diff --git a/perl-xCAT/xCAT/Schema.pm b/perl-xCAT/xCAT/Schema.pm
index c6b615b4e..2ced68c9e 100755
--- a/perl-xCAT/xCAT/Schema.pm
+++ b/perl-xCAT/xCAT/Schema.pm
@@ -572,7 +572,7 @@ passed as argument rather than by table value',
             ddnsdomain => 'A domain to be combined with nodename to construct FQDN for DDNS updates induced by DHCP.  This is not passed down to the client as "domain"',
             vlanid   => 'The vlan ID if this network is within a vlan.',
             domain   => 'The DNS domain name (ex. cluster.com).',
-            mtu      => 'The default MTU for the network, if this network is for aliases, mtu value should be the same with its basic network mtu value.',
+            mtu      => 'The default MTU for the network, if the nic belong to multiple networks, mtu value should be the same in all networks entry.',
             comments => 'Any user-written notes.',
             disable  => "Set to 'yes' or '1' to comment out this row.",
         },