MPLS: Embedded Management and MIBs Configuration Guide, Cisco IOS Release x.x

Monitoring MPLS VPNs with MIBs

This module explains how to use the PPVPN-MPLS-VPN management information base (MIB) to monitor and manage Multiprotocol Label Switching (MPLS) Virtual Private Networks. The following MIBs are supported:

•MPLS/BGP Virtual Private Network Management Information Base Using SMIv2 (draft-ietf-ppvpn-mpls-vpn-mib-03.txt)

•CISCO-IETF-PPVPN-MPLS-VPN-MIB, a proprietary MIB that describes the cMplsNumVrfRouteMaxThreshCleared notification

Module History

This module was first published on May 2, 2005, and last updated on May 2, 2005.

Finding Feature Information in This Module

Your Cisco IOS software release may not support all features. To find information about feature support and configuration, use the "Feature Information for PPVPN MPLS VPN MIB" section.

Contents

•Prerequisites for PPVPN MPLS VPN MIB

•Restrictions for PPVPN MPLS VPN MIB

•Information About PPVPN MPLS VPN MIB

•How to Configure PPVPN MPLS VPN MIB

•Configuration Examples for PPVPN MPLS VPN MIB

•Additional References

•Feature Information for PPVPN MPLS VPN MIB

Prerequisites for PPVPN MPLS VPN MIB

The PPVPN-MPLS-VPN MIB agent requires the following:

•SNMP is installed and enabled on the label switching routers.

•MPLS is enabled on the label switching routers.

•Multiprotocol Border Gateway Protocol (BGP) is enabled on the label switching routers.

•Cisco Express Forwarding is enabled on the label switching routers.

Restrictions for PPVPN MPLS VPN MIB

The following restrictions apply to the PPVPN-MPLS-VPN MIB:

•Configuration of the MIB using the SNMP SET command is not supported, except for trap-related objects, such as mplsVpnNotificationEnable and mplsVpnVrfSecIllegalLabelRcvThresh.

•The mplsVpnVrfBgpNbrPrefixTable is not supported.

Information About PPVPN MPLS VPN MIB

This section contains the following topics:

•MPLS VPN Overview

•PPVPN MPLS VPN MIB Overview

•PPVPN MPLS VPN MIB and the IETF

•Capabilities Supported by PPVPN-MPLS-VPN MIB

•Functional Structure of the PPVPN-MPLS-VPN MIB

•Supported Objects in PPVPN-MPLS-VPN MIB

•MIB Objects Not Supported

MPLS VPN Overview

The MPLS VPN technology allows service providers to offer intranet and extranet VPN services that directly connect their customers' remote offices to a public network with the same security and service levels that a private network offers. Each VPN is associated with one or more VPN routing/forwarding instances (VRFs). A VRF is created for each VPN defined on a router and contains most of the information needed to manage and monitor MPLS VPNs: an IP routing table, a derived Cisco Express Forwarding (CEF) table, a set of interfaces that use this forwarding table, and a set of rules and routing protocol parameters that control the information that is included in the routing table.

PPVPN MPLS VPN MIB Overview

The Provider-Provisioned VPN (PPVPN)-MPLS-VPN MIB provides access to VRF information, as well as interfaces included in the VRF, and other configuration and monitoring information.

The PPVPN-MPLS-VPN MIB provides the following benefits:

•A standards-based SNMP interface for retrieving information about critical MPLS VPN events.

•VRF information to assist in the management and monitoring of MPLS VPNs.

•Information, in conjunction with the Interfaces MIB, about interfaces assigned to VRFs.

•Performance statistics for all VRFs on a router.

•The generation and queuing of notifications that call attention to major changes in the operational status of MPLS VPN enabled interfaces; the forwarding of notification messages to a designated network management system (NMS) for evaluation and action by network administrators.

•Advanced warning when VPN routing tables are approaching or exceed their capacity.

•Warnings about the reception of illegal labels on a VRF-enabled interface. Such receptions may indicate misconfiguration or an attempt to violate security.

This document also describes the CISCO-IETF-PPVPN-MPLS-VPN-MIB, which contains the cMplsNumVrfRouteMaxThreshCleared notification.

PPVPN MPLS VPN MIB and the IETF

SNMP agent code operating with the PPVPN-MPLS-VPN MIB enables a standardized, SNMP-based approach to managing MPLS VPNs in Cisco IOS software.

