networking - network setting with xen hypervisor

I have installed xen on my ubuntu 14.04 by following the instructions at here: http://ubuntuforums.org/showthread.php?t=2008795

However, after the reboot, on the logo screen (still no desktop), it said waiting for network connection and then said waiting for 60 more seconds, finally it said starting without full network configuration.
Now I don't have network connection.

I think this is the problem:

auto xenbr0
iface xenbr0 inet dhcp
   bridge_ports eth0

And, at here: http://wiki.xenproject.org/wiki/Network_Configuration_Examples_(Xen_4.1%2B), I saw that what I need to do:

iface eth0 inet manual

iface xenbr0 inet static
    bridge_ports eth0
    address 192.168.1.2
    broadcast 192.168.1.255
    netmask 255.255.255.0
    gateway 192.168.1.1

You may ask why. I am using my university's computer and it requires special IP and DNS settings.

First: Do I think right?

If yes, what is that broadcast thing and where is the DNS settings in this example? I have to use special DNS address.

If no, what should I do to get my network back?

Thanks in advance.