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Versions: 00                                                            
ALTO                                                              K. Gao
Internet-Draft                                        Sichuan University
Intended status: Standards Track                         2 November 2020
Expires: 6 May 2021


             ALTO Extension: New Transport Layer Protocols
                    draft-gao-alto-new-transport-00

Abstract

   The current ALTO transport is based on HTTP/1.x connections between
   ALTO servers and ALTO clients.  On the other hand, recent extensions
   to HTTP/1.x such as HTTP/2 [RFC7540] and HTTP/3 [I-D.ietf-quic-http]
   introduce capabilities such as server push and stream multiplexing,
   which can potentially be integrated into ALTO to improve ALTO
   capabilities such as incremental updates.  This document identifies
   use cases of ALTO and its extensions that may benefit from the
   advanced features of HTTP/2 and HTTP/3, and proposes ALTO extensions
   to fully leverage the benefits.

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 6 May 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 publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components



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   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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions and Terminology . . . . . . . . . . . . . . . . .   2
   3.  HTTP/2 and HTTP/3 Protocol Overview . . . . . . . . . . . . .   3
     3.1.  HTTP/2  . . . . . . . . . . . . . . . . . . . . . . . . .   3
       3.1.1.  Persistent Connection . . . . . . . . . . . . . . . .   3
       3.1.2.  Server Push . . . . . . . . . . . . . . . . . . . . .   3
       3.1.3.  Stream Multiplexing . . . . . . . . . . . . . . . . .   3
     3.2.  HTTP/3  . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  ALTO Use Cases  . . . . . . . . . . . . . . . . . . . . . . .   3
     4.1.  Transport of Dependent Information Resources  . . . . . .   3
     4.2.  Transport of Incremental Update . . . . . . . . . . . . .   4
     4.3.  Transport of Multipart Messages . . . . . . . . . . . . .   4
   5.  Issues  . . . . . . . . . . . . . . . . . . . . . . . . . . .   4
     5.1.  Server Push/Stream Multiplexing for Filtered Services . .   4
   6.  ALTO Extensions . . . . . . . . . . . . . . . . . . . . . . .   4
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   4
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   The ALTO protocol {{RFC7285} and its extensions are based on HTTP/1.x
   connections between ALTO servers and clients.  Recently, newer
   versions of the HTTP protocol, i.e., HTTP/2 [RFC7540] and HTTP/3
   [I-D.ietf-quic-http], are introduced to the IETF.  The upgrades have
   many benefits such as performance gains and new features, most
   notably server push and stream multiplexing.  While the ALTO base
   protocol should work on top of HTTP/2 and HTTP/3 and gain performance
   improvement without modification, it is worth looking into the
   question of whether and how ALTO can further take advantage of the
   new features.

   The purpose of this document is 1) to identify use cases of the ALTO
   protocol and its extensions that may benefit from the new features of
   HTTP/2 and HTTP/3, and 2) to propose extensions to fully leverage the
   benefits.

2.  Conventions and Terminology

   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 [RFC2119].



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   All numeric values are in network byte order.  Values are unsigned
   unless otherwise indicated.  Literal values are provided in decimal
   or hexadecimal as appropriate.  Hexadecimal literals are prefixed
   with "0x" to distinguish them from decimal literals.

   This document uses the following terms defined in RFC 7285 [RFC7285]:
   TBD.

   This document uses the following terms defined in RFC 7540 [RFC7540]:
   TBD.

   This document uses the following terms defined in
   [I-D.ietf-quic-http]: TBD.

3.  HTTP/2 and HTTP/3 Protocol Overview

3.1.  HTTP/2

   TBD

3.1.1.  Persistent Connection

   TBD

3.1.2.  Server Push

   TBD

3.1.3.  Stream Multiplexing

   TBD

3.2.  HTTP/3

   TBD

4.  ALTO Use Cases

4.1.  Transport of Dependent Information Resources

   Features to be used: ~ Persistent connection, server push, and stream
   multiplexing

   Examples: ~ Delivery of Network Map and Cost Map, delivery of Unified
   Property Map(s)

   TBD.




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4.2.  Transport of Incremental Update

   Features to be used: ~ Persistent connection, server push, and stream
   multiplexing

   TBD.

4.3.  Transport of Multipart Messages

   Features to be used: ~ Persistent connection, server push, and stream
   multiplexing

   Example: ~ Path Vector [I-D.ietf-alto-path-vector]

   TBD.

5.  Issues

5.1.  Server Push/Stream Multiplexing for Filtered Services

   An ALTO Client may send multiple requests to the same service with
   different filters, for example, making two different requests to the
   same Filtered Cost Map service.  An intelligent ALTO server may want
   to push the related Filtered Network Maps to the ALTO Client.
   However, the two Filtered Network Maps cannot be distinguished by
   their resource URI alone.

   A similar issue is already discussed in the incremental update
   extension [I-D.ietf-alto-incr-update-sse].

   TBD.

6.  ALTO Extensions

   TBD

7.  Security Considerations

   TBD

8.  Normative References

   [I-D.ietf-alto-incr-update-sse]
              Roome, W. and Y. Yang, "ALTO Incremental Updates Using
              Server-Sent Events (SSE)", Work in Progress, Internet-
              Draft, draft-ietf-alto-incr-update-sse-22, 20 March 2020,
              <http://www.ietf.org/internet-drafts/draft-ietf-alto-incr-
              update-sse-22.txt>.



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   [I-D.ietf-alto-path-vector]
              Gao, K., Lee, Y., Randriamasy, S., Yang, Y., and J. Zhang,
              "ALTO Extension: Path Vector", Work in Progress, Internet-
              Draft, draft-ietf-alto-path-vector-11, 14 July 2020,
              <http://www.ietf.org/internet-drafts/draft-ietf-alto-path-
              vector-11.txt>.

   [I-D.ietf-alto-unified-props-new]
              Roome, W., Randriamasy, S., Yang, Y., Zhang, J., and K.
              Gao, "Unified properties for the ALTO protocol", Work in
              Progress, Internet-Draft, draft-ietf-alto-unified-props-
              new-12, 13 July 2020, <http://www.ietf.org/internet-
              drafts/draft-ietf-alto-unified-props-new-12.txt>.

   [I-D.ietf-quic-http]
              Bishop, M., "Hypertext Transfer Protocol Version 3
              (HTTP/3)", Work in Progress, Internet-Draft, draft-ietf-
              quic-http-32, 20 October 2020, <http://www.ietf.org/
              internet-drafts/draft-ietf-quic-http-32.txt>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC2387]  Levinson, E., "The MIME Multipart/Related Content-type",
              RFC 2387, DOI 10.17487/RFC2387, August 1998,
              <https://www.rfc-editor.org/info/rfc2387>.

   [RFC7285]  Alimi, R., Ed., Penno, R., Ed., Yang, Y., Ed., Kiesel, S.,
              Previdi, S., Roome, W., Shalunov, S., and R. Woundy,
              "Application-Layer Traffic Optimization (ALTO) Protocol",
              RFC 7285, DOI 10.17487/RFC7285, September 2014,
              <https://www.rfc-editor.org/info/rfc7285>.

   [RFC7540]  Belshe, M., Peon, R., and M. Thomson, Ed., "Hypertext
              Transfer Protocol Version 2 (HTTP/2)", RFC 7540,
              DOI 10.17487/RFC7540, May 2015,
              <https://www.rfc-editor.org/info/rfc7540>.

Author's Address










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   Kai Gao
   Sichuan University
   No.24 South Section 1, Yihuan Road
   Chengdu
   610000
   China

   Email: kaigao@scu.edu.cn











































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