The Subnetwork Encapsulation and Adaptation Layer (SEAL)
RFC 5320

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Independent Submission                                   F. Templin, Ed.
Request for Comments: 5320                  Boeing Research & Technology
Category: Experimental                                     February 2010
ISSN: 2070-1721

        The Subnetwork Encapsulation and Adaptation Layer (SEAL)

Abstract

   For the purpose of this document, subnetworks are defined as virtual
   topologies that span connected network regions bounded by
   encapsulating border nodes.  These virtual topologies may span
   multiple IP and/or sub-IP layer forwarding hops, and can introduce
   failure modes due to packet duplication and/or links with diverse
   Maximum Transmission Units (MTUs).  This document specifies a
   Subnetwork Encapsulation and Adaptation Layer (SEAL) that
   accommodates such virtual topologies over diverse underlying link
   technologies.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for examination, experimental implementation, and
   evaluation.

   This document defines an Experimental Protocol for the Internet
   community.  This is a contribution to the RFC Series, independently
   of any other RFC stream.  The RFC Editor has chosen to publish this
   document at its discretion and makes no statement about its value for
   implementation or deployment.  Documents approved for publication by
   the RFC Editor are not a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc5320.

IESG Note

   This RFC is not a candidate for any level of Internet Standard.  The
   IETF disclaims any knowledge of the fitness of this RFC for any
   purpose and in particular notes that the decision to publish is not
   based on IETF review for such things as security, congestion control,
   or inappropriate interaction with deployed protocols.  The RFC Editor
   has chosen to publish this document at its discretion.  Readers of
   this document should exercise caution in evaluating its value for
   implementation and deployment.  See RFC 3932 for more information.

Templin                       Experimental                      [Page 1]
RFC 5320                          SEAL                     February 2010

Copyright Notice

   Copyright (c) 2010 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
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.

Templin                       Experimental                      [Page 2]
RFC 5320                          SEAL                     February 2010

Table of Contents

   1. Introduction ....................................................4
      1.1. Motivation .................................................4
      1.2. Approach ...................................................6
   2. Terminology and Requirements ....................................6
   3. Applicability Statement .........................................7
   4. SEAL Protocol Specification - Tunnel Mode .......................8
      4.1. Model of Operation .........................................8
      4.2. ITE Specification .........................................10
           4.2.1. Tunnel Interface MTU ...............................10
           4.2.2. Accounting for Headers .............................11
           4.2.3. Segmentation and Encapsulation .....................12
           4.2.4. Sending Probes .....................................14
           4.2.5. Packet Identification ..............................15
           4.2.6. Sending SEAL Protocol Packets ......................15
           4.2.7. Processing Raw ICMPv4 Messages .....................15
           4.2.8. Processing SEAL-Encapsulated ICMPv4 Messages .......16
      4.3. ETE Specification .........................................17
           4.3.1. Reassembly Buffer Requirements .....................17
           4.3.2. IPv4-Layer Reassembly ..............................17
           4.3.3. Generating SEAL-Encapsulated ICMPv4
                  Fragmentation Needed Messages ......................18
           4.3.4. SEAL-Layer Reassembly ..............................19
           4.3.5. Delivering Packets to Upper Layers .................20
   5. SEAL Protocol Specification - Transport Mode ...................20
   6. Link Requirements ..............................................21
   7. End System Requirements ........................................21
   8. Router Requirements ............................................21