understanding symbol in send connector

Hi Everyone,

i have searched but not found the answer,
here is questions,  when i create edge subscription , it create automatically two send connector,

one  smart host is   send through edge  with "*" address space (which mean all addresses)
second is create same thing but  with *--*  address space  what is understandable  for  me, please someone explain me what is that exactly mean?

Thanks,