.if false ================================================================================== Copyright (c) 2019 Nokia Copyright (c) 2018-2019 AT&T Intellectual Property. Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. ================================================================================== .fi .if false Mnemonic rmr.7.xfm Abstract The manual page for the whole RMR library Author E. Scott Daniels Date 29 January 2019 .fi .gv e LIB lib .im &{lib}/man/setup.im &line_len(6i) &h1(RMR Library) &h2(NAME) RMR -- Ric Message Router Library &h2(DESCRIPTION) RMR is a library which provides a user application with the ability to send and receive messages to/from other RMR based applications without having to understand the underlying messaging transport environment (e.g., SI95) and without needing to know which other endpoint applications are currently available and accepting messages. To do this, RMR depends on a routing table generated by an external source. This table is used to determine the destination endpoint of each message sent by mapping the message type T (supplied by the user application) to an endpoint entry. Once determined, the message is sent directly to the endpoint. The user application is unaware of which endpoint actually receives the message, and in some cases whether that message was sent to multiple applications. &space RMR functions do provide for the ability to respond to the specific source instance of a message allowing for either a request response, or call response relationship when needed. &h3(The Route Table) The library must be given a route table which maps message numbers to endpoint groups such that each time a message of type T is sent, the message is delivered to one member of each group associated with T. For example, message type 2 might route to two different groups where group A consists of worker1 and worker2, while group B consists only of logger1. &space It is the responsibility of the route table generator to know which endpoints belong to which groups, and which groups accept which message types. Once understood, the route table generator publishes a table that is ingested by RMR and used for mapping messages to end points. .sp The following is a simple route table which causes message types 0 through 9 to be routed to specific applications: &ex_start newrt|start mse|0|-1| %meid mse|1|-1|app10:4560,app11:4560 mse|2|-1|app12:4560 mse|3|-1|app14:4560 mse|4|-1|app18:4560 mse|5|-1|app01:4560 mse|6|-1|app02:4560 mse|7|-1|app03:4560 mse|8|-1|app04:4560 mse|9|-1|app05:4560 newrt|end &ex_end &space The special endpoint "%meid" indicates that the message type (0 in this case) is to be routed to the endpoint which has been listed as the "owner" for the meid appearing in the message. MEID ownership is communicated to RMR using the same Route Table Manager interface and by supplying a "table" such as the one below: &ex_start meid_map | start mme_ar | control1 | meid000 meid001 meid002 meid003 meid004 meid005 mme_ar | control2 | meid100 meid101 meid102 meid103 meid_map | end | 2 &ex_end This table indicates that the application (endpoint) &ital(control1) "owns" 6 MEIDs and &ital(control2) owns 4. When message type 0 is sent, the MEID in the message will be used to select the endpoint via this table. &space The MEID table will update the existing owner relationships, and add new ones; it is necessary to send only the changes with the add/replace (mme_ar) entries in the table. When necessary, MEIDs can be deleted by adding an &cw(mme_del) record to the table. The following example illustrates how this might look: &ex_start meid_map | start mme_ar | control1 | meid000 meid001 meid002 meid003 meid004 meid005 mme_ar | control2 | meid100 meid101 meid102 meid103 mme_del| meid200 meid401 meid_map | end | 3 &ex_end &h3(Route Table Syntax) The following illustrates the syntax for both the route table. &space &ex_start newrt | start mse | [,] | [;]... newrt | end &ex_end &space A round robin group is one or more endpoints from which one will be selected to receive the message. When multiple endpoints are given in a group, they must be separated with a comma. An endpoint is the IP address and port (e.g. 192.158.4.30:8219) or DNS name and port of the application that should receive the message type. If multiple round-robin groups are given, they must be separated by a semicolon, and &h3(MEID Map Syntax) The MEID map is similar to the route table. Entries are used to add or replace the ownership of one or more MEIDs (mme_ar) or to delete one or more MEIDs (mme_del). The following is the syntax for the MEID map. &space &ex_start meid_map | start mme_ar | | [...] mme_del | [...] meid_map | end | [| &ex_end &space The on the end record indicates the number of mme_ar and mme_del records which were sent; if the count does not match the whole map is refused and dropped. The is the endpoint which should receive the message when a message is routed based on the MEID it contains. A MEID may be "owned" by only one endpoint, and if supplied multiple times, the last observed relationship is used. Each of the lists of MEIDs are blank separated. &space The optional on the &ital(end) record should be the computed MD5 hash for all records which appear between the start and and records. This allows for a tighter verification that all data was received exactly as the route manager transmitted them. &h3(Environment) To enable configuration of the library behaviour outside of direct user application control, RMR supports a number of environment variables which provide information to the library. The following is a list of the various environment variables, what they control and the defaults which RMR uses if undefined. &space .** the list of environment vars supported .im &{lib}/man/env_var_list.im &h2(SEE ALSO ) .ju off rmr_alloc_msg(3), rmr_tralloc_msg(3), rmr_call(3), rmr_free_msg(3), rmr_init(3), rmr_init_trace(3), rmr_get_meid(3), rmr_get_src(3), rmr_get_srcip(3), rmr_get_trace(3), rmr_get_trlen(3), rmr_get_xact(3), rmr_payload_size(3), rmr_rcv_msg(3), rmr_rcv_specific(3), rmr_rts_msg(3), rmr_ready(3), rmr_fib(3), rmr_has_str(3), rmr_tokenise(3), rmr_mk_ring(3), rmr_realloc_payload(3), rmr_ring_free(3), rmr_set_trace(3), rmr_torcv_msg(3), rmr_wh_open(3), rmr_wh_send_msg(3) .ju on