Perl ZMQ::LibZMQ3 is a libzmq 3.x(ZeroMQ3) thin wrapper for Perl. It provides an interface to use widely support ZeroMQ. some Perl ZMQ module are distributed through RHEL/CentOS, but not all, you may find similar thing on other platforms.
Keep it in short, here I just describe how to install Perl ZMQ module on RHEL/CentOS, also could be useful reference to other platforms.
1. Install ZeroMQ on RHEL/CentOS
This part is rather easy, for CentOS/RHEL, there are already zeromq/3 builds in EPEL but they are not up-to-date.
Yum install zeromq3 zeromq3-devel perl-ZMQ-LibZMQ3 perl-ZMQ-Constants
2. Get Perl ZMQ package from CPAN
In case you can't find the package from your linux distribution, get the perl zmq package from cpan
or from github
3. Install perl ZMQ package got from CPAN
4. Install required package, Constants.pm
You can install the package form EPEL, however, if you can't find it on you linux distribution, get the package from CPAN, it does mention in ZMQ SYNOPSIS
# separate module
Without it, see what you get
Can't locate ZMQ/Constants.pm in @INC (@INC contains: /usr/local/lib64/perl5 /usr/local/share/perl5 /usr/lib64/perl5/vendor_perl /usr/share/perl5/vendor_perl /usr/lib64/perl5 /usr/share/perl5 .) at /usr/local/lib64/perl5/ZMQ/LibZMQ3.pm line 6.
BEGIN failed--compilation aborted at /usr/local/lib64/perl5/ZMQ/LibZMQ3.pm line 6.
Compilation failed in require at ./mqserver.pl line 12.
BEGIN failed--compilation aborted at ./mqserver.pl line 12.
Seems to me that this package should be included together within ZeroMQ perl package.
Anyway, to get the ZMQ::Constants package
Or, you can download it from github
Similarily, you can get zhelpers.pm