The PPVPN-MPLS-VPN MIB is based on the IETF draft MIB specification draft-ietf-ppvpn-mpls-vpn-mib-03.txt, which includes objects describing features that support MPLS VPN events. This IETF draft MIB, which undergoes revisions from time to time, is being evolved toward becoming a standard. Accordingly, the Cisco implementation of the PPVPN-MPLS-VPN MIB is expected to track the evolution of the IETF draft MIB, and may change accordingly.

Some slight differences between the IETF draft MIB and the actual implementation of MPLS VPNs within Cisco IOS software require some minor translations between the PPVPN-MPLS-VPN MIB and the internal data structures of Cisco IOS. These translations are accomplished by means of the SNMP agent code. Also, while running as a low priority process, the SNMP agent provides a management interface to Cisco IOS. SNMP adds little overhead on the normal functions of the device.

The SNMP objects defined in the PPVPN-MPLS-VPN MIB can be viewed by any standard SNMP utility. The network administrator can retrieve information in the PPVPN-MPLS-VPN MIB using standard SNMP get and getnext operations for SNMP v1, v2, and v3.

All PPVPN-MPLS-VPN MIB objects are based on the IETF draft MIB; thus, no Cisco specific SNMP application is required to support the functions and operations pertaining to the PPVPN-MPLS-VPN MIB features.

Capabilities Supported by PPVPN-MPLS-VPN MIB

The following functionality is supported by the PPVPN-MPLS-VPN MIB. The PPVPN-MPLS-VPN MIB provides you with the ability to do the following:

•Gather routing and forwarding information for MPLS VPNs on a router.

•Expose information in the VRF routing table.

•Gather information on BGP configuration related to VPNs and VRF interfaces and statistics.

•Emit notification messages that signal changes when critical MPLS VPN events occur.

•Enable, disable, and configure notification messages for MPLS VPN events by using extensions to existing SNMP CLI commands.

•Specify the IP address of a network management system (NMS) in the operating environment to which notification messages are sent.

•Write notification configurations into nonvolatile memory.

Functional Structure of the PPVPN-MPLS-VPN MIB

The SNMP agent code supporting the PPVPN-MPLS-VPN MIB follows the existing model for such code in Cisco IOS software and is, in part, generated by the Cisco IOS tool set, based on the MIB source code.

The SNMP agent code, which has a layered structure that is common to MIB support code in Cisco IOS, consists of four layers:

•Platform-independent layer—This layer is generated primarily by the MIB development Cisco IOS tool set and incorporates platform- and implementation-independent functions. The Cisco IOS MIB development tool set creates a standard set of files associated with a MIB.

•Application interface layer—The functions, names, and template code for MIB objects in this layer are also generated by the MIB development Cisco IOS tool set.

•Application-specific layer—This layer provides an interface between the application interface layer and the API and data structures layer below and performs tasks needed to retrieve required information from Cisco IOS, such as searching through data structures.

•API and data structures layer—This layer contains the data structures or APIs within Cisco IOS that are retrieved or called in order to set or retrieve SNMP management information.

Supported Objects in PPVPN-MPLS-VPN MIB

The PPVPN-MPLS-VPN MIB contains numerous tables and object definitions that provide read-only SNMP management support for the MPLS VPN feature in Cisco IOS. The PPVPN-MPLS-VPN MIB conforms to Abstract Syntax Notation One (ASN.1), thus reflecting an idealized MPLS VPN database.

Using any standard SNMP network management application, you can retrieve and display information from the PPVPN-MPLS-VPN MIB using GET operations; similarly, you can traverse information in the MIB database for display using GETNEXT operations.

The PPVPN-MPLS-VPN MIB tables and objects are described briefly in the following sections:

•Scalar Objects

•MIB Tables

•Notifications

Objects that are not supported are listed in the "MIB Objects Not Supported" section.

