Questions About Axia Networking


Some other console companies brag about using inexpensive unmanaged switches. They imply that an Axia network costs more because of the managed switches you specify

 

Some folks will say anything to make a sale! Your Axia network might not even require a third-party switch, since we build zero-configuration switches (designed just for AoIP broadcasting) into our console engines. Even the most wallet-friendly Axia consoles come with this feature. No other console company does this! So you save the cost of an external switch, plus the time and effort of programming that switch. And if your plans are for a very large studio network that requires a core switch, Axia works with industry-standard switches that can be had very affordably from a wide range of sellers.

 
Multicast network architecture is a recognized advantagecompared to unicast. It allows Axia gear to interoperate with the largest number of partner companies - broadcast manufacturers that make a wide range of phone systems, program delays, transmitters, audio processors, playout systems, satellite receivers, voice processors, loggers and much more. Be sure to ask the other guys how many radio partners their system has -- the answer might surprise you

 

Other systems built around un-managed networks say they're just as good as Axia. Is there a downside to un-managed networks?

 

First, lets talk about one of the plusses of an unmanaged switch: it has no configuration options. You just plug it in and go. All types of traffic - data, video, voice, file traffic, e-mail - has the same priority; none is more important than the other. This is great for networks that will connect primarily PC traffic, like small business or home networks, etc.

However, an IP-Audio network needs prioritization. While your studio network can conveniently carry types of data other than your audio (like file transfers, IM sessions, etc.), its main duty is getting the audio to air. Nothing should be more important than that. That's one reason Axia uses managed networks, exclusively. Enterprise VoIP, which shares some DNA with IP-Audio, also insists on managed networks for these same reasons. Some other advantages of managed networks:
  • Security. Even LAN installations such as your studio network occasionally have gateways to the outside world. Managed switches can be set to allow only specific connections, preventing your network from being hacked into. 
  • Network management. Managed networks can be remotely administered, allowing granular control down to the individual switch ports, if desired. Unmanaged networks' ports are all on, all the time. Managed switches can also be administered from a friendly web-based interface.
  • Guaranteed Audio Delivery. As mentioned previously, an unmanaged network cannot use Class of Service (CoS) and Quality of Service (QoS) priority tagging, which means that all traffic is equal - and your program stream could conceivably be interrupted by, say, a morning jock browsing Facebook or downloading a huge audio file from a website. Axia employs QoS tagging to ensure that audio is always first priority, and nothing can interrupt it.
  • Redundancy. Managed networks can make use of Spanning Tree Protocol (STP), which allows an interrupted connection to automatically "route around" the interruption and find an alternate path to its destination, should the need arise. Unmanaged networks can't do this.
One additional note: while other systems rely exclusively on third-party switches, only Axia lets you choose industry-standard Cisco switchgear, or zero-configuration, built-for-broadcast Axia switches like xSwitch, in conjunction with the edge switches built into every Axia console engine, to design your network. No other IP console company gives you this choice.

 

Do Axia networks have any single points of failure? Is there a central 'brain' I can lose that will take the system down?

 

Axia networks are distributed, with no central box. Ethernet networks can be designed any number of ways, including those that are fully-redundant and self-healing. Normally, our clients build larger facilities with "edge switches" serving each studio, connected to a redundant core. Each studio is able to operate stand-alone

 

I've been hearing about IPv6 a lot. Will this affect how Axia networks operate?

 

Internet Protocol version 4 (IPv4) is the IP addressing structure that powers the Internet. The Internet Engineering Task Force (IETF) has designated IPv6 as the successor to version 4, due to its larger address space, which offers more flexibility in routing traffic and allocating addresses, providing hundreds of billions more possible IP addresses than IPv4.

There are no compatibility issues between products using IPv4 or IPv6 addressing. Both addressing schemes can co-exist on the same network and interoperate smoothly. Axia systems employ Multicast streaming for audio routing. This is fully developed within IPv4, but it it not widely used under IPv6. For this reason, Axia will continue to use IPv4 until such time as IPv6 will provide the same consistent performance. We monitor the technology standards very closely and we plan to move to IPv6 when Multicasting is widely implemented.

