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The EPE Planner Application in the Web UI



The EPE Planner application in the NorthStar Controller UI is built on the NorthStar EPE functionality and is designed for the formulation of plans to minimize the cost of traffic destined for peers. You can use it to plan how to steer traffic into tunnels, taking costs into consideration, and generally manage the EPE planning and execution workflow.

You work in planning sessions called “projects”. A session begins with a “current plan”, represented by a snapshot of the live network. From there, you formulate plan changes, along with step-by-step execution plans to make the proposed changes safely in the network. Ultimately, you can execute the plans in the live network.

This topic introduces you to the EPE Planner UI. See Understanding the EPE Planner Application for information on traffic steering concepts and how the EPE Planner works.

Start a Project - Get the Current EPE Plan

Launch the EPE Planner application by navigating to Applications > EPE Planner. The application window opens. If you already have active projects, they are listed in this window. To start a new project, click Create Project in the upper right corner. The Create EPE Planner Project window is displayed as shown in Figure 1.

Figure 1: Create EPE Planner Project Window
Create EPE Planner Project

Complete the fields in this window (see Table 1).

Table 1: Create EPE Planner Project Window Field Descriptions



Project Name

Required. The name used to identify the planning session.

Unassigned Traffic Penalty

Required. Used to weight the cost of the traffic that is not engineered by a plan (unassigned traffic). The cost of unassigned traffic is the sum of the bandwidth for that traffic times the unassigned penalty.

The default is 100000. The higher the value, the greater the cost of unassigned traffic.

Note: The default is deliberately high in order to keep the EPE Planner from changing all traffic to unassigned. You can lower the value as needed.

Excess PeerLink Rate

If a change plan assigns more traffic to a peer link than the maximum peering cost bound, then this cost factor is used to rate the excess traffic. See Peering Costs in Understanding the EPE Planner Application for more information.

Keep For (Minutes)

The number of minutes for which the planning session remains active. The current plan becomes out of sync with the live network over time, so planning would be invalid if the current plan gets old. The default is 180 minutes.

Once you have completed the form, click Submit. Your new project is displayed in a “card” on the main EPE Planner window, as shown in Figure 2. If you have multiple active projects, they are all displayed there. Searching and sorting functions are available in the upper right corner of the window to help you locate a particular project.

Figure 2: Project “Card” in the EPE Planner Main Window
Project “Card” in
the EPE Planner Main Window

The information displayed for each project includes the time window in which the project will be available. The Number of Traffic, Total Bandwidth, and Cost fields are all null for new projects because no planning has taken place yet.

To proceed with the planning session, click Load at the bottom of the project card. The project loads an EPE network and associated current plan which is created based on a snapshot of the live network’s demands, tunnels, links, and nodes. This snapshot is your starting place. See Figure 3 for an example of the initial display.

Figure 3: Current Plan Topology and Detail Display
Current Plan Topology and
Detail Display

There are two tabs in this window: Detail and Topology (the default initial display) and Plan Changes.

In the Detail and Topology tab, the following features are available:

  • The topology elements are arranged with PEs on the left, peer links in the middle, and prefixes on the right. The size and color of elements in the topology are significant:

    • Relative Gb/s is represented by size. Larger has more bandwidth, smaller has less.

    • Relative cost is represented by color. Red is expensive, green is not, and blue is in between.

  • The peer links in the middle are represented by a dot inside a circle:

    • The dot represents the actual use of the peer link.

    • The circle represents the traffic available for EPE.

    • When the dot and circle are nearly the same size, the peer link is close to capacity. If the dot becomes larger than the circle, the peer link is overloaded.

  • Tunnels are shown connecting PEs to peer links. External routes are shown connecting peer links to prefixes. Thick red tunnels/external routes cost more than thinner green tunnels/external routes.

  • Unsteered (unassigned) traffic is shown as connecting directly from a PE to a prefix without being routed through a peer link in between.

  • To the right of the display are buttons to center the topology (bullseye icon), zoom in (+ symbol), zoom out (minus symbol), and open the topology Settings window (gear icon).


    You can also zoom in and out using your mouse if it is equipped with a wheel.

  • The topology settings available in the NorthStar Controller 5.1.0 release are:

    • Show Tooltips

      When tooltips are enabled, you can mouse over an element in the topology to display information about that element, as shown in Figure 4.

      Figure 4: Tooltips Example
      Tooltips Example
    • Show Labels

      When labels are enabled, the elements in the topology are labeled as shown in Figure 5.

      Figure 5: Labels Example
      Labels Example

    Click the check box to enable or disable tooltips or labels.

  • Drag-and-drop functionality is supported for arranging elements in the topology display.

  • The Details window is minimized initially, but you can slide it into view by clicking the arrow in the upper right corner of the display as shown in Figure 6.

    Figure 6: Click the Arrow to Display Details
    Click the Arrow to Display Details

    Initially, the Details window, as shown in Figure 7, has two tabs: PE/PeerLink/Prefix and Traffic Assignments.

    Figure 7: Details Window Example, PE/PeerLink/Prefix Tab
    Details Window Example,
PE/PeerLink/Prefix Tab

    Click an element in the Details window to highlight it in the topology. To hide the Details window, click the arrow in the upper right corner again.

