Table Of Contents
MPLS Traffic Engineering—Fast Reroute MIB
First Published: March 30, 2001Last Updated: May 31, 2007
The MPLS Traffic Engineering—Fast Reroute MIB provides Simple Network Management Protocol (SNMP)-based network management of the Multiprotocol Label Switching (MPLS) Fast Reroute (FRR) feature in Cisco IOS software.
The Fast Reroute MIB has the following features:
•Notifications can be created and queued.
•Command-line interface (CLI) commands enable notifications, and specify the IP address to where the notifications will be sent.
•The configuration of the notifications can be written into nonvolatile memory.
The MIB includes objects describing features within MPLS FRR, and it includes the following tables:
The MIB also includes scalar objects (that is, objects that are not in a table). For more information, see the "FRR MIB Scalar Objects" section.
Finding Feature Information in This Module
Your Cisco IOS software release may not support all of the features documented in this module. To reach links to specific feature documentation in this module and to see a list of the releases in which each feature is supported, use the "Feature Information for MPLS Traffic Engineering—Fast Reroute MIB" section.
Finding Support Information for Platforms and Cisco IOS and Catalyst OS Software Images
Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for the MPLS Traffic Engineering—Fast Reroute MIB
•The network must support the Intermediate System-to-Intermediate System (IS-IS) or Open Shortest Path First (OSPF) protocol.
•The SNMP is installed and enabled on the label switch routers (LSRs).
•MPLS is enabled globally on each LSR.
•Cisco Express Forwarding is enabled on the LSRs.
•Traffic engineering (TE) tunnels are enabled.
•MPLS FRR is enabled on one of the TE tunnels.
•The Resource Reservation Protocol (RSVP) is enabled.
Restrictions for the MPLS Traffic Engineering—Fast Reroute MIB
•The implementation of the FRR MIB is limited to read-only (RO) permission for MIB objects.
•Configuration of the FRR MIB using the SNMP SET command is not supported in Cisco IOS Release 12.2(33)SRA or in prior releases.
•The following tables are not implemented in the specified releases:
–mplsFrrOne2OnePlrTable—Not implemented in Cisco IOS Release 12.2(33)SRA or in prior releases.
–mplsFrrDetourTable—Not implemented in Cisco IOS Release 12.2(33)SRA or in prior releases.
–cmplsFrrLogTable—Not implemented in Cisco IOS Release 12.2(33)SRA.
Information About the MPLS Traffic Engineering—Fast Reroute MIB
To use the MPLS Traffic Engineering—Fast Reroute MIB, you need to understand the following concepts:
Feature Design of the MPLS Traffic Engineering—Fast Reroute MIB
The FRR MIB enables standard, SNMP-based network management of FRR in Cisco IOS software. This capability requires that SNMP agent code executes on a designated network management station (NMS) in the network. The NMS serves as the medium for user interaction with the network management objects in the MIB.
The FRR MIB is based on the Internet Engineering Task Force (IETF) draft MIB specification draft-ietf-mpls-fastreroute-mib-02.txt. The IETF draft MIB, which undergoes revisions periodically, is evolving toward becoming a standard. The Cisco implementation of the FRR MIB is expected to track the evolution of the IETF draft MIB, and may change accordingly.
Slight differences between the IETF draft MIB and the implementation of FRR within Cisco IOS software require some minor translations between the FRR MIB objects and the internal data structures of Cisco IOS software. These translations are accomplished by the SNMP agent, which runs in the background on the NMS workstation as a low priority process and provides a management interface to Cisco IOS software.
You can use an SNMP agent to access FRR MIB objects using standard SNMP GET operations. All the objects in the FRR MIB follow the conventions defined in the IETF draft MIB.
Functional Structure of the MPLS Traffic Engineering—Fast Reroute MIB
The SNMP agent code supporting the FRR 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 basis for the generated code is the Cisco version of the FRR MIB CISCO-ietf-frr-mib.
The SNMP agent code, which has a layered structure that is common to MIB support code in Cisco IOS software, consists of the following layers:
•Platform-independent layer—This layer is generated primarily by the MIB development Cisco IOS tool set and incorporates platform- and implementation-independent functions. These functions handle SNMP standard functionality in the context of the specific MIB. This layer handles indexes and range or enumeration value checks for GET, GET-NEXT, and SET SNMP operations. A function is generated for each SNMP table or group of objects. This layer calls into the next layer.
•Application interface layer—The Cisco IOS tool set generates the function names and template code for MIB objects.
•Application-specific layer—This layer provides the mechanism for retrieving relevant data from the managed application layer. It includes an entry point function for each table. This function calls two other functions; one that searches the TE tunnel database that RSVP maintains for the relevant data according to the indexes, and another function that fills the data into the structure.
•Managed application layer—This layer includes all the structures and mechanisms, and is managed by the MIB.