Figure 1 shows a simple MPLS VPN configuration. This configuration includes two customer MPLS VPNs, labeled VPN1 and VPN2, and a simple provider network that consists of two provider edge (PE) routers, labeled PE1 and PE2, and a provider core router labeled P. Figure 1 shows the following sample configuration:

•VRF names—VPN1 and VPN2

•Interfaces associated with VRFs—Et1, Et2, and At3/0

•Routing protocols—OSPF, RIP, and IBGP

•Routes associated with VPN1—10.1.0.0, 10.2.0.0, and 10.3.0.0

•Routes associated with VPN2—172.16.1.0 and 172.16.2.0

•Routes associated with the provider network—192.168.1.0, 192.168.2.0, and 192.168.3.0

This configuration is used in this document to explain MPLS VPN events that are monitored and managed by the PPVPN-MPLS-VPN MIB.

Figure 1 Sample MPLS VPN Configuration

Scalar Objects

Table 1 shows the supported PPVPN-MPLS-VPN MIB scalar objects.

MIB Tables

The PPVPN-MPLS-VPN MIB implementation supports the following tables described in this section:

•mplsVpnVrfTable

•mplsVpnInterfaceConfTable

•mplsVpnVrfRouteTargetTable

•mplsVpnVrfBgpNbrAddrTable

•mplsVpnVrfSecTable

•mplsVpnVrfPerfTable

•mplsVpnVrfRouteTable

mplsVpnVrfTable

Entries in the VRF configuration table (mplsVpnVrfTable) represent the VRFs that are defined on the router. This includes recently deleted VRFs. The information in this table is also displayed with the show ip vrf command.

Each VRF is referenced by its VRF name (mplsVpnVrfName).

Table 2 lists the MIB objects and their functions for this table.

Router(config)# ip vrf vrf-name

Router(config-vrf)# description vrf-description

Router(config)# ip vrf vrf-name

Router(config-vrf)# rd route-distinguisher

Router(config)# ip vrf vpn1

Router(config-vrf)# maximum routes 1000 50

Router(config-vrf)# maximum routes 1000 warn-only

Router(config)# ip vrf vpn2

mplsVpnInterfaceConfTable

In Cisco IOS, a VRF is associated with one MPLS VPN. Zero or more interfaces can be associated with a VRF. A VRF uses an interface that is defined in the ifTable of the Interfaces Group of MIB II (IFMIB). The IFMIB defines objects for managing interfaces. The ifTable of this MIB contains information on each interface in the network. The mplsVpnInterfaceConfTable associates a VRF from the mplsVpnVrfTable with a forwarding interface from the ifTable. Figure 2 shows the relationship between VRFs and interfaces defined in the ifTable and the mplsVpnInterfaceConfTable.

Figure 2 VRFs, the Interfaces MIB, and the mplsVpnInterfaceConfTable

Entries in the VPN interface configuration table (mplsVpnInterfaceConfTable) represent the interfaces that are assigned to each VRF. The information available in this table is also displayed with the show ip vrf command.

The mplsVpnInterfaceConfTable shows how interfaces are assigned to VRFs. A label switch router (LSR) creates an entry in this table for every interface capable of supporting MPLS VPNs.

The mplsVpnInterfaceConfTable is indexed by the following:

•mplsVpnVrfName—The VRF name

•mplsVpnInterfaceConfIndex—An identifier that is the same as the ifIndex from the Interface MIB of the interface assigned to the VRF

Table 3 lists the MIB objects and their functions for this table.

mplsVpnVrfRouteTargetTable

The route target table (mplsVpnVrfRouteTargetTable) describes the route target communities that are defined for a particular VRF. An LSR creates an entry in this table for each target configured for a VRF supporting an MPLS VPN instance.

The distribution of VPN routing information is controlled through the use of VPN route target communities, implemented by Border Gateway Protocol (BGP) extended communities. Distribution of VPN routing information works as follows:

•When a VPN route learned from a CE router is injected into BGP, a list of VPN route target extended community attributes are associated with it. Typically the list of route target community values is set from an export list of route targets associated with the VRF from which the route was learned.

•An import list of route target extended communities is associated with each VRF. The import list defines route target extended community attributes a route must have for the route to be imported into the VRF. For example, if the import list for a particular VRF includes route target communities A, B, and C, then any VPN route that carries any of those route target extended communities—A, B, or C—is imported into the VRF.

Figure 3 shows a sample configuration and its relationship to an mplsVpnVrfRouteTargetTable. A route target table exists on each PE router. Routers with route distinguishers (RDs) 100:1, 100:2, and 100:3 are shown in the sample configuration. Routers with RDs 100:4 and 100:5 are not shown in Figure 3, but are included in the route targets for PE2 and in the mplsVpnVrfRouteTargetTable.

