JN0-683 Online Practice Questions

Explanation:
Issue Overview:
The leaf devices in an IP fabric using eBGP are advertising and receiving all routes, but the routes are not being installed in the routing table and are marked as hidden. This typically indicates an issue with the BGP configuration, particularly with next-hop handling or AS path concerns. Corrective Actions:
B. You need to configure a next-hop self policy: This action ensures that the leaf devices modify the next-hop attribute to their own IP address before advertising routes to their peers. This is particularly important in eBGP setups where the next-hop may not be directly reachable by other peers.
D. You need to configure multipath multiple-as: This setting allows the router to accept multiple paths from different autonomous systems (ASes) and use them for load balancing. Without this, the BGP process might consider only one path and mark others as hidden.
Incorrect Statements:
A. You need to configure as-override: AS-override is used to replace the AS number in the AS-path attribute to prevent loop detection issues in MPLS VPNs, not in a typical eBGP IP fabric setup.
C. You need to configure loops 2: There is no specific BGP command loops 2 relevant to resolving hidden routes in this context. It might be confused with allowas-in, which is used to allow AS path loops under certain conditions.
Data Center
Reference: Proper BGP configuration is crucial in IP fabrics to ensure route propagation and to prevent routes from being marked as hidden. Configuration parameters like next-hop self and multipath multiple-as are common solutions to ensure optimal route installation and load balancing in a multi-vendor environment.

Explanation:
Understanding the Problem:
Host1 (10.1.1.1) is failing to communicate with Host2 (10.1.2.1) within an EVPN-VXLAN environment using ERB architecture.
Analysis of the Exhibit:
The provided output includes information from the show route forwarding-table matching command for IP 10.1.2.1. The next hop is shown as vtep.32769, which indicates that the traffic destined for 10.1.2.1 is being forwarded into the VXLAN tunnel with the correct VTEP (VXLAN Tunnel Endpoint).
Conclusion:
Option B: Correct―The traffic from Host1 is entering the VXLAN tunnel, as evidenced by the next hop pointing to a VTEP. However, the issue could lie elsewhere, possibly with the remote VTEP, routing configurations, or the receiving leaf/spine devices.

Explanation:
Multicast-Signaled VXLAN:
In traditional multicast-signaled VXLAN, VTEPs (VXLAN Tunnel Endpoints) use multicast to flood and learn about remote VTEPs. This method relies on multicast in the underlay network to distribute BUM (Broadcast, Unknown unicast, and Multicast) traffic.
This approach can be resource-intensive due to the need for multicast group management and increased network traffic, especially in large deployments.
EVPN-Signaled VXLAN:
EVPN-signaled VXLAN uses BGP (Border Gateway Protocol) to signal the presence of VTEPs and distribute MAC address information. BGP is used for VTEP autodiscovery and the distribution of endpoint information.
This method is more efficient because it reduces the reliance on multicast, instead using BGP control-
plane signaling to handle VTEP discovery and MAC learning, which reduces the overhead on the
network and improves scalability.
Correct Statements:
B. An EVPN-signaled VXLAN can perform autodiscovery of VTEPs using BGP: This is correct because EVPN uses BGP for VTEP autodiscovery, making it more efficient and scalable compared to multicast-based methods.
C. An EVPN-signaled VXLAN is less resource-intensive: This is correct because it eliminates the need for multicast flooding in the underlay, instead using BGP for signaling, which is less demanding on network resources.
Incorrect Statements:
A. An EVPN-signaled VXLAN can perform autodiscovery of VTEPs using IS-IS: This is incorrect because EVPN relies on BGP, not IS-IS, for VTEP discovery and signaling.
D. An EVPN-signaled VXLAN features slower and more complete convergence: This is incorrect; EVPN with BGP typically provides faster convergence due to its use of a control plane rather than relying on data plane learning.
Data Center
Reference: EVPN-VXLAN is widely adopted in modern data center designs due to its scalability, efficiency, and reduced resource consumption compared to multicast-based VXLAN solutions. It leverages the strengths of BGP for control-plane-driven operations, resulting in more efficient and scalable networks.

Explanation:
Issue Analysis:
The problem in the exhibit suggests a mismatch in configuration parameters between Leaf-1 and Leaf-2, leading to communication issues between hosts connected to these leaf devices.
Configuration Mismatches:
Service-ID: Leaf-1 has service-id 1 configured, while Leaf-2 does not have this parameter. For consistency and proper operation, the service-id should be the same across both leaf devices. VRF Target: Leaf-1 is configured with vrf-target target:65000:1, while Leaf-2 is configured with vrf-target target:65000:2. To allow proper VRF import/export between the two leafs, these should match.
Corrective Actions:
C. Configure the set switch-options vrf-target target:65000:1 parameter on Leaf-2: This aligns the VRF targets between the two leaf devices, ensuring they can correctly import and export routes.
E. Configure the set switch-options service-id 1 parameter on Leaf-2: This ensures that both Leaf-1 and Leaf-2 use the same service ID, which is necessary for consistency in the EVPN-VXLAN setup. Data Center
Reference: Correct configuration of VRF targets and service IDs is critical in EVPN-VXLAN setups to ensure that routes and services are correctly shared and recognized between different devices in the network fabric.

Explanation:
Understanding ERB Architecture:
ERB (Edge Routed Bridging) architecture is a network design where the routing occurs at the edge (leaf devices) rather than in the spine devices. In a VXLAN overlay network with EVPN as the control plane, leaf devices typically act as both Layer 2 (L2) and Layer 3 (L3) VXLAN gateways.
Placement of VXLAN Gateways:
Option B: All leaf devices will have L2 VXLAN gateways to handle the bridging of VLAN traffic into VXLAN tunnels.
Option C: All leaf devices will also have L3 VXLAN gateways to route traffic between different VXLAN segments (VNIs) and external networks.
Option E: Spine devices in an ERB architecture generally do not function as VXLAN gateways. They primarily focus on forwarding traffic between leaf nodes and do not handle VXLAN encapsulation/decapsulation.
Conclusion:
Option B: Correct―All leaf devices will have L2 VXLAN gateways.
Option C: Correct―All leaf devices will have L3 VXLAN gateways.
Option E: Correct―Spine devices will not act as VXLAN gateways