System Flow of SNMP Protocol Requests and Response Messages
All SNMP protocol requests and response messages are ultimately handled by the SNMP master agent. When such a message is received on a router, the master agent parses the requests and identifies the MIB to which the request refers. The master agent then queries the subagent responsible for the MIB with a GET, GET-NEXT, or SET request. The FRR MIB subagent retrieves the appropriate data, and returns it to the master agent. The master agent is then responsible for returning an SNMP response to the NMS. All queries occur within the IP SNMP Cisco IOS process, which runs as a low priority task.
FRR MIB Scalar Objects
Scalar objects are objects that are not in tables. A scalar object has one instance (that is, one occurrence).
Table 1 describes the FRR MIB scalar objects supported in Cisco IOS Release 12.2(33)SRA and in prior releases.
FRR MIB Notifications
Notifications are issued after particular FRR events occur. This section provides the following information about FRR MIB notifications supported in Cisco IOS Release 12 2(33)SRA and in prior releases:
Notification Generation Events
When you enable FRR MIB notification functionality by issuing the snmp-server enable traps mpls fast-reroute command, notification messages are generated and sent to a designated NMS in the network to signal the occurrence of specific events in Cisco IOS software.
The FRR MIB objects involved in FRR status transitions and event notifications include cmplsFrrProtected. This message is sent to an NMS if there is a major TE tunnel change (that is, fast rerouting of TE tunnels).
Each FRR notification has a generic type identifier and an enterprise-specific type identifier for identifying the notification type. The generic type for all FRR notifications is "enterprise Specific" because this is not one of the generic notification types defined for SNMP. The enterprise-specific type is 1 for cmplsFrrProtected.
Each notification contains the following objects from the FRR MIB so that the FRR tunnel can be easily identified:
•ifIndex of the broken tunnel
•ifIndex of the protecting tunnel
•ifIndex of the protecting tunnel instance
Upon being invoked, the appropriate FRR interface indexes have already been retrieved by existing FRR code. The FRR interfaces are then used to fill in data for the three objects included in the notification.
When FRR MIB notifications are enabled (see the snmp-server enable traps command), notification messages relating to specific FRR events within Cisco IOS software are generated and sent to a specified NMS in the network. Any utility that supports SNMPv1 or SNPv2 notifications can receive notification messages.
To monitor FRR MIB notifications, log in to an NMS that supports a utility that displays SNMP notifications, and start the display utility.
MIB Tables in the MPLS Traffic Engineering—Fast Reroute MIB
The FRR MIB consists of the following tables:
The tables access various data structures to obtain information regarding detours, the FRR database, and logging.
cmplsFrrConstTable displays the configuration of an FRR-enabled tunnel and the characteristics of its accompanying backup tunnels. For each protected tunnel, there can be multiple backup tunnels.
The table is indexed by the following:
•cmplsFrrConstIfIndex—The interface on which the protected tunnel is configured
•cmplsFrrConstTunnelIndex—The SNMP interface index
•cmplsFrrConstTunnelInstance—The tunnel instance
Table 2 describes the MIB objects for cmplsFrrConstTable.
Note cmplsFrrLogTable and the show mpls traffic-eng fast-reroute log reroutes command are not supported in Cisco IOS Release 12.2(33)SRA.
cmplsFrrLogTable is indexed by the object cmplsFrrLogIndex. The index corresponds to a log entry in the FRR feature's show mpls traffic-eng fast-reroute log reroutes command. That show command stores up to 32 entries at a time. If entries are added, the oldest entry is overwritten with new log information.
cmplsFrrLogTable can store up to 32 entries at a time, overwriting older entries as newer ones are added. The index cmplsFrrLogIndex is incremented to give each log table entry of the MIB a unique index value. Therefore, it is possible to have indexes greater than 32 even though only 32 entries are displaying.
Table 3 describes the MIB objects for cmplsFrrLogTable.
The following indexes specify which interface and tunnel are being protected by the FRR feature:
The following indexes specify the backup tunnel that provides protection to the protected tunnel:
This implementation will attempt to leverage the work already done for the MPLS TE MIB because it contains similar lookup functions for TE tunnels.
Table 4 describes the MIB objects for cmplsFrrFacRouteDBTable.
How to Configure the MPLS Traffic Engineering—Fast Reroute MIB
This section contains the following procedures:
•Enabling Cisco Express Forwarding (required)
•Enabling MPLS Globally on Each LSR (required)
•Enabling TE Tunnels (required)
•Enabling MPLS FRR on Each TE Tunnel (required)
•Enabling a Backup Tunnel on an Interface (required)
Enabling the SNMP Agent for FRR MIB Notifications
To enable the SNMP agent for FRR MIB notifications, perform the following steps.
2. show running-config
3. configure terminal
4. snmp-server community string [view view-name] [ro] [access-list-number]
5. snmp-server enable traps mpls fast-reroute protected
7. write memory
Enabling Cisco Express Forwarding
To enable Cisco Express Forwarding, perform the following steps.
