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Fri, 29 Jul 2022 08:19:49 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Gyan Mishra Date: Fri, 29 Jul 2022 11:19:38 -0400 Message-ID: To: "Scharf, Michael" Cc: Jeffrey Haas , Michael Tuexen , Robert Raszuk , Susan Hares , "Van De Velde, Gunter (Nokia - BE/Antwerp)" , tcpm IETF list , "touch@strayalpha.com" Content-Type: multipart/alternative; boundary="000000000000609a4d05e4f32e36" Archived-At: Subject: Re: [tcpm] IETF 114 TCPM WG - NG TCPM Yang Model X-BeenThere: tcpm@ietf.org X-Mailman-Version: 2.1.39 Precedence: list List-Id: TCP Maintenance and Minor Extensions Working Group List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 29 Jul 2022 15:19:55 -0000 --000000000000609a4d05e4f32e36 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Michael See in-line Thanks Gyan On Wed, Jul 27, 2022 at 10:13 AM Scharf, Michael < Michael.Scharf@hs-esslingen.de> wrote: > Hi all, > > See below... > > > -----Original Message----- > > From: tcpm On Behalf Of touch@strayalpha.com > > Sent: Wednesday, July 27, 2022 4:13 AM > > To: Michael Tuexen > > Cc: Gyan Mishra ; tcpm IETF list > > ; Robert Raszuk ; Van De Velde, > > Gunter (Nokia - BE/Antwerp) ; Jeffrey > > Haas ; Susan Hares > > Subject: Re: [tcpm] IETF 114 TCPM WG - NG TCPM Yang Model > > > > Notes below. > > > > > On Jul 26, 2022, at 6:19 PM, Michael Tuexen > > wrote: > > > > > >> > > >> > > >> Dear TCPM > > >> > > >> Attached is the slide deck for the NG TCP Yang model discussion. > > >> > > >> Sue, Robert, Jeff, Gunter > > >> > > >> Please review and let me know if I missed any talking points for the > NG > > TCP Yang model. > > > A couple of clarifying questions related to slide "What to add to NG > TCP > > Yang Model?", > > > especially since I know almost nothing about YANG: > > > > > > =E2=80=A2 All TCP states part of the FSM state machine. > > > Understood. > > These make sense. > > Indeed. > > draft-ietf-tcpm-yang-tcp-07 already models the states of a TCP connection= , > using the definitions from 793bis: > > > leaf state { > type enumeration { > enum closed { > value 1; > description > "Connection is closed. Connections in this state > may not appear in this list."; > } > enum listen { > value 2; > description > "Represents waiting for a connection request from any > remote TCP peer and port."; > } > enum syn-sent { > value 3; > description > "Represents waiting for a matching connection request > after having sent a connection request."; > } > enum syn-received { > value 4; > description > "Represents waiting for a confirming connection > request acknowledgment after having both received > and sent a connection request."; > } > enum established { > value 5; > description > "Represents an open connection, data received can be > delivered to the user. The normal state for the data > transfer phase of the connection."; > } > enum fin-wait-1 { > value 6; > description > "Represents waiting for a connection termination > request from the remote TCP peer, or an > acknowledgment of the connection termination request > previously sent."; > } > enum fin-wait-2 { > value 7; > description > "Represents waiting for a connection termination > request from the remote TCP peer."; > } > enum close-wait { > value 8; > description > "Represents waiting for a connection termination > request from the local user."; > } > enum last-ack { > value 9; > description > "Represents waiting for an acknowledgment of the > connection termination request previously sent to > the remote TCP peer (this termination request sent > to the remote TCP peer already included an > acknowledgment of the termination request sent from > the remote TCP peer)"; > } > enum closing { > value 10; > description > "Represents waiting for a connection termination > request acknowledgment from the remote TCP peer."; > } > enum time-wait { > value 11; > description > "Represents waiting for enough time to pass to be > sure the remote TCP peer received the acknowledgment > of its connection termination request, and to avoid > new connections being impacted by delayed segments > from previous connections."; > } > } > description > "The state of this TCP connection."; > } > description > "List of TCP connections with their parameters. The