IP Accounting (Layer 3) Principles

The principles of IP Accounting (Layer 3) can be summarized as follows:

• IP Layer 3 outbound (egress) traffic is collected.

• Only transit traffic that enters and leaves the router is collected; traffic that is generated by the router or terminated in the router is not included.

• IP Accounting (Layer 3) also collects IPX traffic. In this case, IPX source and destination addresses are reported instead of IP addresses.

• Egress MPLS core traffic collection is a new feature.

• Active and checkpoint databases enable “snapshot” collections.

• Collection data is accessible via CLI and SNMP; however, the initial configuration must be done via CLI. To retrieve the collection results via SNMP, you need to enable SNMP first. When configuring SNMP, distinguish between read-only access and read-write access. For more details about SNMP configuration, see Chapter 4, “SNMP and MIBs.”

• The MIB contains only 32-bit SNMP counters.