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Add Diverse Tunnels

When creating a route between two sites, you might not want to rely on a single tunnel to send traffic from one site to another. By creating a second tunnel (routing path) between the two sites, you can protect your network against failures and balance the network load.

Note:
  • If the PCE is unable to achieve the diversity level you request, it still creates the diverse tunnel pair, using a diversity level as close as possible to the level you requested.

  • By default, the PCE does not reroute a diverse tunnel pair when there is a network outage. For diverse tunnels to be rerouted, you can use the Path Optimization feature (Network > Topology > Path Optimization) and schedule path optimization to occur at regular intervals.

  • When provisioning diverse tunnels, the PCE might return an error if the value you specified in the Site field on the Edit Node page (Network > Topology > Node tab > Edit icon) contains special characters. Hence, we recommend using alphanumeric characters only.

To add diverse tunnels:

  1. Select Network > Topology.

    The Topology page is displayed with the topology map at the center and the network information table at the bottom of the page.

  2. In the Tunnel tab, select Provisioning > Diverse tunnels.

    The Add Diverse Tunnels page appears.

  3. Complete the configuration on each tab of the Add Diverse Tunnels page according to the guidelines in Table 1.
    Note:

    Fields marked with an asterisk (*) are mandatory.

  4. (Optional) Click Preview Paths at the bottom of the page to see the paths drawn on the topology map.
  5. Click Add to add the tunnels.

    A confirmation message appears on the top of the page, indicating that an add tunnel request was successfully created:

    • If you have the Auto-approve permission assigned to your user role, the request is automatically approved and deployed on the devices.
    • If you don't have Auto-approve permission, the request must be manually approved and then, deployed. See About the Change Control Management Page.

    The tunnels then appear in the Tunnel tab of the network information table (in the Topology page).

Table 1: Fields on the Add Diverse Tunnels Page

Field

Description

Properties

Provisioning Method

From the list, select one of the following methods to be used to provision the tunnel:

  • NETCONF (default)—The tunnels are statically provisioned and the associated configuration statements appear in the router configuration file. Upon provisioning, these tunnels are added as device-controlled tunnels.

  • PCEP (Path Computation Element Protocol)—The tunnels are initiated by the path computation element (PCE) and the associated configuration statements do not appear in the router configuration file. Upon provisioning, these tunnels are added as PCE-initated tunnels.

Note:

For IOS-XR routers, NETCONF-based tunnel provisioning has the same capabilities as PCEP-based tunnel provisioning.

Provisioning Type

From the list, select the type of tunnel that you want to provision:

  • RSVP
  • Segment Routing (SR)
  • SRv6

Diversity Group

Specify the name of a group of tunnels to which this tunnel belongs, and for which diverse paths are desired.

Diversity Level

From the list, select the level of diversity for the tunnel:

  • Default—No diversity level is applied.

  • Site—Two paths don’t intersect at any given site (aside from the source and destination). Site diversity is the strongest as it includes SRLG and link diversity.

  • SRLG (Shared Risk Link Group)—Two paths don't intersect at any of the group’s links or nodes (aside from the source and destination). SRLG diversity includes link diversity.

    Note:

    If two paths are SRLG-diverse, the paths will not be routed over links which are in the same SRLG. The SRLGs can be learned from network protocols such as BGP-LS and NETCONF. The SRLGs can change dynamically and are displayed in the SRLG/Facility tab in the network information table. If the links become part of the same SRLG, the previously computed tunnels are no more diverse. In this scenario, new tunnels will not be automatically computed and applied in the network. You must manually select each tunnel (from the Tunnel tab) that is no longer diverse and request reprovisioning (Tunnel tab > Provisioning > Reprovision).

  • Link—Two paths don’t intersect at any given link. Link diversity is the weakest.

Tunnel 1

Note:

The same fields are available for Tunnel 2. Use the same guidelines to configure the fields for Tunnel 2.

Name

Specify a unique name for the first tunnel. You can use any number of alphanumeric characters, hyphens, and underscores.

Node A

From the list, select the node that you want to use as the ingress node.

Node Z

From the list, select the node that you want to use as the egress node.

IP Z

From the list, select the IP address for Node Z (that is, the egress node).

The options in the list are populated based on the Node Z that you selected.

Admin Status

The PCS uses the administration status of the tunnel to decide whether to route or provision, or both route and provision the tunnel.

