Internet DRAFT - draft-jiang-service-oriented-ip
draft-jiang-service-oriented-ip
Network Working Group B. E. Carpenter
Internet-Draft Univ. of Auckland
Intended status: Informational S. Jiang
Expires: 16 November 2020 Huawei Technologies Co., Ltd
G. Li
Huawei Technologies
15 May 2020
Service Oriented Internet Protocol
draft-jiang-service-oriented-ip-03
Abstract
This document proposes a new, backwards-compatible, approach to
packet forwarding, where the service required rather than the IP
address required acts as the vector for routing packets at the edge
of the network. Deeper in the network, the mechanism can interface
to conventional and future methods of service or application aware
networking.
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
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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 16 November 2020.
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
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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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provided without warranty as described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Proposed Solution . . . . . . . . . . . . . . . . . . . . . . 3
3. Coexistence Issues . . . . . . . . . . . . . . . . . . . . . 8
4. Some Usage Examples . . . . . . . . . . . . . . . . . . . . . 8
5. Continuity with the Existing Internet . . . . . . . . . . . . 9
6. Interface with Service and Application Domains . . . . . . . 9
7. Security Considerations . . . . . . . . . . . . . . . . . . . 9
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
Appendix A. Possible TLV and CBOR Encodings . . . . . . . . . . 11
A.1. TLV Mapping . . . . . . . . . . . . . . . . . . . . . . . 11
A.2. CBOR Mapping . . . . . . . . . . . . . . . . . . . . . . 13
Appendix B. Change log [RFC Editor: Please remove] . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
An important aspect of the Internet today is that it is no longer a
uniform space with uniform requirements. For both technical and
economic reasons, we see an emerging trend of usage scenarios that
are confined to some form of limited domain, and which inevitably
lead to applications and protocols that are only suitable within a
given scope [I-D.carpenter-limited-domains]. In particular, various
techniques have emerged for packet treatments that are specific to a
type of application or service. This trend collides immediately with
two factors: the original design concept of an Internet with end to
end IP transparency (such that any locally defined protocol running
over IP is almost certain to escape the local network), and with the
increasing presence of middleboxes. In this emerging context, where
end to end IP service is no longer a safe assumption, and where there
is increasing demand for specific services, this document proposes a
new, backwards-compatible, approach to packet forwarding, where the
service required rather than the IP address required acts as the
vector for routing packets at the edge of the network, close to the
host requiring a particular service or application. This form of
service based packet forwarding is referred to as Service Oriented IP
(SOIP).
We propose an addition to the existing core function of the network,
which is reachability over IPv6 or IPv4. Today, IP is focussed on
reachability, using best effort forwarding both to find a route and
to automatically share transmission resources in a simple and low-
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cost way. As a result, transport protocols such as TCP and UDP learn
little or nothing about the network, beyond congestion or loss
signals. Several ISPs may lie on the path between a user and a
server, but they are largely ignorant about the services a user
requires. Typical services could be streamed content, regular
content, user posting, storage access, or calculation, but this list
is not exclusive.
Both service providers and users will benefit if a packet stream can
be identified intrinsically as requiring a certain kind of service.
This is particularly applicable for edge networks, such as those
supported by 5G technology, where there is an emphasis on upper layer
service provision. Whatever the business model - for example the ISP
operates all types of service, or the ISP operates no user services
at all and has contracts with specific service providers, or the ISP
is agnostic about user services - SOIP will allow for optimised
packet delivery. The ISP will have the choice to provide some or all
services. The user will have the choice to use ISP services or
bypass them. Traffic that leaves the domain where SOIP is in use
will be perfectly normal IPv6 or IPv4 traffic, sent by an exit node
acting as a proxy (not an IP-layer translator) for the user.
Additionally, IPv6 and IPv4 will be modelled as services available to
the user, thereby giving continuity of access to everything the user
has today. This is a logical extension of a principle already
adopted to model IPv4 as a service available via IPv6 [RFC8585].
As new service and application oriented features are deployed in the
network, SOIP will provide a seamless interface to both existing and
future mechanisms. Effectively it will make client hosts future-
proof as the network evolves.
