diff --git a/UPGRADE-2.2.md b/UPGRADE-2.2.md
new file mode 100644
index 0000000000000..dde82a19936ff
--- /dev/null
+++ b/UPGRADE-2.2.md
@@ -0,0 +1,11 @@
+UPGRADE FROM 2.1 to 2.2
+=======================
+
+### Routing
+
+  * Added possibility to generate URLs that include the default param, whereas before a param
+    that equals the default value of an optional placeholder was never part of the URL.
+    Example: Given the route `new Route('/index.{_format}', array('_format' => 'html'));`
+    Previously generating this route with params `array('_format' => 'html')` resulted in `/index` 
+    which means one could not generate `/index.html` at all. This has been changed. You can of course
+    still generate just `/index` by passing array('_format' => null) or not passing the param at all.
diff --git a/src/Symfony/Component/Routing/CHANGELOG.md b/src/Symfony/Component/Routing/CHANGELOG.md
index d02009d84f6b7..49759b0575e0b 100644
--- a/src/Symfony/Component/Routing/CHANGELOG.md
+++ b/src/Symfony/Component/Routing/CHANGELOG.md
@@ -19,6 +19,12 @@ CHANGELOG
    check on URL generation completely by calling `setStrictRequirements(null)`. It
    improves performance in production environment as you should know that params always
    pass the requirements (otherwise it would break your link anyway).
+ * [BC BREAK] Added possibility to generate URLs that include the default param, whereas before
+   a param that equals the default value of an optional placeholder was never part of the URL.
+   Example: Given the route `new Route('/index.{_format}', array('_format' => 'html'));`
+   Previously generating this route with params `array('_format' => 'html')` resulted in `/index` 
+   which means one could not generate `/index.html` at all. This has been changed. You can of course
+   still generate just `/index` by passing array('_format' => null) or not passing the param at all.
 
 2.1.0
 -----
diff --git a/src/Symfony/Component/Routing/Generator/UrlGenerator.php b/src/Symfony/Component/Routing/Generator/UrlGenerator.php
index c1c1aefe8e7c8..baee0ad37d811 100644
--- a/src/Symfony/Component/Routing/Generator/UrlGenerator.php
+++ b/src/Symfony/Component/Routing/Generator/UrlGenerator.php
@@ -144,7 +144,7 @@ protected function doGenerate($variables, $defaults, $requirements, $tokens, $pa
         $optional = true;
         foreach ($tokens as $token) {
             if ('variable' === $token[0]) {
-                if (!$optional || !array_key_exists($token[3], $defaults) || (string) $mergedParams[$token[3]] !== (string) $defaults[$token[3]]) {
+                if (!$optional || !array_key_exists($token[3], $defaults) || isset($parameters[$token[3]]) || $this->context->hasParameter($token[3])) {
                     // check requirement
                     if (null !== $this->strictRequirements && !preg_match('#^'.$token[2].'$#', $mergedParams[$token[3]])) {
                         $message = sprintf('Parameter "%s" for route "%s" must match "%s" ("%s" given).', $token[3], $name, $token[2], $mergedParams[$token[3]]);
diff --git a/src/Symfony/Component/Routing/Tests/Generator/UrlGeneratorTest.php b/src/Symfony/Component/Routing/Tests/Generator/UrlGeneratorTest.php
index 224744f7dbaf6..92ed9dc465d17 100644
--- a/src/Symfony/Component/Routing/Tests/Generator/UrlGeneratorTest.php
+++ b/src/Symfony/Component/Routing/Tests/Generator/UrlGeneratorTest.php
@@ -277,6 +277,17 @@ public function testWithAnIntegerAsADefaultValue()
         $this->assertEquals('/app.php/foo', $this->getGenerator($routes)->generate('test', array('default' => 'foo')));
     }
 
+    public function testUrlWithDefaultIncluded()
+    {
+        $routes = $this->getRoutes('test', new Route('/index.{_format}', array('_format' => 'html'), array('_format' => '.*')));
+        $generator = $this->getGenerator($routes);
+
+        $this->assertSame('/app.php/index.html', $generator->generate('test', array('_format' => 'html')), 'parameter that equals default is included when explicitly given');
+        $this->assertSame('/app.php/index', $generator->generate('test'), 'the default is not included when param not given');
+        $this->assertSame('/app.php/index', $generator->generate('test', array('_format' => null)), 'null for an optional variable is ignored');
+        $this->assertSame('/app.php/index.', $generator->generate('test', array('_format' => '')), 'empty string is treated as-is (the requirement allows it)');
+    }
+
     public function testQueryParamSameAsDefault()
     {
         $routes = $this->getRoutes('test', new Route('/test', array('default' => 'value')));