diff --git a/gql_test.go b/gql_test.go
index e775998..bb19016 100644
--- a/gql_test.go
+++ b/gql_test.go
@@ -10,7 +10,7 @@ import (
 )
 
 func TestGQLDB(t * testing.T) {
-  ctx := logTestContext(t, []string{"loop", "node", "thread", "test", "signal", "policy", "db"})
+  ctx := logTestContext(t, []string{})
 
   TestUserNodeType := NodeType("TEST_USER")
   err := ctx.RegisterNodeType(TestUserNodeType, []ExtType{})
diff --git a/graph_test.go b/graph_test.go
index 7804a0d..b4be029 100644
--- a/graph_test.go
+++ b/graph_test.go
@@ -13,6 +13,35 @@ import (
 type GraphTester testing.T
 const listner_timeout = 50 * time.Millisecond
 
+func (t * GraphTester) WaitForLinkState(ctx * Context, listener *ListenerExt, state string, timeout time.Duration, str string) Signal {
+  timeout_channel := time.After(timeout)
+  for true {
+    select {
+    case signal := <- listener.Chan:
+      if signal == nil {
+        ctx.Log.Logf("test", "SIGNAL_CHANNEL_CLOSED: %s", listener)
+        t.Fatal(str)
+      }
+      if signal.Type() == LinkSignalType {
+        sig, ok := signal.(LinkSignal)
+        if ok == true {
+          ctx.Log.Logf("test", "Link state received: %s", sig.State)
+          if sig.State == state {
+            return signal
+          }
+        } else {
+          ctx.Log.Logf("test", "Failed to cast signal to LinkSignal: %+v", signal)
+        }
+      }
+    case <-timeout_channel:
+      pprof.Lookup("goroutine").WriteTo(os.Stdout, 1)
+      t.Fatal(str)
+      return nil
+    }
+  }
+  return nil
+}
+
 func (t * GraphTester) WaitForStatus(ctx * Context, listener *ListenerExt, status string, timeout time.Duration, str string) Signal {
   timeout_channel := time.After(timeout)
   for true {
@@ -57,7 +86,7 @@ func (t * GraphTester) CheckForNone(listener *ListenerExt, str string) {
 const SimpleListenerNodeType = NodeType("SIMPLE_LISTENER")
 
 func NewSimpleListener(ctx *Context, buffer int) (*Node, *ListenerExt) {
-  policy := NewAllNodesPolicy([]string{"signal.status", "requirements.write", "requirements.read", "dependencies.write", "dependencies.read", "owner.read", "owner.write"})
+  policy := NewAllNodesPolicy([]SignalType{SignalType("status")})
   listener_extension := NewListenerExt(buffer)
   listener := NewNode(ctx,
                       RandID(),
diff --git a/lockable.go b/lockable.go
index d9988bd..895eaab 100644
--- a/lockable.go
+++ b/lockable.go
@@ -2,6 +2,7 @@ package graphvent
 
 import (
   "encoding/json"
+  "fmt"
 )
 
 type ListenerExt struct {
@@ -41,15 +42,20 @@ func (ext *ListenerExt) Process(ctx *Context, princ_id NodeID, node *Node, signa
   return
 }
 
-func (ext *ListenerExt) Serialize() ([]byte, error) {
-  return json.MarshalIndent(ext.Buffer, "", "  ")
+func LoadLockableExt(ctx *Context, data []byte) (Extension, error) {
+  var ext LockableExt
+  err := json.Unmarshal(data, &ext)
+  if err != nil {
+    return nil, err
+  }
+
+  ctx.Log.Logf("db", "DB_LOADING_LOCKABLE_EXT_JSON: %+v", ext)
+
+  return &ext, nil
 }
 
