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

In a single-active EVPN multi-homing design, the connected PE routers perform Designated Forwarder election to determine which PE is active for the relevant service or Ethernet Segment. The DF is responsible for forwarding toward the attached segment and, in a Layer 3 multi-homing case, only the active/DF PE advertises the customer IP prefix route toward the EVPN control plane. Single-active redundancy is communicated using Ethernet Segment-related EVPN procedures, including Ethernet A-D information, so remote PEs can identify the redundancy behavior and avoid forwarding traffic to an inactive attachment. The false statement is that the elected DF uses an AD per EVI update to identify itself as primary. AD per EVI is primarily used to advertise per-service Ethernet Segment reachability and support aliasing/load-balancing behavior in multi-homed services. DF election itself is driven by Ethernet Segment route procedures, not by the DF declaring itself primary through AD per EVI. Therefore, option B misstates the role of AD per EVI in the single-active L3 multi-homing control plane. Reference: EVPN DF election, single-active multi-homing, Ethernet A-D routes.

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

A decoupled gateway-based DCI model separates the data center border-leaf function from the WAN PE function. This separation is the key design point. The border leaf remains part of the data center EVPN/VXLAN environment, while the WAN PE participates in WAN VPN transport and policy enforcement. Because the roles are split across two devices, the handoff between the border leaf and WAN PE provides a clean administrative and operational boundary. That boundary is useful for security policy, QoS marking, traffic classification, and troubleshooting ownership. The WAN does not need direct reachability to every leaf and route reflector as in a gateway-less model. The WAN PE also does not peer directly with the data center route reflector in a decoupled model; route exchange occurs through the border-leaf/WAN-PE handoff. VXLAN tunnels between leaf routers across different data centers are characteristic of gateway-less extension, not decoupled gateway operation. Therefore, the statement about clear demarcation between the data center border leaf and WAN PE is the accurate description. Reference: decoupled gateway-based DCI, security/QoS demarcation, WAN PE separation.

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

A route distinguisher is used in MP-BGP VPN and EVPN address families to make otherwise overlapping tenant routes unique in the BGP control plane. In EVPN, different tenants or EVPN instances may legitimately use the same MAC or IP values. The route distinguisher makes the NLRI globally unique by prepending a unique value to the tenant route. It is typically unique per PE and per EVI, and it is carried in EVPN route advertisements. However, the route distinguisher does not control route import, export, or service membership. That role belongs to the route target, which is a BGP extended community used by receiving PEs to decide which EVPN instance should import the route. Therefore, option D is not part of the correct description of a route distinguisher. Saying that the RD identifies the EVPN instance in the control plane confuses RD uniqueness with route-target membership. The RD makes routes unique; the route target associates those routes with the appropriate MAC-VRF or IP-VRF import policy. Reference: EVPN route distinguisher, overlapping tenant addresses, route target separation.

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

When Leaf-1 receives an ARP request from Host-1, it learns the source MAC address in the local MAC table and learns the source IP/MAC binding in the proxy ARP table. For EVPN distribution, the relevant control-plane advertisement is an EVPN route type 2 MAC/IP advertisement containing Host-1's MAC and the actual host IP address, 192.168.100.1. This allows remote PEs to populate their EVPN-derived forwarding and proxy ARP state with the correct endpoint binding. Option A is false because advertising the host MAC with the IP address set to 0.0.0.0 does not represent the learned MAC/IP binding required for proxy ARP synchronization. A MAC-only RT-2 advertisement may exist in EVPN contexts, but the question specifically states that Leaf-1 has learned the MAC/IP binding through ARP and is distributing that information. Therefore, the valid advertisement must include the real host IP address. Remote PEs use the MAC/IP route to learn the endpoint, not an all-zero IP placeholder for this proxy ARP learning event. Reference: EVPN RT-2 MAC/IP advertisement, proxy ARP table population, endpoint synchronization.

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

In interface-less symmetric L3 EVPN routing, hosts in a subnet may be attached to different leaf routers, while inter-subnet forwarding is performed through the IP-VRF using VXLAN routed interfaces. The ingress and egress PEs both participate in L3 forwarding, and the routed VXLAN interface provides the per-IP-VRF overlay data-plane construct needed for symmetric routing. The IRB interfaces on the local MAC-VRFs must advertise learned local host routes so that remote PEs have the necessary host reachability information. The MAC-VRFs also need the appropriate EVPN control-plane configuration so host MAC/IP information can be exchanged, while the IP-VRF participates in L3 VPN-style route exchange for routed reachability. Option A is false because anycast gateway is not optional in this design for Leaf1 and Leaf2. Anycast gateway allows the same default-gateway IP and virtual MAC behavior to exist consistently on multiple leaves serving the same subnet. Without it, host default-gateway behavior would be inconsistent and traffic mobility across the fabric would break expected distributed gateway operation. Reference: interface-less symmetric routing, IRB, anycast gateway, routed VXLAN interface.

