Symmetric routing needs an extra VLAN with an IRB interface for each L3 VRF instance:
Symmetric routing requires an additional VLAN (and corresponding VNI) with an IRB interface for every Layer 3 VRF instance, supporting inter-VLAN routing at every VTEP.
Symmetric routing supports higher scaling numbers: Symmetric routing is preferred for environments with high scaling needs (such as 1024 VLANs and up to 250 switches) because it avoids the scalability limitations seen in asymmetric routing, which requires all VLANs and VNIs to be configured on every switch, leading to configuration complexity and overhead.

* Understanding VPN Route Table Association:
* In MPLS/VPN and EVPN networks, theroute-target communityis a BGP extended community attribute used to control the import and export of VPN routes. It associates received routes with the appropriate VPN route tables on the PE (Provider Edge) routers.
* Function of Route-Target Community:
* The route-target community tag ensures that routes are imported into the correct VRF (Virtual Routing and Forwarding) instance, allowing them to be correctly routed within the VPN.
Conclusion:
* Option A:Correct-The route-target community is used to associate received routes with a local VPN route table.

* Requirement Analysis:
* The scenario requires a solution to interconnect two data centers that supports EVPN Type 2 connectivity. The solution must be highly scalable and must minimize the number of VXLAN tunnels between border leaf devices.
* Understanding Type 2 Seamless Stitching:
* Option D:Type 2 seamless stitchingis a method used in EVPN to provide Layer 2 connectivity (such as MAC address mobility) across different VXLAN segments. It is scalable because it allows only necessary tunnels to be established between border leaf devices, reducing the overhead of maintaining a full mesh of VXLAN tunnels.
Conclusion:
* Option D:Correct-Type 2 seamless stitching satisfies the requirement by enabling scalable, efficient interconnection of two data centers with minimal VXLAN tunnels.

* Understanding Multihomed CE-to-PE VXLAN Environment:
* In a VXLAN environment using EVPN signaling, multiple PEs (Provider Edge devices) can be connected to the same CE (Customer Edge device). This setup is referred to as multihoming, where a CE device has multiple connections to the network to ensure redundancy and load balancing.
* Role of the Designated Forwarder:
* The designated forwarder (DF) is a mechanism used in EVPN to manage the forwarding of broadcast, unknown unicast, and multicast (BUM) traffic in a multihomed environment. The DF is selected to ensure that only one of the PEs forwards this type of traffic to the CE, preventing loops and unnecessary duplicate packets.
* Avoiding Duplicate Packets:
* Without a designated forwarder, all PEs connected to a multihomed CE could potentially forward the same packet to the CE, resulting in duplicate packets. This duplication can cause issues with packet processing on the CE, leading to inefficiencies and potential network problems.
Conclusion:
* Option D:Correct-The designated forwarder is essential to prevent duplicate packets from being received on multihomed hosts, ensuring that only one PE forwards BUM traffic to the CE.

All leaf VTEPs in each network must be reachable: In over-the-top Data Center Interconnect (DCI) using EVPN-VXLAN, the leaf VTEPs (VXLAN Tunnel Endpoints) in both data centers need to be reachable from each other. This is crucial for the successful exchange of VXLAN traffic and the proper operation of the overlay network between the data centers.
EVPN route-types must be advertised to all leaf devices: To extend Layer 2 and Layer 3 services seamlessly across data centers in OTT DCI, EVPN route types must be advertised to all leaf devices to maintain the unified control plane and support endpoint reachability.