feat(isn): VLAN-4 routed sub-interface + addr on spine ISN ospfIf; ISN-CSW LLDP neighbor (v0.19.0)

Real ACI multi-site spines carry the OSPF address toward the ISN on a
routed sub-interface, not the bare port: ospfIf id/dn are now
eth1/{49+si}.4 with addr=172.16.{site}.{si+1}/24 (same /24 as the
existing .254 peer); ospfAdjEp nests under the sub-if. Each spine ISN
uplink physical port also gets an ISN-CSW lldpAdjEp/cdpAdjEp
(sysName ISN-CSW{site}, portIdV Ethernet1/{si+1}, model N9K-C9364C,
locally-administered 02:1B:0D MAC hashed from site.id). Single-site
fabrics build none of this. Closes the autoACI Fabric (physical) gap
where spine uplink rows showed blank Local IP / Neighbor Port.
908 tests green.

tests/test_build_fabric.py

@@ -105,7 +105,7 @@ def test_fabric_links_reference_real_nodes(store, site_a):
 # Test: LLDP/CDP neighbor set matches cabling graph
 # ---------------------------------------------------------------------------
 
-def test_lldp_cdp_matches_cabling(store, site_a):
+def test_lldp_cdp_matches_cabling(store, site_a, topo):
     """lldpAdjEp sysName values on each node match what the cabling graph predicts."""
     pod = site_a.pod
     node_map = {n.id: n for n in site_a.all_nodes()}
@@ -124,6 +124,12 @@ def test_lldp_cdp_matches_cabling(store, site_a):
         for leaf in site_a.leaf_nodes()[:2]:
             expected_lldp.add((leaf.id, f"{site_a.name}-ACI-APIC{cid:02d}"))
 
+    # v0.19.0: multi-site fabrics also see the ISN CSW on each spine's
+    # dedicated uplink port (fabric.py's ISN-CSW add_adjacency block).
+    if len(topo.sites) > 1:
+        for spine in site_a.spine_nodes():
+            expected_lldp.add((spine.id, f"ISN-CSW{site_a.id}"))
+
     actual_lldp: set[tuple[int, str]] = set()
     for mo in store.by_class("lldpAdjEp"):
         dn = mo.attrs["dn"]

tests/test_lldp_cdp_fidelity.py

@@ -285,7 +285,7 @@ def test_backward_compat_sysname_and_mgmtip_present(store, site_a):
             assert mo.attrs.get("mgmtIp"), f"{cls} missing mgmtIp: {mo.attrs['dn']}"
 
 
-def test_backward_compat_matches_cabling_graph(store, site_a):
+def test_backward_compat_matches_cabling_graph(store, site_a, topo):
     """Same assertion test_build_fabric.py's test_lldp_cdp_matches_cabling
     already makes (sysName set matches the cabling graph) — re-verified here
     to prove the enrichment didn't alter the pre-existing neighbor set."""
@@ -299,6 +299,11 @@ def test_backward_compat_matches_cabling_graph(store, site_a):
     for cid in range(1, site_a.controllers + 1):
         for leaf in site_a.leaf_nodes()[:2]:
             expected.add((leaf.id, f"{site_a.name}-ACI-APIC{cid:02d}"))
+    # v0.19.0: multi-site fabrics also see the ISN CSW on each spine's
+    # dedicated uplink port (fabric.py's ISN-CSW add_adjacency block).
+    if len(topo.sites) > 1:
+        for spine in site_a.spine_nodes():
+            expected.add((spine.id, f"ISN-CSW{site_a.id}"))
 
     actual: set[tuple[int, str]] = set()
     for mo in store.by_class("lldpAdjEp"):

tests/test_pr19_tier2.py

@@ -87,6 +87,82 @@ class TestIsnDefaults:
             assert mo.attrs["mtu"] == "9150"
 
