App Config (TCP/UDP/SCTP Sub-Classes)

Overview

Serveral Application types implement UDP or TCP/SCTP connectivity based on the TcpApp base class. In addition to the common Application configuration parameters and their application-specific attributes, all of these Applications typically require UDP/TCP/SCTP configuration as indicated here.

<?xml version="1.0" encoding="utf-8"?>
<n2svcd>
  ...
  <applications>
    ...
    <application name="(name)" module="(module)">
      <include><lib>/path/to/library</lib></include>
      <parameters>
        <!-- application-specific parameters -->
        ...
        <!-- TCP/UDP application parameters (server example) -->
        <parameter name="listen_queue" value="20"/>
        <parameter name="local_hosts" value="192.168.10.10"/>
        <parameter name="local_port" value="8118"/>
        <parameter name="local_timeout_secs" value="2.5"/>
        ...
        <!-- TCP/UDP application parameters (client example, identical) -->
        <parameter name="num_client_connections" value="5"/>
        <parameter name="local_hosts" value="192.168.10.10"/>
        <parameter name="remote_hosts" value="192.168.10.44"/>
        <parameter name="remote_port" value="8080"/>
        <parameter name="reconnect_interval" value="60"/>
        <parameter name="request_unassigned_timeout" value="2"/>
        <parameter name="request_remote_timeout" value="5"/>
        ...
        <!-- TCP application parameters (client example, disparate) -->
        <parameter name="local_hosts" value="192.168.10.10"/>
        <parameter name="remote_hosts" value="prod-prim.telco.com"/>
        <parameter name="reconnect_interval" value="60"/>
        <parameter name="request_unassigned_timeout" value="2"/>
        <parameter name="request_remote_timeout" value="5"/>
        ...
        <!-- SSL configuration for a simple SSL-encrypted server -->
        <parameter name="ssl" value="yes"/>
        <parameter name="ssl.SSL_cert_file" value="../etc/ssl/localhost.crt"/>
        <parameter name="ssl.SSL_key_file" value="../etc/ssl/localhost.key"/>
        ...
        <!-- SSL configuration for a simple SSL-encrypted client using self-generated CA -->
        <parameter name="ssl" value="yes"/>
        <parameter name="ssl.SSL_ca_file" value="../etc/ssl/localhost.crt"/>
      </parameters>
      <config>
        <client_connections>
          <client_connection remote_port="8080"/>
          <client_connection remote_port="8081"/>
          <client_connection remote_port="8082"/>
          <client_connection remote_port="8080"
            remote_hosts="prod-sec.telco.com" local_hosts="192.168.11.10" priority="2"/>
        </client_connections>
      </config>     
    </application>
    ...
  </applications>
  ...
</n2svcd>

Here are the currently-available productised sub-classes of TcpApp.

The following applications are UDP-only. They bind to a local UDP port and use that to send and receive messages via UDP datagrams.

• DnsClientApp
• DnsServerApp
• RadiusApp

The following applications are TCP/SCTP Stream Transient Client-mode only.
They perform outbound socket connect on-demand.
They do not pre-establish or maintain Permanent connections.

• RestClientApp
• SoapClientApp

The following applications are TCP/SCTP Stream Transient Server-mode only.
They accept inbound socket requests on-demand, including the potential for keep-alive if requested by the far-end Client.
They do not pre-establish or maintain Permanent connections.

• RestServerApp
• SoapServerApp

The following applications are TCP/SCTP Stream Permanent connections in either Client or Server socket mode. Run-time configuration determines if Client or Socket mode is used.

• DiameterApp
• SMPPApp

Note that the terms “client” and “server” in this context apply purely to the TCP/SCTP socket establishment mode, i.e. a “client” will perform a socket “connect” and a “server” will perform a socket “listen”/“accept”.

Furthermore, each application has specific capabilities in terms of whether they can support the sending of an Outbound Request message, and/or receive an Inbound Request message. Applications such as DiameterApp and SMPPApp for example can support Inbound and/or Outbout Requests, regardless of the direction of the initial socket establishment.

Configuration Details

The application element attributes for all TCP Application instances are as below. For details of the various parameter types used, refer to Common Configuration.

TCP Client Connection

In the simplest case, a TCP Client application will create a single client connection, or will create multiple identical client connections. In that case the parameters mechanism will suffice.

However, there are cases where an TCP Client application wishes to connect to disparate remote hosts and/or ports. In this case the config.client_connections element must be configured to define two or more client_connection elements.

A client_connection entry within the config.client_connections element of a TCP Client application has the following attributes:

Note that the num_client_connections parameter is incompatible with config.client_connections.