Delay-Tolerant Networking E. Birrane
Internet-Draft E. DiPietro
Intended status: Experimental D. Linko
Expires: January 3, 2019 Johns Hopkins Applied Physics Laboratory
July 2, 2018

ION Licklider Transmission Protocol Admin Application Data Model


This document describes the Application Data Model (ADM) for the configuration of licklider transmission protocol (LTP) in ION in compliance with the template provided by [I-D.birrane-dtn-adm].

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Table of Contents

1. Introduction

An Application Data Model (ADM) provides a guaranteed interface for the management of an application or protocol in accordance with the Asynchronous Management Architecture (AMA) defined in [I-D.birrane-dtn-ama]. The ADM described in this document complies with the ADM Template provided in [I-D.birrane-dtn-adm] as encoded using the JSON syntax.

The ION Licklider Transmission Protocol (LTP) Administration ADM contains all of the functionality that is required to properly configure LTP in ION in accordance with [RFC5326]. LTP is a convergence layer protocol. There is no flow control or congestion control in LTP. LTP must run either over UDP or directly over a link layer protocol. Because of this, LTP cannot be used in every situation. This LTP Admin ADM provides the set of information necessary to provide retransmission based reliability on challenged networks, focusing on the information that are needed to manage LTP properly on the network.

1.1. Technical Notes

1.2. Scope

This ADM specifies those components of the Asynchronous Management Model (AMM) common to the configuration of LTP in ION.

Any Manager software implementing this ADM MUST perform the responsibilities of an AMA Manager as outlined in [I-D.birrane-dtn-adm] as they relate to the objects included in this document.

Any Agent software implementing this ADM MUST perform the responsibilities of an AMA Agent as outlined in [I-D.birrane-dtn-adm] as they relate to the objects included in this document.

1.3. Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119.

2. Structure and Design of this ADM

The LTP Admin ADM's structure is in accordance to [I-D.birrane-dtn-adm]. This ADM contains metadata, table templates, and controls. Table Templates are column templates that will be followed by any instance of this table available in the network. They may not be created dynamically within the network by Managers. Controls are predefined and sometimes parameterized opcodes that can be run on an Agent. Controls are preconfigured in Agents and Managers as part of ADM support.There are no variables, report templates, macros, edd, constants, or operators in this ADM at this time. The contents of this ADM are derived from the main functions and data that are needed to manage LTP RFC 5326.

All ADMs have metadata that includes the name, namespace, and version of the ADM as well as the name of the organization that is issuing that particular ADM. This is important for identification purposes of the ADMs and to ensure version control.

The main idea identified in LTP that is present in this ADM is a span of potential LTP data interchange between engines(nodes on a network that use LTP).

3. Naming and Identification

This section outlines the namespaces used to uniquely identify ADM objects in this specification.

3.1. Namespace and Nicknames

In accordance with [I-D.birrane-dtn-adm], every ADM is assigned a moderated Namespace. In accordance with [I-D.birrane-dtn-amp], these namespaces may be enumerated for compactness. The namespace and ADM identification for these objects is defined as follows.

Namespace Information
Identifier Value
Namespace DTN/ION/ltpadmin
ADM Enumeration 9

Given the above ADM enumeration, in accordance with [I-D.birrane-dtn-amp], the following AMP nicknames are defined.

ION BP ADM Nicknames
Nickname Collection
180 DTN/ION/ltpadmin//Const
181 DTN/ION/ltpadmin//Ctrl
182 DTN/ION/ltpadmin//Edd
183 DTN/ION/ltpadmin//Mac
184 DTN/ION/ltpadmin//Oper
185 DTN/ION/ltpadmin//Rptt
187 DTN/ION/ltpadmin//Tblt
189 DTN/ION/ltpadmin//Var
190 DTN/ION/ltpadmin//Mdat
191-199 DTN/ION/ltpadmin//Reserved