list > is modeled as writeable, but implementations may not > allow creation of new TCP connections by adding entries to > the list. Furthermore, the behavior upon removal is > implementation-specific. Implementations may support > closing or resetting a TCP connection upon an operation > that removes the entry from the list."; > } > > > This creates feature parity with the TCP MIB regarding state. > > All: Please have a look at this model, which was added to address the IET= F > LC feedback, and let us know if anything is missing. > > > > =E2=80=A2 All TCP flags and respective states. > > > Do you mean the TCP flags SYN, FIN, PSH, ... Does a YANG module all t= o > > describe > > > packets sent and received? > > > > I can=E2=80=99t see how this can model the TCP flags; all it should be = modeling > is the > > states of the connection. The model is for TCP, not TCP packets. > > I am very confused here, too. > > > > =E2=80=A2 All TCP parameters that would be accessible with a local OS= kernel > hook. > > > Doesn't that mean the complete set of state variable the kernel has a= nd > > isn't that implementation dependent? > > > =E2=80=A2 All windowing parameters including window scaling as well a= s any > > windowing related optimizations. > > > You mean the receiver window including the window scaling. > > > =E2=80=A2 All TCP options and optimizations set such as Selective ACK= . > > > I guess you mean the set of TCP extensions which have been negotiated= . > > > =E2=80=A2 All TCP slow start congestion control parameters CWIN etc. > > > There are a multiple Congestion Controls, even ones not being > specified by > > the IETF. > > > So this might get very hard to do. Or do you require a specific CC wh= en > > using TCP for BGP? > > > > This is where things get confusing to me; it seems that there is either > a model > > for TCP or a model for TCP implementations. The two should not be > confused > > with each other > > Yep, and a lot of details are very implementation specific and differ a > lot in the long tail of existing TCP implementations. Gyan> Understood. Maybe if we focused on router vendor TCP implementations. Also maybe commonality across compute node TCP implementations > > > In the first discussions regarding draft-scharf-tcpm-yang-tcp, I have > shown some examples for TCP parameters that are implemented relatively > similarly across major TCP stacks and that a more comprehensive TCP YANG > model could possibly include. Gyan> Thank you This includes for instance enabling/disabling ECN, Window Scaling, > Timestamps, etc. Gyan> Perfect But even in that case different stacks differ *a lot* and I am not aware of > a simple way to work around that. Gyan> Understood Details can be found in the IETF proceedings for previous TCPM meetings. Gyan> Ok > > > If there is interest in modeling TCP beyond draft-ietf-tcpm-yang-tcp-07, > the discussion needs to ensure that the model roughly corresponds to > running code. Gyan> Understood > > > Unfortunately, I probably cannot attend this TCPM session because of my > day job, but I obviously follow the mailing list. > > Thanks > > Michael > > > > > > Joe > > > > > > > > Best regards > > > Michael > > >> > > >> Thanks > > >> > > >> Gyan > > >> > > >> ---------- Forwarded message --------- > > >> From: Mishra, Gyan S > > >> Date: Mon, Jul 25, 2022 at 11:36 PM > > >> Subject: IETF 114 TCPM WG - NG TCPM Yang Model > > >> To: Hayabusanew > > >> > > >> > > >> -- > > >> > > >> > > >> Gyan Mishra > > >> Network Solutions Architect > > >> Email gyan.s.mishra@verizon.com > > >> M 301 502-1347 > > >> > > >> > > >> > Model.pdf>_______________________________________________ > > >> tcpm mailing list > > >> tcpm@ietf.org > > >> https://www.ietf.org/mailman/listinfo/tcpm > > > > > > _______________________________________________ > > > tcpm mailing list > > > tcpm@ietf.org > > > https://www.ietf.org/mailman/listinfo/tcpm > > > > _______________________________________________ > > tcpm mailing list > > tcpm@ietf.org > > https://www.ietf.org/mailman/listinfo/tcpm > --=20 *Gyan Mishra* *Network Solutions A**rchitect * *Email gyan.s.mishra@verizon.com * *M 301 502-1347* --000000000000609a4d05e4f32e36 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hi Michael=C2=A0

