The SNMP Notification Support over VPNs feature allows the sending and receiving of SNMP notifications (traps and informs)
using VPN routing and forwarding (VRF) instance tables. In particular, this feature adds support to Cisco software for the
sending and receiving of SNMP notifications (traps and informs) specific to individual VPNs.
SNMP is an application-layer protocol that provides a message format for communication between SNMP managers and agents.
A VPN is a network that provides high-connectivity transfers on a shared system with the same usage guidelines as a private
network. A VPN can be built on the Internet over IP, Frame Relay, or ATM networks.
A VRF stores per-VPN routing data. It defines the VPN membership of a customer site attached to the network access server
(NAS). A VRF consists of an IP routing table, a derived Cisco Express Forwarding (formerly known as CEF) table, and guidelines
and routing protocol parameters that control the information that is included in the routing table.
The SNMP Support for VPNs—Context-Based Access Control feature provides configuration commands that allow users to associate
SNMP agents and managers with specific VRFs. The associated VRF is used for the sending of SNMP notifications (traps and informs)
and responses between agents and managers. If a VRF is not specified, the default routing table for the VPN is used.