Day: September 12, 2016

224.0.23.158

Yes VSCP has a multicast channel assigned. The above is the assigned IPv4 address for it.

Announcements

All higher level IP equipment should send announcements  on this multicast address. The port used is 9598, the registered VSCP port.

This means that if you want to know what units are on a multicast segment you just listen on this channel.

Announcements can be of three different types

• VSCP daemon announcements. Announce the availability of a VSCP daemon (or other server with exported interfaces) and tell its capabilities.
• High end device announce. Announce the availability of the device and its capability. All Level II nodes should have this functionality. At the bottom line they just look to the system as a VSCP daemon with fewer capabilities.
• Heart beats: Heart beats come in the form of heartbeats from VSCP daemons and from high-end nodes. Both send them out each minute. Also heartbeats are available form devices connected to a daemon or through a high-end node.

• CLASS2.Protocol Type=20 is used for announcements.
• CLASS1.INFORMATION Type=9 is used for heartbeats

User multicast channels

Users can set up proprietary multicast channels  using some other port than the VSCP assigned 9598. This makes it easy to create groups of VSCP nodes that can communicate with each other in much the same way as on a CAN bus.

Two factors that must be taken into account is the unsecured nature of this type of communication. Delivery is never guaranteed. But most of the time this is not a problem in VSCP if one design the event exchange around it. That is that a node that digest an event also send some sort of confirm/information event when doing so. The other problem is that it is easy to go in a mess about with the traffic for a user that is not allowed to do that.  Something that is  easily solved with cryptographic routines. Some VSCP standardization (and samples)  will come here in the future.

You can read more here.