I have found that the thing that musicians do nearly as well, if not better than making music, is to talk. There is nothing at all wrong with this but trying to combine the two, when the main object of a session is to make music, does not make a lot of sense to me. As neither tends to get done very well by combining two separate activities.

In a pub you are never going to get a church like hush and it is supposed to be fun and should be, but it is seldom that there are not other parts of the pub where you can catch up on the gossip, without talking over the music. The best solution is to find such a place to talk that does not affect the main point of the gathering, which is making music.

Is not, before the music starts or at the end, the best time to catch up with friends?

The pub is available for talking most of the time but usually only one night a week (or less) for music making so why not make the most of that one night to make music? You can always make a date to meet up with the folk you meet, on another night of the week.