2. Proposed Solution
NOTE: This is a preliminary draft expected to stimulate discussion,
so many details are not yet defined.
The approach is to make the service be the central component of the
network, from the end user's point of view. Conceptually, the user's
packets will be directed at a service, not at an IP host. The first
hop SOIP router will either forward the packets to an upstream SOIP
router, or immediately dispatch the session to a suitable service.
At least one SOIP router in a domain must be capable of acting as a
dispatcher. The dispatched traffic may either remain in SOIP format,
or be transformed by a proxy mechanism into a conventional IP-based
format. Figure 1 gives an overview, and Section 5 and Section 6
discuss this further.
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----------- -----------
|End-user | <-----> | SOIP |
| Host | | router |
----------- -----------
^
|
v
-------------- ----------- -----------------
| SOIP-based | | SOIP | | Unknown |
| services |---| router + |---| future |
| | |dispatcher| | services |
-------------- ------------ -----------------
| | |
-------------- | | | -----------------
|Traditional |____/ | \____|Segment Routing|
|IP services | | |services |
-------------- ------------ -----------------
| SDN |
| services |
------------
Figure 1
The service actions that the network can provide are abstracted into
a number of classes called Service Action Types (SATs). While there
needs to be flexibility and extensibility, the number of service
action types will be limited. They will not be numerous like IP
protocol numbers or well-known TCP or UDP port numbers. Along with
the SAT, a source IPv6 address is used to identify the client system.
As will be seen below, the destination IPv6 address becomes optional.
A consequence is that the IP header and some aspects of the protocol
stack have to be redesigned. We will show below how this can be done
without disturbing most of the running network. Another consequence
is that the first step in processing a packet is to process the SAT,
not the destination address (if there is one).
Traditional reachability, when required, is provided by classical
IPv6, or by IPv4 as-a-service.
When an SOIP packet enters a router, it is classified at line speed
according to the SAT. Routing to upstream SOIP routers will be based
on the SAT, not on a destination IP address. Routing from a
dispatcher may be based on the SAT if the service required is based
on SOIP, or on a conventional IP address otherwise. A preliminary
list of SATs is shown in Figure 2, with brief descriptions:
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------------------------------------------------------------------
| SATs | Direction | Description |
|----------------------------------------------------------------|
| IPv4 reachability| Request | IPv4 destination host |
| |___________| |
| | Response | IPv4 source host |
|----------------------------------------------------------------|
| IPv6 reachability| Request | IPv6 destination host |
| |___________| |
| | Response | IPv6 source host |
|----------------------------------------------------------------|
| Discovery Service| Request | Discover network services, e.g. |
| |___________| DNS, CDN. May map to IP Anycast |
| | Response | Content ID, service ID. |
| | | Or "service not available" error|
|----------------------------------------------------------------|
| Multicast Service| Request | Join multicast service for some |
| |___________| content, e.g. video stream |
| | Response | Multicast directory answers |
| | | request, provides m/c source. |
|----------------------------------------------------------------|
| Computation | Request | Submit task to network, with |
| Service | | computation type, task |
| |___________| descriptor and requester ID |
| | Response | Computation resource ID, or |
| | | direct result of task. |
| | | Or "service not available" error|
|----------------------------------------------------------------|
| Storage Service | Request | Submit/retrieve data to/from |
| | | network storage, with data |
| |___________| description and/or data ID |
| | Response | Storage locator, data ID. |
| | | Or "service not available" error|
|----------------------------------------------------------------|
| App Server | Request | To submit source code or deploy |
| Service | | package to application platform,|
| |___________| with necessary configurations. |
| | Response | Answer with service ID. |
| | | Or "service not available" error|
------------------------------------------------------------------
Figure 2
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For each request there will be a corresponding response. The details
remain to be worked out - probably a generic response message
including the SAT. To allow multiple overlapping sessions, each
request/response sequence should have a unique ID, which will be used
by the SOIP dispatcher to match service responses to the appropriate
user session.