Figure 3 Sample Configuration and the mplsVpnVrfRouteTargetTable

The mplsVpnVrfRouteTargetTable shows the import and export route targets for each VRF. The table is indexed by the following:

•mplsVpnVrfName—The VRF name

•mplsVpnVrfRouteTargetIndex—The route target entry identifier

•mplsVpnVrfRouteTargetType—A value specifying whether the entry is an import route target, export route target, or is defined as both

Table 4 lists the MIB objects and their functions for this table.

mplsVpnVrfBgpNbrAddrTable

The BGP neighbor address table (mplsVpnVrfBgpNbrAddrTable) represents the MPLS eBGP neighbors that are defined for a particular VRF. An LSR creates an entry for every BGP neighbor that is defined in the VRF's address-family.

The mplsVpnVrfBgpNbrAddrTable is indexed by the following:

•mplsVpnVrfName—The VRF name

•mplsVpnInterfaceConfIndex—An identifier that is the same as the ifIndex from the Interface MIB of the interface assigned to the VRF

•mplsVpnVrfBgpNbrIndex—The IP address of the neighbor

Table 5 lists the MIB objects and their functions for this table.

mplsVpnVrfSecTable

The VRF security table (mplsVpnVrfSecTable) provides information about security for each VRF. An LSR creates an entry in this table for every VRF capable of supporting MPLS VPN.

The mplsVpnVrfSecTable augments the mplsVpnVrfTable and has the same indexing.

Table 6 lists the MIB objects and their functions for this table.

mplsVpnVrfPerfTable

The VRF performance table (mplsVpnVrfPerfTable) provides statistical performance information for each VRF. An LSR creates an entry in this table for every VRF capable of supporting MPLS VPN.

The mplsVpnVrfPerfTable augments the mplsVpnVrfTable and has the same indexing.

Table 7 lists the MIB objects and their functions for this table.

mplsVpnVrfRouteTable

The VRF routing table (mplsVpnVrfRouteTable) provides the IP routing table information for each VRF. The information available in this table can also be accessed with the show ip route vrf vrf-name command. For example, for PE1 in Figure 1:

•With the show ip route vrf vpn1 command, you would see results like the following:

Router# show ip route vrf vpn1

Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area

* - candidate default, U - per-user static route, o - ODR 
P - periodic downloaded static route 
!

Gateway of last resort is not set

!

     10.0.0.0/32 is subnetted, 3 subnets

B       10.3.0.0 [200/0] via 192.168.2.1, 04:36:33

C       10.1.0.0/16 is directly connected, Ethernet1

C       10.2.0.0/16 [200/0] directly connected Ethernet2, 04:36:33

•With the show ip route vrf vpn2 command, you would see results like the following:

Router# show ip route vrf vpn2

Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area 

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area

* - candidate default, U - per-user static route, o - ODR 
P - periodic downloaded static route 
!

Gateway of last resort is not set

!

     172.16.0.0/32 is subnetted, 2 subnets

B       172.16.2.0 [200/0] via 192.168.2.1, 04:36:33

C       172.16.1.0 is directly connected, ATM 3/0

Figure 4 shows the relationship of the routing tables, the VRFs, and the mplsVpnVrfRouteTable. You can view information about the VPN1 and VPN2 route tables using the show ip route vrf vrf-name command. The global route table is the same as ipCidrRouteTable in the IP-FORWARD-MIB. You can view information about the global route table with the show ip route command.

Figure 4 Route Table, VRFs, and the mplsVpnVrfRouteTable

An LSR creates an entry in this table for every route that is configured, either dynamically or statically, within the context of a specific VRF capable of supporting MPLS VPN.

The mplsVpnVrfRouteTable is indexed by the following:

•mplsVpnVrfName—The VRF name, which provides the VRF routing context

•mplsVpnVrfRouteDest—The IP destination address

•mplsVpnVrfRouteMask—The IP destination mask

•mplsVpnVrfRouteTos—The IP header ToS bits

•mplsVpnVrfRouteNextHop—The IP address of the next hop for each route entry

Note The ToS bits are not supported and, therefore, are always 0.

Table 8 lists the MIB objects and their functions for the mplsVpnVrfRouteTable. This table represents VRF-specific routes. The global routing table is the ipCidrRouteTable in the IP-FORWARD-MIB.

