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4 Copyright (c) 2019 Nokia
5 Copyright (c) 2018-2019 AT&T Intellectual Property.
7 Licensed under the Apache License, Version 2.0 (the "License");
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15 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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22 .dv term ^&half_space ^&di($1)
25 &h1(Appendix &gloss_appendix -- Glossary)
27 Many terms in networking can be interpreted with multiple meanings,
28 and several terms used in this document are RMR specific. The
29 following definitions are the meanings of terms used within this
30 document and should help the reader to understand the intent of
33 &beg_dlist( &1.0i Helvetica-bold )
34 &term(application) A programme which uses RMR to send and/or receive
35 messages to/from another RMR based application.
37 &term(Critical error) An error that RMR has encountered which will
38 prevent further successful processing by
39 RMR. Critical errors usually indicate that the
40 application should abort.
42 &term(Endpoint) An RMR based application that is defined as being
43 capable of receiving one or more types of
44 messages (as defined by a &ital(message key.)
47 &term(Environment variable) A key/value pair which is set externally
48 to the application, but which is available to
49 the application (and referenced libraries)
50 through the &cw(getenv) system
51 call. Environment variables are the main
52 method of communicating information such as
55 &term(Error) An abnormal condition that RMR has encountered, but will
56 not affect the overall processing by RMR, but
57 may impact certain aspects such as the ability
58 to communicate with a specific endpoint.
59 Errors generally indicate that something,
60 usually external to RMR, must be addressed.
62 &term(Host name) The name of the host as returned by the
63 &cw(gethostbyname) system call. In a
64 containerised environment this might be the
65 container or service name depending on how the
66 container is started. From RMR's point of
67 view, a host name can be used to resolve an
68 &ital(endpoint) definition in a &ital(route
71 &term(IP) Internet protocol. A low level transmission protocol
72 which governs the transmission of datagrams
73 across network boundaries.
75 &term(Listen socket) A &ital(TCP) socket used to await incoming
76 connection requests. Listen sockets are
77 defined by an interface and port number
78 combination where the port number is unique
81 &term(Message) A series of bytes transmitted from the application to
82 another RMR based application. A message is
83 comprised of RMR specific data (a header), and
84 application data (a payload).
86 &term(Message buffer) A data structure used to describe a message
87 which is to be sent or has been received. The
88 message buffer includes the payload length,
89 message type, message source, and other
92 &term(Messgae type) A signed integer (0-32000) which identifies the
93 type of message being transmitted, and is one
94 of the two components of a &ital(routing key.)
95 See &ital(Subscription ID.)
97 &term(Payload) The portion of a message which holds the user data to
98 be transmitted to the remote &ital(endpoint.)
99 The payload contents are completely
102 &term(RMR context) A set of information which defines the current
103 state of the underlying transport connections
104 that RMR is managing. The application will be
105 give a context reference (pointer) that is
106 supplied to most RMR functions as the first
109 &term(Round robin) The method of selecting an &ital(endpoint) from a
110 list such that all &ital(endpoints) are
111 selected before starting at the head of the list.
113 &term(Route table) A series of "rules" which define the possible
114 &ital(endpoints) for each &ital(message key.)
116 &term(Route table manager) An application responsible for building a
117 &ital(route table) and then distributing it to
118 all applicable RMR based applications.
120 &term(Routing) The process of selecting an &ital(endpoint) which will
121 be the recipient of a message.
123 &term(Routing key) A combination of &ital(message type) and
124 &ital(subscription ID) which RMR uses to
125 select the destination &ital(endpoint) when
128 &term(Source) The sender of a message.
131 &term(Subscription ID) A signed integer value (0-32000) which
132 identifies the subscription characteristic of
133 a message. It is used in conjunction with the
134 &ital(message type) to determine the
137 &term(Target) The &ital(endpoint) selected to receive a message.
139 &term(TCP) Transmission Control Protocol. A connection based
140 internet protocol which provides for lossless
141 packet transportation, usually over IP.
143 &term(Thread) Also called a &ital(process thread, or pthread.) This
144 is a lightweight process which executes in
145 concurrently with the application and shares
146 the same address space. RMR uses threads to
147 manage asynchronous functions such as route
150 &Term(Trace information) An optional portion of the message buffer
151 that the application may populate with data
152 that allows for tracing the progress of the
153 transaction or application activity across
154 components. RMR makes no use of this data.
156 &term(Transaction ID) A fixed number of bytes in the &ital(message
157 buffer) which the application may populate
158 with information related to the
159 transaction. RMR makes use of the transaction
160 ID for matching response messages with the
161 &c(rmr_call) function is used to send a
164 &term(Transient failure) An error state that is believed to be short
165 lived and that the operation, if retried by
166 the application, might be successful. C
167 programmers will recognise this as
170 &term(Warning) A warning occurs when RMR has encountered something
171 that it believes isn't correct, but has a
174 &term(Wormhole) A direct connection managed by RMR between the user
175 application and a remote, RMR based, application.