4. ION LTP Admin ADM JSON Encoding

  "Mdat": [
      "name": "name",
      "type": "STR",
      "value": "ion_ltp_admin",
      "description": "The human-readable name of the ADM."
      "name": "namespace",
      "type": "STR",
      "value": "DTN/ion_ltp_admin",
      "description": "The namespace of the ADM."
      "name": "version",
      "type": "STR",
      "value": "V0.0",
      "description": "The version of the ADM."
      "name": "organization",
      "type": "STR",
      "value": "JHUAPL",
      "description": "The name of the issuing organization of the ADM."
  "Edd": [
      "name": "ion_version",
      "type": "STR",
      "description": "This is the version of ION that is currently 
  "Tblt": [
      "name": "spans",
      "columns": [
      "description": "This table lists all spans of potential LTP data
        interchange that exists between the local LTP engine and the 
        indicated (neighboring) LTP engine."
  "Ctrl": [
      "name": "init",
      "parmspec": [{"type":"UINT","name":"est_max_export_sessions"}],
      "description": "Until this control is executed, LTP is not in 
        operation on the local ION node and most ltpadmin controls will
        fail. The control uses estMaxExportSessions to configure the
        hashtable it will use to manage access to export transmission 
        sessions that are currently in progress. For optimum
        performance, estMaxExportSessions should normally equal or
        exceed the summation of maxExportSessions over all spans as 
        discussed below. Appropriate values for the parameters 
        configuring each \"span\" of potential LTP data exchange 
        between the local LTP and neighboring engines are non-trivial
        to determine."
      "name": "manage_heap",
      "parmspec": [
      "description": "This control declares the maximum number of bytes
        of SDR heap space that will be occupied by the acquisition of
        any single LTP block. All data acquired in excess of this limit
        will be written to a temporary file pending extraction and 
        dispatching of the acquired block. Default is the minimum 
        allowed value (560 bytes), which is the approximate size of a
        ZCO file reference object; this is the minimum SDR heap space
        occupancy in the event that all acquisition is into a file."
      "name": "manage_max_ber",
      "parmspec": [
      "description": "This control sets the expected maximum bit error 
        rate(BER) that LTP should provide for in computing the maximum 
        number of transmission efforts to initiate in the transmission
        of a given block.(Note that this computation is also sensitive
        to data segment size and to the size of the block that is to 
        be transmitted.) The default value is .0001 (10^-4)."
      "name": "manage_own_queue_time",
      "parmspec": [{"type":"UINT","name":"own_queing_latency"}],
      "description":"This control sets the number of seconds of predicted
        additional latency attributable to processing delay within the 
        local engine itself that should be included whenever LTP 
        computes the nominal round-trip time for an exchange of data
        with any remote engine.The default value is 1."
      "name": "manage_screening",
      "parmspec": [{"type":"UINT","name":"new_state"}],
      "description": "This control enables or disables the screening of
        received LTP segments per the periods of scheduled reception in
        the node's contact graph. By default, screening is disabled. 
        When screening is enabled, such segments are silently discarded.
        Note that when screening is enabled the ranges declared in the
        contact graph must be accurate and clocks must be synchronized;
        otherwise, segments will be arriving at times other than the
        scheduled contact intervals and will be discarded."
      "name": "span_add",
      "parmspec": [
      "description": "This control declares that a span of potential 
      LTP data interchange exists between the local LTP engine and 
        the indicated (neighboring) LTP engine."
      "name": "span_change",
      "parmspec": [
      "description": "This control sets the indicated span's 
        configuration parameters to the values provided as arguments"
      "name": "span_del",
      "parmspec": [{"type":"UINT","name":"peer_engine_number"}],
      "description": "This control deletes the span identified by 
        peerEngineNumber. The control will fail if any outbound 
        segments for this span are pending transmission or any inbound
        blocks from the peer engine are incomplete."
      "name": "stop",
      "description": "This control stops all link service input and 
        output tasks for the local LTP engine."
      "name": "watch_set",
      "parmspec": [
      "description": "This control enables and disables production of a 
        continuous stream of user- selected LTP activity indication
        characters. Activity parameter of \"1\" selects all LTP 
        activity indication characters; \"0\" de-selects all LTP 
        activity indication characters; any other activitySpec such as
        \"df{]\" selects all activity indication characters in the 
        string, de-selecting all others. LTP will print each selected 
        activity indication character to stdout every time a processing
        event of the associated type occurs: d bundle appended to block
        for next session, e segment of block is queued for transmission,
        f block has been fully segmented for transmission, g segment 
        popped from transmission queue, h positive ACK received for 
        block and session ended, s segment received, t block has been
        fully received, @ negative ACK received for block and segments
        retransmitted, = unacknowledged checkpoint was retransmitted,
        + unacknowledged report segment was retransmitted, { export 
        session canceled locally (by sender), } import session canceled
        by remote sender, [ import session canceled locally 
        (by receiver), ] export session canceled by remote receiver"


5. IANA Considerations

At this time, this protocol has no fields registered by IANA.

6. References

6.1. Informative References

[I-D.birrane-dtn-ama] Birrane, E., "Asynchronous Management Architecture", Internet-Draft draft-birrane-dtn-ama-07, June 2018.

6.2. Normative References

[I-D.birrane-dtn-adm] Birrane, E., DiPietro, E. and D. Linko, "AMA Application Data Model", Internet-Draft draft-birrane-dtn-adm-02, June 2018.
[I-D.birrane-dtn-amp] Birrane, E., "Asynchronous Management Protocol", Internet-Draft draft-birrane-dtn-amp-04, June 2018.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC5326] Ramadas, M., Burleigh, S. and S. Farrell, "Licklider Transmission Protocol - Specification", RFC 5326, DOI 10.17487/RFC5326, September 2008.

Authors' Addresses

Edward J. Birrane Johns Hopkins Applied Physics Laboratory EMail:
Evana DiPietro Johns Hopkins Applied Physics Laboratory EMail:
David Linko Johns Hopkins Applied Physics Laboratory EMail: