Wired Intelligent Edge

Hello, I'm looking for some help in setting up IP Directed Broadcast in a mixed CX and AOS environment.

The server sending the broadcast sits in VLAN 60 on a CX VSX stack.  It then routes to other buildings over VLAN 3 using OSPF.  I need to be able to send the WOL packets to all other buildings and have them only broadcast over specific VLANs.

So on the source CX switch, do I set the ip directed-broadcast command on the SVI for VLAN 60, or for VLAN 3?

The receiving buildings have core switches that are a mix of CX and and AOS 5406Rs.  On the receiving CX cores, do I also set ip directed-broadcasting on the SVI for VLAN 3 or for the specific VLAN I want to broadcast out to clients?

On the cores that are AOS, it looks like ip directed-broadcasting is global to the switch and I would just need to create an ACL that only allows it to broadcast to the VLAN I want.

Any help would be appreciated!

Generally, the source subnet doesn't know about the directed broadcast - the last hop is the key here, and you need to activate subnet-directed broadcast there (ie. on VLAN 60).

Alternatively, you could remove the need for (activating) directed broadcast by using a dedicated dummy IP address in each subnet. Since ARP wouldn't work, you'd add a static ARP entry on the last hop for that IP with a MAC group LAA (bits 0 and 1 in first octet set). Actually, any unused MAC would do (would be flooded by the switches), but using a group/broadcast address with LAA bit set is the neatest.

on CX switches "IP Directed Broadcast " are supported on Routed ports, SVIs and LAGs. 

check this example of the flow and you can also use the ACL to control the final broadcast.

------------------------------
If my post was useful accept solution and/or give kudos.
Any opinions expressed here are solely my own and not necessarily that of HPE or Aruba.
------------------------------

Original Message:
Sent: Jan 11, 2025 05:42 AM
From: Zac67
Subject: IP Directed Broadcast

Generally, the source subnet doesn't know about the directed broadcast - the last hop is the key here, and you need to activate subnet-directed broadcast there (ie. on VLAN 60).

Alternatively, you could remove the need for (activating) directed broadcast by using a dedicated dummy IP address in each subnet. Since ARP wouldn't work, you'd add a static ARP entry on the last hop for that IP with a MAC group LAA (bits 0 and 1 in first octet set). Actually, any unused MAC would do (would be flooded by the switches), but using a group/broadcast address with LAA bit set is the neatest.