-type LockableExt struct {
-  Owner *NodeID `json:"owner"`
-  Requirements []NodeID `json:"requirements"`
-  Dependencies []NodeID `json:"dependencies"`
-  LocksHeld map[NodeID]*NodeID `json:"locks_held"`
+func (ext *ListenerExt) Serialize() ([]byte, error) {
+  return json.MarshalIndent(ext.Buffer, "", "  ")
 }
 
 const LockableExtType = ExtType("LOCKABLE")
@@ -61,7 +67,15 @@ func (ext *LockableExt) Serialize() ([]byte, error) {
   return json.MarshalIndent(ext, "", "  ")
 }
 
-func NewLockableExt(owner *NodeID, requirements []NodeID, dependencies []NodeID, locks_held map[NodeID]*NodeID) *LockableExt {
+func NewLockableExt(owner *NodeID, requirements map[NodeID]string, dependencies map[NodeID]string, locks_held map[NodeID]*NodeID) *LockableExt {
+  if requirements == nil {
+    requirements = map[NodeID]string{}
+  }
+
+  if dependencies == nil {
+    dependencies = map[NodeID]string{}
+  }
+
   if locks_held == nil {
     locks_held = map[NodeID]*NodeID{}
   }
@@ -74,22 +88,79 @@ func NewLockableExt(owner *NodeID, requirements []NodeID, dependencies []NodeID,
   }
 }
 
-func LoadLockableExt(ctx *Context, data []byte) (Extension, error) {
-  var ext LockableExt
-  err := json.Unmarshal(data, &ext)
+type LockableExt struct {
+  Owner *NodeID `json:"owner"`
+  Requirements map[NodeID]string `json:"requirements"`
+  Dependencies map[NodeID]string `json:"dependencies"`
+  LocksHeld map[NodeID]*NodeID `json:"locks_held"`
+}
+
+func LinkRequirement(ctx *Context, dependency *Node, requirement NodeID) error {
+  dep_ext, err := GetExt[*LockableExt](dependency)
   if err != nil {
-    return nil, err
+    return err
   }
 
-  ctx.Log.Logf("db", "DB_LOADING_LOCKABLE_EXT_JSON: %+v", ext)
-
-  return &ext, nil
-}
+  _, exists := dep_ext.Requirements[requirement]
+  if exists == true {
+    return fmt.Errorf("%s is already a requirement of %s", requirement, dependency.ID)
+  }
 
+  _, exists = dep_ext.Dependencies[requirement]
+  if exists == true {
+    return fmt.Errorf("%s is a dependency of %s, cannot link as requirement", requirement, dependency.ID)
+  }
 
+  dep_ext.Requirements[requirement] = "start"
+  return ctx.Send(dependency.ID, requirement, NewLinkSignal("req_link"))
+}
 
 func (ext *LockableExt) HandleLinkSignal(ctx *Context, source NodeID, node *Node, signal LinkSignal) {
-  ctx.Log.Logf("lockable", "LINK_SIGNAL: %+v", signal)
+  ctx.Log.Logf("lockable", "LINK_SIGNAL: %s->%s %+v", source, node.ID, signal)
+  state := signal.State
+  switch state {
+  // sent by a node to link this node as a requirement
+  case "req_link":
+    _, exists := ext.Requirements[source]
+    if exists == false {
+      dep_state, exists := ext.Dependencies[source]
+      if exists == false {
+        ext.Dependencies[source] = "start"
+        ctx.Send(node.ID, source, NewLinkSignal("dep_link"))
+      } else if dep_state == "start" {
+        ext.Dependencies[source] = "linked"
+        ctx.Send(node.ID, source, NewLinkSignal("dep_linked"))
+      }
+    } else {
+      delete(ext.Requirements, source)
+      ctx.Send(node.ID, source, NewLinkSignal("req_reset"))
+    }
+  case "dep_link":
+    _, exists := ext.Dependencies[source]
+    if exists == false {
+      req_state, exists := ext.Requirements[source]
+      if exists == false {
+        ext.Requirements[source] = "start"
+        ctx.Send(node.ID, source, NewLinkSignal("req_link"))
+      } else if req_state == "start" {
+        ext.Requirements[source] = "linked"
+        ctx.Send(node.ID, source, NewLinkSignal("req_linked"))
+      }
+    } else {
+      delete(ext.Dependencies, source)
+      ctx.Send(node.ID, source, NewLinkSignal("dep_reset"))
+    }
+  case "dep_reset":
+    ctx.Log.Logf("lockable", "%s reset %s dependency state", node.ID, source)
+  case "req_reset":
+    ctx.Log.Logf("lockable", "%s reset %s requirement state", node.ID, source)
+  case "dep_linked":
+    ctx.Log.Logf("lockable", "%s is a dependency of %s", node.ID, source)
+  case "req_linked":
+    ctx.Log.Logf("lockable", "%s is a requirement of %s", node.ID, source)
+  default:
+    ctx.Log.Logf("lockable", "LINK_ERROR: unknown state %s", state)
+  }
 }
 
