(PHP >= 5.2.0)
snmp2_walk — Fetch all the SNMP objects from an agent
$host
   , string $community
   , string $object_id
   [, string $timeout = 1000000
   [, string $retries = 5
  ]] )
   snmp2_walk() function is used to read all the values from
   an SNMP agent specified by the hostname.
  
hostThe SNMP agent (server).
communityThe read community.
object_id
      If NULL, object_id is taken as the root of
      the SNMP objects tree and all objects under that tree are returned as
      an array.
     
      If object_id is specified, all the SNMP objects
      below that object_id are returned.
     
timeoutThe number of microseconds until the first timeout.
retriesThe number of times to retry if timeouts occur.
   Returns an array of SNMP object values starting from the
   object_id as root or FALSE on error.
  
Example #1 snm2_pwalk() Example
<?php
$a = snmp2_walk("127.0.0.1", "public", "");
foreach ($a as $val) {
    echo "$val\n";
}
?>
Above function call would return all the SNMP objects from the SNMP agent running on localhost. One can step through the values with a loop