There is one case in which IPv4 could be a limitation: If you plan to have several hundred billion devices on your network. If you have plans to build such a large network, call us. We'll gladly implement IPv6 for you right away!

 

Your competitors say that your networks can catch viruses. Are they serious?

 

There are no general purpose operating systems in Axia devices, so the answer is "No." You can keep computers attached to your Livewire audio network safe by keeping it isolated from data networks

 

Why can't I just use my favorite switch with Axia?

 

People ask us this question every so often. When clients require a third-party switch, we recommend Cisco because their reliability, feature sets and performance are the best we've found. They also offer a wide range of switches at all price points to meet individual users' needs.

How come other manufacturers' switches don't measure up? This is mostly due to individual manufacturers' differing implementation of the same "standards". For file transfers and e-mail, these differences are immaterial. But for VoIP and, most especially, IP-Audio, these implementations become more important. It's quite possible for a given switch to "work" with just a few nodes attached, but when a more robust test of Axia's capabilities is applied, that same switch can fail.

For example, we found a nice, inexpensive switch from a well-known manufacturer which, on paper, met all specs and worked with small systems in the lab. However, it turned out to not actually meet its own published specs when deployed for rigorous service in a large Livewire system.

For this reason, we recommend and qualify only selected Cisco switches for Axia clients whose network designs require a large switch fabric. And for more moderately-sized networks, there are Axia-designed switches built into our PowerStation, QOR and xSwitch products — which employ some of the very same high-performance chipsets found in Cisco switches.

 

What happens if someone accidentally unplugs a cable? What then?

 

Axia audio nodes "advertise" the presence of their audio streams to the entire Livewire network. So if someone unplugs an xNode, the sources attached to it will be offline. But all you have to do is plug that xNode back in, and it will "advertise" that the audio streams are available again. Within 10 seconds, all destinations that need those sources will be back up and running.

Additionally, among the many features of Pathfinder is a silence detect function that can be programmed to switch to another feed should one stop working for any reason.

 

I read an article recently about broadcast audio networks and how they relate to the Open Systems Interconnection (OSI) Reference Model. Where does Axia fit in that model, and how does it compare to Cobranet and EtherSound?

 

You might have read Brent Harshbarger's article in ProAV Magazine. As the article says, the OSI model is a seven-layer framework that defines network functions.

Axia operates on Levels 1 through 5 of the OSI model. The IP Network Layer provides routing capabilities. The UDP Layer provides transport service using port numbers. The RTP Layer provides additional information about streams, helping to identify media format and look for dropped or duplicate packets, as well as other useful functionality using the RTP standard for best compatibility with other media streaming solutions. By comparison, EtherSound and Cobranet function on only the first two network layers.

 

A friend in the PA business told me about Cobranet. That's something like Livewire, right?

 

Cobranet was not developed for broadcast use, which demands very low latency in the DJ-to-headphones path. Cobranet is much higher latency than Livewire, making trouble for live listening. It also will not allow non-audio traffic on the links — an important consideration for broadcasters who wish to have machine control, PAD, RDS, etc. integrated within their facility.

There are also limits to the number of audio sources Cobranet can handle. Cobranet groups audio channels into "bundles" (which are packets), 8 mono audio channels per bundle. According to the Cobranet website, there is a systemwide network limit of 8 bundles. 8 bundles x 8 channels = a 64-channel limit, whereas IP-Audio networks using the Livewire protocol can handle upwards of 10,000 stereo streams.

