145-newguard-flag.txt 1.3 KB

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  1. Filename: 145-newguard-flag.txt
  2. Title: Separate "suitable as a guard" from "suitable as a new guard"
  3. Version: $Revision$
  4. Last-Modified: $Date$
  5. Author: Nick Mathewson
  6. Created: 1-Jul-2008
  7. Status: Open
  8. [This could be obsoleted by proposal 141, which could replace NewGuard
  9. with a Guard weight.]
  10. Overview
  11. Right now, Tor has one flag that clients use both to tell which
  12. nodes should be kept as guards, and which nodes should be picked
  13. when choosing new guards. This proposal separates this flag into
  14. two.
  15. Motivation
  16. Balancing clients amoung guards is not done well by our current
  17. algorithm. When a new guard appears, it is chosen by clients
  18. looking for a new guard with the same probability as all existing
  19. guards... but new guards are likelier to be under capacity, whereas
  20. old guards are likelier to be under more use.
  21. Implementation
  22. We add a new flag, NewGuard. Clients will change so that when they
  23. are choosing new guards, they only consider nodes with the NewGuard
  24. flag set.
  25. For now, authorities will always set NewGuard if they are setting
  26. the Guard flag. Later, it will be easy to migrate authorities to
  27. set NewGuard for underused guards.
  28. Alternatives
  29. We might instead have authorities list weights with which nodes
  30. should be picked as guards.