Contemporary Control Systems BASrouter Portable Installation Tips - Manual (Page 3)

BBMD Considerations:
Broadcast Distribution Table (BBMD) and Foreign Device Registration (FDR) Table:
1. BASRT-B or BASRTP-B: Each table (BBMD or FDR) has a limit of FIVE addresses.
2. BASRTLX-B: Each table (BBMD or FDR) has a limit of FIFTY addresses.
3. The BASrouter's
own IP Address should NOT be in the table.
4. BBMD table does not save: Clear your browser cache or try another browser. (The entry
seems accepted, but the table does not update.)
The BASrouter can only be a partner BBMD: It can have foreign devices register with it — but
it cannot register as a foreign device to another BBMD.
Multiple BBMD-enabled devices: In any given subnet, only 1 device can do BBMD (otherwise,
messaging gets confused). It is OK to have multiple BBMD-enabled devices — if only 1 such
unit has entries in BBMD table. Often our router must communicate to a central BBMD for the
whole internetwork. This requires the central BBMD be entered in our BBMD table and our
router must be entered in the BBMD table of the central BBMD.
BBMD table Subnet Mask: A subnet mask of 255.255.255.255 is used when messages must
traverse an IP router that blocks all broadcasts — by far the most common type of IP router. If
the IP router can forward BACnet broadcasts (a rarity), then it is OK to another mask value. In
this case (rare, but may save you a BBMD), use the subnet mask of the network.
The BASRTP-B portable router has no BBMD functionality: This is because the BASrouter
makes a temporary connection to commission or troubleshoot a system. If the BASRTP-B had
BBMD and got the system working, once the BASRTP-B was removed the system would fail —
since BBMD functionality would be gone.