[tor-dev] estimating traffic/bandwidth needed to run a Tor node

Yawning Angel yawning at schwanenlied.me
Sun May 22 22:47:02 UTC 2016

On Mon, 23 May 2016 00:56:56 +0300
Razvan Dragomirescu <razvan.dragomirescu at veri.fi> wrote:

> Hello everyone,
> I'm working on an Internet of Things project and Tor will be a part
> of it (Hidden Services to be more precise). The nodes however may be
> battery powered or have slow (or metered) Internet connectivity, so
> I'm trying to estimate the traffic patterns for a fully functional
> Tor node. Has this been measured at all? I mean how much traffic
> should I expect per hour/day/month whatever in order to maintain a
> good "Tor citizen" node, serving a very low traffic hidden service?

Not sure what you mean by "good citizen" since there will be 0
beneficial contributory behavior to the network assuming you are just
hosting hidden services (The server side of an HS is a client in the

The sort of link characteristics you mention doesn't make it seem like
the nodes would be able to contribute meaningfully either.

(I assume that someone just hosting HSes won't engage in pathologically
 bad behavior like having each tor instance slam the directory
 auths/directory caches, just for the lols.)

> I do remember reading something about it needing 4MB per day or
> something like that, but I can't seem to find that link or page
> anywhere now... :(.
> Any hints on where to find this type of info (or maybe how to measure
> it myself) would be appreciated.

At a minimum to function as a tor client you will need to fetch:

Microdesc consensus documents every 2 hours or so (fetch interval is
randomized for load balancing reasons), microdescriptors depending on
the relay churn.  Look at dir-spec.txt for behavior, and the data
directory of a running tor instance for an example.

(This is omitting various forms of overhead for breavity.  Both types
of documents will be compressed.)


Yawning Angel
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