 
+# ---------------------------------------------------------------------------
+# PR-22 — ISN OSPF sub-interface + ISN CSW LLDP neighbor
+#
+# Real ACI multi-site spines carry the ISN-facing OSPF address on a routed
+# VLAN-4 sub-interface (e.g. "eth1/49.4"), not the bare physical port, and
+# the ISN switch advertises LLDP on that physical port. autoACI's Topology
+# "Fabric (physical)" view stitches these together: ospfIf (port + local IP)
+# + ospfAdjEp (remote IP) + lldpAdjEp (CSW-side port/name).
+# ---------------------------------------------------------------------------
+
+
+class TestIsnOspfSubInterfaceAndLldp:
+    def test_ospfIf_id_is_vlan4_subinterface(self, repo_topo: Topology) -> None:
+        site = repo_topo.site_by_name("LAB1")
+        store = orchestrator.build_site(repo_topo, site)
+        ospf_ifs = store.by_class("ospfIf")
+        assert ospf_ifs, "expected at least one ospfIf"
+        spine_ids = sorted(n.id for n in site.spine_nodes())
+        for si, sid in enumerate(spine_ids):
+            expected_id = f"eth1/{49 + si}.4"
+            mo = next(
+                m for m in ospf_ifs
+                if m.dn == f"topology/pod-{site.pod}/node-{sid}/sys/ospf/inst-default/dom-overlay-1/if-[{expected_id}]"
+            )
+            assert mo.attrs["id"] == expected_id
+
+    def test_ospfIf_addr_in_site_isn_subnet(self, repo_topo: Topology) -> None:
+        site = repo_topo.site_by_name("LAB1")
+        store = orchestrator.build_site(repo_topo, site)
+        ospf_ifs = store.by_class("ospfIf")
+        assert ospf_ifs
+        for mo in ospf_ifs:
+            assert mo.attrs["addr"].startswith(f"172.16.{site.id}.")
+            assert mo.attrs["addr"].endswith("/24")
+
+    def test_ospfAdjEp_dn_nests_under_subinterface_segment(self, repo_topo: Topology) -> None:
+        site = repo_topo.site_by_name("LAB1")
+        store = orchestrator.build_site(repo_topo, site)
+        spine_ids = sorted(n.id for n in site.spine_nodes())
+        for si, sid in enumerate(spine_ids):
+            expected_segment = f"if-[eth1/{49 + si}.4]"
+            adj = next(
+                m for m in store.by_class("ospfAdjEp")
+                if f"/node-{sid}/" in m.dn and expected_segment in m.dn
+            )
+            assert adj.attrs["peerIp"] == f"172.16.{site.id}.254"
+
+    def test_lldpAdjEp_exists_for_isn_csw_on_physical_port(self, repo_topo: Topology) -> None:
+        site = repo_topo.site_by_name("LAB1")
+        store = orchestrator.build_site(repo_topo, site)
+        spine_ids = sorted(n.id for n in site.spine_nodes())
+        lldp_adjs = list(store.by_class("lldpAdjEp"))
+        for si, sid in enumerate(spine_ids):
+            local_port = f"eth1/{49 + si}"
+            adj = next(
+                m for m in lldp_adjs
+                if m.dn == f"topology/pod-{site.pod}/node-{sid}/sys/lldp/inst/if-[{local_port}]/adj-1"
+            )
+            assert adj.attrs["sysName"] == f"ISN-CSW{site.id}"
+            assert adj.attrs["portIdV"] == f"Ethernet1/{si + 1}"
+            assert adj.attrs["mgmtIp"] == f"172.16.{site.id}.254"
+
+    def test_single_site_fabric_builds_no_isn_ospf_or_lldp(self) -> None:
+        """Single-site fabrics never peer OSPF/LLDP with an ISN — no ospfIf/
+        ospfAdjEp/ospfDom, and no lldpAdjEp named "ISN-CSW*", should exist."""
+        topo_dict = generate_topology(sites=1, leaves_per_site=1, spines_per_site=1, border_pairs=0)
+        topo = Topology.model_validate(topo_dict)
+        site = topo.sites[0]
+        store = orchestrator.build_site(topo, site)
+        assert store.by_class("ospfIf") == []
+        assert store.by_class("ospfAdjEp") == []
+        assert store.by_class("ospfDom") == []
+        isn_lldp = [m for m in store.by_class("lldpAdjEp") if "ISN-CSW" in m.attrs.get("sysName", "")]
+        assert isn_lldp == []
+
+
 # ---------------------------------------------------------------------------
 # ISN ospf_area / mtu — overrides
 # ---------------------------------------------------------------------------

tests/test_pr3b_batch1.py

@@ -405,6 +405,11 @@ def test_ospf_adj_ep_sits_on_an_ospf_if(store_name, request):
 
