[tcpm] draft-ietf-tcpm-rack-02 - TLP algorithm question

Felix Weinrank <ietf@weinrank.net> Tue, 21 March 2017 22:53 UTC

To: "tcpm@ietf.org Extensions" <tcpm@ietf.org>
From: Felix Weinrank <ietf@weinrank.net>
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Date: Tue, 21 Mar 2017 23:53:00 +0100
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Subject: [tcpm] draft-ietf-tcpm-rack-02 - TLP algorithm question
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Hey all,

I have a question regarding the TLP algorithm in draft-ietf-tcpm-rack-02
In 6.2.1.  Phase 1: Scheduling a loss probe:

>         If an SRTT estimate is available:
>             PTO = 2 * SRTT
>         Else:
>             PTO = initial RTO of 1 sec
>         If FlightSize = 1:
>             PTO = max(PTO, 1.5 * SRTT + WCDelAckT)
>         PTO = max(10ms, PTO)
>         PTO = max(RTO, PTO)
The last line "PTO = max(RTO, PTO)" makes no sense to me.
It has been changed from "min" to "max" in the 02 version.

The explaining paragraph below also hints for "min"
> If RTO is smaller than the computed value for PTO, then a probe is scheduled to be sent
> at the RTO time.

Greetings
Felix Weinrank

[tcpm] draft-ietf-tcpm-rack-02 - TLP algorithm qu… Felix Weinrank
Re: [tcpm] draft-ietf-tcpm-rack-02 - TLP algorith… Neal Cardwell