 func (ext *LockableExt) Process(ctx *Context, source NodeID, node *Node, signal Signal) {
@@ -98,7 +169,7 @@ func (ext *LockableExt) Process(ctx *Context, source NodeID, node *Node, signal
   switch signal.Direction() {
   case Up:
     owner_sent := false
-    for _, dependency := range(ext.Dependencies) {
+    for dependency, _ := range(ext.Dependencies) {
       err := ctx.Send(node.ID, dependency, signal)
       if err != nil {
         ctx.Log.Logf("signal", "LOCKABLE_SIGNAL_ERR: %s->%s - %e", node.ID, dependency, err)
@@ -120,16 +191,16 @@ func (ext *LockableExt) Process(ctx *Context, source NodeID, node *Node, signal
       }
     }
   case Down:
-    for _, requirement := range(ext.Requirements) {
+    for requirement, _ := range(ext.Requirements) {
       err := ctx.Send(node.ID, requirement, signal)
       if err != nil {
         ctx.Log.Logf("signal", "LOCKABLE_SIGNAL_ERR: %s->%s - %e", node.ID, requirement, err)
       }
     }
   case Direct:
-    switch sig := signal.(type) {
-    case LinkSignal:
-      ext.HandleLinkSignal(ctx, source, node, sig)
+    switch signal.Type() {
+    case LinkSignalType:
+      ext.HandleLinkSignal(ctx, source, node, signal.(LinkSignal))
     default:
     }
   default:
diff --git a/lockable_test.go b/lockable_test.go
index 9177bb2..6437efb 100644
--- a/lockable_test.go
+++ b/lockable_test.go
@@ -2,11 +2,12 @@ package graphvent
 
 import (
   "testing"
+  "time"
 )
 
 const TestLockableType = NodeType("TEST_LOCKABLE")
 func lockableTestContext(t *testing.T) *Context {
-  ctx := logTestContext(t, []string{"lockable", "signal"})
+  ctx := logTestContext(t, []string{"lockable", "test"})
 
   err := ctx.RegisterNodeType(TestLockableType, []ExtType{ACLExtType, LockableExtType, ListenerExtType})
   fatalErr(t, err)
@@ -15,9 +16,9 @@ func lockableTestContext(t *testing.T) *Context {
 }
 
 
-var link_policy = NewAllNodesPolicy([]string{"link", "status"})
+var link_policy = NewAllNodesPolicy([]SignalType{LinkSignalType})
 
-func Test(t *testing.T) {
+func TestLinkStatus(t *testing.T) {
   ctx := lockableTestContext(t)
 
   l1_listener := NewListenerExt(10)
@@ -33,6 +34,10 @@ func Test(t *testing.T) {
                  NewLockableExt(nil, nil, nil, nil),
                )
 
-  ctx.Send(l1.ID, l2.ID, NewLinkSignal("start", l1.ID))
-}
+  // Link l2 as a requirement of l1
+  err := LinkRequirement(ctx, l1, l2.ID)
+  fatalErr(t, err)
 
