Abstract

Generally, A__mic8 devices can be used in a standalone mode where parameter control is done exclusively using the integrated http control surface for web browser operation or in mcx mode where parameter control is mostly done using the mcx console surface. In the latter mode, parallel control connections (e.g. via the http control surface mentioned above or mxGUI applications, etc.) are possible with a “last control command wins” strategy.

The connection between A__ and mcx allows using a maximum of 16 devices per RAVENNA port on Nova73 981/61 card where the devices are statically configured, and the streaming setup is done by internal configuration execution.

If the system setup needs to fulfil a more dynamic approach, since Release 5-14 of the mcx series, a VSM gadget server can be used to map A__ devices “virtually” to the static slots inside the mcx control environment. Stream management in this case has to be done by external controllers. Depending on the level of complexity of the system arrangement, customers need to know the different strategies for control and audio transport and the resulting signal flow as well as the control connection path. This document shall provide a short overview for these strategies and a setup guide for the initial integration.

IP Control Traffic Routing inside the Nova73 Series

Control commands generally are issued by the Nova73 audio router cards which provide two separate IP interfaces, one for a direct connection to a console surface and the other for management. IP network I/O nodes typically are arranged in an additional network (media network) which is not connected or routed to the management network mentioned above.

So, control commands somehow have to be transported from the management network to the media network. As the Nova73 internal structure does not support direct IP transport via the backplane, packet traffic has to be either forwarded to a host inside the media network or converted to something that the internal backplane can handle and a proxy on this host (re-)issues the control command. In Nova73 setups, often both methods are used in parallel:

DALLIS and LocalIO control is converted, transported via backplane and re-issued from a service running on the 981/61 RAVENNA port card. On the other hand, A__ and several other devices use Ember+ as control connection protocol where a conversion to a backplane compatible format is not implemented. Instead, the Nova73 router card establishes a host route via the so-called service network. This network is run in parallel on the same interface as the management network mentioned above. It is a freely configurable but fully reserved class C network (24-bit netmask) with dedicated address schema for all potential nodes inside a Nova73 environment. All 981/61 RAVENNA cards must be connected to this network for full functionality.

Direct A__ - MCX Attachment without SMPTE 2022-7 (Single Link)

This is the basic setup for attaching A__ devices to the mcx series: no redundancy configuration, simple control routing. The Nova73 router card opens an Ember+ control connection directly to the A__ media network IP address. The necessary IP routing from Service/Management Network to Media Network is done on the 981/61 card. All stream and routing configuration is done by AdminHD and the A__ configuration script (settings preconfig activate). Please note, that in the figure below, the interface configuration A refers to the service network (default 192.168.110.0/24). If using this default, A1 is 192.168.110.217, A2 is 192.168.110.218 and A3 is 192.168.110.216 if the RAVENNA card is installed in slot 16 of the Nova73.

Setup Overview

(for Direct A__ - MCX Attachment without SMPTE 2022-7 (Single Link))

Direct A__ - MCX Attachment with SMPTE 2022-7

This setup extends the simple setup by adding redundancy according to SMPTE 2022-7 (Seamless Protection Switching). Typically, this is done using separate networks for the primary and the secondary link which is not mandatory – a single network will do as well with the price of less redundancy. IP routing is still the same as before, but parameter control and monitoring will be done by a single network connection to the first reachable port of the 2022-7 unit. If a connection gets lost, the system will continuously try to connect to the next available port.

Setup Overview

(for Direct A__ - MCX Attachment without SMPTE 2022-7)

Adding vsmGadgetserver for Dynamic A__ Attachment

In a very simple setup with only one single RAVENNA port in the Nova73 included, the vsmGadgetserver could be only part of the media network (just like the A__ itself) and replace the A__ device by means of receiving the control traffic and forward it to the chosen A__ connection.

This approach could map 16 A__ devices on a single RAVENNA port to an arbitrary number of A__ devices in the network. As it is very likely that projects use more than one port or SMPTE 2022-7 (which also uses at least two ports), this simple approach is not described in full detail here. As soon as a second port on the Nova73 is used, the control routing reverse route from the vsmGadgetserver to the Nova73 gets ambiguous. This is neither allowed nor supported in network routing setup options.

To avoid ambiguity, projects could also make use of a separate IP router doing the forward and reverse routing between management/service network and media network(s). This could be done in the switching fabrics of the network switches, but this solution is rather complicated to configure. So, the following description refers to a solution where the vsmGadgetserver is part of both, the media network(s) as well as the management/service network.

In case of SMPTE 2022-7 connections, the vsmGadgetserver is responsible for setting up control connections to both media network ports and mapping them to separate IP addresses in the management/service network using the same TCP port. As described above, the mcx system will connect to only one of these addresses and send control data there as long as the connection is available. If the connection gets lost, mcx will use the second address and try back and forth until a new connection can be established.

The depicted setup can be reduced to a single link setup (without SMPTE 2022-7) by not connecting C network and hence not using A5 interface.

Setup Overview

(for Direct A__ - MCX Attachment via vsmGadgetserver with SMPTE 2022-7)

Adding vsmGadgetserver Redundancy

If the project setup requires vsmGadgetserver redundancy, currently the best choice is to separate A4-B4-B3 and A5-C4-C3 and put them to different vsmGadgetserver installations. At present there not possibility in vsmGadgetserver to combine Ember+ control trees of a redundant set of connections to a single tree and mcx does not support more than two outbound control connections on a single or SMPTE 2022-7 port.

The latter would be needed if the structure depicted above would just be extended with a second vsmGadgetserver (also holding two IPs in the device/MGMT Network). The mcx system does not care about this topology change, so the configuration does not change compared to the topology with a single vsmGadgetserver. Hence the table provided there is also valid here.

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