Better to run Squid on router or bridge network topology

[On Offer All <clearallstock@xxxxxxxxx>]

Hi


I have a server going to run SQUID (see simple diagram below). 

Like to know whether the server should be configure as a router or bridge ?
Kindly advise pros & cons for each implementation.
(I do not need WCCP solution)


firewall
   |
server w 2 network port (SQUID)

   |
switch (connect to 10 workstations)


Thanks
Steve