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

When Host-1 sends its first Ethernet frame into MAC VRF-1, Leaf-1 performs normal local data-plane MAC learning on the access interface and installs Host-1's MAC address into the MAC forwarding table. In an L2 EVPN MAC-VRF, host MAC reachability is then advertised into the EVPN control plane using EVPN route type 2, the MAC/IP Advertisement route. Route type 5 is not used for host MAC advertisement; RT-5 is used for IP prefix advertisement in Layer 3 EVPN services. Therefore, option B is false because it incorrectly states that Leaf-1 generates an EVPN RT-5 update with the host MAC address. In this topology, Leaf-1 sends the correct EVPN update to the route reflector, Spine-1. The route reflector then reflects the update to Leaf-2 and Leaf-3, and those remote leaves import the route if the route target matches their MAC VRF-1 import policy. The route target controls service membership, ensuring that only PEs participating in the same EVPN instance import the MAC route. Reference: L2 EVPN MAC learning, RT-2 MAC/IP advertisement, route-reflector distribution, route-target import.

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

A Gratuitous ARP is an ARP message a host sends to announce or refresh its own IP-to-MAC binding without waiting for another host to request it. In a traditional Ethernet subnet, the GARP is sent as a broadcast so that other hosts can update their ARP caches with the sender's current MAC address. This is useful after a host boots, changes NICs, moves to another attachment point, or takes over an IP address in a redundancy scenario. In EVPN environments, GARPs are also important because a leaf can snoop the ARP information and update local proxy ARP and EVPN MAC/IP state. Option D is false because recipients do not acknowledge a gratuitous ARP with a reply. GARP is an announcement mechanism, not a request/response transaction. If every receiving host acknowledged a broadcast GARP, the result would be unnecessary ARP traffic amplification. The correct behavior is passive update of ARP state by receiving systems and, in EVPN, potential control-plane propagation of the learned binding by the local PE. Reference: GARP behavior, proxy ARP learning, Layer 2 EVPN endpoint update procedures.

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

In asymmetric L3 EVPN routing, each participating PE must have the MAC-VRFs needed to forward traffic in the destination bridge domain. However, the specific exhibit describes two MAC-VRFs interconnected through IP-VRF3, with Leaf-1 hosting MAC-VRF1 and Leaf-2 hosting MAC-VRF2. The false statement is that Leaf-1 and Leaf-2 must both have instances of MAC-VRF1 and MAC-VRF2. That requirement is not true for this described deployment. Each local MAC-VRF connects to IP-VRF3 using an IRB interface, and host MAC/IP information is advertised using EVPN route type 2 so remote PEs can learn endpoint reachability. The question's answer also implies that IP prefix advertisement using route type 5 is part of the control-plane exchange between the leaves for the routed service context. What matters is that the fabric can resolve host and prefix reachability through EVPN without forcing every PE to instantiate every MAC-VRF in this topology. Option B overstates the MAC-VRF placement requirement and is therefore false. Reference: asymmetric L3 EVPN routing, RT-2 host advertisements, RT-5 IP prefix routes, IRB attachment.

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

PE-CE routing is the mechanism used to exchange customer prefix reachability between a provider edge or data center leaf and the attached customer edge router. It can be implemented statically or dynamically. Static routing is operationally simple but does not scale well when many prefixes or frequent changes are involved. BGP is preferred for larger deployments because it supports policy, route filtering, attributes, and automated advertisement of changing reachability. In most EVPN PE-CE designs, eBGP is preferred because it creates a clean routing boundary between the PE and CE, with each device operating in a different autonomous system. Option D is false because the CE does not advertise BGP EVPN route type 5 updates to the PE. The CE advertises ordinary IPv4 or IPv6 unicast prefixes over the PE-CE routing session. The PE then imports those customer prefixes into the IP-VRF and advertises them into the EVPN overlay as route type 5 IP Prefix routes toward other PEs. This distinction matters: EVPN signaling is a PE-to-PE overlay function, not a CE-originated EVPN control-plane role. Reference: PE-CE routing, eBGP, EVPN RT-5 prefix advertisement.

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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.

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