This article explains an issue with OSPFv3 between QFX5100 and a Cisco router where the OSPFv3 neighborship is down on both sides even with correct configuration on both the sides.

• OSPFv3 neighborship not formed between the devices.
• The issue is seen when the OSPFv3 is configured over the IPSEC tunnel

protocols {
    ospf {
        area area-id {
            interface interface-name {
                ipsec-sa sa-name;
            }

• We can see the ospf hellos exchanged and the tcpdump on the interface but still the adjacency is not formed.
• OSPFv3 traceoptions doesnt show much details.
• IPSEC keys are same on both the sides.

In the above case the issue can be resolved by deactivate/activate the physical interface on which the ospf and ipsec authentication is enabled.
Issue could be due to the incorrect IPSEC negotiation.