For IPv6-only networks, is expected that IPv4 reachability will be
provided by a solution such as 464XLAT. Also, no separate SAT is
needed for IPv6 to IPv4 translation. For example, if a host requests
IPv4 reachability but supplies an IPv6 address as its own locator,
NAT64 [RFC6146] is implied.
For the moment codes for the SATs are undefined, but they are assumed
to be small integers. There are two possible approaches to the
packet format. One is to use a traditional Type-Length-Value (TLV)
layout. Another is to use a more flexible encoding at the lowest
level, taking advantage of some form of network processor in the
routers. An obvious choice would be Concise Binary Object
Representation (CBOR) [RFC7049], which combines flexibility with
efficiency. In either case we could require that the first four bits
of the wire format are a new IP version number other than 4 or 6. An
alternative, at least for early experimentation, is to run SOIP over
UDP and IPv6.
Examples of both encoding choices are described below. In either
case, the essential content of a packet header is as follows:
* The SAT code (small integer)
* Flag bits
* Traffic class (as for IPv6)
* Session Identifier (so that sessions can be tracked regardless of
IP address)
* Hop limit (small integer)
* User locator (IP address or identifier)
* Service data length (not needed in CBOR version)
* Service data (length depends on SAT)
* Payload length (not needed in CBOR version)
* Payload
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Experience with IPv4 options, and IPv6 extension headers and options,
has shown that new ones are very hard to deploy on an operational
network, and that the ones defined during the initial design are not
always useful. Therefore we propose that all options and extensions
are defined as part of the service data and are not visible as part
of the basic packet header, giving good flexibility.
We propose to include the exact equivalent of the IPv6 Traffic Class
[RFC8200], which can work exactly as for IPv6. In contrast, one
defect in the IPv6 flow label [RFC6437] is that it is different in
the two directions of a flow. Instead we propose a session ID that
is the same in both directions, which has various advantages by
allowing immediate session identification.
The flag bits provide useful indications to the routing system, if
set:
* Mobile - set if the user system is mobile
* Flow size (3 bits)
- 000 means a single packet, no flow/congestion state needed
- other values TBD indicate type of flow/congestion state
* Authenticated - set if packet authenticated (details TBD)
* Encrypted - set if encryption applied (details TBD)
Note that fragmentation is not supported. Fragmentation, and the
related mechanisms of MTU discovery, are a significant operational
problem in the current Internet [I-D.ietf-intarea-frag-fragile]. We
simply abolish this problem area in SOIP, which is designed for use
in managed networks where a single size of maximum transmission unit
(MTU) is available everywhere. An SOIP network will have a globally
defined MTU. Of course, IPv4 and IPv6 reachability services via the
open Internet will have to support PMTUD and fragmentation as best
they can, but this concerns the embedded IP packets, not the SOIP
packets, and will be invisible locally.
Appendix A outlines possible TLV and CBOR encodings of the SOIP
protocol.
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3. Coexistence Issues
SOIP is expected to coexist with IPv6; in a sense it is a low-level
method of orchestrating IPv6 connections. We assume that each SOIP
client host has at least one IPv6 address, and that SOIP routers will
announce themselves using a suitable IPv6 Router Advertisement
extension [I-D.troan-6man-universal-ra-option]. Normally, the first-
hop SOIP router will be the same as the IPv6 first-hop router.
As a result of this, all standard management mechanisms such as
NETCONF may be used without further specification. Also, when a data
connection of any kind is established after a SOIP request/response
exchange, all standard transport mechanisms are available over IPv6.
As noted above, they are subject to the locally defined MTU as long
as they remain within the SOIP domain.
We do not define how SOIP would operate in an IPv4-only network.
4. Some Usage Examples
* Storage request (upload content):
- Service data identifies storage requirement (temporary/
permanent, private/public, encryption, etc.)
- Payload identifies data (path/name.format, etc.)
* Storage request (download content):
- Service data identifies transmission requirement (streamed,
block, etc. and the specific transport protocol - UDP, TCP,
QUIC, etc. - if needed)
- Payload identifies data (path/name.format, etc.)
