Consider the following AutoNOC OSP expression (this is the expression used by AutoNOC to compute total traffic for an interface):

((SNMP_GetByRowMatch(
         %IP,%COMMUNITY,
         .1.3.6.1.2.1.2.2.1.10,
         .1.3.6.1.2.1.2.2.1.2,
          %SNMPNAME,
         .1.3.6.1.2.1.2.2.1.1,
         %SNMPINDEX)-Previous(0))
+(SNMP_GetByRowMatch(
         %IP,%COMMUNITY,
       .1.3.6.1.2.1.2.2.1.16,
         .1.3.6.1.2.1.2.2.1.2,
         %SNMPNAME,
         .1.3.6.1.2.1.2.2.1.1
        ,%SNMPINDEX)-Previous(1)))
          / ( (Elapsed(0)+Elapsed(1)) / 2 )
          / 1024 * 8

When AutoNOC parses this expression, in order to compute Total Traffic, it finds two calls to the function SNMP_GetByRowMatch that need to be evaluated. So how does AutoNOC handle this kind of an expression in terms of acquiring the data?

It all boils down to AutoNOC's device acquisition stacks. Each call to a function is translated internally into what is called a Receiver. A receiver is an internal construct that gets added to the protocol acquisition stack for the device. This function is processed and then the expression is recombined and solved by AutoNOC.

For every unique IP address that the core engine is working on, AutoNOC 2 creates a set of IP specific protocol stacks such as those shown in the following diagram.

Each protocol has it's own acquisition stack for the device and it processes each receiver one after another after another. This process occurs in a fully asynchronous manner on a by-protocol, by-IP address basis.

This results in an extremely high performance data acquisition model that avoids any problems that might occur related to poorly implemented client device agents. Some agents, for instance, are not able to readily solve multiple simultaneous queries on the same IP address or they may support only a limited number of simultaneous queries. In this model we have sought to maximize performance while staying within the sweet spot of safety in terms of how most third party protocol agents are constructed.

AutoNOC's by-IP protocol acquisition stack capability is a significant achievement in the realm of operations management. The model is extensible to support new protocols that might merge. AutoNOC's multi-protocol, multi-threaded, and asynchronous data acquisition stack technology is a key to how it is able to outperform many other management products.

For more information on this topic, read about 3.11 - Polling and 4.3 - Interpreter.