doc for enabling CSP support on xenserver 6.1

https://issues.apache.org/jira/browse/CLOUDSTACK-6574

Signed-off-by: Sebastien Goasguen <runseb@gmail.com>
diff --git a/source/hypervisor_installation.rst b/source/hypervisor_installation.rst
index 5582cf0..802a8a3 100644
--- a/source/hypervisor_installation.rst
+++ b/source/hypervisor_installation.rst
@@ -1171,6 +1171,29 @@
 (CSP). After installing XenServer, perform the following additional
 steps on each XenServer host.
 
+**For XenServer 6.1:**
+
+CSP functionality is already present in XenServer 6.1
+
+#. Run the below command
+   
+   .. sourcecode:: bash
+
+      xe-switch-network-backend bridge
+
+#. update sysctl.conf with the following
+
+   .. sourcecode:: bash
+   
+      net.bridge.bridge-nf-call-iptables = 1
+      net.bridge.bridge-nf-call-ip6tables = 0
+      net.bridge.bridge-nf-call-arptables = 1
+      
+      $ sysctl -p /etc/sysctl.conf
+
+
+**For XenServer 6.0.2, 6.0, 5.6 SP2:**
+
 #. 
 
    Download the CSP software onto the XenServer host from one of the
@@ -1187,7 +1210,8 @@
    For XenServer 6.0:
 
    `http://download.cloud.com/releases/3.0/xenserver-cloud-supp.tgz <http://download.cloud.com/releases/3.0/xenserver-cloud-supp.tgz>`_
-
+   
+   
 #. 
 
    Extract the file: