What happens to X2 created link if a target eNodeB is migrated to other MME?

Hello Experts.

Can you kindly help to know what would happen to X2 created link if a target eNodeB is migrated to other MME which is not in pool.

Will X2 link be auto disabled or we have to manually delete?

In our case we are observing HO drop and HO attempts on X2 despite of the fact that both eNodeBs are parented to different MMEs now but before migration they were on same MME.

Vendor is Ericsson.

I believe make ANR off, then delete ncell, external relations with RMV X2.
Then make ANR on.
Try in one site for example.
But S1 definition are proper.

Thanks.
That we have done and it’s happening now, but my query is so we need to manually delete Or X2 link gets auto disabled?

You need to delete X2 and then make ANR ON.
After deleting neighbor’s I believe.
So that ANR may take proper X2 relations (I believe).

In Samsung we faced exact same issue.
Previously all MMEs were in pool so all MMEs have all eNB definitions, but after independent MMEs, the eNBs which are not in MME pool now, their end definitions are removed from MME end and then X2 stopped happening, only through S1 HO takes place.

Comparing S1 HO and X2 HO, what is impact on user experience?

We’re planning to disable X2 HO and go for S1 HO.

I have deleted X2 links toward eNodeB which belongs to another pool. ANR recreated it but it was DISABLED immediately after. My question is why X2 Handovers are attempted towards eNodeB in another MME Pool and we have to LOCK those X2 Links to force S1 Handovers. The vendor is Ericsson.

We fix this kind of issue by locking TermPointToENB toward eNodeBs in another MME Pool. Or you can delete TermPointToENB and let ANR recreate them again which once recreated will be DISABLED most probably.

As long as eNB X2 IP is identifiable, it should not create an issue.

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Will X2 be identifiable if the target eNodeB belongs to another MME Pool?

Mobility and Retainability will degrade!