In Multicast VPN （MVPN） implementations， which two of the following statements are regarding the DefaultMDT Group？（）

• A、It is used for PIM control traffic
• B、It is optionally configured for a high bandwidth multicast source to reduce multicast traffic replication to uninterested PE routers
• C、Within the VPF configuration in the PE router， multiple Default MDT groups are configured so each VPF can support multiple multicast sources
• D、There is a reduced multicast state in the MPLS core P routers
• E、When multicast traffic exceeds a certain configured threshold， traffic from the Data MDT is switched to the Default MDT to conserve bandwidth