# Shoutcast DNAS Server CDN Features

(Last Updated 08 Sep 2018)

## 1. Introduction

When running the Shoutcast DNAS server in a CDN sitatuation, since v2.4.1, there are some additional configuration options which can be used to make it easier to automatically setup CDN master-slave (relay) configurations and allow for streams not listed in the Shoutcast Directory to still be able to make use of the DNAS+ functionality i.e. the monetisation services when streaming.

The automatic setup provided is where a CDN slave is able to inherit the authhash of the CDN master when it connects to the CDN master which can make it quicker to create snd update multi-DNAS clusters without having to manually configure all aspects of the DNAS configurations (though you can still do that it you prefer to do so).

## 2. Configuration Options [top]

The configuration options work in-conjunction with the existing DNAS server configuration options (unless otherwise stated) as detailed in the DNAS Server (section 4.0) documentation. It is assumed throughout that the DNAS server has been correctly configured with all applicable passwords, etc as needed so that the DNAS server will allow the YP server, source clients and listener clients to connect as required.

cdn : This is used to control whether the DNAS is running in CDN mode or not and the specific level of functionality enabled [Default = <no value>]

This has to be one of the following values when using the DNAS+ for CDN service:

- on → This enables opt-in mode where all streams needing CDN behaviour have to be specifically configured to use it
- always → This enables opt-out mode where all streams will by default be able to work as CDN masters and CDN slaves
- master → This is a hybrid mode so all streams will by default be able to work as a CDN master but need to be manually configured to work as a CDN slave (if required)

    Using 'cdn=master' is recommended for source DNAS in a master-slave
    configuration where it is not needed to have any CDN slave configured.

<MULTI> (one set for each stream configuration as required). See DNAS Server - section 4.0 if unsure how to use <MULTI> options.

    In all cases it is possible to override the behaviour (opt-in or opt-out)
    on a per-stream basis. If not specified then the global value is used.

cdnmaster : This controls if the stream is allowed to act as a CDN master [Default = <automatic>]

If not specified then this is assumed as one of the following values based on the 'cdn' mode:

- cdn=on → cdnmaster=0
- cdn=always → cdnmaster=1
- cdn=master → cdnmaster=1

cdnslave : This controls if the stream is allowed to act as a CDN slave [Default = <automatic>]

If not specified then this is assumed as one of the following values based on the 'cdn' mode:

- cdn=on → cdnslave=0
- cdn=always → cdnslave=1
- cdn=master → cdnslave=0

The Server Admin Summary page (admin.cgi?sid=0) will show the CDN mode that each of the streams have been configured. Additionally the Admin Summary page (admin.cgi?sid=x where x is the stream number) will indicate if a CDN slave is connected to the stream.

## 2.1 Relay Streams [top]

A key feature of the CDN functionality is the ability to make it simpler to create master-slave relay setups and so allow for easier multiple DNAS clustering if such functionality is required for the stream(s). If not required see Standard Streams.

By configuring the DNAS for a stream as master(s) and slave(s) as needed and following the requirements detailed in the following sections, it is possible to have a CDN slave automatically obtain the details needed (via authhash inheritence) to then be listed in the Shoutcast Directory or to act as an intermediary DNAS server which in-turn is able to provide authhash inheritence to CDN slaves connected to it and so on.

## 2.1.1 Master [top]

When a stream is configured as a CDN master, it will only allow authhash inheritence for a CDN slave if the connecting CDN slave is correctly reported as one and that the address of the slave is in the Reserved List (section 4.11).

This requirement of the CDN slave being in the Reserved List is force enabled (equivalent of setting 'riponly=1' or 'streamriponly=1') when enabling CDN mode and is done to ensure that only allowed CDN slave connections can join the stream(s) on the CDN master.

## 2.1.2 Slave [top]

When a stream is configured as a CDN slave, it will only be allowed to connect to a CDN master if the master has been correctly configured to allow connections from the host / IP address reported by the CDN slave on connection.

If the master is not configured as a valid CDN master then the CDN slave will not inherit the authhash of the CDN master and it also may not be allowed to connect as relay (due to the Reserved List (section 4.11) requirement).

## 2.1.3 Intermediary [top]

When a stream is configured as a CDN intermediary, it will work as both a CDN master and as a CDN slave. This is helpful if wanting to have intermediary layers in a CDN setup whilst still being able to have authhash inheritence to ensure that all of the public facing CDN slaves provide the correct stream details.

## 2.2 Standard Streams [top]

A standard stream is one where you are not needing to have a master-slave pairing (when there is no relaying required) or you do not require authhash inheritence support but still require the monetisation functionality to work.

For such setups, ensuring you have 'cdn=on' specified in the DNAS server configuration file is all that is needed so the streams are handled in the opt-in mode which will prevent unwanted master-slave relay configurations whilst still allowing all other functionality to work.

This mode does not prevent you from configuring other streams on the same DNAS server to be able to work as a CDN master or CDN slave which requires specifying the 'cdnmaster' and / or 'cdnslave' configuration options as required for the setup