[c-nsp] VS broadcast address relaying from Vlan to Vlan

[Arne Larsen / Region Nordjylland]

Hi Folks.

I hope someone can help me out here. I have a problem with devices from a supplier to our ventilation system.
There units are IP based, but they aren't very clever units. When the temperature is being propagated to all units the sending device sends it to the broadcast address on its own LAN.
Furthermore the devices are sending information to each other the same way, by sending to the broadcast address.
So as long all devices is on the same broadcast domain everything works fine. The units sends to port 49152 udp on the broadcast address.
But, there can only be 32 units on each broadcast domain for some reason that I'm not aware off.
So I have to segment it into more VLan on our core switch (its 6500).
Now, how do I propagate the packets that are sent to a broadcast address on one VLan to all others VLan.
I've setup helper-addresses for relaying the broadcast traffic to the broadcast address on all others VLan and I've appended port 49152 udp in the forward-protocol.

Here is the what I've tried to get working, but it's not.


interface Vlan400
 ip address 10.8.40.1 255.255.255.192
 ip broadcast-address 10.8.40.63
ip helper-address 10.2.40.127
 ip helper-address 10.2.40.191
 ip directed-broadcast

interface Vlan401
 ip address 10.8.40.65 255.255.255.192
 ip broadcast-address 10.8.40.127
 ip helper-address 10.2.40.191
 ip helper-address 10.2.40.63
 ip directed-broadcast
!
interface Vlan402
 ip address 10.8.40.129 255.255.255.192
 ip broadcast-address 10.8.40.191
 ip helper-address 10.2.40.63
 ip helper-address 10.2.40.127
 ip directed-broadcast




/Arne