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Table Of Contents
MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
Prerequisites for MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
Restrictions for MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
Information About MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
Overview of MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
Protection and Why It Is Important
How to Configure MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
Establishing MPLS Backup AutoTunnels to Protect Fast Reroutable TE LSPs
Establishing One-Hop Tunnels to All Neighbors
Configuration Examples for MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
Establishing MPLS Backup AutoTunnels to Protect Fast Reroutable TE LSPs: Example
Establishing One-Hop Tunnels to Neighbors: Example
clear mpls traffic-eng auto-tunnel primary
mpls traffic-eng auto-tunnel backup
mpls traffic-eng auto-tunnel backup config
mpls traffic-eng auto-tunnel backup nhop-only
mpls traffic-eng auto-tunnel backup timers
mpls traffic-eng auto-tunnel backup tunnel-num
mpls traffic-eng auto-tunnel primary config
mpls traffic-eng auto-tunnel primary config mpls ip
mpls traffic-eng auto-tunnel primary onehop
mpls traffic-eng auto-tunnel primary timers
mpls traffic-eng auto-tunnel primary tunnel-num
Feature Information for MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
First Published: January 26, 2004Last Updated: May 31, 2007The MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup feature enables a router to dynamically build backup tunnels and to dynamically create one-hop primary tunnels on all interfaces that have been configured with Multiprotocol Label Switching (MPLS) traffic engineering (TE) tunnels.
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 (TE)—AutoTunnel Primary and Backup" 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.
Contents
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Prerequisites for MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
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Prerequisites for MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
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Restrictions for MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
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Information About MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
To configure autotunnel, you need to understand the following concepts:
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Overview of MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup has the following features:
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If no backup tunnels exist, the following types of backup tunnels are created:
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The MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup feature has the following benefits:
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MPLS Traffic Engineering
MPLS is an Internet Engineering Task Force (IETF)-specified framework that provides for the efficient designation, routing, forwarding, and switching of traffic flows through the network.
TE is the process of adjusting bandwidth allocations to ensure that enough bandwidth is left for high-priority traffic.
In MPLS TE, the upstream router creates a network tunnel for a particular traffic stream, then sets the bandwidth available for that tunnel.
Backup AutoTunnels
Without MPLS backup autotunnels, to protect a label-switched path (LSP) you had to do the following:
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An LSP requests backup protection from Resource Reservation Protocol (RSVP) FRR in the following situations:
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If there was no backup tunnel protecting the interface used by the LSP, the LSP remained unprotected.
Backup autotunnels enable a router to dynamically build backup tunnels when they are needed. This prevents you from having to build MPLS TE tunnels statically.
Backup tunnels may not be available for the following reasons:
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If a backup tunnel is not available, the following two backup tunnels are created dynamically:
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Link Protection
Backup tunnels that bypass only a single link of the LSP's path provide link protection. They protect LSPs if a link along their path fails by rerouting the LSP's traffic to the next hop (bypassing the failed link). These are referred to as NHOP backup tunnels because they terminate at the LSP's next hop beyond the point of failure. Figure 1 illustrates an NHOP backup tunnel.
Figure 1 Next-Hop Backup Tunnel
Node Protection
Backup tunnels that bypass next-hop nodes along LSP paths are called NNHOP backup tunnels because they terminate at the node following the next-hop node of the LSPs, thereby bypassing the next-hop node. They protect LSPs by enabling the node upstream of a link or node failure to reroute the LSPs and their traffic around the failure to the next-hop node. NNHOP backup tunnels also provide protection from link failures because they bypass the failed link and the node.
Figure 2 illustrates an NNHOP backup tunnel.
Figure 2 Next-Next Hop Backup Tunnel
Explicit Paths
Explicit paths are used to create backup autotunnels as follows:
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Range for Backup AutoTunnels
The tunnel range for backup autotunnels is configurable. By default, the last 100 TE tunnel IDs are used; that is 65,436 to 65,535. Autotunnels detect tunnel IDs that are being used. IDs are allocated starting with the lowest number.
