tor/changes/bug2749

  o Changed parameters (authorities):
    - Authorities are now a little more lenient at accepting older
      router descriptors, or newer router descriptors that don't make
      big changes. This should help ameliorate past and future issues
      where routers think they have uploaded valid descriptors, but the
      authorities don't think so. Fix for ticket 2479.
Twiddle ROUTER_{MAX_COSMETIC_TIME_DIFFERENCE,MAX_AGE_TO_PUBLISH} This is ticket 2479. Roger's original explanation was: We have a series of bugs where relays publish a descriptor within 12 hours of their last descriptor, but the authorities drop it because it's not different "enough" from the last one and it's too close to the last one. The original goal of this idea was to a) reduce the number of new descriptors authorities accept (and thus have to store) and b) reduce the total number of descriptors that clients and mirrors fetch. It's a defense against bugs where relays publish a new descriptor every minute. Now that we're putting out one consensus per hour, we're doing better at the total damage that can be caused by 'b'. There are broader-scale design changes that would help here, and we've had a trac entry open for years about how relays should recognize that they're not in the consensus, or recognize when their publish failed, and republish sooner. In the mean time, I think we should change some of the parameters to make the problem less painful. 2012-03-30 21:38:16 +02:00			`o Changed parameters (authorities):`
			`- Authorities are now a little more lenient at accepting older`
			`router descriptors, or newer router descriptors that don't make`
			`big changes. This should help ameliorate past and future issues`
			`where routers think they have uploaded valid descriptors, but the`
			`authorities don't think so. Fix for ticket 2479.`