module ietf-tcp-common {

    yang-version 1.1;

    namespace
      "urn:ietf:params:xml:ns:yang:ietf-tcp-common";

    prefix tcpcmn;

    organization
      "IETF NETCONF (Network Configuration) Working Group and the
IETF TCP Maintenance and Minor Extensions (TCPM) Working Group";

    contact
      "WG Web:   https://datatracker.ietf.org/wg/netconf
	  https://datatracker.ietf.org/wg/tcpm
WG List:  NETCONF WG list <mailto:netconf@ietf.org>
	  TCPM WG list <mailto:tcpm@ietf.org>
Authors:  Kent Watsen <mailto:kent+ietf@watsen.net>
	  Michael Scharf
	  <mailto:michael.scharf@hs-esslingen.de>";

    description
      "This module define a reusable 'grouping' that is common
to both TCP clients and TCP servers.  This grouping statement
is used by both the 'ietf-tcp-client' and 'ietf-tcp-server'
modules.

The key words 'MUST', 'MUST NOT', 'REQUIRED', 'SHALL',
'SHALL NOT', 'SHOULD', 'SHOULD NOT', 'RECOMMENDED',
'NOT RECOMMENDED', 'MAY', and 'OPTIONAL' in this document
are to be interpreted as described in BCP 14 (RFC 2119)
(RFC 8174) when, and only when, they appear in all
capitals, as shown here.

Copyright (c) 2024 IETF Trust and the persons identified
as authors of the code.  All rights reserved.

Redistribution and use in source and binary forms, with
or without modification, is permitted pursuant to, and
subject to the license terms contained in, the Revised
BSD License set forth in Section 4.c of the IETF Trust's
Legal Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info).

This version of this YANG module is part of RFC 9643
(https://www.rfc-editor.org/info/rfc9643); see the RFC
itself for full legal notices.";

    revision "2024-10-10" {
      description "Initial version.";
      reference
        "RFC 9643: YANG Groupings for TCP Clients and TCP Servers";

    }


    feature keepalives-supported {
      description
        "Indicates that keepalives are supported.";
    }

    grouping tcp-common-grouping {
      description
        "A reusable grouping for configuring TCP parameters common
to TCP connections as well as the operating system as a
whole.";
      container keepalives {
        if-feature keepalives-supported;
        presence
          "Indicates that keepalives are enabled, aligning to
the requirement in Section 3.8.4 of RFC 9293 that
states keepalives are off by default.";
        description
          "Configures the keepalive policy to proactively test the
aliveness of the TCP peer.  An unresponsive TCP peer is
dropped after approximately (idle-time + max-probes *
probe-interval) seconds.  Further guidance can be found
in Section 2.1.5 of RFC 9643.";
        reference
          "RFC 9293: Transmission Control Protocol (TCP)";

        leaf idle-time {
          type uint16 {
            range "1..max";
          }
          units "seconds";
          default "7200";
          description
            "Sets the amount of time after which a TCP-level probe
message will be sent to test the aliveness of the TCP
peer if no data has been received from the TCP peer.
Two hours (7200 seconds) is a safe value, per Section
3.8.4 of RFC 9293.";
          reference
            "RFC 9293: Transmission Control Protocol (TCP)";

        }

        leaf max-probes {
          type uint16 {
            range "1..max";
          }
          default "9";
          description
            "Sets the maximum number of sequential keepalive probes
that can fail to obtain a response from the TCP peer
before assuming the TCP peer is no longer alive.";
        }

        leaf probe-interval {
          type uint16 {
            range "1..max";
          }
          units "seconds";
          default "75";
          description
            "Sets the time interval between failed probes.  The
interval SHOULD be significantly longer than one second
in order to avoid harm on a congested link.";
        }
      }  // container keepalives
    }  // grouping tcp-common-grouping
  }  // module ietf-tcp-common