See in-line=C2=A0

Thanks=C2=A0

Gyan

On Wed, Jul 27, 2022 at 10:13 AM Scharf, Michael <Michael.Scharf@hs-esslingen.de> wrote= :
Hi all,

See below...

> -----Original Message-----
> From: tcpm <tcpm-bounces@ietf.org> On Behalf Of touch@strayalpha.com
> Sent: Wednesday, July 27, 2022 4:13 AM
> To: Michael Tuexen <michael.tuexen@lurchi.franken.de>
> Cc: Gyan Mishra <hayabusagsm@gmail.com>; tcpm IETF list
> <tcpm@ietf.org>; Robert Raszuk <robert@raszuk.net>; Van De Velde,
> Gunter (Nokia - BE/Antwerp) <gunter.van_de_velde@nokia.com>; Jeffrey=
> Haas <jhaas@pfr= c.org>; Susan Hares <shares@ndzh.com>
> Subject: Re: [tcpm] IETF 114 TCPM WG - NG TCPM Yang Model
>
> Notes below.
>
> > On Jul 26, 2022, at 6:19 PM, Michael Tuexen
> <michael.tuexen@lurchi.franken.de> wrote:
> >
> >>
> >>
> >> Dear TCPM
> >>
> >> Attached is the slide deck for the NG TCP Yang model discussi= on.
> >>
> >> Sue, Robert, Jeff, Gunter
> >>
> >> Please review and let me know if I missed any talking points = for the NG
> TCP Yang model.
> > A couple of clarifying questions related to slide "What to a= dd to NG TCP
> Yang Model?",
> > especially since I know almost nothing about YANG:
> >
> > =E2=80=A2 All TCP states part of the FSM state machine.
> > Understood.
> These make sense.

Indeed.

draft-ietf-tcpm-yang-tcp-07 already models the states of a TCP connection, = using the definitions from 793bis:

<snip>
leaf state {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0type enumeration {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0enum closed {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0value 1;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0description =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0"= Connection is closed. Connections in this state
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 may n= ot appear in this list.";
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0enum listen {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0value 2;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0description =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0"= Represents waiting for a connection request from any
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 remot= e TCP peer and port.";
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0enum syn-sent {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0value 3;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0description =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0"= Represents waiting for a matching connection request
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 after= having sent a connection request.";
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0enum syn-received {<= br> =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0value 4;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0description =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0"= Represents waiting for a confirming connection
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 reque= st acknowledgment after having both received
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 and s= ent a connection request.";
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0enum established { =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0value 5;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0description =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0"= Represents an open connection, data received can be
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 deliv= ered to the user. The normal state for the data
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 trans= fer phase of the connection.";
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0enum fin-wait-1 { =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0value 6;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0description =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0"= Represents waiting for a connection termination
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 reque= st from the remote TCP peer, or an
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 ackno= wledgment of the connection termination request
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 previ= ously sent.";
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0enum fin-wait-2 { =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0value 7;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0description =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0"= Represents waiting for a connection termination
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 reque= st from the remote TCP peer.";
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0enum close-wait { =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0value 8;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0description =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0"= Represents waiting for a connection termination
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 reque= st from the local user.";
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0enum last-ack {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0value 9;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0description =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0"= Represents waiting for an acknowledgment of the
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 conne= ction termination request previously sent to
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 the r= emote TCP peer (this termination request sent
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 to th= e remote TCP peer already included an
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 ackno= wledgment of the termination request sent from
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 the r= emote TCP peer)";
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0enum closing {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0value 10;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0description =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0"= Represents waiting for a connection termination
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 reque= st acknowledgment from the remote TCP peer.";
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0enum time-wait {
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0value 11;
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0description =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0"= Represents waiting for enough time to pass to be
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 sure = the remote TCP peer received the acknowledgment
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 of it= s connection termination request, and to avoid
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 new c= onnections being impacted by delayed segments
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 from = previous connections.";
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0description
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0"The state of t= his TCP connection.";
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0description
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0"List of TCP connectio= ns with their parameters. The list
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 is modeled as writeable, b= ut implementations may not
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 allow creation of new TCP = connections by adding entries to
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 the list. Furthermore, the= behavior upon removal is
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 implementation-specific. I= mplementations may support
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 closing or resetting a TCP= connection upon an operation
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 that removes the entry fro= m the list.";
=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0}
</snip>

This creates feature parity with the TCP MIB regarding state.