Foe example, if you configure a tunnel range 1000 to 1100 and statically configured TE tunnel are in that range, routers do not use those IDs. If those static tunnels are removed, the MPLS TE dynamic tunnel software can use those IDs.
Primary AutoTunnels
The MPLS Traffic Engineering AutoTunnel Primary and Backup feature enables a router to dynamically create one-hop primary tunnels on all interfaces that have been configured with MPLS traffic. The tunnels are created with zero bandwidth. The constraint-based shortest path first (CSPF) is the same as the shortest path first (SPF) when using zero bandwidth, so the router's choice of the autorouted one-hop primary tunnel is the same as if there were no tunnel. Because it is a one-hop tunnel, the encapsulation is tag-implicit (that is, there is no tag header).
Explicit Paths
Explicit paths are used to create autotunnels as follows:
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Range for AutoTunnels
The tunnel range is configurable. By default, the last 100 TE tunnel IDs are used; that is 65,436 to 65,535. Autotunnels detect tunnel IDs that are being used. IDs are allocated starting with the lowest number.
For example, if you configure a tunnel range 100 to 200 and statically configured TE tunnels are in that range, routers do not use those IDs. If those static tunnels are removed, the IDs become available for use by the MPLS TE dynamic tunnel software.
Label-Based Forwarding
Routers receive a packet, determine where it needs to go by examining some fields in the packet, and send it to the appropriate output device. A label is a short, fixed-length identifier that is used to forward packets. A label switching device normally replaces the label in a packet with a new value before forwarding the packet to the next hop. For this reason, the forwarding algorithm is called label swapping. A label switching device, referred to as a label switch router (LSR), runs standard IP control protocols (that is, routing protocols, RSVP, and so forth) to determine where to forward packets.
Protection and Why It Is Important
This section describes the following:
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Delivery of Packets During a Failure
Backup tunnels that terminate at the NNHOP protect both the downstream link and node. This provides protection for link and node failures.
Multiple Backup Tunnels Protecting the Same Interface
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Scalability
A backup tunnel can protect multiple LSPs. Furthermore, a backup tunnel can protect multiple interfaces. This is called many-to-one (N:1) protection. N:1 protection has significant scalability advantages over one-to-one (1:1) protection, where a separate backup tunnel must be used for each LSP needing protection.
An example of N:1 protection is that when one backup tunnel protects 5000 LSPs, each router along the backup path maintains one additional tunnel.
An example of 1:1 protection is that when 5000 backup tunnels protect 5000 LSPs, each router along the backup path must maintain state for an additional 5000 tunnels.
RSVP Hello
RSVP Hello allows a router to detect when its neighbor has gone down but its interface to that neighbor is still operational. When Layer 2 link protocols are unable to detect that the neighbor is unreachable, Hellos provide the detection mechanism; this allows the router to switch LSPs onto its backup tunnels and avoid packet loss.
How to Configure MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
This sections contains the following procedures:
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Establishing MPLS Backup AutoTunnels to Protect Fast Reroutable TE LSPs
To establish an MPLS backup autotunnel to protect fast reroutable TE LSPs, perform the following steps.
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SUMMARY STEPS
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DETAILED STEPS
Establishing One-Hop Tunnels to All Neighbors
To establish one-hop tunnels to all neighbors, perform the following steps.
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SUMMARY STEPS
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DETAILED STEPS
Configuration Examples for MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
This section contains the following configuration examples:
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Establishing MPLS Backup AutoTunnels to Protect Fast Reroutable TE LSPs: Example
Note
To determine if there are any backup tunnels, enter the show ip rsvp fast-reroute command. This example shows that there is a static configured primary tunnel and no backup tunnels. For a description of the command output fields, refer to the "show ip rsvp fast-reroute" section.
