Which of the following is a characteristic of a data center core？（）

• A、 Server-to-server traffic always remains in the core layer.
• B、 The recommended practice is for the core infrastructure to be in Layer 3.
• C、 The boundary between Layer 2 and Layer 3 should be implemented in the aggregation layer.
• D、 The Cisco Express Forwarding hashing algorithm is the default， based on the IP address andLayer 4 port.
• E、 Core layer should run BGP along with an IGP because iBGP has a lower administrativedistance than any IGP.