Why should you use a single integration gateway for all applications that reside on the same side of

Hi All

In document

PeopleTools 8.57: Integration Broker ( https://docs.oracle.com/cd/E99484_01/psft/pdf/pt857tibr-b092018.pdf )

Page 608 states:

• You should use a single integration gateway for all applications that reside on the same side of a firewall.

What is the reason for this recommendation? I'm trying to gather and understand the pros and cons of this recommendation.

I'm being told that this is only valid for demo systems and that full sized production systems should be setup with each environment having both a local and remote gateway as per config across firewalls e.g. when application A is in a the UK and Application B (both PeopleSoft) is located in the USA.