A data center provider has designed a network using these requirements:
Two data center sites are connected to the public Internet.
Both data centers are connected to different Internet providers.
Both data centers are also directly connected with a private connection for the internal traffic,
and public Internet traffic can also be routed at this direct connection.
The data center provider has only one /19 public IP address block.
Under normal conditions, Internet traffic should be routed directly to the data center where the
services are located. When one Internet connection fails, the complete traffic for both data centers
should be routed by using the remaining Internet connection. In which two ways can this routing
be achieved? (Choose two.)

A.
The data center provider must have an additional public IP address block for this routing.

B.
One /20 block is used for the first data center and the second /20 block is used for the second
data center. The /20 block from the local data center is sent out with a low BGP weight and the /20
block from the remote data center is sent out with a higher BGP weight at both sites.

C.
One /20 block is used for the first data center and the second /20 block is used for the second
data center. The /20 block from the local data center is sent out without path prepending and the
/20 block from the remote data center is sent out with path prepending at both sites.

D.
One /20 block is used for the first data center and the second /20 block is used for the second
data center. Each /20 block is only sent out locally. The /19 block is sent out at both Internet
connections for the backup case to reroute the traffic through the remaining Internet connection.

E.
One /20 block is used for the first data center and the second /20 block is used for the second
data center. The /20 block from the local data center is sent out with a low BGP local preference
and the /20 block from the remote data center is sent out with a higher BGP local preference at
both sites.

F.
BGP will always load-balance the traffic to both data center sites.