About Spark 2.6.3 how many local network bandwidth used? is this an AD Integrated Chat System?
Bandwidth usage is related to the usage pattern. If a user send huge files, then the usaga will be big. If he just sends a message once in a while, then it will be just a few bytes, as this is just a simple xml.
Openfire (server part) can be integrated with LDAP, but this is not a Next > Next > Ok experience. One will ahve to read a lot of threads and wiki docs here and customize ldap queries. I have tried this and decided it is not worth my time to try to get it working as i want.