I need some little explanations about boundary

Hello guys,
im a student in computer science and i don’t understand why boundary use 3 ports 9200/9201/9202 ?
actually, i can connect to a redis service(only exposed for boundary on docker) with all these 3 ports with commands:

  • boundary connect -exec redis-cli -target-id ttcp_rt6noReMNj – -p 9200
  • boundary connect -exec redis-cli -target-id ttcp_rt6noReMNj – -p 9201
  • boundary connect -exec redis-cli -target-id ttcp_rt6noReMNj – -p 9202

so if someone know why these 3 work fine, that would be cool.
ty in advance for ur explanation