Cobranet is not IP Audio, since it works only at the Ethernet level. Axia networks use state-of-the-art IGMP (Internet Group Management Protocol) to manage the transmission of Multicast audio streams, which allow multiple subscribers to receive and use audio from the same origination point. IGMP also makes it possible to dynamically add and subtract subscribers from a stream. Cobranet does not use IGMP; users must map out individual point-to¬-point connections with Unicast IP addressing. If more than one destination wants to listen to a given source, the source has to send multiple copies of the stream, which then hits Cobranet's limit of 8 streams coming from any given source. You could choose to send audio as Multicast IP data to all points on the network, but with 8 bundles of channels active, all 100Base-T links everywhere in the system would be at full capacity. These limitations make Cobranet unsuitable for broadcast audio networks.

 

What about network collisions? Isn't Ethernet going to drop audio packets?

 

Years ago, Ethernet used a shared coax cable. In rare cases two devices would grab the bus simultaneously. When this happened, one would back-off and send a few milliseconds later. These were the famous collisions. But with today's switched Ethernet, there is no shared bus – each device completely owns its own full-duplex link. There are never collisions or lost packets as a result of network congestion; it's physically impossible.

 

Your competition says that you have to be an IT expert to run an Axia system.

 

We're engineers, and we like to talk tech. Sometimes, we talk about the tech more than we need to! But in this respect, an IP-Audio network is like a car: you don't have to understand how the engine works in order to drive it. Just connect two pieces of gear together with CAT-5e and they will talk to each other — like plugging a mic into a mixer. We’ve even created an Ethernet switch just for Livewire – xSwitch – that requires zero programming. You just plug it in, assign an IP address, connect your Livewire devices, and start passing audio, with no other setup required. The Livewire protocol takes care of routing the audio without any need for intervention from you. And the equipment interface is all web-based with GUI control. It works intuitively, and you don't have to know anything about the tech inside to make it work.

That having been said, another of the advantages of Ethernet and IP is that bookshop shelves are full of well-written books that can explain any aspect of standards-based networking at any level of detail you might want.

 

They also say that Axia networks only work with one switch, and if they stop making that switch, I won't be able to expand or modify my network.

 

Axia has qualified many different switches from Cisco, the most respected outfit in the field, to suit the needs of different-sized installations. Ethernet has been around for more than 30 years. It is supported by hundreds of vendors. It continues to evolve to be faster and more powerful, to use different connection media, etc., but backward compatibility is always maintained (that’s part of the standard!).

Not only that, we’ve built switches into our console mixing engines, and developed a stand-alone switch to suit the needs of broadcasters. With Axia, you always get plenty of choices.

 

One of your competitors says that you'll have to replace the Ethernet switches every 3-4 years. And when you do, you'll have to load all new software to work with it (if you can even make your stuff work with it)

 

Ethernet is a standard, IEEE 802.3. Axia gear works with any switch or router that supports the standard. We do generally need higher-end switches because Livewire uses advanced multicast and Quality-of-Service features that are not included in low-end switches.

You might want to upgrade to a larger or more powerful switch for some reason in the future; for example, if you were to add more studios to a cluster. Or maybe you would like to change from copper to fiber for some kind of remote uplink connection. Or you might want to replace an older switch at some point. Thanks to IEEE 802.3, the replacement switch would simply plug into the network and function, with no software changes needed on any equipment. But there is certainly no requirement to do this at any particular time interval. Ethernet's open and evolving nature gives you choices that closed systems don't. That's an advantage.

 

They also say that Livewire systems can run out of capacity because they use 100Base-T networking. Can they?

 

Not true: Axia employs both Gigabit and 100BaseT network links. And Axia networks can handle up to 10,000 stereo streams at once. That’s a lot! They’re deployed in some very large facilities, such as Radio Free Europe, Minnesota Public Radio, NPR Network Operations Center, Sirius-XM Satellite Radio, and more. These broadcasters create and consume a huge number of audio channels, and they don’t run out of bandwidth. Here’s why.

The backplane of a modern Ethernet switch can handle full duplex traffic on all ports simultaneously without any packet loss. And since Axia component links are designed so that they never exceed any port's capacity, we never exceed the switch capacity. The way we prevent port overload is simple: we "own" each port. Every Axia audio node is plugged into an unshared 100Base-T port on the switch. Even when all of a node's inputs and outputs are active, we are still well under the bandwidth of the ports, and the switch is completely under control. Because the switch has the backplane capacity to handle all ports fully loaded, the system performance doesn't change from one to thousands of audio channels.

