Stream Control Transmission Protocol (SCTP) Network Address Translation Support
draft-ietf-tsvwg-natsupp-16
Network Working Group R. R. Stewart
Internet-Draft Netflix, Inc.
Intended status: Standards Track M. Tuexen
Expires: 10 September 2020 I. Ruengeler
Muenster Univ. of Appl. Sciences
9 March 2020
Stream Control Transmission Protocol (SCTP) Network Address Translation
Support
draft-ietf-tsvwg-natsupp-16
Abstract
The Stream Control Transmission Protocol (SCTP) provides a reliable
communications channel between two end-hosts in many ways similar to
the Transmission Control Protocol (TCP). With the widespread
deployment of Network Address Translators (NAT), specialized code has
been added to NAT for TCP that allows multiple hosts to reside behind
a NAT and yet share a single IPv4 address, even when two hosts
(behind a NAT) choose the same port numbers for their connection.
This additional code is sometimes classified as Network Address and
Port Translation (NAPT).
This document describes the protocol extensions required for the SCTP
endpoints and the mechanisms for NAT devices necessary to provide
similar features of NAPT in the single point and multi point
traversal scenario.
Finally, a YANG module for SCTP NAT is defined.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 10 September 2020.
Stewart, et al. Expires 10 September 2020 [Page 1]
Internet-Draft SCTP NAT Support March 2020
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. SCTP NAT Traversal Scenarios . . . . . . . . . . . . . . 6
4.1.1. Single Point Traversal . . . . . . . . . . . . . . . 6
4.1.2. Multi Point Traversal . . . . . . . . . . . . . . . . 7
4.2. Limitations of Classical NAPT for SCTP . . . . . . . . . 8
4.3. The SCTP-Specific Variant of NAT . . . . . . . . . . . . 8
5. Data Formats . . . . . . . . . . . . . . . . . . . . . . . . 13
5.1. Modified Chunks . . . . . . . . . . . . . . . . . . . . . 13
5.1.1. Extended ABORT Chunk . . . . . . . . . . . . . . . . 13
5.1.2. Extended ERROR Chunk . . . . . . . . . . . . . . . . 13
5.2. New Error Causes . . . . . . . . . . . . . . . . . . . . 14
5.2.1. VTag and Port Number Collision Error Cause . . . . . 14
5.2.2. Missing State Error Cause . . . . . . . . . . . . . . 14
5.2.3. Port Number Collision Error Cause . . . . . . . . . . 15
5.3. New Parameters . . . . . . . . . . . . . . . . . . . . . 15
5.3.1. Disable Restart Parameter . . . . . . . . . . . . . . 16
5.3.2. VTags Parameter . . . . . . . . . . . . . . . . . . . 16
6. Procedures for SCTP Endpoints and NAT Devices . . . . . . . . 17
6.1. Association Setup Considerations for Endpoints . . . . . 18
6.2. Handling of Internal Port Number and Verification Tag
Collisions . . . . . . . . . . . . . . . . . . . . . . . 18
6.2.1. NAT Device Considerations . . . . . . . . . . . . . . 19
6.2.2. Endpoint Considerations . . . . . . . . . . . . . . . 19
6.3. Handling of Internal Port Number Collisions . . . . . . . 19
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