* Computation request
- Service data identifies computing requirement
- Payload identifies computing application
* Reachability request
- Service data gives destination IP address (or DNS name)
- Indication of transport protocol required (details TBD)
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- Indication of options or extension headers required (details
TBD)
5. Continuity with the Existing Internet
Continuity is provided in two ways:
1. A user node can simply use IP completely in parallel with SOIP.
The network stack in the user node will simply encode the IP
packets as SOIP packets with the SAT for IP reachability, and a
SOIP dispatcher will send and receive IP packets at the SOIP
domain boundary.
2. If a service in the SOIP domain needs service from elsewhere in
the IP Internet to respond to a user request, it will use a
similar dispatcher function to do so.This could also be described
as a proxy mechanism. (Of course, services in interconnected
SOIP domains may talk to each other directly.)
6. Interface with Service and Application Domains
Various techniques are emerging for service or application specific
networking within operators' networks. An overview of the
motivations is given in [I-D.li-apn6-problem-statement-usecases], and
specific techniques have been defined such as Network Service Headers
[RFC8300] and Segment Routing [RFC8402], as well as Software-Defined
Networking in general [RFC7426]. A SOIP dispatcher that is aware of
such techniques may convert SOIP traffic into one of these
mechanisms, for example by encapsulation or proxying. Furthermore,
the model is future-proof. The dispatcher could be upgraded to
support unknown future service or application oriented networking
mechanisms, without requiring changes to SOIP clients or routers.
7. Security Considerations
It is intended that both authentication and encryption should be
available for all SOIP packets. However, this requires further work,
especially to determine whether existing mechanisms for key
management can be used.
Since clients are identified by an IPv6 address, existing layer 3
privacy considerations for IPv6 addresses will apply to SOIP
[RFC7721]. Upper layer privacy considerations will depend on the
service concerned.
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8. IANA Considerations
This document makes no request of the IANA.
9. References
[I-D.carpenter-limited-domains]
Carpenter, B. and B. Liu, "Limited Domains and Internet
Protocols", Work in Progress, Internet-Draft, draft-
carpenter-limited-domains-13, 2 February 2020,
<https://tools.ietf.org/html/draft-carpenter-limited-
domains-13>.
[I-D.ietf-intarea-frag-fragile]
Bonica, R., Baker, F., Huston, G., Hinden, R., Troan, O.,
and F. Gont, "IP Fragmentation Considered Fragile", Work
in Progress, Internet-Draft, draft-ietf-intarea-frag-
fragile-17, 30 September 2019,
<https://tools.ietf.org/html/draft-ietf-intarea-frag-
fragile-17>.
[I-D.li-apn6-problem-statement-usecases]
Li, Z., Peng, S., Voyer, D., Xie, C., Liu, P., Liu, C.,
Ebisawa, K., Previdi, S., and J. Guichard, "Problem
Statement and Use Cases of Application-aware IPv6
Networking (APN6)", Work in Progress, Internet-Draft,
draft-li-apn6-problem-statement-usecases-01, 3 November
2019, <https://tools.ietf.org/html/draft-li-apn6-problem-
statement-usecases-01>.
[I-D.troan-6man-universal-ra-option]
Troan, O., "The Universal IPv6 Configuration Option
(experiment)", Work in Progress, Internet-Draft, draft-
troan-6man-universal-ra-option-02, 2 April 2020,
<https://tools.ietf.org/html/draft-troan-6man-universal-
ra-option-02>.
[RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful
NAT64: Network Address and Protocol Translation from IPv6
Clients to IPv4 Servers", RFC 6146, DOI 10.17487/RFC6146,
April 2011, <https://www.rfc-editor.org/info/rfc6146>.
[RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme,
"IPv6 Flow Label Specification", RFC 6437,
DOI 10.17487/RFC6437, November 2011,
<https://www.rfc-editor.org/info/rfc6437>.
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[RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
October 2013, <https://www.rfc-editor.org/info/rfc7049>.
[RFC7426] Haleplidis, E., Ed., Pentikousis, K., Ed., Denazis, S.,
Hadi Salim, J., Meyer, D., and O. Koufopavlou, "Software-
Defined Networking (SDN): Layers and Architecture
Terminology", RFC 7426, DOI 10.17487/RFC7426, January
2015, <https://www.rfc-editor.org/info/rfc7426>.
