What are two characteristics of SLB router mode?（）

• A、The design supports multiple server subnets.
• B、An end-user sees the IP address of the real server.
• C、SLB routes between the outside and inside subnets.
• D、The source or destination MAC address is rewritten, but the IP addresses left alone.
• E、SLB acts as a "bump in the wire" between servers and upstream firewall or Layer 3 devices.