Use the Plan Changes tab to instruct the EPE Planner to find potential plan changes that meet the criteria you specify, and to view the results. This is discussed further in Find Plan Changes.

Find Plan Changes

Use the EPE Planner as a tool to find plan changes that could improve the performance of the EPE plan in your network. Click the Plan Changes tab to begin; the Find Plan Changes window is displayed. Use the Free Traffic Test drop-down menu to specify what currently-assigned traffic the EPE Planner application is free to move as it searches for improvements to the current plan. The choices are shown in Figure 8.

Figure 8: Free Traffic Test Options
Free Traffic Test

Fields for additional criteria are also displayed, depending on the free traffic test you select, but there is always a field in which to specify a time limit for searching for and improving upon the current plan.

Once you complete the criteria fields, click Find Plan Changes. Possible plan changes appear in the table below the criteria fields, displaying their:

  • Cost ($)

  • Cost Change (%)

  • Number of Traffic Changes

  • Number of Tunnel Changes

  • Number of Peer Link Changes

  • Bandwidth Moved (Xb/s)

In the Load column, click the check box beside a plan change you want to consider implementing. The display switches to the Detail and Topology view and the plan change information is displayed to the left of the topology. Below the plan change information is an Execution Plan section where you will build your step-by-step execution plan. This is described further in Create Execution Plan Steps.

Once a plan change is loaded, the Detail window shows both current and optimized bandwidth and cost so you can see what would be gained or lost. Elements in the Details window (PE/PeerLink/Prefix or Traffic Assignments tab) that show as red would get bigger/more expensive. Elements that show as green would get smaller/less expensive. This information should help you decide whether the change should be executed. When a plan change is loaded, a third tab (Execution Plan Steps) becomes available on the Details window. Figure 9 shows an example of the Details window at this stage.

Figure 9: Current/Optimized Bandwidth and Cost Example
Current/Optimized Bandwidth
and Cost Example

There is nothing in the Execution Plan Steps tab until you start building your execution plan. See Create Execution Plan Steps.

Right-click on the topology and select Animate Plan Change to see the topology elements change as they go from the current plan to the new plan. You can also use the right-click menu to open a pop-up window displaying a Sankey diagram. In a Sankey diagram, the width of the bands is proportional to the volume of traffic. An example Sankey diagram is shown in Figure 10.

Figure 10: Sankey Diagram Example
Sankey Diagram Example

The Sankey diagram uses the same color scheme used in the plan topology. Animate the Sankey diagram using the arrow buttons in the upper right corner.

Create Execution Plan Steps

Once you have selected a plan change to work with and the Execution Plan fields are displayed below the Plan Change details on the left side of the window, you can start building your execution plan, step by step. An execution plan is a way of breaking down the plan change into steps that are smaller, safely executable plan changes. The goal is to create an execution plan that implements the whole plan change, but you can also create partial execution plans that only implement some of the overall plan change.

The execution plan updates LSP bandwidths and bindings in the network until the new plan is achieved. You control this by specifying which of the remaining traffic changes not already in a step should be included in the next step.

Use the Traffic Change Test drop-down menu (lower left corner of the window) to select how the EPE Planner should evaluate whether each of the remaining traffic changes should be included in the next step. Figure 11 shows the traffic change test options that are available.

Figure 11: Traffic Change Test Options for Execution Plan Steps
Traffic Change Test Options
for Execution Plan Steps

A second field for qualifying information appears, appropriate for the traffic change test you select. For example, if you select Involving Peer Link as the traffic change test, a second field called Peer Link requires you to specify a peer link. You can type the peer link name or you can place your cursor in the Peer Link field and click your selected peer link on the topology map; the Peer Link field is automatically populated for you. If you specify ASBR01/001, the execution step would include all the traffic changes that involve that peer link.

Click Add Step to add the step to the execution plan. In the Execution Plan Steps tab on the Details window, you can see the steps being added as you build your plan. If you change your mind about the last step, you can remove it from the plan by clicking Remove Last Step. You can also right-click on the topology map to bring up the option to animate the plan. If you have a step highlighted in the Execution Plan Steps tab, you can animate that single step.

If there are no traffic changes that would qualify for inclusion in the step, based on the criteria you specify, a message is displayed to that effect, and you are not allowed to create that step. When the total number of traffic changes in your Plan Change (displayed in the Plan Change information on the left side of the window) is the same as the number of traffic changes in your execution plan (displayed in the Execution Plan Steps tab in the Details window), you have reached the end of your plan change and there are no more traffic changes to be added to a step. The cost and cost change figures will also match.

Execute the Steps in the Network

Some considerations for a good execution plan:

  • A good plan does not create undesirable conditions, like the overloading of peer links or tunnels, along the way.

  • A good plan usually divides the needed changes up fairly evenly among the steps.

  • Important changes that reduce the cost considerably are tackled early in a good plan. Taking traffic off already overloaded peer links is an example.

Once you are happy with the execution plan, click Execute to execute the steps in the network. You should be able to see differences in the Demands tab of the network information table in the main UI if the optimization was successful.