Add fabric.p4 basic 2x2 topology

Change-Id: I121b042cc519bdddad313ea83fd3d3e3d1d4d217
diff --git a/trellis/trellisp4.json b/trellis/trellisp4.json
new file mode 100644
index 0000000..5fa8849
--- /dev/null
+++ b/trellis/trellisp4.json
@@ -0,0 +1,92 @@
+{
+    "ports" : {
+        "device:bmv2:204/3" : {
+            "interfaces" : [
+                {
+                    "name": "h1",
+                    "ips" : [ "10.0.10.254/24" ],
+                    "vlan-untagged": 10
+                }
+            ]
+        },
+        "device:bmv2:204/4" : {
+            "interfaces" : [
+                {
+                    "name": "h2",
+                    "ips" : [ "10.0.10.254/24" ],
+                    "vlan-untagged": 10
+                }
+            ]
+        },
+        "device:bmv2:205/3" : {
+            "interfaces" : [
+                {
+                    "name": "h3",
+                    "ips" : [ "10.0.20.254/24" ],
+                    "vlan-untagged": 20
+                }
+            ]
+        },
+        "device:bmv2:205/4" : {
+            "interfaces" : [
+                {
+                    "name": "h4",
+                    "ips" : [ "10.0.20.254/24" ],
+                    "vlan-untagged": 20
+                }
+            ]
+        }
+    },
+    "devices" : {
+        "device:bmv2:204" : {
+            "segmentrouting" : {
+                "name" : "s204",
+                "ipv4NodeSid" : 204,
+                "ipv4Loopback" : "192.168.0.204",
+                "ipv6NodeSid" : 214,
+                "ipv6Loopback" : "2000::c0a8:0204",
+                "routerMac" : "00:00:00:00:02:04",
+                "isEdgeRouter" : true,
+                "adjacencySids" : []
+            }
+        },
+        "device:bmv2:205" : {
+            "segmentrouting" : {
+                "name" : "s205",
+                "ipv4NodeSid" : 205,
+                "ipv4Loopback" : "192.168.0.205",
+                "ipv6NodeSid" : 215,
+                "ipv6Loopback" : "2000::c0a8:0205",
+                "routerMac" : "00:00:00:00:02:05",
+                "isEdgeRouter" : true,
+                "adjacencySids" : []
+            }
+        },
+        "device:bmv2:226" : {
+            "segmentrouting" : {
+                "name" : "s226",
+                "ipv4NodeSid" : 226,
+                "ipv4Loopback" : "192.168.0.226",
+                "ipv6NodeSid" : 236,
+                "ipv6Loopback" : "2000::c0a8:0226",
+                "routerMac" : "00:00:00:00:02:26",
+                "isEdgeRouter" : false,
+                "adjacencySids" : []
+            }
+        },
+        "device:bmv2:227" : {
+            "segmentrouting" : {
+                "name" : "s227",
+                "ipv4NodeSid" : 227,
+                "ipv4Loopback" : "192.168.0.227",
+                "ipv6NodeSid" : 237,
+                "ipv6Loopback" : "2000::c0a8:0227",
+                "routerMac" : "00:00:00:00:02:27",
+                "isEdgeRouter" : false,
+                "adjacencySids" : []
+            }
+        }
+    },
+    "apps" : {
+    }
+}