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. Target: 0.2.1.x
  9. [This could be obsoleted by proposal 141, which could replace NewGuard
  10. with a Guard weight.]
  11. Overview
  12. Right now, Tor has one flag that clients use both to tell which
  13. nodes should be kept as guards, and which nodes should be picked
  14. when choosing new guards. This proposal separates this flag into
  15. two.
  16. Motivation
  17. Balancing clients amoung guards is not done well by our current
  18. algorithm. When a new guard appears, it is chosen by clients
  19. looking for a new guard with the same probability as all existing
  20. guards... but new guards are likelier to be under capacity, whereas
  21. old guards are likelier to be under more use.
  22. Implementation
  23. We add a new flag, NewGuard. Clients will change so that when they
  24. are choosing new guards, they only consider nodes with the NewGuard
  25. flag set.
  26. For now, authorities will always set NewGuard if they are setting
  27. the Guard flag. Later, it will be easy to migrate authorities to
  28. set NewGuard for underused guards.
  29. Alternatives
  30. We might instead have authorities list weights with which nodes
  31. should be picked as guards.