All: Please have a look at this model, which was added to address the IETF = LC feedback, and let us know if anything is missing.

> > =E2=80=A2 All TCP flags and respective states.
> > Do you mean the TCP flags SYN, FIN, PSH, ... Does a YANG module a= ll to
> describe
> > packets sent and received?
>
> I can=E2=80=99t see how this can model the TCP flags; all it should be= modeling is the
> states of the connection. The model is for TCP, not TCP packets.

I am very confused here, too.

> > =E2=80=A2 All TCP parameters that would be accessible with a loca= l OS kernel hook.
> > Doesn't that mean the complete set of state variable the kern= el has and
> isn't that implementation dependent?
> > =E2=80=A2 All windowing parameters including window scaling as we= ll as any
> windowing related optimizations.
> > You mean the receiver window including the window scaling.
> > =E2=80=A2 All TCP options and optimizations set such as Selective= ACK.
> > I guess you mean the set of TCP extensions which have been negoti= ated.
> > =E2=80=A2 All TCP slow start congestion control parameters CWIN e= tc.
> > There are a multiple Congestion Controls, even ones not being spe= cified by
> the IETF.
> > So this might get very hard to do. Or do you require a specific C= C when
> using TCP for BGP?
>
> This is where things get confusing to me; it seems that there is eithe= r a model
> for TCP or a model for TCP implementations. The two should not be conf= used
> with each other

Yep, and a lot of details are very implementation specific and differ a lot= in the long tail of existing TCP implementations.

=C2=A0 =C2=A0 Gyan> Understood.=C2=A0 = Maybe if we focused on router vendor TCP implementations.=C2=A0 Also maybe = commonality across compute node TCP implementations=C2=A0


In the first discussions regarding draft-scharf-tcpm-yang-tcp, I have shown= some examples for TCP parameters that are implemented relatively similarly= across major TCP stacks and that a more comprehensive TCP YANG model could= possibly include.

=C2=A0 =C2=A0 Gyan> Thank you

This includes for instance enabling/d= isabling ECN, Window Scaling, Timestamps, etc.

=C2=A0 =C2=A0 Gyan> Perfect=C2=A0

But e= ven in that case different stacks differ *a lot* and I am not aware of a si= mple way to work around that.

=C2=A0 =C2=A0 Gyan> Understood=C2=A0

Details can be foun= d in the IETF proceedings for previous TCPM meetings.

=C2=A0 =C2=A0Gyan> Ok


If there is interest in modeling TCP beyond draft-ietf-tcpm-yang-tcp-07, th= e discussion needs to ensure that the model roughly corresponds to running = code.

=C2=A0 =C2= =A0 Gyan> Understood=C2=A0


Unfortunately, I probably cannot attend this TCPM session because of my day= job, but I obviously follow the mailing list.

Thanks

Michael


>
> Joe
>
> >
> > Best regards
> > Michael
> >>
> >> Thanks
> >>
> >> Gyan
> >>
> >> ---------- Forwarded message ---------
> >> From: Mishra, Gyan S <gyan.s.mishra@verizon.com>
> >> Date: Mon, Jul 25, 2022 at 11:36 PM
> >> Subject: IETF 114 TCPM WG - NG TCPM Yang Model
> >> To: Hayabusanew <hayabusagsm@gmail.com>
> >>
> >>
> >> --
> >>
> >>
> >> Gyan Mishra
> >> Network Solutions Architect
> >> Email gyan.s.mishra@verizon.com
> >> M 301 502-1347
> >>
> >>
> >> <IETF-114 TCPM TCP Yang
> Model.pdf>_______________________________________________
> >> tcpm mailing list
> >> tcpm@ietf.= org
> >> https://www.ietf.org/mailman/listinfo/tcpm
> >
> > _______________________________________________
> > tcpm mailing list
> > tcpm@ietf.org<= /a>
> > https://www.ietf.org/mailman/listinfo/tcpm >
> _______________________________________________
> tcpm mailing list
> tcpm@ietf.org > https://www.ietf.org/mailman/listinfo/tcpm
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