If the tunnel is routed, no traffic flows through the tunnel and its operational status is Up. If the tunnel is provisioned, traffic flows through the tunnel and its operational status is Active.

Select one of the following options as the administration status:

  • Up—If you select this option, the PCS routes and provisions the tunnel.

  • Planned—If you select this option, the PCS routes the tunnel and reserves capacities for the tunnel. However, the PCS doesn’t provision the tunnel.

  • Shutdown—If you select this option, the PCS neither routes nor provisions the tunnel. The tunnel is maintained in the datastore and is associated with a persist state so that the tunnel can be brought back up at a later time, if required.

Planned Bandwidth

Specify the planned bandwidth (along with valid units, with no space between the bandwidth and units) for the tunnel.

If you specify a value without units, bps is applied.

The valid units are:

  • B or b

  • M or m

  • K or k

  • G or g

Examples: 50M, 1000b, 25g.

Planned Metric

Specify the static tunnel metric.

The PCE uses this metric to route the tunnel instead of allowing the router itself to choose a path.

Bandwidth Sizing

Note:

This option is displayed only when you select PCEP as the provisioning method.

Click the toggle button to enable bandwidth sizing for the tunnel.

If enabled, the tunnel is included in the periodic re-computation of planned bandwidth based on aggregated tunnel traffic statistics.

If you enable bandwidth sizing, you must configure the following parameters:

  • Adjustment Threshold

  • Minimum Bandwidth

  • Maximum Bandwidth

  • Minimum Variation Threshold

Adjustment Threshold (%)

Note:

This option is available only when you enable bandwidth sizing.

Specify the sensitivity (in %) of the automatic bandwidth adjustment.

The new planned bandwidth is considered only if it differs from the existing bandwidth by the value of this setting or more. The default value is 10%.

Minimum Bandwidth

Note:

This option is available only when you enable bandwidth sizing.

Specify the minimum planned bandwidth (along with valid units, with no space between the bandwidth and units) for the tunnel. If you specify a value without units, bps is applied.

If the new planned bandwidth is less than the minimum setting, the PCE signals the tunnel with the minimum bandwidth. However, if the new planned bandwidth falls in between the maximum and minimum settings, the PCE signals the tunnel with the new planned bandwidth.

The valid units are:

  • B or b

  • M or m

  • K or k

  • G or g

Examples: 50M, 1000b, 25g.

Maximum Bandwidth

Note:

This option is available only when you enable bandwidth sizing.

Specify the maximum planned bandwidth (along with valid units, with no space between the bandwidth and units) for the tunnel. If you specify a value without units, bps is applied.

If the new planned bandwidth is greater than the maximum setting, the PCE signals the tunnel with the maximum bandwidth. However, if the new planned bandwidth falls in between the maximum and minimum settings, the PCE signals the tunnel with the new planned bandwidth.

The valid units are:

  • B or b

  • M or m

  • K or k

  • G or g

Examples: 50M, 1000b, 25g.

Minimum Variation Threshold

Note:

This option is available only when you enable bandwidth sizing.

Specify the sensitivity of the automatic bandwidth adjustment when the new planned bandwidth is compared to the current planned bandwidth.

Default: Zero.

The new planned bandwidth is only considered if the difference is greater than or equal to the value of this setting. Because it is not a percentage, this can be used to prevent small fluctuations from triggering unnecessary bandwidth changes.

If both the adjustment threshold and the minimum variation threshold are greater than zero, both settings are taken into consideration. In that case, the new planned bandwidth is considered if the percentage difference is greater than or equal to the adjustment threshold, and, the actual difference is greater than or equal to the minimum variation.

Color Community

Note:

This field is available only for segment routing tunnels.

Assign a color for the segment routing tunnel that can be used to map traffic on the tunnel.

Use Penultimate Hop as Signaling Address

Note:

This field is available only for segment routing tunnels.

Click the toggle button to enable the PCS to use the penultimate hop as the signaling address for Egress Peer Engineering (EPE).

If you haven’t specified a color community, the setting applies to all traffic. If you’ve specified a color community, the setting applies to traffic in that color community.

Setup

Specify the setup priority for the tunnel traffic.

Priority levels range from 0 (highest priority) through 7 (lowest priority). The default is 7, which is the standard MPLS tunnel definition in Junos OS.

