Before messages can flow across connections, the connections must be established, or opened. This is necessary because a service does not initially know the LPI address of the service with which it wishes to communicate; indeed, there may not even be a suitable service for it to communicate with.
When a local node wishes to communicate with an SNALink, it attempts to open a connection by sending an Open(LINK) request to the SNALink. This message will have LPI values already set up by the Base, which the SNALink should save for referencing the connection in the future.
The DLC interface does not permit the SNALink to issue an Open request.