RESPONDER Characteristic

RESPONDER CharacteristicAccess Server Mapping

In order to connect to other nodes on the LAN, the access server must be able to map node names, port names, and services to specific nodes.

Datagram Types

LAT provides the following specific types of datagrams that facilitate this mapping:

Datagram Name

Description

 

 

Service Announcement

A mulicasted datagram used by slave nodes

 

to advertise services

Solicit Information

A multicasted or physically addressed

 

datagram used by any node to solicit service

 

information from another node

Response Information

A physically addressed datagram sent in

 

response to a received Solicit Information

 

message

 

 

LAT V5.2 nodes operating as LAT masters can address Solicit Information datagrams to V5.2 slave nodes and be almost assured of a direct response. However, nodes operating as V5.1 masters can only address Solicit Information datagrams to other V5.1 masters since V5.1 slaves do not enable multicast addresses for the reception of directory service datagrams. Therefore, V5.1 and V5.2 nodes are allowed to respond to Solicit Information datagrams for slave nodes that cannot respond for themselves.

The RESPONDER characteristic determines whether the access server may act as an agent for other nodes. By configuring one or more access servers to act as responders, the other access servers can operate with a node limit of 1 and still be assured access to LAT services. This frees up the dynamic memory and reduces the overhead that would otherwise have been required to maintain the LAT node database.

6-16 Configuring LAT Characteristics