What is the purpose of the fight between Benvolio and Tybalt in Act I scene 1 of Romeo and Juliet?

One of the reasons that this play has such a dramatic
opening is that it completely plunges us as an audience into the thick of the action, as
we see the reality of the Montague/Capulet feud in all of its gory realism, and at the
same time are introduced to two characters who are inextricably intertwined with it. It
is interesting to note, however, how this fight between Benvolio and Tybalt actually
forshadows the confrontation later on with Romeo and Tybalt in Act III scene 1. Note how
in Act I scene 1 Benvolio tries to play the role of peacemaker, but is forced into
conflict against his wishes, just as Romeo tries to avoid violence in Act III scene 1.
Note what Benvolio says to Tybalt as he pleads for
peace:

I do
but keep the peace. Put up thy sword,

Or manage it to part
these men with me.

In spite
of his best intentions, Benvolio finds himself sucked into violence against Tybalt,
because of the way that Tybalt's character is so opposed to peace, just as Romeo,
against his desires and wishes, fights Tybalt later on in the
play.

Thus the importance of this fight lies in the way it
foreshadows the later confrontation of Romeo and Tybalt, and also in how it focuses on
the way that, in spite of our better judgement and our attempt to avoid violence, we can
nonetheless find ourselves sucked into it, just as Benvolio was forced to fight
Tybalt.