Link blocking procedure is asymmetrical. AN requests link block, LE decides, LE releases connection, LE re-establishes semi-perm and pre-connected connections. An E1 is added in a blocked state and must be unblocked by the LE before the E1 becomes operational. An E1 must be administratively locked or blocked by the LE before it can be deleted. The default value is unblocked and valid values are: * deferredBlocked - wait until there is no active calls on the link. * nonDeferredBlocked - disconnect any connection after approval from LE. * forceBlocked - This is a forced blocking from AN without LE's approval. * unblocked - Unlock the link.