diff --git a/lib/cache.coffee b/lib/cache.coffee
index 8a5f22c..d0bd9f6 100644
--- a/lib/cache.coffee
+++ b/lib/cache.coffee
@@ -21,6 +21,8 @@ crypto = require 'crypto'
 later = require 'later'
 
 db = require './db'
+query = require './query'
+
 
 REFRESH = 3000
 
@@ -124,7 +126,7 @@ refresh = (callback) ->
 
           events = preset.events ? {}
 
-          precondition = JSON.parse(preset.precondition)
+          precondition = query.convertMongoQueryToFilters(JSON.parse(preset.precondition))
 
           _provisions = preset.provisions or []
 
diff --git a/lib/cwmp.coffee b/lib/cwmp.coffee
index cb9888c..b6afc2d 100644
--- a/lib/cwmp.coffee
+++ b/lib/cwmp.coffee
@@ -179,8 +179,9 @@ applyPresets = (currentRequest) ->
         (p.schedule.schedule and testSchedule(p.schedule, currentRequest.sessionData.timestamp)[0]))
 
       filteredPresets.push(p)
-      for a in Object.keys(query.queryProjection(p.precondition))
-        parameters[a] = common.parsePath(a)
+      for k of p.precondition
+        p = k.split(/([^a-zA-Z0-9\-\_\.].*)/, 1)[0]
+        parameters[p] = common.parsePath(p)
 
     declarations = []
     for k, v of parameters
@@ -196,12 +197,14 @@ applyPresets = (currentRequest) ->
         unpacked = device.unpack(currentRequest.sessionData.deviceData, v)
         if unpacked[0] and (vv = currentRequest.sessionData.deviceData.attributes.get(unpacked[0]).value?[1])?
           parameters[k] = vv[0]
+        else
+          delete parameters[k]
 
       if whiteList?
         session.addProvisions(currentRequest.sessionData, whiteList, whiteListProvisions)
 
       for p in filteredPresets
-        if query.test(parameters, p.precondition)
+        if query.testFilter(parameters, p.precondition)
           session.addProvisions(currentRequest.sessionData, p.channel, p.provisions)
 
       session.rpcRequest(currentRequest.sessionData, null, (err, id, rpcRequest) ->
diff --git a/lib/query.coffee b/lib/query.coffee
index d7a4f42..c82f493 100644
--- a/lib/query.coffee
+++ b/lib/query.coffee
@@ -242,6 +242,74 @@ test = (params, query) ->
   return true
 
 
+testFilter = (obj, filter) ->
+  for k, v of filter
+    [param, op] = k.split(/([^a-zA-Z0-9\-\_\.].*)/, 2)
+    val = common.matchType(obj[param], v)
+    switch op
+      when '=', undefined
+        return false if obj[param] != val
+      when '>'
+        return false if not (obj[param] > val)
+      when '>='
+        return false if not (obj[param] >= val)
+      when '<'
+        return false if not (obj[param] < val)
+      when '<='
+        return false if not (obj[param] <= val)
+      when '!'
+        return false if obj[param] == val
+      else
+        throw new Error("Unrecognized operator #{op}")
+
+  return true
+
+
+convertMongoQueryToFilters = (query, filters) ->
+  filters ?= {}
+  for k, v of query
+    if k[0] == '$'
+      if k == '$and'
+        for vv in v
+          convertMongoQueryToFilters(vv, filters)
+      else
+        throw new Error("Operator #{k} not supported")
+    else if k == '_tags'
+      if common.typeOf(v) is common.OBJECT_TYPE
+        for kk, vv of v
+          vv = vv.replace(/[^a-zA-Z0-9\-]+/g, '_')
+          switch kk
+            when '$ne'
+              filters["Tags.#{vv}!"] = true
+            else
+              throw new Error("Operator #{kk} not supported")
+      else
+        v = v.replace(/[^a-zA-Z0-9\-]+/g, '_')
+        filters["Tags.#{v}"] = true
+    else
+      if common.typeOf(v) is common.OBJECT_TYPE
+        for kk, vv of v
+          switch kk
+            when '$eq'
+              filters[k] = vv
+            when '$ne'
+              filters["#{k}!"] = vv
+            when '$lt'
+              filters["#{k}<"] = vv
+            when '$lte'
+              filters["#{k}<="] = vv
+            when '$gt'
+              filters["#{k}>"] = vv
+            when '$gte'
+              filters["#{k}>="] = vv
+            else
+              throw new Error("Oprator #{kk} not supported")
+      else
+        filters[k] = v
+
+  return filters
+
+
 sanitizeQueryTypes = (query, types) ->
   for k, v of query
     if k[0] == '$' # logical operator
@@ -268,3 +336,5 @@ exports.expand = expand
 exports.queryProjection = queryProjection
 exports.test = test
 exports.sanitizeQueryTypes = sanitizeQueryTypes
+exports.convertMongoQueryToFilters = convertMongoQueryToFilters
+exports.testFilter = testFilter