Notifications

This section provides the following information about supported PPVPN-MPLS-VPN MIB notifications:

•PPVPN-MPLS-VPN MIB Notification Events

•Notification Specification

•Monitoring the PPVPN-MPLS-VPN MIB Notifications

PPVPN-MPLS-VPN MIB Notification Events

The following notifications of the PPVPN-MPLS-VPN MIB are supported:

•mplsVrfIfUp—Sent to an NMS when an interface comes up and is assigned a VPN routing/forwarding table instance (VRF).

•mplsVrfIfDown—Generated and sent to the NMS when a VRF is removed from an interface or the interface transitions from an operationally "up" state to a "down" state.

•mplsNumVrfRouteMidThreshExceeded—Generated and sent when the middle (warning) threshold is crossed. You can configure this threshold in the CLI by using the following commands:

Router(config)# ip vrf vrf-name

Router(config-vrf)# maximum routes limit warn-threshold (% of max)

The warn-threshold argument is a percentage of the maximum routes specified by the limit argument. You can also configure a middle threshold with the following command, in which the limit argument represents the warning threshold:

Router(config-vrf)# maximum routes limit warn-only

This notification is sent to the NMS only at the time the threshold is exceeded. (See Figure 5 for a comparison of the warning and maximum thresholds.) Whenever the number of routes falls below this threshold and exceeds the threshold again, a notification is sent to the NMS.

•mplsNumVrfRouteMaxThreshExceeded—Generated and sent when you attempt to create a route on a VRF that already contains the maximum number of routes as defined by the limit argument of the maximum routes commands:

Router(config)# ip vrf vrf-name

Router(config-vrf)# maximum routes limit warn-threshold (% of max)

A trap notification is sent to the NMS when you attempt to exceed the maximum threshold. Another mplsNumVrfRouteMaxThreshExceeded notification is not sent until the number of routes falls below the maximum threshold and reaches the maximum threshold again. (See Figure 5 for an example of how this notification works and for a comparison of the maximum and warning thresholds.)

Note The maximum routes command sets the number of routes for a VRF. You cannot exceed the number of routes in the VRF that you set with the maximum routes limit warn-threshold command.

Prior to this implementation of the PPVPN-MPLS-VPN MIB, you were not notified when this threshold (or the warning threshold) was reached.

•mplsNumVrfSecIllegalLabelThreshExceeded—Generated and sent when the amount of illegal labels received on a VRF interface exceeds the threshold mplsVpnVrfSecIllegalLabelRcvThresh. This threshold is defined with a value of 0. Therefore, a notification is sent when the first illegal label is received on a VRF. Labels are considered illegal if they are outside of the valid label range, do not have a Label Forwarding Information Base (LFIB) entry, or the table ID of the message does not match the table ID for the label in the LFIB.

CISCO-IETF-PPVPN-MPLS-VPN MIB Notification Events

The following notification of the CISCO-IETF-PPVPN-MPLS-VPN MIB is supported in Cisco IOS Release 12.0(30)S:

•cMplsNumVrfRouteMaxThreshCleared—Generated and sent when the number of routes on a VRF attempts to exceed the maximum number of routes and then drops below the maximum number of routes. If you attempt to create a route on a VRF that already contains the maximum number of routes, the mplsNumVrfRouteMaxThreshExceeded notification is sent (if enabled). When you remove routes from the VRF so that the number of routes falls below the set limit, the cMplsNumVrfRouteMaxThreshCleared notification is sent. You can clear all routes from the VRF by using the clear ip route vrf command. (See Figure 5 to see when the cMplsNumVrfRouteMaxThreshCleared notification is sent.)

Figure 5 Comparison of Warning and Maximum Thresholds

For information on the Cisco IOS CLI commands for configuring PPVPN-MPLS-VPN MIB notifications that are to be sent to an NMS, see the "How to Configure PPVPN MPLS VPN MIB" section and the "Feature Information for PPVPN MPLS VPN MIB" section.

Notification Specification

In an SNMPv1 notification, each VPN notification has a generic type identifier and an enterprise-specific type identifier for identifying the notification type.

•The generic type for all VPN notifications is "enterpriseSpecific" as this is not one of the generic notification types defined for SNMP.