Let's explore the issue of switch capacity a little further. We know how much capacity is required per port for each node, and we know that a node will never produce or consume more than 16 stereo streams total. But what about the mix engine? To support a large console with a lot of buses, inputs, mix-minus outputs, etc., you may have 40 or 50 simultaneous signals (or more). Because this could exceed the port capacity of a 100Base-T port, the mix engine is connected via Gigabit Ethernet only. Using Gigabit for the engine, we could support a 200 fader console with 200 outputs and still have room to spare! Each console's mixing engine gets its own Gigabit port.

 

Some companies say that a network using all-Gigabit links is faster than 100Base-T. They say it has less latency. Is this true?

 

>If you're moving large files around from one computer to another, sure – Gigabit is faster, because you have a larger pipe to shove those big files through – so more data flows concurrently, and the transfer completes faster.

But IP-Audio is packet-based streaming audio – not a file transfer. As such, each channel of IP-Audio data is a fixed size; it can’t vary. That means it’s going to arrive at its destination on a 100Base-T link at exactly the same time as it would on a Gigabit link.

Think of this as cars travelling a roadway. If you have 8 cars travelling a 10 lane highway, would they arrive at their destination any sooner if the highway was increased to 100 lanes? Of course not.

 

The other guys say that their gear doesn't require you to configure Ethernet switches -- that their products are 'plug and play'.

 

You should examine that claim closely. Third-party Ethernet switches, even those from Cisco, must be configured to ensure that IP-Audio signals (which are made up of faster, smaller packets than standard network data packets) receive data priority and are transmitted properly to air. Axia makes switch configuration as painless as possible. If you like, we'll configure your network's switch for you, free of charge. If you prefer to do it yourself, clear, concise "how to" documents are posted at AxiaAudio.com/manuals/ .

Of course, you can also choose to do away with switch configuration altogether by choosing a zero-configuration Axia xSwitch, or an Axia mixing engine with a built-in, pre-configured switch.

 

I’ve heard that Axia built their own standalone network switch. Why?

 

Yes, it’s called xSwitch, and it’s the first of its kind: an Ethernet switch custom-built for the needs of broadcasters using Livewire IP-Audio networks. Here’s why we developed it.

Up until now, configuring the network switch has been the most unwelcome part of setting up an IP-Audio network. You had to load a terminal program onto your computer, hook up a port emulator, and once connected, you’d spend an hour (maybe more) typing commands into a prompt box, hoping that they all “took”.

To eliminate this frustration, we built an Ethernet switch (using industry-standard chipsets found in high-performance, brand-name switches) and pre-configured it for use with Livewire systems. So, no configuration, no programming, and virtually no setup. Just assign an IP address, plug it into your network, and it’s ready to go

 

What Ethernet switches will I need for my Axia network?

 

You won’t need any bleeding-edge products from the skunkworks, if that’s what you mean. In fact, you may not need a third-party switch at all! Every console we make has a custom-built, zero-configuration Ethernet switch built in – perfect for standalone studio deployment, but these switches can also be daisy-chained to create larger studio networks. If you just need a few local switch ports on the edge of your network, or if you’re building a smaller studio, our standalone xSwitch might be what you’re looking for – it’s pre-configured to install in under a minute.

Of course, facilities with multiple rooms and large routing networks require core switches with larger capacity. For these systems, we’ve qualified a number of switches from Cisco, the industry leader in switchware. You can see the selection at AxiaAudio.com/switches/

 

I want to send audio to my Axia network from a PC workstation. What Ethernet NIC (Network Interface Card) should I use?

 

Axia recommends the Intel PRO/1000 GT for computers with PCI slots, and the PRO 1000 CT for PCIexpress. Customers will also want to make sure they use the most current Intel ProSet driver for whatever operating system they use.

 



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