Happy Eyeballs Version 2: Better Connectivity Using Concurrency
draft-ietf-v6ops-rfc6555bis-05

Summary: Has a DISCUSS. Needs 7 more YES or NO OBJECTION positions to pass.

Mirja K├╝hlewind Discuss

Discuss (2017-10-16)
I would totally be a yes on this document, but I would like to first discuss a processing issue: I do not agree with the assessment that this draft should obsolete RFC6555. The draft itself says: "This document expands on "Happy Eyeballs" [RFC6555]..." which sounds to me like an update. Further I believe RFC6555 is still a valid algorithm that can be used as specified, also RFC6555 provides probably more useful background info that is not captured by this new draft. I would recommend to update instead. Also, in any case the obsolete or update should to be mentioned in the abstract.
Comment (2017-10-16)
Question on the equation in section 5:
"MAX( 1.25 * RTT_MEAN + 4 * RTT_VARIANCE, 2 *RTT_MEAN )"
While it is not well explained how RTT_MEAN and RTT_VARIANCE are measured, I would recommend to just use *3RTT instead (where RTT is the value you have cached for a certain destination address, no matter how that has been measured/calculated), as RFC2988 says:

"When the first RTT measurement R is made, the host MUST set

            SRTT <- R
            RTTVAR <- R/2
            RTO <- SRTT + max (G, K*RTTVAR)"

which translates to 3*R if you only have one value.

I also don't think that is is necessary to talk about exponential backoff. To me that seems more confusing than helpful here. 

However, it might be helpful to note that 3*RTT also means that in the best case the handshake is already completed before you try the next address. And further, I would assume that you might still want to have a fixed max default value (of e.g. 300ms or 250ms?) because otherwise on paths where you have high delay sequential probing might be too slow, no?

Warren Kumari Yes

Benoit Claise No Objection

Comment (2017-10-19)
Someome id-nits:

     (See RFCs 3967 and 4897 for information about using normative references

     to lower-maturity documents in RFCs)


  == Missing Reference: 'Section 3' is mentioned on line 120, but not defined

  == Missing Reference: 'Section 4' is mentioned on line 164, but not defined

  == Missing Reference: 'Section 5' is mentioned on line 202, but not defined

  == Missing Reference: 'Section 6' is mentioned on line 169, but not defined

     Summary: 0 errors (**), 0 flaws (~~), 4 warnings (==), 3 comments (--).

Kathleen Moriarty No Objection

Alia Atlas No Record

Deborah Brungard No Record

Ben Campbell No Record

Alissa Cooper No Record

Spencer Dawkins No Record

Suresh Krishnan No Record

Terry Manderson No Record

Alexey Melnikov No Record

Eric Rescorla No Record

Alvaro Retana No Record

Adam Roach No Record