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  1. Qpid Dispatch
  2. DISPATCH-1183

Link state cost propagation takes a long time



    • Type: Improvement
    • Status: Open
    • Priority: Major
    • Resolution: Unresolved
    • Affects Version/s: 1.4.1
    • Fix Version/s: None
    • Component/s: Routing Engine
    • Labels:
    • Environment:

      Fedora 27; current master build.

      Configurations generated by the gen_configs.py attachment.



      A router network of 26 routers in a single ring is started on a single system. The logs are analyzed to find all the ROUTER_LS costs log lines and presented in the az-kill-restart.html attachment. On that web page select 'Router link state' in the table of contents to see the link state table.

      In the link state table there is a column for each router. Then the ROUTER_LS cost lines are shown in rows as follows

      • When a router starts it displays a green mark in it's own column and orange marks in all other columns to indicate that all other routers are unreachable.
      • When a router declares a cost result the costs to known routers are shown in their respective columns. Routers for which no costs were declared are shown with orange marks indicating that they are unreachable.
      • The generation code analyzes the complete link state costs across all routers after each row is shown. When a consistent set of costs is published for all routers then a green row indicating 'stable' is shown.
        Time Event
        14:10:58 Boot network
        14:11:00 Cost propagation begins
        14:11:37 Costs stabilize
        14:12:00 Router D process stopped
        14:12:41 Costs stabilize without D
        14:14:30 Router D restarted
        14:14:50 Costs stabilize

      There's no bug here as the costs stabilize directly. It is an observation that the network reachability and cost state takes 'a long time' to settle. Can this run faster?


        1. gen_configs.py
          11 kB
          Charles E. Rolke
        2. az-kill-restart.html
          1.04 MB
          Charles E. Rolke



            • Assignee:
              chug Charles E. Rolke
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