The OpenVMS System Manager manual contains additional information about LAT in general and service nodes in particular. To configure an application service for a logical port on a LAT service node: Use the /DEDICATED and /SERVICE qualifiers to name a service for a specific application program to be offered locally on a dedicated port. (The service must have been created using the CREATE SERVICE command.) Assign only one service to a dedicated port, but be aware that the same service can be assigned to multiple ports. The third service node, ALEXIS, is an independent node on the LAT network, so its service name is the same as its node name. This command configures the local node to allow inbound and outbound connections. Users on your on-premises node can access service nodes, which belong to user groups 24 and 121 through 127. Users cannot access service nodes in user group 0. Although terminal servers are typically the requesting nodes in an LAT, service nodes sometimes request services from terminal servers. Most commonly, a service node queues print requests to remote printers connected to terminal servers. 26.2.3 Nodes that allow outbound connections Note that in a LAT network, nodes that access services are often referred to as master nodes, which distinguishes them from nodes that only provide services. The SET PORT command can also map a dedicated port on the local node to an application service offered locally.

The service must already exist (see example 3). Note that you must use the /DEDICATED and /SERVICE qualifiers. Figure 26-1 shows an example of an LAT network. The network consists of an Ethernet cable that connects the service nodes and terminal server nodes. LAT allows terminal servers and computers to communicate within a local area network such as Ethernet or Fiber Distributed Data Interconnect (FDDI). LAT adapts endpoints and other devices to the computing resources (services) of the LAN. Because LAT terminals are not directly connected to the computer (service node) they access, the local server must listen for service requests from its terminals and be able to match the terminals with the computers that provide the desired services. Curiously, the title of the xterm is: és In the router, the name is: )ss1 Although terminal connections are grouped, each terminal can be uniquely identified by name.

A terminal name has two parts: the first part is the name of the port on the terminal server to which the terminal line is connected. The second part is the name of the Terminal Server node. 26.2.2.3. Maintenance Nodes If you specify /SERVICE_RESPONDER, your system responds to special LAT multicast messages. (If you specify /NOSERVICE_RESPONDER, your system will not respond to these messages.) Compaq recommends that you configure only one or two nodes on the local network as service responder nodes. Nodes must have the largest databases on the local network. Use this option only if your node allows outbound connections (/CONNECTIONS=OUTGOING_ONLY or /CONNECTIONS=BOTH). If you use multiple LAN addresses for a LAT node, you can configure a system with multiple LANs connected to the same LAN. The LAT software can go through each adapter at the same time and better maintain connections. For example, if a virtual connection selects a primary path and uses it for all LAT message transmissions, the LAT software can continue communication through another adapter or logical path if that origin path is blocked.

A Terminal Server node is the second type of node in a LAT network. A terminal server node is typically located near the terminals and printers it supports. Terminals and printers are physically connected to the terminal server. The terminal server is physically connected to the LAN cable. 26.2.2.1. Locating Service Nodes This command forces your local node to send multicast messages every 50 seconds to announce Duke services to Terminal Server. The command also allows groups 1, 2, 3, 8, and 11 to access the local node and disables group 5 from accessing the local node. Group 5 was previously activated. When a user terminal or application program requests a service, the server node connects to the corresponding service node. This command sets the LTA22: port as the application port to map to port LN02 on the TS33EW terminal server.

This command maps the LTA22: port to a specific printer on the server. In the following example, the SET PORT command maps a port to a group of printers (identified by the service name PRINTER) on a terminal server.