Internet DRAFT - draft-gao-alto-new-transport
draft-gao-alto-new-transport
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.
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Internet-Drafts are draft documents valid for a maximum of six months
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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/
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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
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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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