Re: [quicwg/base-drafts] rate-limiting of CID issuance needs to be allowed (#2436)

Martin Thomson <notifications@github.com> Fri, 08 February 2019 09:13 UTC

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Subject: Re: [quicwg/base-drafts] rate-limiting of CID issuance needs to be allowed (#2436)
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Those are not scary numbers.  It almost fits into the smallest possible connection ID.

Keep in mind that you really don't want to reuse values: if you reuse values over that period, you risk reusing a value for which a stateless reset was sent.  That might increase the number a little.

With 100,000 active connections per server in a 1000 server cluster issuing 16 connection IDs per second for each connection (which is a very high rate, but you have to allow for those connections being new ones), you need 47 bits worth of space if you don't want to repeat once a day.  Add 3 for a week's worth of key identifier and that's 50 bits.  That's still short of the 64 bits that gQUIC had for connection IDs.  If you want to assign randomly, you can do that with 100 bits and avoid the birthday paradox.

The numbers seem to play out nicely.

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