Router(config)# show ip rsvp fast-reroutePrimary Protect BW BackupTunnel I/F BPS:Type Tunnel:Label State Level Type------ ------- ------- ------------ ------ ----- ----R3-PRP_t0 PO3/1 0:G None None NoneThe following command causes AutoTunnel to automatically configure NHOP and NNHOP backup tunnels:
Router(config)# mpls traffic-eng auto-tunnel backupAs illustrated in the show ip interface brief command output, AutoTunnel created two backup tunnels that have tunnel IDs 65436 and 65437:
Router# show ip interface briefInterface IP-Address OK? Method Status ProtocolPOS2/0 10.0.0.14 YES NVRAM down downPOS2/1 10.0.0.49 YES NVRAM up upPOS2/2 10.0.0.45 YES NVRAM up upPOS2/3 10.0.0.57 YES NVRAM administratively down downPOS3/0 10.0.0.18 YES NVRAM down downPOS3/1 10.0.0.33 YES NVRAM up upPOS3/2 unassigned YES NVRAM administratively down downPOS3/3 unassigned YES NVRAM administratively down downGigabitEthernet4/0 10.0.0.37 YES NVRAM up upGigabitEthernet4/1 unassigned YES NVRAM administratively down downGigabitEthernet4/2 unassigned YES NVRAM administratively down downLoopback0 10.0.3.1 YES NVRAM up upTunnel0 10.0.3.1 YES unset up upTunnel65436 10.0.3.1 YES unset up upTunnel65437 10.0.3.1 YES unset up upEthernet0 10.3.38.3 YES NVRAM up upEthernet1 unassigned YES NVRAM administratively down downR3-PRP#The following command prevents AutoTunnel from creating NNHOP backup tunnels:
Router# mpls traffic-eng auto-tunnel backup nhop-onlyThe "Type" field in the following show ip rsvp fast-reroute command shows that there is only an NHOP tunnel:
Router# show ip rsvp fast-reroutePrimary Protect BW BackupTunnel I/F BPS:Type Tunnel:Label State Level Type------ ------- -------- ------------- ------ ------- ----R3-PRP_t0 PO3/1 0:G Tu65436:24 Ready any-unl NhopThe following command changes the minimum and maximum tunnel interface numbers to 1000 and 1100, respectively:
Router# mpls traffic-eng auto-tunnel backup tunnel-num min 1000 max 1100You can verify the ID numbers and autotunnel backup range ID by entering the show ip rsvp fast-reroute and show ip interface brief commands. In this example, only one backup tunnel is protecting the primary tunnel:
Router# show ip rsvp fast-reroutePrimary Protect BW BackupTunnel I/F BPS:Type Tunnel:Label State Level Type------ ------- -------- ------------- ------ ----- ------R3-PRP_t0 PO3/1 0:G Tu1000:24 Ready any-unl NhopRouter# show ip interface briefInterface IP-Address OK? Method Status ProtocolPOS2/0 10.0.0.14 YES NVRAM down downPOS2/1 10.0.0.49 YES NVRAM up upPOS2/2 10.0.0.45 YES NVRAM up upPOS2/3 10.0.0.57 YES NVRAM administratively down downPOS3/0 10.0.0.18 YES NVRAM down downPOS3/1 10.0.0.33 YES NVRAM up upPOS3/2 unassigned YES NVRAM administratively down downPOS3/3 unassigned YES NVRAM administratively down downGigabitEthernet4/0 10.0.0.37 YES NVRAM up upGigabitEthernet4/1 unassigned YES NVRAM administratively down downGigabitEthernet4/2 unassigned YES NVRAM administratively down downLoopback0 10.0.3.1 YES NVRAM up upTunnel0 10.0.3.1 YES unset up upTunnel65436 10.0.3.1 YES unset up upEthernet0 10.3.38.3 YES NVRAM up upEthernet1 unassigned YES NVRAM administratively down downThe default tunnel range for autotunnel backup tunnels is 65,436 through 65,535. The following show ip rsvp fast-reroute command changes the tunnel range IDs:
Router# show ip rsvp fast-reroutePrimary Protect BW BackupTunnel I/F BPS:Type Tunnel:Label State Level Type------ ------- -------- ------------- ------ ----- ------R3-PRP_t0 PO3/1 0:G Tu1001:0 Ready any-unl N-NhopThe results are shown in the show ip interface brief command:
Router# show ip interfaceRouter# show ip interface briefInterface UP-Address OK? Method Status ProtocolPOS2/0 10.0.0.14 YES NVRAM down downPOS2/1 10.0.0.49 YES NVRAM up upPOS2/2 10.0.0.45 YES NVRAM up upPOS2/3 10.0.0.57 YES NVRAM up upPOS3/0 10.0.0.18 YES NVRAM up upPOS3/1 10.0.0.33 YES NVRAM up upPOS3/2 unassigned YES NVRAM administratively down downPOS3/3 unassigned YES NVRAM administratively down downLoopback0 10.0.3.1 YES NVRAM up upTunnel0 10.0.3.1 YES unset up upTunnel1000 10.0.3.1 YES unset up upTunnel1001 10.0.3.1 YES unset up upEthernet0 10.3.38.3 YES NVRAM up upEthernet1 unassigned YES NVRAM administratively down downThe following mpls traffic-eng auto-tunnel backup timers removal unused command specifies that a timer will scan backup autotunnels every 50 seconds and the timer will remove tunnels that are not being used:
Router(config)# mpls traffic-eng auto-tunnel backup timers removal unused 50The following mpls traffic-eng auto-tunnel backup config unnumbered-interface command enables IP processing on interface POS3/1:
Router(config)# mpls traffic-eng auto-tunnel backup config unnumbered-interface POS3/1To verify that IP processing is enabled on POS3/1, enter the show interfaces tunnel command:
Router# show interfaces tunnel 1001Tunnel1001 is up, line protocol is upHardware is TunnelInterface is unnumbered. Using address of POS3/1 (10.0.0.33)MTU 1514 bytes, BW 9 Kbit, DLY 500000 usec, rely 255/255, load 1/255Encapsulation TUNNEL, loopback not setKeepalive not setTunnel source 10.0.0.0, destination 10.0.5.1Tunnel protocol/transport Label Switching, sequencing disabledKey disabledChecksumming of packets disabledLast input never, output never, output hang neverLast clearing of "show interface" counters neverQueueing strategy: fifoOutput queue 0/0, 0 drops; input queue 0/75, 0 drops5 minute input rate 0 bits/sec, 0 packets/sec5 minute output rate 0 bits/sec, 0 packets/sec0 packets input, 0 bytes, 0 no bufferReceived 0 broadcasts, 0 runts, 0 giants, 0 throttles0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort0 packets output, 0 bytes, 0 underruns0 output errors, 0 collisions, 0 interface resets0 output buffer failures, 0 output buffers swapped outEstablishing One-Hop Tunnels to Neighbors: Example
For AutoTunnel to automatically create primary tunnels to all next hops, you must enter the following command:
Router(config)# mpls traffic-eng auto-tunnel primary onehopIn this example there are four primary tunnels and no backup tunnels. To verify that configuration, enter the show ip rsvp fast-reroute command and the show ip interface brief command:
Router# show ip rsvp fast-reroutePrimary Protect BW BackupTunnel I/F BPS:Type Tunnel:Label State Level Type------ ------- -------- ------------- ------ ----- ------R3-PRP_t65337 PO2/2 0:G None None NoneR3-PRP_t65338 PO3/1 0:G None None NoneR3-PRP_t65339 Gi4/0 0:G None None NoneR3-PRP_t65336 PO2/1 0:G None None NoneRouter# show ip interface briefInterface IP-Address OK? Method Status ProtocolPOS2/0 10.0.0.14 YES NVRAM down downPOS2/1 10.0.0.49 YES NVRAM up upPOS2/2 10.0.0.45 YES NVRAM up upPOS2/3 10.0.0.57 YES NVRAM administratively down downPOS3/0 10.0.0.18 YES NVRAM down downPOS3/1 10.0.0.33 YES NVRAM up upPOS3/2 unassigned YES NVRAM administratively down downPOS3/3 unassigned YES NVRAM administratively down downGigabitEthernet4/0 10.0.0.37 YES NVRAM up upGigabitEthernet4/1 unassigned YES NVRAM administratively down downGigabitEthernet4/2 unassigned YES NVRAM administratively down downLoopback0 10.0.3.1 YES NVRAM up upTunnel0 10.0.3.1 YES unset administratively down downTunnel65336 10.0.3.1 YES unset up upTunnel65337 10.0.3.1 YES unset up upTunnel65338 10.0.3.1 YES unset up upTunnel65339 10.0.3.1 YES unset up upEthernet0 10.3.38.3 YES NVRAM up upEthernet1 unassigned YES NVRAM administratively down downR3-PRP#The default tunnel range for primary autotunnels is 65,336 through 65,435. The following mpls traffic-eng auto-tunnel primary tunnel-num command changes the range to 2000 through 2100:
Router(config)# mpls traffic-eng auto-tunnel primary tunnel-num min 2000 max 2100The following sample output from the show ip rsvp fast-reroute command and the show ip interface brief command shows that the tunnel IDs are 2000, 2001, 2002, and 2003:
Router# show ip rsvp fast-reroutePrimary Protect BW BackupTunnel I/F BPS:Type Tunnel:Label State Level Type------ ------- -------- ------------- ------ ----- ------R3-PRP_t2001 PO2/2 0:G None None NoneR3-PRP_t2002 PO3/1 0:G None None NoneR3-PRP_t2003 Gi4/0 0:G None None NoneR3-PRP_t2000 PO2/1 0:G None None NoneRouter# show ip interface briefInterface IP-Address OK? Method Status ProtocolPOS2/0 10.0.0.14 YES NVRAM down downPOS2/1 10.0.0.49 YES NVRAM up upPOS2/2 10.0.0.45 YES NVRAM up upPOS2/3 10.0.0.57 YES NVRAM administratively down downPOS3/0 10.0.0.18 YES NVRAM down downPOS3/1 10.0.0.33 YES NVRAM up upPOS3/2 unassigned YES NVRAM administratively down downPOS3/3 unassigned YES NVRAM administratively down downGigabitEthernet4/0 10.0.0.37 YES NVRAM up upGigabitEthernet4/1 unassigned YES NVRAM administratively down downGigabitEthernet4/2 unassigned YES NVRAM administratively down downLoopback0 10.0.3.1 YES NVRAM up upTunnel0 10.0.3.1 YES unset administratively down downTunnel2000 10.0.3.1 YES unset up upTunnel2001 10.0.3.1 YES unset up upTunnel2002 10.0.3.1 YES unset up upTunnel2003 10.0.3.1 YES unset up upEthernet0 10.3.38.3 ' YES NVRAM up upEthernet1 unassigned YES NVRAM administratively down downThe following mpls traffic-eng auto-tunnel primary timers command specifies that a timer will scan backup autotunnels every 50 seconds and remove tunnels that are not being used:
Router(config)# mpls traffic-eng auto-tunnel primary timers removal rerouted 50The following mpls traffic-eng auto-tunnel primary config unnumbered command enables IP processing on interface POS3/1:
Router(config)# mpls traffic-eng auto-tunnel primary config unnumbered POS3/1To specify that AutoTunnel remove all primary autotunnels and re-create them, enter the following command:
Router(config)# clear mpls traffic-eng auto-tunnel primaryAdditional References
The following sections provide references related to the MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup feature.
Related Documents
Backup tunnels
MPLS Traffic Engineering (TE) Link and Node Protection, with RSVP Hellos Support, Release 12.2(33)S
Link protection
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MPLS traffic engineering
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Standards
No new or modified standards are supported by this release and support for existing standards has not been modified by this feature.
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MIBs
RFCs
No new or modified RFCs are supported by this release and support for existing RFCs has not been modified by this feature.
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Technical Assistance
Command Reference
This section documents only commands that are new or modified.
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clear mpls traffic-eng auto-tunnel primary
To remove all the primary autotunnels and re-create them, use the clear mpls traffic-eng auto-tunnel primary command in global configuration mode.
clear mpls traffic-eng auto-tunnel primary
Syntax Description
This command has no arguments or keywords.