 @pytest.mark.parametrize("store_name", _ALL_STORES)
 def test_ospf_if_references_real_port(store_name, request):
+    """ospfIf is now the routed VLAN-4 sub-interface of the spine's ISN
+    uplink port (id/dn end in ".4", e.g. "eth1/49.4") — real LLDP/physical
+    port state stays on the base port, so this resolves the underlying
+    l1PhysIf via the base port (ifId.split('.')[0]), same fallback autoACI's
+    topology code uses."""
     store = request.getfixturevalue(store_name)
     ports = _l1physif_ports(store)
     ifs = store.by_class("ospfIf")
@@ -413,11 +418,17 @@ def test_ospf_if_references_real_port(store_name, request):
         m = re.search(r"/node-(\d+)/sys/ospf/.*?/if-\[([^\]]+)\]", ospf_if.dn)
         assert m is not None, f"unparsable ospfIf dn {ospf_if.dn!r}"
         node_id, port_id = int(m.group(1)), m.group(2)
-        assert port_id in ports.get(node_id, set()), (
-            f"ospfIf {ospf_if.dn!r} references {port_id!r} on node {node_id}, "
-            f"which has no matching l1PhysIf"
+        assert port_id.endswith(".4"), f"ospfIf {ospf_if.dn!r} id {port_id!r} is not a VLAN-4 sub-if"
+        base_port = port_id.split(".")[0]
+        assert base_port in ports.get(node_id, set()), (
+            f"ospfIf {ospf_if.dn!r} references base port {base_port!r} on node "
+            f"{node_id}, which has no matching l1PhysIf"
         )
         assert ospf_if.attrs.get("id") == port_id
+        addr = ospf_if.attrs.get("addr", "")
+        assert re.fullmatch(r"172\.16\.\d+\.\d+/24", addr), (
+            f"ospfIf {ospf_if.dn!r} addr {addr!r} is not a 172.16.{{site}}.0/24 address"
+        )
 
 
 # ---------------------------------------------------------------------------

tests/test_pr5_topology_consistency.py

@@ -126,6 +126,10 @@ def test_l3out_path_att_references_real_port(store_name, request):
 
 @pytest.mark.parametrize("store_name", ["store_a", "store_b"])
 def test_ospf_adjacency_references_real_port(store_name, request):
+    """ospfAdjEp nests under the ospfIf's VLAN-4 sub-if segment
+    (if-[eth1/{49+si}.4]); resolve the underlying l1PhysIf via the base port
+    (ifId.split('.')[0]) — same fallback autoACI's topology code uses since
+    real LLDP/physical state stays on the base port, not the sub-if."""
     store = request.getfixturevalue(store_name)
     ports = _l1physif_ports(store)
     adjs = list(store.by_class("ospfAdjEp"))
@@ -134,8 +138,10 @@ def test_ospf_adjacency_references_real_port(store_name, request):
         m = re.search(r"/node-(\d+)/sys/ospf/.*?/if-\[([^\]]+)\]", adj.dn)
         assert m is not None, f"unparsable ospfAdjEp dn {adj.dn!r}"
         node_id, port_id = int(m.group(1)), m.group(2)
-        assert port_id in ports.get(node_id, set()), (
-            f"ospfAdjEp {adj.dn!r} references {port_id!r} on node {node_id}, "
+        assert port_id.endswith(".4"), f"ospfAdjEp {adj.dn!r} port {port_id!r} is not a VLAN-4 sub-if"
+        base_port = port_id.split(".")[0]
+        assert base_port in ports.get(node_id, set()), (
+            f"ospfAdjEp {adj.dn!r} references base port {base_port!r} on node {node_id}, "
             f"which has no matching l1PhysIf (has {ports.get(node_id)})"
         )