Added link to radius documentation.

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@1441 44740490-163a-0410-bde0-09ae8108e29a

docs/simplesamlphp-idp.txt

@@ -28,40 +28,42 @@ Authentication module
 
 The next step is to configure the way users authenticate on your IdP. Various modules in the `modules/` directory provides methods for authenticating your users. This is an overview of those that are included in the simpleSAMLphp distribution:
 
-[`authfacebook:Facebook`](https://rnd.feide.no/content/using-facebook-authentication-source)
-: Authenticate with a Facebook ID.
-
-`authYubiKey:YubiKey`
-: Authenticate with an YubiKey.
-
 `exampleauth:UserPass`
 : Authenticate against a list of usernames and passwords.
 
 `exampleauth:Static`
 : Automatically log in as a user with a set of attributes.
 
-[`InfoCard:ICAuth`](http://rnd.feide.no/content/simplesamlphp-infocard-module-usage)
-: Authenticate with an InfoCard.
-
 [`ldap:LDAP`](https://rnd.feide.no/content/configuring-simplesamlphp-ldap-authentication-source)
 : Authenticates an user to a LDAP server.
 
 [`ldap:LDAPMulti`](https://rnd.feide.no/content/configuring-simplesamlphp-ldap-authentication-source)
 : Authenticates an user to one of several LDAP server.
   The user can choose the LDAP server from a dropdown list.
+  
+`sqlauth:SQL`
+: Authenticate an user against a database.
+
+[`radius:Radius`](https://rnd.feide.no/content/radius-authentication-module)
+: Authenticates an user to a Radius server.
+
+[`InfoCard:ICAuth`](http://rnd.feide.no/content/simplesamlphp-infocard-module-usage)
+: Authenticate with an InfoCard.
 
 `openid:OpenIDConsumer`
 : Authenticate against an OpenID provider.
 
 `saml2:SP`
-: Authenticate against a SAML 2.0 IdP.
+: Authenticate against a SAML 2.0 IdP. Can be used for bridging.
+
+`authYubiKey:YubiKey`
+: Authenticate with [an YubiKey](http://www.yubico.com/products/yubikey/).
+
+[`authfacebook:Facebook`](https://rnd.feide.no/content/using-facebook-authentication-source)
+: Authenticate with a Facebook ID.
 
-`sqlauth:SQL`
-: Authenticate an user against a database.
 
-In this guide, we will use the `exampleauth:UserPass` authentication
-module. This module does not have any dependencies, and is therefore
-simple to set up.
+In this guide, we will use the `exampleauth:UserPass` authentication module. This module does not have any dependencies, and is therefore simple to set up.
 
 
 Configuring the authentication module