Command Default
None
Command Modes
Global configuration
Command History
Examples
The following example removes all primary autotunnels and re-creates them:
Router# clear mpls traffic-eng auto-tunnel primaryRelated Commands
show ip rsvp fast-reroute
Displays information about fast reroutable primary tunnels and their corresponding backup tunnels that provide protection.
mpls traffic-eng auto-tunnel backup
To automatically build next-hop (NHOP) and next-next hop (NNHOP) backup tunnels, use the mpls traffic-eng auto-tunnel backup command in global configuration mode. To delete the NHOP and NNHOP backup tunnels, use the no form of this command.
mpls traffic-eng auto-tunnel backup
no mpls traffic-eng auto-tunnel backup
Syntax Description
This command has no arguments or keywords.
Command Default
None
Command Modes
Global configuration
Command History
Usage Guidelines
The no form of this command deletes both NHOP and NNHOP backup tunnels that were configured using either the mpls traffic-eng auto-tunnel backup command or the mpls traffic-eng auto-tunnel backup nhop-only command.
Examples
The following example automatically builds NHOP and NNHOP backup tunnels:
Router# mpls traffic-eng auto-tunnel backupRelated Commands
mpls traffic-eng auto-tunnel backup config
To enable IP processing without an explicit address, use the mpls traffic-eng auto-tunnel backup config command in global configuration mode. To disable IP processing without an explicit address, use the no form of this command.
mpls traffic-eng auto-tunnel backup config unnumbered-interface interface
no mpls traffic-eng auto-tunnel backup config unnumbered-interface interface
Syntax Description
unnumbered-interface interface
Interface on which IP processing will be enabled without an explicit address. Default: Loopback0.
Command Default
None
Command Modes
Global configuration
Command History
Examples
The following example enables IP processing on an Ethernet interface without an explicit address:
Router# mpls traffic-eng auto-tunnel backup config unnumbered-interface ethernet1/0Related Commands
mpls traffic-eng auto-tunnel backup nhop-only
To automatically build next-hop (NHOP) backup tunnels, use the mpls traffic-eng auto-tunnel backup nhop-only command in global configuration mode. To delete the NHOP backup tunnels, use the no form of this command.
mpls traffic-eng auto-tunnel backup nhop-only
no mpls traffic-eng auto-tunnel backup nhop-only
Syntax Description
This command has no arguments or keywords.
Command Default
The dynamically created backup tunnel uses Loopback0.
Command Modes
Global configuration
Command History
Usage Guidelines
This command permits the creation of only NHOP backup tunnels; next-next hop (NNHOP) backup tunnels are not created. The no form of this command deletes only the NHOP backup tunnels; NNHOP backup tunnels are not deleted.
Examples
The following example enables the creation of only dynamic NHOP backup tunnels:
Router# mpls traffic-eng auto-tunnel backup nhop-onlyRelated Commands
mpls traffic-eng auto-tunnel backup timers
To configure how frequently a timer will scan backup autotunnels and remove tunnels that are not being used, use the mpls traffic-eng auto-tunnel backup timers command in global configuration mode. To disable this configuration, use the no form of this command.
mpls traffic-eng auto-tunnel backup timers removal unused [sec]
no mpls traffic-eng auto-tunnel backup timers removal unused [sec]
Syntax Description
removal unused sec
Configures how frequently (in seconds) a timer will scan the backup autotunnels and remove tunnels that are not being used. Valid values are 0 to 604,800.
Command Default
The timer scans backup autotunnels and removes tunnels that are not being used every 3600 seconds (60 minutes).
