zone for the tunnel, only valid zones for a redundant GRE are shown as options.
   2. Optionally, enter the remote BGP ASN, which is a valid 2 or 4-byte value of your choosing. If you leave this field blank, a unique ASN is assigned.
   3. Enter the remote gateway IP for the endpoint of the GRE tunnel.
   4. Enter the local gateway IP that the transit gateway uses to host the underlay network for the GRE tunnel. This user-selected IP address is configured on the transit gateway GRE tunnel after it is created.
   5. Enter a /30 local tunnel IP for both ends of the tunnel, for example 192.168.103.1.
   6. Enter a /30 remote tunnel IP for both ends of the tunnel, for example 192.168.103.2.
   7. Enter a connection name for your GRE tunnel.

7. Depending on where you started this procedure, click either Add or Create to create the redundant GRE.

After you create the redundant GRE, you can expand the redundant GRE section to show its details, including the date created, name, zone, and status.

Creating a redundant GRE from the CLI

To create a redundant GRE from the CLI, you must use a JSON file as input.

ibmcloud tg connection-gre-create|cgrec JSON_FILE_PATH [--output json]

JSON file:

{
    "gateway_id": "47f11b01-471c-47d0-9e84-550c88c94055",
    "name": "redundant_gre1",
    "network_type": "redundant_gre",
    "base_network_type": "classic",
    "network_account_id": "28e4d90ac7504be694471ee66e70d0d5",
    "network_id": "crn:v1:bluemix:public:is:us-south:a/123456::vpc:4727d842-f94f-4a2d-824a-9bc9b02c523b",
    "tunnels": [
       {
          "local_gateway_ip": "192.168.100.1",
          "local_tunnel_ip": "192.168.129.2",
          "name": "gre1",
          "remote_bgp_asn": "65010",
          "remote_gateway_ip": "10.242.63.12",
          "remote_tunnel_ip": "192.168.129.1",
          "zone": {
             "name": "us-south-1"
          }
       }, {
          "local_gateway_ip": "192.168.101.1",
          "local_tunnel_ip": "192.168.128.2",
          "name": "gre2",
          "remote_bgp_asn": "65010",
          "remote_gateway_ip": "10.242.63.12",
          "remote_tunnel_ip": "192.168.128.1",
          "zone": {
             "name": "us-south-1"
          }
       }
    ]
}

Creating a redundant GRE with the API

You can create a redundant Generic Routing Encapsulation (GRE) tunnel connection with the API.

curl -H "Content-Type: application/json" -X POST https://$TS_ENDPOINT/v1/transit_gateways/$GATEWAY_ID/connections?version=2020-03-31   -H "authorization: Bearer $IAM_TOKEN"   -d '{
	"name": "mtp_RGRE",
	"network_type": "redundant_gre",
	"base_network_type": "vpc",
	"network_id": "crn:v1:staging:public:is:us-south:a/aacb87da80cc4a47b9a196fc1713d42d::vpc:r134-285026fa-1d90-4d67-b512-028f4fd8a112",
	"tunnels": [
		{
			"name": "mtp_vpc_tun1",
			"local_gateway_ip": "192.168.200.1",
			"local_tunnel_ip": "192.168.239.2",
			"remote_gateway_ip": "10.240.0.4",
			"remote_tunnel_ip": "192.168.239.1",
			"zone": {
				"name": "us-south-3"
			}
		},
		{
			"name": "mtp_vpc_tun2",
			"local_gateway_ip": "192.168.201.1",
			"local_tunnel_ip": "192.168.238.2",
			"remote_gateway_ip": "10.240.0.4",
			"remote_tunnel_ip": "192.168.238.1",
			"zone": {
				"name": "us-south-3"
			}
		}
	]
}'

{
   "name": "mtp_RGRE",
   "network_type": "redundant_gre",
   "base_network_type": "vpc",
   "id": "47f11b01-471c-47d0-9e84-550c88c94056",
   "created_at": "22024-06-10T14:52:54.918Z",
   "updated_at": "2024-06-10T14:52:54.918Z",
   "status": "up",
   "tunnels": [
      {
         "name": "mtp_vpc_tun1",
         "id": "47f11b01-471c-47d0-9e84-550c88c94057",
         "mtu": 9000,
         "status": "up",
         "updated_at": "2024-06-10T14:52:54.918Z",
         "created_at": "2024-06-10T14:52:54.918Z",
         "local_gateway_ip": "192.168.200.1",
         "local_tunnel_ip": "192.168.239.2",
         "remote_gateway_ip": "10.240.0.4",
         "remote_tunnel_ip": "192.168.239.1",
         "local_bgp_asn": 64490,
         "remote_bgp_asn": 65010,
         "zone": {
            "name": "us-south-3"
         }
      },
      {
         "name": "mtp_vpc_tun2",
         "id": "47f11b01-471c-47d0-9e84-550c88c94058",
         "mtu": 9000,
         "status": "up",
         "updated_at": "2024-06-10T14:52:54.918Z",
         "created_at": "2024-06-10T14:52:54.918Z",
         "local_gateway_ip": "192.168.201.1",
         "local_tunnel_ip": "192.168.238.2",
         "remote_gateway_ip": "10.240.0.4",
         "remote_tunnel_ip": "192.168.238.1",
         "local_bgp_asn": 64490,
         "remote_bgp_asn": 65011,
         "zone": {
            "name": "us-south-3"
         }
      }
   ]
}

Creating a redundant GRE using Terraform

To use Terraform, download the Terraform CLI and configure the IBM Cloud Provider plug-in. For more information, see Getting started with Terraform.

The following example illustrates creating a redundant GRE and adding its tunnels using Terraform:

resource "ibm_tg_connection" "test_ibm_tg_rgre_connection" {
  gateway      = ibm_tg_gateway.test_tg_gateway.id
  name = redundant_ugre_vpc
  network_type = redundant_gre
  base_network_type = vpc
  network_id = ibm_is_vpc.test_tg_vpc.resource_crn
  tunnels {
           local_gateway_ip = "192.129.200.1"
           local_tunnel_ip = "192.158.239.2"
           name =  "tunne1_testtgw1461"
           remote_gateway_ip = "10.186.203.4"
           remote_tunnel_ip = "192.158.239.1"
           zone =  "us-south-1"
        }
 tunnels {
             local_gateway_ip = "192.129.220.1"
             local_tunnel_ip = "192.158.249.2"
             name =  "tunne2_testtgw1462"
             remote_gateway_ip = "10.186.203.4"
             remote_tunnel_ip = "192.158.249.1"
             zone =  "us-south-1"
         }
}

For more information, see the Terraform registry.