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EOS 4.33.2F User Manual - RSVP-TE LER 印刷

RSVP-TE LER

RSVP-TE, the Resource Reservation Protocol (RSVP) for Traffic Engineering (TE), distributes MPLS labels for steering traffic and reserving bandwidth. The Label Edge Router (LER) feature implements the headend functionality, such as RSVP-TE tunnels originating at an LER and used to steer traffic into the tunnel.

To Configure RSVP-TE LER

To configure RSVP-TE LER, use the Router Traffic Engineering Configuration Mode to configureRSVP-TE LER.

Example
switch(config)# router traffic-engineering
switch(config-te)# rsvp
switch(config-te-rsvp)

In the Router Traffic Engineering Configuration Mode, the configuration has three components:

  • Global configuration
  • Path specifications
  • Tunnel specifications

Global Configuration

In the global configuration, all settings apply to all configured tunnels. Path specifications describe a set of constraints for paths. These are referenced from tunnel specifications to describe the path of each tunnel.

Path Specifications

Path specifications can be explicit and dynamic depending on the Constrained Shortest Path First (CSPF) search procedure to find a path in the network topology known to the headend. A path specification with certain name can only be either explicit or dynamic, and as such, share a namespace.

Explicit Path Specifications

In an explicit path specification, the operator provides all hops in the path explicitly. The given path is used directly as the Explicit Route Object (ERO) in RSVP Path messages. All hops are implicitly strict hops. Explicit loose hops are not supported.

Example

Enter the Router Traffic Engineering Configuration Mode to configure explicit paths by specifying the name and the explicit keyword.
switch(config-te-rsvp)# path MyPath explicit
switch(config-te-rsvp-path-expl-MyPath)#

To explicitly specify the order of each hop, use the RSVP-TE explicit path configuration mode. In this example, hop 10.0.12.2. then hop 10.0.34.4 is specified.

Example
switch(config-te-rsvp-path-expl-MyPath)# hop 10.0.12.2
switch(config-te-rsvp-path-expl-MyPath)# hop 10.0.34.4

Adding hops with before and after keywords creates a unique internal ordering represented in a canonical form using either before or after in the show running-config.

Example

Using the keyword before, the configuration places hop 10.0.23.3 before 10.0.34.4. Then, using the keyword after the configuration places hop 10.0.45.5 after 10.0.34.4.
switch(config-te-rsvp-path-expl-MyPath)# hop 10.0.23.3 before 10.0.34.4
switch(config-te-rsvp-path-expl-MyPath)# hop 10.0.45.5 after 10.0.34.4

When you no longer need to have a hop order, use the no hop command.

Example

Use the no hop 10.0.12.2 command when removing hops.
switch(config-te-rsvp-path-expl-MyPath)# no hop 10.0.12.2

The show active command displays the current configuration

Example

Retrieve the currently active configuration using the show active command. 
switch(config-te-rsvp-path-expl-MyPath)# show active
router traffic-engineering
   rsvp
      path MyPath explicit
         hop 10.0.23.3
         hop 10.0.34.4
         hop 10.0.45.5

Example

Retrieve the pending configuration that becomes active after exiting the submode with the show pending command.

switch(config-te-rsvp-path-expl-MyPath)# show pending
   hop 10.0.23.3
   hop 10.0.44.4
   hop 10.0.45.5

Example

The show diff command displays the differences between the show active and show pending commands. 

switch(config-te-rsvp-path-expl-MyPath)# show diff
 hop 10.0.23.3
-hop 10.0.34.4
+hop 10.0.44.4
 hop 10.0.45.5
switch(config-te-rsvp-path-expl-MyPath)#

To keep all your saved changes, use the exit command.

Example

The change in the submode only takes effect when exiting the submode normally.
switch(config-te-rsvp-path-expl-MyPath)# exit
switch(config-te-rsvp)#

To reject all changes, use the abort command.

Example

The abort command discards all changes.
switch(config-te-rsvp-path-expl-MyPath)# abort
switch(config-te-rsvp)#

Dynamic Path Specifications

In a dynamic path specification, the operator provides constraints that a Constained Shortest Path First (CSPF) procedure finds a path in the network topology. Effectively, the path specification serves as a template to get instantiated together with other tunnel constraints, such as bandwidth requirements. The CSPF result is a list of strict hops which form the ERO.

Example

Enter the submode to configure dynamic paths by specifying the name of the path, in this example MyPath, and use the dynamic keyword.
switch(config-te-rsvp)# path MyPath dynamic
switch(config-te-rsvp-path-dyn-MyPath)#

Exclude hop constraints specifies that CSPF must not choose the selected address on the path. Each excluding hops expresses that neither end of a link in the path may have the specified address. Note that other interfaces on the same node may be used.

Example

This example excludes hop 10.0.56.6.
switch(config-te-rsvp-path-dyn-MyPath)# hop 10.0.56.6 exclude

Include hop constraints are supported and specify that these hops must be included in the computed path in a certain order. By default, a hop is strict, meaning that in the computed path, it has to appear directly after the previously specified hop. When a hop is loose it allows other hops to be filled by the CSPF procedure. The keywords before and after apply to the explicit paths.

