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Viewing Equal Cost Multiple-Paths

Equal Cost Multiple-Paths (ECMP) reports provide a list of all the ECMPs available in your network. You can also view each individual paths highlighted in a separate window.

To view ECMPs in your network:

  1. Right-click on the topology map and select Labels > Link Labels > Show Link Metrics.
    Figure 1: Show Link Distance Dialog box titled Link Labels with options to show labels for all, none, or current selection of network links and text choices like Interface Name, Utilization, IP Subnet Address, Metric, Delay, Bandwidth, and Customize. OK and Cancel buttons at the bottom.
  2. The link metrics are displayed.
    Figure 2: Topology Map with Link Distances Network topology diagram with nodes labeled as SFO, DEN, ATL connected by links showing numerical values. Colors indicate connection types.
  3. Select Report > Report Manager to open up the Report Manager.
  4. Select Network Reports > Demand Reports > Equal Cost Multi-Path Report from the left panel to bring up the report listing all of the equal cost multiple-paths of the network. As can be seen in Figure 3, there are many such paths. This report is also saved on the server as EQPATHRPT. runcode. Note that the ECMP paths are calculated based on IP metric only, and do not factor in the influence of MPLS traffic engineering tunnels on the demand routing.
    Figure 3: Equal Cost Multiple-Paths Report Report Manager interface displaying Equal Cost Multi-Path report with routing paths, delays, and performance metrics for network optimization.
  5. Select Network > Path & Capacity > Equivalent Path to bring up the Demand Equivalent Path window.
    Note:

    Use the Equivalent Path option to view ECMPs when there is no demand between two locations.
    Figure 4: Network > Path & Capacity > Equivalent Path Dropdown menu in network management software showing options like Link Rules, Path and Capacity, Equal Metrics at PE, and Show Site Demands.
  6. Select Node A and Node B, then click Show Path. The Path window is displayed.
    Figure 5: Demand Equivalent Path Demand Equivalent Path interface for network configuration. Features node selection fields, IP and IPv6 input, owner and bandwidth fields, connection type, priority, hold settings, and path options. Includes buttons for highlighting nodes, showing paths, and accessing help.
  7. All of the equivalent paths (paths with equal costs) between the two selected nodes will be displayed in the Paths window. Select a path to view its detailed information and highlight it on the topology map.
    Alternatively, select All Paths from the Show Path drop-down list to highlight all the paths between the two locations.
    Figure 6: Equivalent Cost Paths Network visualization tool showing paths between nodes LAX, SDG, ATL, and HOU. Arrows represent data flow, with a color-coded scale for link utilization from 0 to 100 percent. Top panels detail paths, node IDs, and link types. Bottom panels display network topology, with links annotated by metrics. Used for network analysis and optimization.
  8. If you choose your link metrics wisely (such as using the real distance in miles like in Figure 7), you can increase the variability of the path costs which will make it less likely for equal cost multiple-paths to occur.
    Figure 7: Topology Map With New Link Distances Network topology diagram with nodes labeled by city abbreviations connected by directional links. BOS node is highlighted.
  9. Open up the Equal Cost Multi-Path Report again and you will see that there no equal cost multiple-paths in the network with the new link metrics.
    Figure 8: New Equal Cost Multiple-Paths Report Screenshot of Report Manager software showing a network analysis report titled EQUAL COST MULTI-PATH INFO -- mpls-fish. The left panel lists Layer 3 Network and Simulation Reports. The right panel displays report details including software release 4.4.1, report date 6/29/2006, and notes on network path symbols. No ECMP demands have multiple paths. The toolbar includes buttons like Print and Find.