4A0-D03 Exam Dumps : Nokia SR Linux EVPN and Data Center Interconnect

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

This setup represents a Layer 2 EVPN multi-homing attachment where the host is connected to Leaf1 and Leaf2 through an Ethernet Segment named ES-1. In SR Linux EVPN multi-homing, the Ethernet Segment must be associated with the physical or logical attachment interfaces facing the host. This allows the PEs to advertise Ethernet Segment information into EVPN, participate in DF election, and apply the appropriate forwarding behavior for single-active or all-active redundancy. Option D is therefore correct. Option A is not necessarily true because the exhibit indicates an active/standby style attachment, not all-active operation. Option B is also incorrect because ECMP on the remote MAC-VRF is not the mechanism that defines the local ES association or single-active behavior. Option C is wrong in this setup because a host LAG is required for common all-active L2 multi-homing with LACP, but the shown design uses an active/standby-style attachment where the Ethernet Segment is bound to the host-facing ports. The technical anchor is that ES-1 must be associated to the access ports connecting the host into the multi-homed MAC-VRF service. Reference: L2 EVPN multi-homing, Ethernet Segment interface association, DF behavior.

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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.

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

The exhibit describes a Layer 3 multi-homing scenario where the Ethernet Segment is associated with an IP-VRF and the configuration references an EVI value of 1000. The segment is configured with all-active multi-homing, allowing multiple attached leaf routers to advertise reachability for the same external L3 next-hop or third-party prefix attachment. In this model, the Ethernet Segment represents the shared L3 attachment and is used by EVPN to associate remote prefix reachability with the multi-homed segment. The incorrect statement is that a LAG must be configured on the connected leaf routers and the host. That requirement is specific to many Layer 2 all-active host attachment designs, where the host commonly uses LACP toward multiple leaf routers and the leaf LAG subinterfaces are associated with the Ethernet Segment. In Layer 3 multi-homing, the attached device can be a router or VNF, and the EVPN ES association can be used for L3 prefix reachability without mandating that the host side be configured as a LAG. Reference: L3 EVPN multi-homing, EVI association, all-active Ethernet Segment behavior.

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