Example

In the following example hop 10.0.23.3 must be included in the path.

switch(config-te-rsvp-path-dyn-MyPath)# hop 10.0.23.3

In the following example hop 10.0.45.5 loose shows the hop does not have to be in any particular order.

switch(config-te-rsvp-path-dyn-MyPath)# hop 10.0.45.5 loose

The following example shows hop 10.0.12.2 comes before 10.0.23.3. 

switch(config-te-rsvp-path-dyn-MyPath)# hop 10.0.12.2 before 10.0.23.3

The following example shows hop 10.0.67.7 comes loose after 10.0.45.5.

switch(config-te-rsvp-path-dyn-MyPath)# hop 10.0.67.7 loose after 10.0.45.5

Specify administrative group constraints to restrict CSPF path computation to links that match a set of admin groups.IDs are globally significant and the specification contains lists and ranges of admin groups to include or exclude. In particular, every chosen link for a dynamic path must be in all of the admin groups specified in the include all range, must be in one of the admin groups specified in the include any range, and must not be in any of those in the exclude range. The admin group range starts at 0 and ends at 31. On the wire, the admin-group of 0 is translated to 0x1, 1 is translated to 0x2.

Example

In this example include 1 and anything between 2-4, and exclude 7 and 9.
switch(config-te-rsvp-path-dyn-MyPath)# administrative-group include all 1 include any 2-4 exclude 7,9

Specify administrative group constraints using a name as an alias mapped to a numerical value. Configure the mapping under the global TE mode.

Use these names to configure administrative group constraints in addition to the existing numerical format. Configure the admin group constraints for the dynamic path using the following RSVP LER commands:

Example

In this example the administartive-group includes all blue and anything between 2-4 red, and excludes 7 green.
switch(config-te-rsvp-path-dyn-MyPath)# administrative-group include all blue include any 2-4,red exclude green,7

The list of administrative groups is provided as a comma-separated input without spaces.

Local Interface

Use the local-interface Loopback command to derive the source IP address for RSVP-TE tunnels. This is a mandatory setting.

Example
switch(config-te-rsvp)# local-interface Loopback 0

A few settings use the global mpls rsvp configuration like Fast-Reroute (FRR) mode and soft preemption. The SRLG setting from the global mpls rsvp configuration is also used to specify if the secondary path of a tunnel is set up by excluding SRLGs of all the links in the primary path as additional constraints, therefore allowing the secondary path to be disjoint from the primary path.

Tunnel Specifications

A tunnel needs a specification of which tunnel to go to.

Example

In this example, MyTunnel is the name of the submode tunnel to use.
switch(config-te-rsvp)# tunnel MyTunnel
switch(config-te-rsvp-tunnel-MyTunnel)#

Basic Tunnel Configuration

Each tunnel must have a tunnel destination IP.

Example

The this example the selected destination IP is 10.2.2.2.
switch(config-te-rsvp-tunnel-MyTunnel)# destination ip 10.2.2.2

Adding Path Specifications

A tunnel needs to specify the path to establish LSPs. Therefore, a path specification is referenced by its name and configures the primary LSP.

Example

The specified name for the path is MyPath.
switch(config-te-rsvp-tunnel-MyTunnel)# path MyPath

A secondary LSP is specified which provides a fallback in case the primary LSP is not available. The secondary LSP is either established on-demand cold standby once the primary is not available or pre-signaled hot standby regardless. Configuring a secondary path is optional.

Example

To configure the secondary path, in this example, use the name MyOtherPathas a secondary path and configure it as pre-signaled path.
switch(config-te-rsvp-tunnel-MyTunnel)# path MyOtherPath secondary pre-signaled

Only one secondary path can be configured, per tunnel.

Bandwidth Specification

Use the bandwidth command to reserve bandwidth along the path.

Example

In this example, select a bandwidth of 10 mbps as the reserve bandwidth for the myTunnel tunnel path.
switch(config-te-rsvp-tunnel-myTunnel)# bandwidth 10 mbps

Available units are bps, kbps, mbps, and gbps. By default, no bandwidth reservation is signaled, such as a bandwidth of0 bps.

Use the autobandwidth feature as an alternative to explicit bandwidth configuration as the autobandwidth specifies the minimum and maximum bandwidth to be used for the tunnel and otherwise adjusts bandwidth with an adjustment period based on the observed traffic going over the tunnel. The adjustment period is an optional parameter measured in seconds. The default adjustment period is 0 . Use a special value to allow the algorithm to decide when to adjust bandwidth based on statistical measurements (the actual adjustment cannot happen more frequently than the sampling, which occurs every 30 seconds).

Example

In this example, set the bandwidth to auto with a minimum of 1 mbps and a maximum of 5 mbps, and has an adjustment-period of 60 seconds.
switch(config-te-rsvp-tunnel-myTunnel)# bandwidth auto min 1 mbps max 5 mbps adjustment-period 60

The adjustment period is specified in seconds.

Tunnel Priorities

Configure setup and hold priorities from 0 to 7 with 0 meaning most preferred, and 7 least preferred.

Example

In this example, configure the setup priority with a value of 5 and the hold priority as 3.
switch(config-te-rsvp-tunnel-myTunnel)# priority setup 5 hold 3

The CLI does not impose restrictions on the priority values. Therefore, hold priority should be more preferred than setup priority to avoid cycles where an LSP is continuously established and immediately preempted.

Enabling The Tunnel

You must explicitly enable the tunnel.

Example

Use the no shutdown command to explicitly enable the tunnel.
switch(config-te-rsvp-tunnel-MyTunnel)# no shutdown

As for path specifications, the submode provides show active, show pending and show diff commands. It has abort/commit semantics.

When you want to keep all your saved changes, use the exit command.

Example

Exit the submode to implement the changes.
switch(config-te-rsvp-tunnel-MyTunnel)# exit
switch(config-te-rsvp)#

Example

The abort command discards all changes.
switch(config-te-rsvp-tunnel-MyTunnel)# abort
switch(config-te-rsvp)#

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