Controlling RMC IP packet sizes
The instances of Resource Monitoring and Control (RMC) subsystem on different nodes use User Datagram Protocol (UDP) traffic on the port 657 to communicate with each other. Currently, the maximum packet size is limited to 1500 bytes because of the limitations in communication across mixed maximum transmission unit (MTU) networks.
You can use the /var/ct/cfg/ctrmc.maxpktsz configuration file to change the
maximum size of a packet that is sent by RMC. The configuration file must contain only one integer
value that specifies the maximum packet size in bytes, that you want RMC to send.
Notes:
- You cannot specify different values for different networks or remote hosts. The value that is provided must be the maximum size for a packet that RMC can send for all communication across any network.
- Packet sizes less than 800 bytes are treated as 800 bytes.
- Packet sizes larger than 60 KB are treated as 60 KB.
- On a node that is configured with cluster-aware AIX® (CAA), the upper bound of the packet size is 8 KB instead of 60 KB.