In an MVPN network, a provider pdge (PE) router has a multicast routing table and a Protocol Independent Multicast (PIM) instance associated with every VPN routing and forwarding (VRF) table that is used to define the VPN membership of customer sites attached to the router. There is one global multicast routing table and a table per multicast VRF (MVRF) used to route multicast packets received from a customer edge (CE) router. A set of MVRFs form a multicast domain (MD) when they are connected to potential sources and receivers of multicast traffic. A distinct group address, also known as the Multicast Distribution Tree (MDT) group address, obtained from an administrative pool, is assigned to each multicast domain. MDT groups are used by PE routers to encapsulate and transport multicast traffic within an MD through multicast tunnel interfaces (MTIs).

Initially all multicast data is forwarded using preconfigured MDT default groups. When certain multicast streams exceed a configured bandwidth threshold on the PE router, the multicast data is moved to an MDT data group that is dynamically chosen from an available pool of multicast addresses.

Using the MVPN MIB, network administrators can access MVRF information from PE routers for VPN traffic across multiple CE sites in real time. SNMP operations can be performed to monitor the MVRFs on the PE routers using get and set commands entered on the network management system (NMS) workstation for which SNMP has been implemented. The NMS workstations is also known as the SNMP manager.

SNMP has historically been used to collect network information. SNMP permits retrieval of critical information from network elements such as routers, switches, and workstations. The MVPN MIB uses SNMP to configure MVRF trap notifications and to gather useful MVPN information in real time.

The MVPN MIB allows MVPN data for the managed devices on your system to be retrieved by SNMP. You can specify the retrieval of MVPN information from a managed device (for example, a router) either by entering commands on that managed device or by entering SNMP commands from the NMS workstation to gather MVPN information. MVPN MIB requests for information are sent from an NMS workstation to the router using SNMP and are retrieved from the router. This information can then be stored or viewed, thus allowing MVPN information to be easily accessed and transported across a multivendor programming environment.

The MVPN MIB defines managed objects that enable a network administrator to remotely monitor the following MVPN information:

• The state of the MVRFs including the name of the MVRF, whether they are active, and the number of active multicast-enabled interfaces
• MDT default group address and encapsulation information
• Next hop information used to receive Border Gateway Protocol (BGP) MDT updates for Source Specific Multicast (SSM) mode
• Traffic threshold that determines switchover to an MDT data group
• Type of MDT group being used for a given (S, G) multicast route entry that exists on each configured MVRF, source address, and group address of the multicast route entry
• Source and group address used for encapsulation
• Information on MDT data groups currently joined
• Information on MVPN-specific MDT tunnels present in the device
• Trap notifications enabled on the router

Note	For a complete description of the objects supported by the MVPN MIB, see the CISCO_MVPN_MIB.my file, available on Cisco.com at http://www.cisco.com/go/mibs .

• MVRF Trap Notifications

Perform this task to configure the router to use SNMP to send MVRF trap notifications.

Note	Before the MVPN MIB can be used, the SNMP server for the router must be configured. To enable the SNMP server on the router, perform Steps 3 and 4. If an SNMP server is already available, omit Steps 3 and 4 and proceed to Step 5.

1.    enable

2.    configure terminal

3.   Do one of the following:

4.    snmp-server host { hostname | ip - address } version 2c community - string

5.    snmp-server enable traps mvpn

6.    end