Based on the setup priority, the PCE determines whether a new tunnel can be established, by preempting an existing tunnel. The existing tunnel can be preempted if the setup priority of the new tunnel is higher than that of the existing tunnel and the preemption releases enough bandwidth for the new tunnel.

Hold

Specify the hold priority for the tunnel traffic.

Priority levels range from 0 (highest priority) through 7 (lowest priority). The default is 7, which is the standard MPLS tunnel definition in Junos OS.

Based on the hold priority, the PCE determines whether the tunnel can be preempted or not. If the hold priority for an tunnel is higher, it is unlikely for the tunnel to be preempted.

Routing Method

From the list, select a routing method for the tunnel to specify whether the PCE should compute and provision the path for the tunnel, or not :

The available options are:

  • routeByDevice—This is the default routing method when a PCC-controlled tunnel is created or learned by the PCE. For this method, the PCE does not compute and provision a path.

    This method is appropriate for three types of tunnels: RSVP TE PCC-controlled tunnels, segment routing Path Computation Element Protocol-based tunnels, and segment routing NETCONF-based tunnels.

  • Other routing methods (default, delay, adminWeight, constant, distance, ISIS, OSPF)—When a PCC-controlled tunnel has a routing method that is not routeByDevice, the PCE computes and provisions the path as a strict explicit route when provisioning the tunnel. The tunnel’s existing explicit route might be modified to a the PCE-computed strict explicit route. For example, a loose explicit route specified by you or learned from the router would be modified to a strict explicit route.

Constraints

Note:

The same fields are available for Tunnel 2. Use the same guidelines to configure the fields for Tunnel 2.

Tunnel 1

Admin Group Include All

From the list, select one or more admin group bits for the tunnel to traverse links that include all of the admin groups specified in this field. You can select a maximum of 32 admin group bits.

The admin group bits are mapped to meaningful names, such as colors (configured in the Configuration > Network > Admin Group page), so that you can easily differentiate the different traffic routes in the display and also use coloring constraints to influence the path of the tunnel.

Admin Group Include Any

From the list, select one or more admin group bits for the tunnel to traverse links that include at least one of the admin groups specified in this field. The maximum selections allowed is 32.

Admin Group Exclude

From the list, select one or more admin group bits for the tunnel to traverse links that do not include any of the admin groups specified in this field. The maximum selections allowed is 32.

Advanced

Note:

The same fields are available for Tunnel 2. Use the same guidelines to configure the fields for Tunnel 2.

Tunnel 1

Description

Specify a comment or description for the tunnel for your reference.

Symmetric Pair Group

Specify a unique name for the symmetric pair group. You can use any number of alphanumeric and special characters.

tunnels with the same group name (as specified in this field) are considered part of a symmetric pair group.

You create a symmetric pair group so that the tunnel from the ingress node to the egress node follows the same path as the tunnel from the egress node to the ingress node. When there are two tunnels with the same end nodes but in opposite directions, the path routing uses the same set of links. For example, suppose Tunnel1 source to destination is NodeA to NodeZ, and Tunnel2 source to destination is NodeZ to NodeA. Selecting Tunnel1-Tunnel2 as a symmetric pair group places both tunnels along the same set of links. Tunnels in the same group are paired based on the source and destination node.

Create Symmetric Pair

Note:

This option is displayed only when you specify a symmetric pair group.

Click the toggle button to enable the creation of a symmetric pair.

This option allows you to create the symmetric pair in the same operation as creating the diverse tunnel.

Custom Attributes

Click the Add icon (+) to specify provisioning properties not directly supported by the GUI.

For example, you cannot specify a hop-limit when you provision a tunnel. However, you can add hop-limit as a custom attribute.

At the edit > protocols > mpls > label-switched-path hierarchy level in the NETCONF template file, you must add the statements needed to provision with the property you are adding. If the property is present with the defined value, then the provisioning statement is executed.

Schedule

Plan

  • No Schedule—(Default) tunnel provisioning is not scheduled (that is, tunnels are provisioned immediately upon submission of the provisioning request).

  • Once—In the Start and End fields that appear, specify the start date and time and end date and time at which you want to provision the tunnels. The tunnels are provisioned once at the specified date and time.

  • Recurring Daily—Specify the start and end dates and start and end times in the Start Date, End Date, Start Time, and End Time fields that appear. The tunnels are provisioned daily.