Instant Aps use different messages for election and inter communication between IAPs. The protocol type value for all IAP Messages is 0x8ffd.
Message Sub-types that are related to master election are below:
- Master election
- Master Beacon (Sub type 3)
- Beacon Request (Sub type 7)
- Hierarchy Messages
- Hierarchy Message (Sub type 4)
- Hierarchy Message to Master (Sub type 5)
Environment : Master Beacon and Beacon Request Message are sent in a flat network on all port(uplink, meshlink and downlink) of Master. Hierarchy beacon are sent only on downlink eth port of both Master and Slave IAP.
Master Beacon: These beacons are sent by Master every second as broadcast packets in the local subnet. They have information about Swatch state, Uptime, Master IP address, CPU utilization and 3G modem connectivity.
Beacon Requests: These are packets sent by IAPs when they become potential masters and try to reach the last known master through unicast packets.
Hierarchy Message: These are very similar to Master beacons but are only sent to downlink eth port by both master and slave. They help in setting up on private VLANs with master being the Root AP.
Hierarchy Message to Master: These are acknowledgement packets sent by Slave Aps to Root AP for received Hierarchy Messages.
Show election provides statistics about all the 4 kinds of message sub-types.
Troubleshooting can be done for issues related to these messages through "debug-master-beacon".