Command Modes
Global configuration
Command History
Examples
The following example shows that a timer will scan backup autotunnels every 80 seconds and remove tunnels that are not being used:
Router# mpls traffic-eng auto-tunnel backup timers removal unused 80Related Commands
mpls traffic-eng auto-tunnel backup tunnel-num
To configure the range of tunnel interface numbers for backup autotunnels, use the mpls traffic-eng auto-tunnel backup tunnel-num command in global configuration mode. To disable this configuration, use the no form of this command.
mpls traffic-eng auto-tunnel backup tunnel-num [min num] [max num]
no mpls traffic-eng auto-tunnel backup tunnel-num [min num] [max num]
Syntax Description
Command Default
None
Command Modes
Global configuration
Command History
Examples
The following example configures the range of backup autotunnel numbers to be between 1000 and 1100:
Router# mpls traffic-eng auto-tunnel backup tunnel-num min 1000 max 1100Related Commands
mpls traffic-eng auto-tunnel primary config
To enable IP processing without an explicit address, use the mpls traffic-eng auto-tunnel primary config command in global configuration mode. To disable this capability, use the no form of this command.
mpls traffic-eng auto-tunnel primary config unnumbered interface
no mpls traffic-eng auto-tunnel primary config unnumbered interface
Syntax Description
Command Default
Loopback0
Command Modes
Global configuration
Command History
Examples
The following example enables IP processing on an Ethernet interface:
Router# mpls traffic-eng auto-tunnel primary config unnumbered ethernet1/0Related Commands
mpls traffic-eng auto-tunnel primary config mpls ip
To enable Label Distribution Protocol (LDP) on primary autotunnels, use the mpls traffic-eng auto-tunnel primary config mpls ip command in global configuration mode. To disable LDP on primary autotunnels, use the no form of this command.
mpls traffic-eng auto-tunnel primary config mpls ip
no mpls traffic-eng auto-tunnel primary config mpls ip
Syntax Description
This command has no arguments or keywords.
Command Default
LDP is not enabled.
Command Modes
Global configuration
Command History
Examples
The following example enables LDP on primary autotunnels:
Router# mpls traffic-eng auto-tunnel primary config mpls ipRelated Commands
mpls traffic-eng auto-tunnel primary onehop
To automatically create primary tunnels to all next hops, use the mpls traffic-eng auto-tunnel primary onehop command in global configuration mode. To disable the automatic creation of primary tunnels to all next hops, use the no form of this command.
mpls traffic-eng auto-tunnel primary onehop
no mpls traffic-eng auto-tunnel primary onehop
Syntax Description
This command has no arguments or keywords.
Command Default
The dynamically created one-hop tunnels use Loopback0.
Command Modes
Global configuration
Command History
Examples
The following example automatically creates primary tunnels to all next hops:
Router# mpls traffic-eng auto-tunnel primary onehopRelated Commands
mpls traffic-eng auto-tunnel primary timers
To configure how many seconds after a failure primary autotunnels are removed, use the mpls traffic-eng auto-tunnel primary timers command in global configuration mode. To disable this configuration, use the no form of this command.
mpls traffic-eng auto-tunnel primary timers removal rerouted sec
no mpls traffic-eng auto-tunnel primary timers removal rerouted sec
Syntax Description
removal rerouted sec
Number of seconds after a failure that primary autotunnels are removed. Valid values are 30 to 604,800. Default: 0.
Command Default
None
Command Modes
Global configuration
Command History
Examples
The following example shows that primary autotunnels are removed 100 seconds after a failure:
Router# mpls traffic-eng auto-tunnel primary timers removal rerouted 100Related Commands
mpls traffic-eng auto-tunnel primary tunnel-num
To configure the range of tunnel interface numbers for primary autotunnels, use the mpls traffic-eng auto-tunnel primary tunnel-num command in global configuration mode. To disable this configuration, use the no form of this command.
mpls traffic-eng auto-tunnel primary tunnel-num [min num] [max num]
no mpls traffic-eng auto-tunnel primary tunnel-num [min num] [max num]
Syntax Description
Command Default
None
Command Modes
Global configuration
Command History
Examples
The following example shows that the primary tunnel numbers can be between 2000 and 2100:
Router# mpls traffic-eng auto-tunnel primary tunnel-num min 2000 max 2100Related Commands
show ip rsvp fast-reroute
To display information about fast reroutable primary tunnels and their corresponding backup tunnels that provide protection, use the show ip rsvp fast-reroute command in privileged EXEC mode.
show ip rsvp fast-reroute
Syntax Description
This command has no arguments or keywords.
