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BACnet/IP Bandwidth Estimator

ASHRAE 135 Annex J · UDP/IP · Subnet Sizing

When to use: Use when sizing a BACnet /IP network segment. Estimate the polling traffic from a controller or supervisor reading points across many devices. Each poll is a ReadProperty request + response (2 packets), and every BACnet/IP packet carries roughly 50 bytes of BVLC/UDP/IP/Ethernet overhead on top of the APDU. The tool reports bandwidth, link utilisation on 100 Mbps and 10 Mbps links, and the smallest IPv4 subnet that fits your device count plus the BBMD/router.

Network Parameters
#
0.2 = every 5s
/s
default ~50
B
BVLC+UDP+IP+Eth
B
Recommended Subnet
/25
126 usable hosts
102
IPs needed (+BBMD/router)
✓ LIGHT LINK LOAD
32.0
Bandwidth (kbps)
Results
Packets / Second40.0 pps
Avg Packet Size100 B
Bandwidth32.0 kbps
Bandwidth0.032 Mbps
% of 100 Mbps Link0.0%
% of 10 Mbps Link0.3%
Recommended Subnet/25 · 255.255.255.128
References
ASHRAE 135 Annex J — BACnet/IP
BVLC + UDP/IP overhead ≈ 50 bytes/packet
ReadProperty = request + response (2 packets)
Subnet sizing per host count