How Theme Parks Work
Networks have been used in one form or another in major theme parks since the 70's.
To deploy a network, one doesn't need Ethernet -- communication links with RS-422/RS-485 are
quite common, even today.
One of the measures of quality of major theme parks is the degree of maintenance given to the attractions and rides.
Good parks work hard to achieve short down times, high throughput, and a safe experience in their attractions.
Maintaining equipment to its best performance requires good monitoring, making fault monitoring systems an important element of good system design.
When performed electronically, fault monitoring can take place either locally (at or near the equipment)
or centrally. Central monitoring could take place in a central office in a theme park, or off-site
by a service provider or at another location owned by the theme park owner. The more sophisticated parks
built today employ distributed remote monitoring, where one can log on from one of several remote
locations and observe the status of equipment in the park.
Older parks achieved centralized monitoring through serial communiation line
between the attraction and the central office. In a sophisticated design today,
Ethernet networks provide the communication link. A savvy network implementation can provide
access to the entire park's monitoring functions from many locations, on or off the park.
Of course, access is restricted from public networks through firewalls and/or the use of
private networks. The result is that maintenance engineers can observe the status of equipment from many different locations,
allowing them to solve problems over the phone or pick up a spare before driving out to the site.
While some products continue to employ proprietary protocols for monitoring,
a public protocol called the Simple Network Management Protocol (SNMP) is often specified
for large theme park installations. SNMP comes from the IT world, where the daunting
problem of monitoring equipment spread out over many locations across a network required a standard solution.
SNMP, by design, is not a real-time method for control and monitoring. But for system monitoring
and supervisory-type controls, SNMP does the job.
The diagram above shows illustrates a simple monitoring scenario.
A few monitoring stations are connected to a network, which in turn interconnects
equipment in several attractions. The attractions are interconnected with a
"network backbone". The network backbone is an important concept, as it eliminates the
point-to-point wiring that encumbers many older installations.
It's not wise, however, for all traffic on the network to be available to all users.
Practical implementations employ a technique known as virtual local area networks, or VLANs.
VLANs provide a way to manage traffic over the network, ensuring sufficient bandwidth for particular
applications. Where security is a concern, a virtual private network (VPM) may be used,
where traffic across the segment is encrypted. Not all network backbones are Ethernet at
the lower layers. Disney's Animal Kingdom was built in the mid-90's using an ATM backbone,
over which Ethernet traffic rides. Newer parks employing backbones look to GigaBit Ethernet.
Networks traffic isn't limited to SNMP communication. Audio can also travel over a network.
While audio within an attraction is usually sourced locally, there are many audio applications in
a park that are easier to maintain when audio is sourced centrally. Typically, these applications
fall into a class called "parkwide audio", which is used to provide atmosphere to the park,
as well as provide a means for public address.
In the mid-90's, Disney's Animal Kingdom became the first contracted application for a new
audio-over-ethernet technology called Cobranet™.
Developed by Peak Audio, now a division of Cirrus Logic, Cobranet has since become a defacto standard
in the commercial audio industry. (The reader can learn more at the Cobranet
site, or by reading the article
on this site written during the construction of Disney's Animal Kingdom.)
Cobranet places 24-bit / 48kHz audio over Ethernet in groups of 8 channels, with the total number of channels
limited by the bandwidth of the network. It is not an IP (internet protocol) based protocol,
which means it cannot travel through Ethernet routers, but it can be switched by Ethernet switches.
Cobranet I/O can be found on many sophisticated audio processing devices today, reducing audio
signal wiring to a CAT 5 Ethernet cable and network. Perhaps the earlier article on Cobranet
was written by Kevin Gross and Rich Zwiebel in an article published by Sound and Video Contractor [no longer on the web].
Networks have become an important element of theme park system design. They allow for sophisticated
distributed monitoring and supervisory controls, and they can provide an elegant solution for
distributing centralized audio sources and paging.
We hope these pages have given you some insight into good theme park system design!