The less stable European states are already in the process of collapsing. In the telematic universe which is being created, two towns, however far apart they might be from each other, will have the chance to be in immediate contact, according to their common economic or cultural interests. Thus permanent commercial and cultural exchanges will be set up in the four corners of Europe, through a network of associated towns, while the unit represented by the nation state will progressively lose power. We have immigration when a reduced portion of a population looks for jobs in another nation, as happened with Italian or Irish people in America, or Italians and Spaniards in Argentina during the last century, and even more recently with Turkish workers in Germany or Albanian refugees in Italy. Immigration can be controlled by laws and border police.
Migrations are a different affair.
There were prehistoric migrations of entire populations from Africa to Europe and Asia, and from Asia to America. There were migrations of German populations toward the Roman empire, and I would define as migration the European invasion of the American continent, from Canada to the Southern Cone. When there is migration, the migrators do not accept the language and habits of the host. We are today facing an enormous migratory movement from the third world to Europe, not to speak of the increasing hispanisation of various parts of the United States, which are already bilingual communities. Considering the differences in birthrates between migrating and host nations, it seems to me that in the following decades Europe will become a coloured continent.