I actually figured out the sub. All that it does is check list of active IP's pulled in from SNMP against the hash and adds the new ones. I still need to add the part to strip out the old ones.

anyway, the working code is:

sub loadIPs {

  my $datahashref = shift;
  my $parmhashref = shift;
  my $IPs   = '1.3.6.1.2.1.10.127.1.3.3.1.3';

my ($session, $error) = Net::SNMP->session(%$parmhashref);

my $reply = $session->get_table(-baseoid=> $IPs);
my %reply =  %$reply;

while ( my ($oid, $ip) = each(%reply) ) {

  my %tmpHash = ('rx'=>undef, 'tx'=>undef);
  $$datahashref{$ip} = %tmpHash unless exists $$datahashref{$ip};

    }
}
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it was the $$ reference I wasn't grasping.

When I mentioned stale data, I didn't mean it as a bad thing; just a word to differentiate it from the new stuff, and I want the script to just update the hash on the fly. No clearing out the whole thing and starting fresh.

I was actually hoping to keep the GUI refresh rate higher then the time it takes to query all the modems. On a large plant, the query process can take a full minute or two, and I'd like to be able to watch the changes trickle in.

I'll have to read up on the threads::shared mod

thanks