•The enterprise-specific type is identified as follows:

–1 for mplsVrfIfUp

–2 for mplsVrfIfDown

–3 for mplsNumVrfRouteMidThreshExceeded

–4 for mplsNumVrfRouteMaxThreshExceeded

–5 for mplsNumVrfSecIllegalLabelThreshExceeded

–6 for cMplsNumVrfRouteMaxThreshCleared

In SNMPv2, the notification type is identified by an SnmpTrapOID varbind (variable binding consisting of an object identifier [OID] type and value) included within the notification message.

Each notification also contains two additional objects from the PPVPN-MPLS-VPN MIB. These objects provide additional information about the event, as follows:

•The VRF interface up/down notifications provide additional variables—mplsVpnInterfaceConfIndex and mplsVpnVrfName—in the notification. These variables describe the SNMP interface index and the VRF name, respectively.

•The mid and max threshold notifications include the mplsVpnVrfName variable (VRF name) as well as the mplsVpnVrfPerfCurrNumRoutes variable that indicates the current number of routes within the VRF.

•The illegal label notification includes the mplsVpnVrfName variable (VRF name) and the mplsVpnVrfSecIllegalLabelViolations variable that maintains the current count of illegal labels on a VPN.

Monitoring the PPVPN-MPLS-VPN MIB Notifications

When PPVPN-MPLS-VPN MIB notifications are enabled (see the snmp-server enable traps mpls vpn command), notification messages relating to specific MPLS VPN events within Cisco IOS software are generated and sent to a specified NMS in the network. Any utility that supports SNMPv1 or SNMPv2 notifications can receive notification messages.

To monitor PPVPN-MPLS-VPN MIB notification messages, log in to an NMS that supports a utility that displays SNMP notifications, and start the display utility.

MIB Objects Not Supported

The following objects from the mplsVpnVrfBgpPathAttrTable are not supported:

•mplsVpnVrfBgpPathAttrPeer

•mplsVpnVrfBgpPathAttrIpAddrPrefixLen

•mplsVpnVrfBgpPathAttrIpAddrPrefix

•mplsVpnVrfBgpPathAttrOrigin

•mplsVpnVrfBgpPathAttrASPathSegment

•mplsVpnVrfBgpPathAttrNextHop

•mplsVpnVrfBgpPathAttrMultiExitDisc

•mplsVpnVrfBgpPathAttrLocalPref

•mplsVpnVrfBgpPathAttrAtomicAggregate

•mplsVpnVrfBgpPathAttrAggregatorAS

•mplsVpnVrfBgpPathAttrAggregatorAddr

•mplsVpnVrfBgpPathAttrCalcLocalPref

•mplsVpnVrfBgpPathAttrBest

•mplsVpnVrfBgpPathAttrUnknown

How to Configure PPVPN MPLS VPN MIB

This section describes configuration tasks for PPVPN MPLS VPN MIB. Each task in the list is identified as either required or optional.

•Configuring the SNMP Community (required)

•Configuring the Router to Send SNMP Traps (required)

•Configuring Threshold Values for MPLS VPN—SNMP Notifications (required)

Configuring the SNMP Community

An SNMP community string defines the relationship between the SNMP manager and the agent. The community string acts like a password to regulate access to the agent on the router.

Perform this task to configure an SNMP community.

SUMMARY STEPS

1. enable

2. show running-config [options]

3. configure terminal

4. snmp-server community string [view view-name] [ro | rw] [acl-number]

5. do copy running-config startup-config

6. exit

7. show running-config [options]

DETAILED STEPS

Configuring the Router to Send SNMP Traps

Perform this task to configure the router to send traps to a host.

The snmp-server host command specifies which hosts receive traps. The snmp-server enable traps command globally enables the trap production mechanism for the specified traps.

For a host to receive a trap, an snmp-server host command must be configured for that host, and, generally, the trap must be enabled globally through the snmp-server enable traps command.

Note Although you can set the community-string argument using the snmp-server host command by itself, we recommend you define this string using the snmp-server community command before using the snmp-server host command.

