Cisco Cisco IOS Software Release 12.0(17)S

The following new functionality is supported in this release of the MPLS TE MIB:

The ability to generate and queue notification messages that signal changes in the operational status 
of MPLS traffic engineering tunnels.

Extensions to existing SNMP CLI commands that provide the ability to enable, disable, and 
configure notification messages for MPLS traffic engineering tunnels.

The ability to specify the name or the IP address of a network management station (NMS) in the 
operating environment to which notification messages are to be sent.

The ability to write notification configurations into non-volatile memory.

When MPLS traffic engineering notifications are enabled (see the 

command), notification messages relating to specific events within Cisco IOS are generated and sent to 
a specified network management station (NMS) in the network. 

For example, an mplsTunnelUp notification is sent to an NMS when an MPLS traffic engineering tunnel 
is configured and the tunnel transitions from an operationally “down” state to an “up” state. 

Conversely, an mplsTunnelDown notification is generated and sent to the NMS when an MPLS traffic 
engineering tunnel transitions from an operationally “up” state to a “down” state. 

Finally, an mplstunnelRerouted notification is sent to the NMS under the following conditions: 

The signalling path of an existing MPLS traffic engineering tunnel fails for some reason and a new 
path option is signalled and placed into effect (that is, the tunnel is rerouted). 

The signalling path of an existing MPLS traffic engineering tunnel is fully operational, but a better 
path option can be signalled and placed into effect (that is, the tunnel can be reoptimized). This 
reoptimazation can be triggered by: a) a timer, b) the issuance of an mpls traffic-eng reoptimize 
command, or c) a configuration change that requires the resignalling of a tunnel.

Path options are configurable parameters that you can use to specify the order of priority for establishing 
a new tunnel path. For example, you can create a tunnel head configuration and define any one of many 
path options numbered 1 through n, with “1” being the highest priority option and “n” being an unlimited 
number of lower priority path options. Thus, there is no limit to the number of path options that you can 
specify in this manner.

When an MPLS traffic engineering tunnel interface (or any other device interface, such as an Ethernet 
or POS interface) transitions between an up or down state, an Interfaces MIB (ifMIB) link notification 
is generated. When such a notification occurs in an MPLS TE MIB environment, the interface is checked 
by software to determine if the notification is associated with an MPLS traffic engineering tunnel. If so, 
the interfaces MIB link notification is interlinked with the appropriate mplsTunnelUp or 
mplsTunnelDown notification to provide notification to the NMS regarding the operational event 
occurring on the tunnel interface. Hence, the generation of an interfaces MIB link notification pertaining 
to an MPLS traffic engineering tunnel interface begets an appropriate mplsTunnelUp or 
mplsTunnelDown notification that is transmitted to the specified NMS.