User Manual

Overview
Networking Ethernet/IP networks
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3.2 Networking Ethernet/IP networks
The function and application summarized above are implemented on an automation station or room
automation station. These devices must be networked together. Preliminary clarifications must define the
number of room automation stations, automation stations for primary plants and superposed functions as
well as central functions are required and how they are distributed.
The functions, guidelines and recommended set forth in
Practical Guide on IP Networks in Building
Automation and Control Systems
(CM110668) apply to networking the devices.
3.2.1 Scalable Desigo system - System design
We must take a closer look at various aspects of the scalable Desigo system to properly define the design
criteria here and then subdivide them to ultimately derive system limits and system topologies.
Project and network size Designing a system
Small to mid-size project and networks of a lower complexity
One building, up to 200 primary plants, 500 rooms, and just a few
central functions
Example:
School, hotel, small to mid-size commercial unit (office, retail)
Restricted to max. 500 automation stations
The devices must be on a common IP segment. For example,
subnet mask 255.255.254.0 = max. 512 IP addresses.
For details, see
Overview of IPv4 address space .
Medium to large project and network of medium complexity
Large building complexes, more than 200 primary plants, 500 to
1500 rooms, lots of distributed central functions, multiple,
different user groups
Example:
University, hospital, office building, residential and office
complex, shopping mall
Restriction of max. 250 devices on one IP segment.
Multiple IP segments for plant, building, and floor scopes via
layer 2 switches, VLAN and layer 3 switches.
BACnet internetwork over multiple IP segments with BBMD.
Large project and network of high complexity
Multiple buildings, more than 200 primary plants, 500 to 1500
rooms, lots of distributed central functions, multiple, different
user groups
Example:
University campus, hospital, large residential and office complex,
pharmaceutical or automobile companies, industrial parks
Restriction of max. 250 devices on one IP segment.
Multiple IP segments for plant, building, and floor space via layer
2 switches, VLAN and layer 3 switches.
Multiple BACnet internetworks with up to 2,000 devices each,
distributed on different BACnet networks with BBMD.
3.2.2 Zones on the IP network
Switches are a decisive element on a network: Core, distribution, and edge switches. Moreover, they are
available as managed or unmanaged layer 2 and managed layer 3 switches. An overview follows.
For details, see Practical guide on IP networks in building automation and control (CM110668).