foreach my $oid (sort keys(%iface)) {
  %oids = ("$iface{$oid}" => `$snmpwalk $ip $community $oid`);
}

##</code><code>##

foreach my $oid (sort keys(%iface)) {
  $oids{$iface{$oid}} = `$snmpwalk $ip $community $oid`;
}