Traffic monitoring

In order to determine the amount of traffic traversing on a router's particular interface (i.e., for ifIndex=X), look at the values for the following OID variables:

• interfaces.ifTable.ifEntry.ifEnrty.ifInOctets.X

• interfaces.ifTable.ifEntry.ifEnrty.ifOutOctets.X

SNMP defines the former as the total number of octets (a group of 8 bits) received on the interface, including framing characters. The latter OID variable represents the total number of octets transmitted on the particular interface, including framing characters. SNMP defines the former as the total number of octets (a group of 8 bits) received on the interface, including framing characters. The latter OID variable represents the total number of octets transmitted on the particular interface, including framing characters.

These OID variables indicate the total number of octets received/transmitted. However, the per unit time versions of these variables may be of interest. That is, it may be desirable to know:

• the number of octets per second received on the interface

• the number of octets per second transmitted on the interface

PI SNMP performs such a measurement if a PI point is configured with Location2 set to 1. (See the main section of this manual for details.)

So, for the three example scenarios cited above, use PI SNMP to monitor the amount of traffic for each interface provisioned on the router. Consequently, it becomes easy to determine which department (e.g., Sales, Accounting, or Engineering), which customer (Customer1, Customer2, or Customer3), or which area of the plant (Foxboro, Honeywell, or Yokogawa) is utilizing the most bandwidth.