2. configure terminal
3. ip cef distributed
Enabling MPLS Globally on Each LSR
To enable MPLS globally on each LSR, perform the following steps.
2. configure terminal
3. mpls ip
Enabling TE Tunnels
To enable TE tunnels, perform the following steps.
2. configure terminal
3. ip cef
4. mpls traffic-eng tunnels
Enabling MPLS FRR on Each TE Tunnel
To enable MPLS FRR on each TE tunnel, perform the following steps.
2. configure terminal
3. tunnel mpls traffic-eng fast-reroute
Enabling a Backup Tunnel on an Interface
To enable a backup tunnel on an interface, perform the following steps.
2. configure terminal
3. mpls traffic-eng backup-path tunnel interface
Configuration Examples for the MPLS Traffic Engineering—Fast Reroute MIB
Enabling an SNMP Agent on a Host NMS: Example
The following example shows how to enable an SNMP agent on the host NMS:enableshow running-configconfigure terminalsnmp-server community public rosnmp-server enable traps mpls fast-reroute protectedendwrite memory
Enabling Cisco Express Forwarding: Example
The following example shows how to enable Cisco Express Forwarding:enableconfigure terminalip cef distributedend
Enabling MPLS Globally on Each LSR: Example
The following example shows how to enable MPLS globally on each LSR:enableconfigure terminalmpls ipend
Enabling TE Tunnels: Example
The following example shows how to enable traffic engineering tunnels:enableconfigure terminalip cefmpls traffic-eng tunnelsend
Enabling MPLS FRR on Each TE Tunnel: Example
The following example shows how to enable MPLS Fast Reroute on each TE tunnel:enableconfigure terminaltunnel mpls traffic-eng fast-rerouteend
Enabling a Backup Tunnel on an Interface: Example
The following example shows how to enable a backup tunnel on an interface:enableconfigure terminalmpls traffic-eng backup-path tunnel1end
The following sections provide references related to the MPLS Traffic Engineering—Fast Reroute MIB feature.
Related Topic Document Title
SNMP agent support for the MPLS Traffic Engineering MIB (MPLS TE MIB)
MPLS Traffic Engineering (TE)--Fast Reroute (FRR) Link and Node Protection, Release 12.2(33)SRA
MIB MIBs Link
MPLS Traffic Engineering (TE) MIB
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:
Multiprotocol Label Switching (MPLS) Traffic Engineering Management Information Base for Fast Reroute
This feature uses no new or modified commands.
Feature Information for MPLS Traffic Engineering—Fast Reroute MIB
Table 5 lists the release history for this feature.
Cisco Express Forwarding—An advanced Layer 3 IP switching technology. Cisco Express Forwarding optimizes network performance and scalability for networks with large and dynamic traffic patterns.
index—A method of uniquely identifying a tunnel.
instance—An occurrence. An object can have one or more instances.
IS-IS—Intermediate System-to-Intermediate System. OSI link-state hierarchical routing protocol based on DECnet Phase V routing whereby ISs (routers) exchange routing information based on a single metric to determine network topology.
label—A short, fixed-length data construct that tells switching nodes how to forward data (packets or cells).
LFIB—Label Forwarding Information Base. The data structure for storing information about incoming and outgoing tags (labels) and associated equivalent packets suitable for labeling.
LSR—label switching router. A device that forwards MPLS packets based on the value of a fixed-length label encapsulated in each packet.
MIB—Management Information Base. A database of network management information that is used and maintained by a network management protocol such as Simple Network Management Protocol (SNMP). The value of a MIB object can be changed or retrieved by using SNMP commands, usually through a network management system. MIB objects are organized in a tree structure that includes public (standard) and private (proprietary) branches.
NMS—network management station. A powerful, well-equipped computer (typically an engineering workstation) that is used by a network administrator to communicate with other devices in the network. An NMS is typically used to manage network resources, gather statistics, and perform a variety of network administration and configuration tasks.
notification—A message sent by a Simple Network Management Protocol (SNMP) agent to a network management station, console, or terminal to indicate that a significant event within Cisco IOS software has occurred.
object—A variable that has a specific instance associated with it.
OSPF—Open Shortest Path First. Link-state, hierarchical Interior Gateway Protocol (IGP) routing algorithm proposed as a successor to Routing Information Protocol (RIP) in the Internet community. OSPF features include least-cost routing, multipath routing, and load balancing. OSPF was derived from an early version of the IS-IS protocol.
RSVP—Resource Reservation Protocol. Protocol for reserving network resources to provide quality of service (QoS) guarantees to application flows.
scalar object—Objects that are not instances. A scalar object has one instance.
SNMP—Simple Network Management Protocol. A network management protocol used almost exclusively in TCP/IP networks. SNMP provides a means to monitor and control network devices, manage configurations, collect statistics, monitor performance, and ensure network security.
SNMP agent—A managed node or device. The router that has the MIB implementation on it.
Note See the Internetworking Terms and Acronyms for terms not included in this glossary.
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