TCP Usage Guidance in the Internet of Things (IoT)
draft-ietf-lwig-tcp-constrained-node-networks-13
Document | Type | Active Internet-Draft (lwig WG) | ||
---|---|---|---|---|
Authors | Carles Gomez , Jon Crowcroft , Michael Scharf | |||
Last updated | 2021-02-25 (latest revision 2020-10-30) | |||
Replaces | draft-gomez-lwig-tcp-constrained-node-networks | |||
Stream | IETF | |||
Intended RFC status | Informational | |||
Formats | plain text xml pdf htmlized (tools) htmlized bibtex | |||
Reviews | ||||
Stream | WG state | Submitted to IESG for Publication | ||
Document shepherd | Zhen Cao | |||
Shepherd write-up | Show (last changed 2020-10-08) | |||
IESG | IESG state | RFC Ed Queue | ||
Action Holders |
(None)
|
|||
Consensus Boilerplate | Yes | |||
Telechat date | ||||
Responsible AD | Erik Kline | |||
Send notices to | Zhen Cao <zhencao.ietf@gmail.com> | |||
IANA | IANA review state | Version Changed - Review Needed | ||
IANA action state | No IANA Actions | |||
RFC Editor | RFC Editor state | RFC-EDITOR | ||
Details |
LWIG Working Group C. Gomez Internet-Draft UPC Intended status: Informational J. Crowcroft Expires: May 3, 2021 University of Cambridge M. Scharf Hochschule Esslingen October 30, 2020 TCP Usage Guidance in the Internet of Things (IoT) draft-ietf-lwig-tcp-constrained-node-networks-13 Abstract This document provides guidance on how to implement and use the Transmission Control Protocol (TCP) in Constrained-Node Networks (CNNs), which are a characteristic of the Internet of Things (IoT). Such environments require a lightweight TCP implementation and may not make use of optional functionality. This document explains a number of known and deployed techniques to simplify a TCP stack as well as corresponding tradeoffs. The objective is to help embedded developers with decisions on which TCP features to use. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on May 3, 2021. Copyright Notice Copyright (c) 2020 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (https://trustee.ietf.org/license-info) in effect on the date of Gomez, et al. Expires May 3, 2021 [Page 1] Internet-Draft TCP in IoT October 2020 publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Characteristics of CNNs relevant for TCP . . . . . . . . . . 4 2.1. Network and link properties . . . . . . . . . . . . . . . 4 2.2. Usage scenarios . . . . . . . . . . . . . . . . . . . . . 5 2.3. Communication and traffic patterns . . . . . . . . . . . 6 3. TCP implementation and configuration in CNNs . . . . . . . . 6 3.1. Addressing path properties . . . . . . . . . . . . . . . 7 3.1.1. Maximum Segment Size (MSS) . . . . . . . . . . . . . 7 3.1.2. Explicit Congestion Notification (ECN) . . . . . . . 8 3.1.3. Explicit loss notifications . . . . . . . . . . . . . 9 3.2. TCP guidance for single-MSS stacks . . . . . . . . . . . 9 3.2.1. Single-MSS stacks - benefits and issues . . . . . . . 9 3.2.2. TCP options for single-MSS stacks . . . . . . . . . . 10 3.2.3. Delayed Acknowledgments for single-MSS stacks . . . . 10 3.2.4. RTO calculation for single-MSS stacks . . . . . . . . 11 3.3. General recommendations for TCP in CNNs . . . . . . . . . 12 3.3.1. Loss recovery and congestion/flow control . . . . . . 12 3.3.1.1. Selective Acknowledgments (SACK) . . . . . . . . 13 3.3.2. Delayed Acknowledgments . . . . . . . . . . . . . . . 13 3.3.3. Initial Window . . . . . . . . . . . . . . . . . . . 14 4. TCP usage recommendations in CNNs . . . . . . . . . . . . . . 14 4.1. TCP connection initiation . . . . . . . . . . . . . . . . 14 4.2. Number of concurrent connections . . . . . . . . . . . . 15 4.3. TCP connection lifetime . . . . . . . . . . . . . . . . . 15 5. Security Considerations . . . . . . . . . . . . . . . . . . . 17 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 7. Annex. TCP implementations for constrained devices . . . . . 18 7.1. uIP . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 7.2. lwIP . . . . . . . . . . . . . . . . . . . . . . . . . . 19 7.3. RIOT . . . . . . . . . . . . . . . . . . . . . . . . . . 19 7.4. TinyOS . . . . . . . . . . . . . . . . . . . . . . . . . 20Show full document text