+  (*GraphTester)(t).WaitForLinkState(ctx, l1_listener, "dep_link", time.Millisecond*100, "No dep_link")
+  (*GraphTester)(t).WaitForLinkState(ctx, l2_listener, "req_linked", time.Millisecond*100, "No req_linked")
+}
diff --git a/node.go b/node.go
index d4d0621..9b82474 100644
--- a/node.go
+++ b/node.go
@@ -156,7 +156,7 @@ func NodeLoop(ctx *Context, node *Node) error {
     case msg := <- node.MsgChan:
       signal = msg.Signal
       source = msg.Source
-      err := Allowed(ctx, msg.Source, string(signal.Type()), node)
+      err := Allowed(ctx, msg.Source, signal.Type(), node)
       if err != nil {
         ctx.Log.Logf("signal", "SIGNAL_POLICY_ERR: %s", err)
         continue
@@ -307,7 +307,7 @@ func NewNode(ctx *Context, id NodeID, node_type NodeType, queued_signals []Queue
   return node
 }
 
-func Allowed(ctx *Context, principal_id NodeID, action string, node *Node) error {
+func Allowed(ctx *Context, principal_id NodeID, action SignalType, node *Node) error {
   ctx.Log.Logf("policy", "POLICY_CHECK: %s %s.%s", principal_id, node.ID, action)
   // Nodes are allowed to perform all actions on themselves regardless of whether or not they have an ACL extension
   if principal_id == node.ID {
diff --git a/node_test.go b/node_test.go
index 384c875..9d77d47 100644
--- a/node_test.go
+++ b/node_test.go
@@ -5,17 +5,13 @@ import (
 )
 
 func TestNodeDB(t *testing.T) {
-  ctx := logTestContext(t, []string{"test", "db", "node", "policy"})
+  ctx := logTestContext(t, []string{})
   node_type := NodeType("test")
   err := ctx.RegisterNodeType(node_type, []ExtType{GroupExtType})
   fatalErr(t, err)
 
   node := NewNode(ctx, RandID(), node_type, nil, NewGroupExt(nil))
 
-  ser, err := node.Serialize()
-  ctx.Log.Logf("test", "NODE_SER: %+v", ser)
-  fatalErr(t, err)
-
   ctx.Nodes = NodeMap{}
   _, err = LoadNode(ctx, node.ID)
   fatalErr(t, err)
diff --git a/policy.go b/policy.go
index f2e098d..b3017f5 100644
--- a/policy.go
+++ b/policy.go
@@ -7,15 +7,15 @@ import (
 
 type Policy interface {
   Serializable[PolicyType]
-  Allows(principal_id NodeID, action string, node *Node) error
+  Allows(principal_id NodeID, action SignalType, node *Node) error
 }
 
 //TODO: Update with change from principal *Node to principal_id so sane policies can still be made
-func (policy *AllNodesPolicy) Allows(principal_id NodeID, action string, node *Node) error {
+func (policy *AllNodesPolicy) Allows(principal_id NodeID, action SignalType, node *Node) error {
   return policy.Actions.Allows(action)
 }
 
-func (policy *PerNodePolicy) Allows(principal_id NodeID, action string, node *Node) error {
+func (policy *PerNodePolicy) Allows(principal_id NodeID, action SignalType, node *Node) error {
   for id, actions := range(policy.NodeActions) {
     if id != principal_id {
       continue
@@ -29,13 +29,13 @@ func (policy *PerNodePolicy) Allows(principal_id NodeID, action string, node *No
   return fmt.Errorf("%s is not in per node policy of %s", principal_id, node.ID)
 }
 
-func (policy *RequirementOfPolicy) Allows(principal_id NodeID, action string, node *Node) error {
+func (policy *RequirementOfPolicy) Allows(principal_id NodeID, action SignalType, node *Node) error {
   lockable_ext, err := GetExt[*LockableExt](node)
   if err != nil {
     return err
   }
 
-  for _, id := range(lockable_ext.Requirements) {
+  for id, _ := range(lockable_ext.Requirements) {
     if id == principal_id {
       return policy.Actions.Allows(action)
     }
@@ -58,9 +58,9 @@ func NewRequirementOfPolicy(actions Actions) RequirementOfPolicy {
   }
 }
 
