Comprehensive and Detailed 150 to 250 words of Explanation From [SR Linux EVPN and Data Center Interconnect/Course Guide/topics]:

This setup represents single-active Layer 2 EVPN multi-homing. In single-active mode, the Ethernet Segment is configured so that only one PE acts as the active forwarding node for a given service, while the other remains standby. The ports connecting to the host are associated with ES-1 so the EVPN control plane can perform Ethernet Segment discovery, DF election, and standby behavior. If Leaf1 is the active/DF node for the service, all traffic to and from the host flows through Leaf1 until a failure or DF transition occurs. Option D is false because a host LAG is not required for this single-active topology. A LAG is typically required for all-active L2 multi-homing, where the host must treat multiple physical links toward different leaf routers as one logical bundle. In single-active operation, the host can be connected through separate physical links or active/standby access behavior without requiring LACP bundling. The EVPN PEs enforce the active path selection through DF and ES state rather than relying on host-side LAG hashing. Reference: single-active EVPN multi-homing, Ethernet Segment port association, DF-controlled active forwarding.

================

Comprehensive and Detailed 150 to 250 words of Explanation From [SR Linux EVPN and Data Center Interconnect/Course Guide/topics]:

MAC mobility is the EVPN mechanism used when a host MAC moves from one PE to another. The control plane uses a MAC Mobility extended community and sequence number behavior to determine the most recent valid location for the MAC. When a PE locally learns a MAC that was previously learned through EVPN, it advertises the MAC with an incremented sequence number, allowing remote PEs to prefer the newer location. Therefore, option B is wrong because the sequence number is not decremented. Option A is also wrong because the original PE does not advertise the locally learned MAC with a maximum sequence value as a normal mobility procedure. Option D is inaccurate because PEs do not need direct MAC table synchronization; they rely on EVPN control-plane advertisements and withdrawals. The true statement is option C: the originating PE generates a withdraw message after the same locally learned MAC ages out. This withdrawal removes stale reachability from remote PEs and prevents continued forwarding toward a PE that no longer has the host locally attached. Reference: EVPN MAC mobility, sequence-number handling, MAC route withdrawal after aging.

================

Comprehensive and Detailed 150 to 250 words of Explanation From [SR Linux EVPN and Data Center Interconnect/Course Guide/topics]:

In an all-active Layer 2 EVPN multi-homing design, the host is normally dual-attached through a LAG to multiple leaf routers that share the same Ethernet Segment Identifier. Leaf1 and Leaf2 both participate in the Ethernet Segment and may receive traffic from the host. For BUM traffic sourced by the host, the host-side hashing can send frames toward either attached leaf. For BUM traffic sent from the EVPN overlay toward the multi-homed segment, DF election controls which PE forwards that replicated traffic toward the local Ethernet Segment to prevent duplicate delivery. The false statement is option B. A remote leaf such as Leaf3 does not simply enable ECMP on the MAC-VRF to load-balance traffic between Leaf1 and Leaf2. EVPN all-active forwarding uses Ethernet Segment discovery, Ethernet A-D routes, aliasing, and split-horizon procedures to determine valid next-hops and prevent loops. ECMP alone is an underlay or routing-table behavior; it is not the MAC-VRF mechanism that authorizes multi-homed L2 forwarding across an Ethernet Segment. Reference: all-active L2 EVPN multi-homing, Ethernet Segment association, DF election, aliasing.

================