SUMMARY STEPS

1. enable

2. configure terminal

3. snmp-server host host-addr [traps | informs] [version {1 | 2c | 3 [auth | noauth | priv]}] community-string [udp-port port] [notification-type] [vrf vrf-name]

4. snmp-server enable traps mpls vpn [illegal-label] [max-thresh-cleared] [max-threshold] [mid-threshold] [vrf-down] [vrf-up]

5. end

DETAILED STEPS

Configuring Threshold Values for MPLS VPN—SNMP Notifications

Perform this task to configure the following threshold values for MPLS VPN—SNMP notifications:

•The mplsNumVrfRouteMidThreshExceeded notification event is generated and sent when the middle (warning) threshold is crossed. You can configure this threshold in the CLI by using the maximum routes command in VRF configuration mode. This notification is sent to the NMS only at the time the threshold is exceeded. Whenever the number of routes falls below this threshold and exceeds the threshold again, a notification is sent to the NMS.

•The mplsNumVrfRouteMaxThreshExceeded notification event is generated and sent when you attempt to create a route on a VRF that already contains the maximum number of routes as defined by the maximum routes command in VRF configuration mode. A trap notification is sent to the NMS when you attempt to exceed the maximum threshold. Another mplsNumVrfRouteMaxThreshExceeded notification is not sent until the number of routes falls below the maximum threshold and reaches the maximum threshold again.

See Figure 5 for an example of how this notification works and for a comparison of the maximum and warning thresholds.

Note The maximum routes command sets the number of routes for a VRF. You cannot exceed the number of routes in the VRF that you set with the maximum routes limit warn-threshold command.

Prior to this implementation of the PPVPN-MPLS-VPN MIB, you were not notified when this threshold (or the warning threshold) was reached.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip vrf vrf-name

4. maximum routes limit {warn-threshold | warn-only}

5. end

DETAILED STEPS

Configuration Examples for PPVPN MPLS VPN MIB

This section contains the following configuration examples for the PPVPN MPLS VPN MIB feature:

•Configuring the SNMP Community: Examples

•Configuring the Router to Send SNMP Traps: Example

•Configuring Threshold Values for MPLS VPN—SNMP Notifications: Examples

Configuring the SNMP Community: Examples

The following example shows enabling a simple SNMP community group. This configuration permits any SNMP client to access all PPVPN-MPLS-VPN MIB objects with read-only access using the community string comaccess.

Router# configure terminal

Router(config)# snmp-server community comaccess ro

Verify that the SNMP master agent is enabled for the PPVPN MPLS VPN MIB feature:

Router# show running-config | include snmp-server

Building configuration... 

.... 

snmp-server community comaccess RO 

.... 

Note If you do not see any "snmp-server" statements, SNMP is not enabled on the router.

Configuring the Router to Send SNMP Traps: Example

The following example shows you how to enable the router to send MPLS VPN notifications to host 172.20.2.160 using the comaccess community string if a VRF transitions from an up or down state.

Router# configure terminal

Router(config)# snmp-server host 172.20.2.160 traps comaccess mpls-vpn

Router(config)# snmp-server enable traps mpls vpn vrf-up vrf-down

Configuring Threshold Values for MPLS VPN—SNMP Notifications: Examples

The following example shows how to set a maximum threshold of 10000 routes and a warning threshold that is 80 percent of the maximum threshold for a VRF named vpn1 on a router:

Router(config)# ip vrf vpn1

Router(config-vrf)# maximum routes 10000 80

The following example shows how to set a warning threshold of 10000 routes for a VRF named vpn2 on a router. An error message is generated; however, additional routes are still allowed because a maximum route threshold is not set with this command.

Router(config)# ip vrf vpn2

Router(config-vrf)# maximum routes 10000 warn-only

Additional References

The following sections provide references related to MPLS VPNs.

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Feature Information for PPVPN MPLS VPN MIB

Table 9 lists the features in this module and provides links to specific configuration information.

Not all commands may be available in your Cisco IOS software release. For details on when support for specific commands was introduced, see the command reference documents.

Cisco IOS software images are specific to a Cisco IOS software release, a feature set, and a platform. Use Cisco Feature Navigator to find information about platform support and Cisco IOS software image support. Access Cisco Feature Navigator at http://www.cisco.com/go/fn. You must have an account on Cisco.com. If you do not have an account or have forgotten your username or password, click Cancel at the login dialog box and follow the instructions that appear.

Note Table 9 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.

Any Internet Protocol (IP) addresses used in this document are not intended to be actual addresses. Any examples, command display output, and figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses in illustrative content is unintentional and coincidental.

© 2007 Cisco Systems, Inc. All rights reserved.