Question 80 - JN0-664 discussion

In an L2VPN scenario, the provider network connects two customer edge (CE) devices across a Layer 2 virtual private network. Let's analyze how OSPF operates in this setup.

1. **OSPF Neighborship in L2VPN**:

- An L2VPN provides a Layer 2 connection between two sites, making it transparent to Layer 3 protocols like OSPF. This means the CEs can form OSPF adjacencies directly with each other as if they were on the same local network.

2. **OSPF Configuration on CEs and PEs**:

- **Statement A: OSPF neighborship is formed between the CEs and PEs**:

- Incorrect. In an L2VPN, the provider's network is transparent to the OSPF running on the CEs. OSPF neighborship forms directly between the CEs, not between the CEs and PEs.

- **Statement B: The CE and PE OSPF areas can be different**:

- Correct. Since OSPF adjacencies form directly between the CEs and not between CEs and PEs, the OSPF areas on the CEs and PEs can be different. The provider network acts as a transparent bridge, and OSPF doesn't see the PEs.

- **Statement C: The CE and PE OSPF areas must match**:

- Incorrect. As noted above, because the OSPF neighborship forms directly between the CEs, the OSPF areas on the CEs and PEs do not need to match.

- **Statement D: OSPF neighborship is formed between the two CEs**:

- Correct. The L2VPN makes the connection between the two CEs appear as a direct Layer 2 link, allowing them to form an OSPF adjacency directly.

**Conclusion**:

Given the above analysis, the correct statements are:

**B. The CE and PE OSPF areas can be different.**

**D. OSPF neighborship is formed between the two CEs.**

**Reference**:

- Juniper Networks Documentation on L2VPNs: [Configuring Layer 2 VPNs](https://www.juniper.net/documentation/en_US/junos/topics/task/configuration/layer-2-vpns-configuring.html)

- OSPF Configuration Guide: [Junos OS OSPF Configuration](https://www.juniper.net/documentation/en_US/junos/topics/concept/ospf-routing-overview.html)