Opened 6 years ago

Closed 2 years ago

#9346 closed task (wontfix)

Make Guard flag easier to get

Reported by: hsn Owned by:
Priority: Medium Milestone: Tor: unspecified
Component: Core Tor/Tor Version:
Severity: Normal Keywords: tor-relay needs-proposal
Cc: Actual Points:
Parent ID: Points:
Reviewer: Sponsor:

Description

Currently if you restart relay every few days its difficult to get Guard flag. Guard should have continuous availability, not long uptime.

I propose to change measurements for guard - do not use uptime for calculation, calculate only downtime.

This will allow more relays to get Guard flag and shift guard flag and workload from exit nodes to new location. There are only 1300 guards but 2500 relays with stable.

Child Tickets

Change History (3)

comment:1 Changed 6 years ago by nickm

Keywords: tor-relay needs-proposal added
Milestone: Tor: unspecified

Right now, the Guard flag is supposed to be based on *fraction* of time up recently; restarting shouldn't affect it.

From dir-spec.txt:

   "Guard" -- A router is a possible 'Guard' if its Weighted Fractional
   Uptime is at least the median for "familiar" active routers, and if
   its bandwidth is at least median or at least 250KB/s.

        To calculate weighted fractional uptime, compute the fraction
        of time that the router is up in any given day, weighting so that
        downtime and uptime in the past counts less.

        A node is 'familiar' if 1/8 of all active nodes have appeared more
        recently than it, OR it has been around for a few weeks.

For information on the proposal process, see https://gitweb.torproject.org/torspec.git/blob_plain/HEAD:/proposals/001-process.txt .

comment:2 Changed 6 years ago by hsn

I have experience that new relay gets Guard flag 7th day if it was never restarted. I do not object against this - its good enough. It gets stable flag 2 days sooner.

But if you take an older relay with 9 days of uptime, it will not get guard or stable. That older relay had bw limit set and it was down for few hours (about 4-6) per day before i turned off that bw limit.

Older relay was known for larger time and given exactly same conditions (about 1 week uptime) as new relay its history is considered as disadvantage instead of advantage. It would be more likely to be available in future because it has longer "known" records.

Thats probably reason why 1200 relays are not guards even they could be.

comment:3 Changed 2 years ago by nickm

Resolution: wontfix
Severity: Normal
Status: newclosed

I don't think that we're moving in this direction any time soon. Having the Guard flag arrive slowly helps defend against quite a few attacks that we'd like to stay ahead of.

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