Subject: [tcpm] Comments for draft-ietf-tcpm-rto-consider-05.txt

From: Michael Tuexen <[email-masked]>
Date: Fri, 24 Mar 2017 22:59:37 +0100

Hi Mark,

I read the ID with a special focus on SCTP and have three comments:

1. S.3 states:
   Protocols such as SCTP [RFC4960] and MP-TCP [RFC6182] that
   communicate in a unicast fashion with multiple specific
   endpoints can leverage the requirements in this document
   provided they track state and follow the requirements for each
   endpoint independently.

   SCTP requires this and I think MP-TCP also for its subflows.
   So it seems strange that you restrict the statement to
   SCTP implementations fulfilling a requirement which has to be true. 

2. S.3 states:
   I.e., if host A communicates with hosts B and C, A must use
   independent RTOs for traffic sent to B and C.
   
   SCTP association are between two hosts. Each host can have
   multiple IP-addresses. But you can't have an SCTP association
   between host A on one side and multiple hosts (B and C) on the
   other side. I think the same applies to MP-TCP. SO you might want
   to use a term different from host.

3. S.5 states:
   E.g., a protocol like SCTP [RFC4960] could leverage the
   requirements for data that is sent only "partially reliably".

   It might be useful to add a reference to RFC 3758.

Best regards
Michael (as an individual)

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From: Mark Allman <[email-masked]>
Date: Fri, 24 Mar 2017 22:48:13 -0400

> I read the ID with a special focus on SCTP and have three comments:

Many thanks!

>    SCTP implementations fulfilling a requirement which has to be true. 

The statement is meant to be general not really specific to SCTP or
MP-TCP.  That is, this is not normatively saying something that SCTP
already says, somehow.  The "such as" was meant to indicate these
are just two examples.  I can reword this to more explicitly
indicate these are exemplars that follow the guidance, but the
guidance is general.  Make sense?

>    to use a term different from host.

Do you have a favorite word?  "Endpoint"?

>    It might be useful to add a reference to RFC 3758.

Will do.

Many thanks!

allman

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From: Michael Tuexen <[email-masked]>
Date: Sat, 25 Mar 2017 21:25:31 +0100

> On 25 Mar 2017, at 03:48, Mark Allman <[email-masked]> wrote:
> 
> 
Yepp.

Something like

  Protocols that communicate in a unicast fashion with multiple
  specific transport addresses (pairs of an IP address and a port number)
  can leverage the requirements in this document provided they track state
  and follow the requirements for each transport address independently.
  Therefore, SCTP [RFC4960] and MP-TCP [RFC6182] can leverage the requirements
  in this document.

> Do you have a favorite word?  "Endpoint"?
Transport address? Something like

  I.e., if an endpoint with transport address A communicates with
  an endpoint having transport addresses B and C, it must use
  independent RTOs for traffic sent to B and C.

>>   It might be useful to add a reference to RFC 3758.
Great.
> Many thanks!
You are welcome!

Best regards
Michael