You install a new server named Server1 that runs Windows Server 2008 R2.
The server has the Streaming Media Services server role installed.
You install and activate all Windows Media Services control protocols.
Users connect to Server1 locally and remotely through a firewall.

You need to ensure that the protocol rollover will occur only if the users are accessing Server1 from the Internet.

What should you do?

A.
Install the Reliable Multicast Protocol on Server1.

B.
Install the Quality of Service (QoS) service on the network adapter.

C.
Configure the firewall to forward incoming port 1755 traffic to Server1.

D.
Use announcements to enable users to access the streaming media.

Explanation:
You can force your Windows Media server to use a specific protocol by identifying the protocol to be used in the announcement file (for example, rtspu:// server/publishing_point/file). However, to provide an optimal streaming experience for all client versions, we recommend that the URL use the general MMS protocol. If clients connect to your stream using a URL with an MMS URL moniker, any necessary protocol rollover occurs automatically. Be aware that users can disable streaming protocols in the property settings of Windows Media Player. If a user disables a protocol, it is skipped during rollover. For example, if HTTP is disabled, then URLs will not roll over to HTTP.

Source: http://technet.microsoft.com/en-us/library/ee126137.aspx