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. Author: Nick Mathewson
  4. Created: 1-Jul-2008
  5. Status: Open
  6. Target: 0.2.1.x
  7. [This could be obsoleted by proposal 141, which could replace NewGuard
  8. with a Guard weight.]
  9. Overview
  10. Right now, Tor has one flag that clients use both to tell which
  11. nodes should be kept as guards, and which nodes should be picked
  12. when choosing new guards. This proposal separates this flag into
  13. two.
  14. Motivation
  15. Balancing clients amoung guards is not done well by our current
  16. algorithm. When a new guard appears, it is chosen by clients
  17. looking for a new guard with the same probability as all existing
  18. guards... but new guards are likelier to be under capacity, whereas
  19. old guards are likelier to be under more use.
  20. Implementation
  21. We add a new flag, NewGuard. Clients will change so that when they
  22. are choosing new guards, they only consider nodes with the NewGuard
  23. flag set.
  24. For now, authorities will always set NewGuard if they are setting
  25. the Guard flag. Later, it will be easy to migrate authorities to
  26. set NewGuard for underused guards.
  27. Alternatives
  28. We might instead have authorities list weights with which nodes
  29. should be picked as guards.