Command Default
None
Command Modes
Privileged EXEC
Command History
Examples
The following example displays information about fast reroutable primary tunnels and their corresponding backup tunnels that provide protection:
Router# show ip rsvp fast-reroutePrimary Protect BW BackupTunnel I/F BPS:Type Tunnel:Label State Level Type------ ------- -------- ------------- ------ ----- ---GSR1---R2---_t65336 PO1/0 0:G Tu1002:0 Ready any-unl NhopGSR1---R2---_t65338 PO4/0 0:G Tu1004:0 Ready any-unl NhopTable 1 describes the significant fields shown in the display.
Related Commands
Feature Information for MPLS Traffic Engineering (TE)—AutoTunnel Primary and Backup
Table 2 lists the release history for this feature.
Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Note
Glossary
backup tunnel—An MPLS traffic engineering tunnel used to protect other (primary) tunnel's traffic when a link or node failure occurs.
egress router—A router at the edge of the network where packets are leaving.
Fast Reroute—Fast Reroute (FRR) is a mechanism for protecting MPLS traffic engineering (TE) LSPs from link and node failure by locally repairing the LSPs at the point of failure, allowing data to continue to flow on them while their headend routers attempt to establish end-to-end LSPs to replace them. FRR locally repairs the protected LSPs by rerouting them over backup tunnels that bypass failed links or nodes.
hop—Passage of a data packet between two network nodes (for example, between two routers).
interface—A network connection.
IP address—A 32-bit address assigned to hosts using TCP/IP. An IP address belongs to one of five classes (A, B, C, D, or E) and is written as four octets separated by periods (dotted decimal format). Each address consists of a network number, an optional subnetwork number, and a host number. The network and subnetwork numbers together are used for routing, and the host number is used to address an individual host within the network or subnetwork. A subnet mask is used to extract network and subnetwork information from the IP address.
IP explicit path—A list of IP addresses, each representing a node or link in the explicit path.
LDP—Label Distribution Protocol. A standard protocol between MPLS-enabled routers to negotiate the labels (addresses) used to forward packets.
link—Point-to-point connection between adjacent nodes.
LSP—label-switched path. A path that is followed by a labeled packet over several hops, starting at an ingress LSR and ending at an egress LSR.
LSR—label switch router. A Layer 3 router that forwards a packet based on the value of a label encapsulated in the packet.
MPLS—Multiprotocol Label Switching. A method for forwarding packets (frames) through a network. It enables routers at the edge of a network to apply labels to packets. ATM switches or existing routers in the network core can switch packets according to the labels with minimal lookup overhead.
node—Endpoint of a network connection or a junction common to two or more lines in a network. Nodes can be interconnected by links, and serve as control points in the network.
penultimate router—The second-to-last router; that is, the router that is immediately before the egress router.
primary tunnel—An MPLS tunnel whose LSP can be fast rerouted if there is a failure.
router—A network layer device that uses one or more metrics to determine the optimal path along which network traffic should be forwarded. Routers forward packets from one network to another based on network layer information.
router ID—Something by which a router originating a packet can be uniquely distinguished from all other routers. For example, an IP address from one of the router's interfaces.
scalability—An indicator showing how quickly some measure of resource usage increases as a network gets larger.
traffic engineering—The techniques and processes used to cause routed traffic to travel through the network on a path other than the one that would have been chosen if standard routing methods had been used.
tunnel—A secure communication path between two peers, such as two routers. A traffic engineering tunnel is a label-switched tunnel that is used for traffic engineering. Such a tunnel is set up through means other than normal Layer 3 routing; it is used to direct traffic over a path different from the one that Layer 3 routing could cause the tunnel to take.
Note
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All other trademarks mentioned in this document or Website are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (0705R)
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© 2004—2007 Cisco Systems, Inc. All rights reserved.
