1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
|
<?xml version="1.0" encoding="ISO-8859-1"?>
<!--
-
- This file is part of the OpenLink Software Virtuoso Open-Source (VOS)
- project.
-
- Copyright (C) 1998-2018 OpenLink Software
-
- This project is free software; you can redistribute it and/or modify it
- under the terms of the GNU General Public License as published by the
- Free Software Foundation; only version 2 of the License, dated June 1991.
-
- This program is distributed in the hope that it will be useful, but
- WITHOUT ANY WARRANTY; without even the implied warranty of
- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
-
- You should have received a copy of the GNU General Public License along
- with this program; if not, write to the Free Software Foundation, Inc.,
- 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
-
-
-->
<sect3 id="rendezvous"><title>ZeroConfig ("Zero Configuration") Support</title>
<para>The "ZeroConfig" protocol, also known as "Zeroconf" or
"Zero Configuration" is a protocol that allows discovery of services on the
network that are advertised by their hosts. It also has provisions for
automatic discovery of computers and various devices.
The main benefit of ZeroConfig is that it does not require DHCP, DNS or
directory servers.</para>
<para>ZeroConfig is an open protocol that Apple submitted to the IETF for
a standard-creation process.</para>
<para>The Virtuoso server and ODBC driver use the capabilities of ZeroConfig to
facilitate DSN (Data Source Name) setup and usage. This is divided in two parts:
Server-side and Client-side.</para>
<para>The Virtuoso server (Server-side) is configured via the Virtuoso INI
file to advertise its availability on a network with a given name. This allows
applications, and in particular the Virtuoso ODBC driver, to receive information
about a server, such as its network address, default login, etc, and use it
for configuring a data source or directory making a connection.</para>
<para>The Virtuoso ODBC driver (Client side) uses ZeroConfig to locate
the desired Virtuoso server during the set-up phase of a data source, and
determine available connection options such as:</para>
<simplelist>
<member>secure connection options</member>
<member>default database</member>
<member>default user </member>
<member>default password (if public/demo login is required)</member>
<member>default character set </member>
</simplelist>
<para>ZeroConfig provides the client with a service name, which must be bound to
the IP address/port of a host of the chosen service during DSN configuration.
This is used when existing DSN using a ZeroConfig name is used to connect,
it will map name with IP address and port before making a connection.</para>
<sect4 id="rendezvousserverside"><title>Setting-up the Server for Service Advertising</title>
<para>The Virtuoso server is configured to advertise itself based on the
details specified in the <computeroutput>[Zero Config]</computeroutput>
section of the Virtuoso INI file. Below is an example of such:</para>
<programlisting><![CDATA[
...
[Zero Config]
ServerName = Virtuoso Server
ServerDSN = UID=demo;PWD=
SSLServerName = Virtuoso Server (via SSL)
SSLServerDSN = UID=dba;PWD=;ENCRYPT=1
...
]]></programlisting>
<para>The ServerName and SSLServerName are human readable
strings chosen by the administrator to provide clients with a suitable
description of the service being provided.</para>
<note><title>Note:</title>
<para>If the Virtuoso does not have the SSL listener enabled then the
SSL service will not be advertised automatically.
The SSL* keys will simply be ignored and do not need to be removed.
</para></note>
<para>The ServerDSN and SSLServerDSN are default connection
strings that can be used by clients to make the advertised connection. You only
need to to specify default username and password in these strings. The
default database can be specified or left to the setting for the username.
You cannot specify the server hostname, IP address or port number, these
are supplied by Virtuoso automatically.</para>
<para>ZeroConfig service advertising is multicast, hence it is advertised
on all available network interfaces.</para>
</sect4>
<sect4 id="rendezvous"><title>Using the Windows ODBC Driver with ZeroConfig</title>
<para>Upon DSN set-up the ODBC driver listens for advertising servers, and
compiles a roster. This is displayed for the user to choose the desired
service to connect to. </para>
<para>If ZeroConfig is used to for data source set-up then the
set-up dialog will be initialized based on the details in the connection
string configured on the server.</para>
<para>When a DSN is configured based on a ZeroConfig service, the driver will
resolve the service name before making the connection to the server. The driver
does not store the network address or port number of the Virtuoso server, only
the ZeroConfig server name, so if the server's physical address is changed
the client DSNs associated with it do not all have to reconfigured; they will
resolve to the new address automatically on next use.</para>
</sect4>
</sect3>
|
