Comprehensive and Detailed 150 to 250 words of Explanation From [SR Linux EVPN and Data Center Interconnect/Course Guide/topics]:
In SR Linux, a Layer 2 EVPN service is implemented using a MAC-VRF network instance. The MAC-VRF represents the tenant bridge domain and is associated with access subinterfaces and a VXLAN data-plane mapping. Local hosts are learned through the data plane when Ethernet frames arrive on local interfaces. Remote hosts, however, are not learned by flooding or by configuring static per-peer VXLAN interfaces. They are learned through MP-BGP EVPN updates, especially EVPN route type 2 MAC/IP Advertisement routes. Option B is false because SR Linux does not require a separate manually configured VXLAN interface toward each remote VTEP for the MAC-VRF. Instead, the MAC-VRF is bound to VXLAN encapsulation and a VNI, while remote VTEPs and their MAC reachability are discovered dynamically through the EVPN control plane. This is one of the central advantages of EVPN compared with static VXLAN flood-and-learn models: the overlay endpoints and endpoint reachability are signaled through BGP, reducing manual configuration and improving scale. Reference: SR Linux L2 EVPN MAC-VRF configuration, MP-BGP EVPN learning, VXLAN data-plane mapping.

Comprehensive and Detailed 150 to 250 words of Explanation From [SR Linux EVPN and Data Center Interconnect/Course Guide/topics]:
A gateway-less DCI design extends the data center EVPN/VXLAN model across the WAN without a distinct gateway function separating the data center fabric from the WAN VPN edge. Because the leaf routers or route reflectors must establish the necessary EVPN control-plane and VXLAN data-plane reachability across data centers, the WAN must provide reachability for those fabric endpoints. This design can simplify service continuity and preserve the EVPN overlay model end-to-end, but it does not provide the clean security and QoS demarcation that exists in a decoupled gateway model. A clear demarcation between a border leaf and a separate gateway/WAN PE is specifically a property of decoupled gateway-based DCI, not gateway-less DCI. The gateway-less model also requires reachability between route reflectors or EVPN control-plane endpoints across sites. Therefore, option A is false because it incorrectly assigns the demarcation benefit to the gateway-less design. Reference: gateway-less DCI, stretched EVPN overlay, route-reflector and leaf reachability requirements.

Comprehensive and Detailed 150 to 250 words of Explanation From [SR Linux EVPN and Data Center Interconnect/Course Guide/topics]:
The scenario describes Layer 3 EVPN multi-homing with an IP-VRF service and an external CE VNF advertising the 40.40.40.0/24 prefix through BGP. A DF election can occur among the leaf routers participating in the Ethernet Segment, and the active/primary forwarding node is used for the relevant service behavior. The AD per EVI route can participate in identifying service-level reachability for the Ethernet Segment, and the prefix traffic follows the valid advertised path toward the CE VNF. Because Leaf3 has the BGP connection to the CE VNF, traffic for 40.40.40.0/24 is forwarded through Leaf3. Option B is false because it incorrectly states that all connected leaf routers will use single-active redundancy. The exhibit and answer context indicate a more specific forwarding/primary selection for the service, not a blanket statement that every connected leaf operates using single-active redundancy. In L3 multi-homing, redundancy behavior depends on the ES mode, prefix advertisement, next-hop association, and CE connectivity. The forwarding decision for the customer prefix is tied to the active/valid route advertisement, not to every leaf uniformly acting as single-active. Reference: L3 EVPN multi-homing, DF election, AD per EVI role, PE-CE BGP prefix forwarding.

Comprehensive and Detailed 150 to 250 words of Explanation From [SR Linux EVPN and Data Center Interconnect/Course Guide/topics]:
Layer 3 EVPN multi-homing with a centralized router uses an Ethernet Segment to associate multiple leaf routers with a common external L3 attachment. The centralized router is part of that attached segment from the forwarding perspective, and the connected leaf routers advertise third-party or customer prefixes into EVPN so that remote leaves can reach those prefixes through the multi-homed attachment. For L3 EVPN, learned customer prefixes are normally advertised using EVPN route type 5, which carries IP prefix reachability. In an all-active design, remote leaf routers may load balance traffic to the customer prefix through multiple attached leaf routers because the ES next-hop allows the remote PE to understand that the prefix is reachable through a multi-homed Ethernet Segment. The false statement is that every router participating in the Ethernet Segment must be configured with all-active mode. Multi-homing mode is a design and configuration property of the EVPN PEs participating in the ES, and designs may use single-active or all-active behavior depending on redundancy and forwarding requirements. Reference: L3 EVPN multi-homing, centralized router attachment, EVPN RT-5 prefix advertisement.

Comprehensive and Detailed 150 to 250 words of Explanation From [SR Linux EVPN and Data Center Interconnect/Course Guide/topics]:
Layer 3 multi-homing is fundamentally about redundant or load-balanced L3 reachability for external prefixes, not about Layer 2 broadcast-domain flooding toward a host. In single-active L3 multi-homing, DF election determines which attached leaf is active for the Ethernet Segment, and only that leaf advertises or forwards for the attached customer route as required by the redundancy model. In all-active L3 multi-homing, multiple leaf routers can be valid next-hops for the same learned third-party prefix, and remote PEs may load-balance toward them based on the Ethernet Segment association. Learned external prefixes are carried as EVPN route type 5 IP Prefix routes, which is the correct route type for L3 reachability. The Ethernet Segment is associated with the next-hop for those prefixes so that remote PEs understand the multi-homed nature of the path. Option B is false because BUM forwarding is a Layer 2 EVPN concern. In an all-active L3 multi-homing scenario, DF election is not used to identify a BUM-forwarding leaf for host traffic in the same way it is used in Layer 2 multi-homing services. Reference: L3 EVPN multi-homing, RT-5 prefix routes, ES next-hop behavior.