-type Actions []string
+type Actions []SignalType
 
-func (actions Actions) Allows(action string) error {
+func (actions Actions) Allows(action SignalType) error {
   for _, a := range(actions) {
     if a == action {
       return nil
@@ -90,28 +90,12 @@ func AllNodesPolicyLoad(init_fn func(Actions)(Policy, error)) func(*Context, []b
 
 func PerNodePolicyLoad(init_fn func(NodeActions)(Policy, error)) func(*Context, []byte)(Policy, error) {
   return func(ctx *Context, data []byte)(Policy, error){
-    var j PerNodePolicyJSON
-    err := json.Unmarshal(data, &j)
+    var policy PerNodePolicy
+    err := json.Unmarshal(data, &policy)
     if err != nil {
       return nil, err
     }
-
-    node_actions := NodeActions{}
-    for id_str, actions := range(j.NodeActions) {
-      id, err := ParseID(id_str)
-      if err != nil {
-        return nil, err
-      }
-
-      _, err = LoadNode(ctx, id)
-      if err != nil {
-        return nil, err
-      }
-
-      node_actions[id] = actions
-    }
-
-    return init_fn(node_actions)
+    return init_fn(policy.NodeActions)
   }
 }
 
@@ -126,11 +110,7 @@ func NewPerNodePolicy(node_actions NodeActions) PerNodePolicy {
 }
 
 type PerNodePolicy struct {
-  NodeActions NodeActions
-}
-
-type PerNodePolicyJSON struct {
-  NodeActions map[string][]string `json:"node_actions"`
+  NodeActions NodeActions `json:"node_actions"`
 }
 
 const PerNodePolicyType = PolicyType("PER_NODE")
@@ -139,14 +119,7 @@ func (policy *PerNodePolicy) Type() PolicyType {
 }
 
 func (policy *PerNodePolicy) Serialize() ([]byte, error) {
-  node_actions := map[string][]string{}
-  for id, actions := range(policy.NodeActions) {
-    node_actions[id.String()] = actions
-  }
-
-  return json.MarshalIndent(&PerNodePolicyJSON{
-    NodeActions: node_actions,
-  }, "", "  ")
+  return json.MarshalIndent(policy, "", "  ")
 }
 
 func NewAllNodesPolicy(actions Actions) AllNodesPolicy {
@@ -294,7 +267,7 @@ func (ext *ACLExt) Type() ExtType {
 }
 
 // Check if the extension allows the principal to perform action on node
-func (ext *ACLExt) Allows(ctx *Context, principal_id NodeID, action string, node *Node) error {
+func (ext *ACLExt) Allows(ctx *Context, principal_id NodeID, action SignalType, node *Node) error {
   ctx.Log.Logf("policy", "POLICY_EXT_ALLOWED: %+v", ext)
   errs := []error{}
   for _, policy := range(ext.Policies) {
diff --git a/signal.go b/signal.go
index ec25568..c63c95b 100644
--- a/signal.go
+++ b/signal.go
@@ -98,14 +98,24 @@ func NewStatusSignal(status string, source NodeID) StatusSignal {
   }
 }
 
+const LinkSignalType = SignalType("LINK")
 type LinkSignal struct {
-  IDSignal
+  BaseSignal
   State string `json:"state"`
 }
 
-func NewLinkSignal(state string, source NodeID) LinkSignal {
+func (signal LinkSignal) Serialize() ([]byte, error) {
+  return json.MarshalIndent(signal, "", "  ")
+}
+
+func (signal LinkSignal) String() string {
+  ser, _ := signal.Serialize()
+  return string(ser)
+}
+
+func NewLinkSignal(state string) LinkSignal {
   return LinkSignal{
-    IDSignal: NewIDSignal("link", Direct, source),
+    BaseSignal: NewDirectSignal(LinkSignalType),
     State: state,
   }
 }