Conference sponsored by a top conference? How related two conferences are if B is sponsored by A? If A is a top conference, does this make B a worth-trusting conference also? For example, SIGCOMM is a top conference in computer networks &amp; communications, and CoNEXT is sponsored by it. Does that automatically make CoNEXT a quality conference?
I'm not sure what it means for one conference to sponsor another. In the particular case you mention, "SIGCOMM" is both the name of a conference and the name of a group within the ACM that sponsors that conference. So it's likely that SIGCOMM (the group) is sponsoring CONEXT, rather than SIGCOMM (the conference).