DLC8023 Name-Discovery Services

In addition to the standard IEEE 802.2 common logical link protocol (CLLP) support and the address resolution services, IEEE 802.3 Ethernet data link control (DLC8023) also provides a name-discovery service that allows the operator to identify local and remote stations by name instead of by six-byte physical addresses.

Each port must have a unique name of up to 20 characters on the network. The character set used depends on the user's protocol. For example, systems network architecture (SNA) requires character set A. Each new service access point (SAP) supported on a particular port may have a unique name, if desired.

Each name is added to the network by broadcasting a find (local name) request. After the find (local name) request is sent the required number of times, if no response is returned, the physical link is declared opened. The name is then assigned to the local port and SAP. If another port on the network has already added the name, a name-found response is sent to the station that issued the find request, and the new attachment fails with a result code (DLC_NAME_IN_USE). This code indicates that a different name must be selected. Calls are established by broadcasting a find (remote name) request to the network and waiting for a response from the port with the specified name. Ports with attachments pending, colliding find requests, or an attachment to the requesting remote station will answer a find request.