[RFC7721] Cooper, A., Gont, F., and D. Thaler, "Security and Privacy
Considerations for IPv6 Address Generation Mechanisms",
RFC 7721, DOI 10.17487/RFC7721, March 2016,
<https://www.rfc-editor.org/info/rfc7721>.
[RFC8200] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", STD 86, RFC 8200,
DOI 10.17487/RFC8200, July 2017,
<https://www.rfc-editor.org/info/rfc8200>.
[RFC8300] Quinn, P., Ed., Elzur, U., Ed., and C. Pignataro, Ed.,
"Network Service Header (NSH)", RFC 8300,
DOI 10.17487/RFC8300, January 2018,
<https://www.rfc-editor.org/info/rfc8300>.
[RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L.,
Decraene, B., Litkowski, S., and R. Shakir, "Segment
Routing Architecture", RFC 8402, DOI 10.17487/RFC8402,
July 2018, <https://www.rfc-editor.org/info/rfc8402>.
[RFC8585] Palet Martinez, J., Liu, H. M.-H., and M. Kawashima,
"Requirements for IPv6 Customer Edge Routers to Support
IPv4-as-a-Service", RFC 8585, DOI 10.17487/RFC8585, May
2019, <https://www.rfc-editor.org/info/rfc8585>.
[RFC8610] Birkholz, H., Vigano, C., and C. Bormann, "Concise Data
Definition Language (CDDL): A Notational Convention to
Express Concise Binary Object Representation (CBOR) and
JSON Data Structures", RFC 8610, DOI 10.17487/RFC8610,
June 2019, <https://www.rfc-editor.org/info/rfc8610>.
Appendix A. Possible TLV and CBOR Encodings
A.1. TLV Mapping
Figure 3 shows a possible type-length-value packet format.
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Version|R R R R| SAT |M F F F A E R R| Traffic Class |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Session Identifier (32 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Hop Limit | |
+-+-+-+-+-+-+-+-+ +
| |
+ +
| Client Locator / Identifier (128 bits) |
+ +
| |
+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | SD length | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| |
+ Service Data (variable length) +
... ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Payload Length | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-| +
| |
+ Payload Data (variable length) +
... ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3
Version - IP version number TBD (not needed over UDP)
R - Reserved, must be zero (not needed over UDP)
SAT - Service Action Type code
M - Mobile flag
FFF - Flow type flags (FFF = 000 for single-packet flows; other
values for longer flows)
A - Authentication flag
E - Privacy (encryption) flag
Traffic class, exactly as for IPv6
Session identifier, 32-bit pseudo random number
Client Locator / Identifier - globally unique IPv6 address
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A.2. CBOR Mapping
The packet consists of a CBOR byte string preceded by a single byte
(Figure 4). For example, for version 7, this byte would be 0x70.
This byte is not decoded as CBOR, and is not needed over UDP.
+-+-+-+-+-+-+-+-+
|Version|R R R R|
+-+-+-+-+-+-+-+-+
Figure 4
The CBOR bytes then obey the CDDL [RFC8610] specification in
Figure 5.
sat-packet = [sat, flags, traffic-class, session-id, hop-limit,
source, service-data, ?payload]
sat = 0..255
flags = bytes .size 1
traffic-class = 0..255
session-id = 0..4294967295 ;up to 32 bits
hop-limit = 0..255
client = ipv6-address
service-data = any
payload = any
ipv6-address = bytes .size 16
Figure 5
The syntax of the various service-data formats can be defined in
separate documents for each SAT value.
We assume that routers capable of handling a CBOR-based layer 3
protocol will exist, and will use some form of programmable network
processor rather than traditional ASIC or FPGA designs. This allows
great flexibility and software-friendly extensibility, especially of
the service data formats. Further investigation is needed whether
this is realistic.
Appendix B. Change log [RFC Editor: Please remove]
* draft-jiang-service-oriented-ip-00, 2019-05-07:
- Initial version
* draft-jiang-service-oriented-ip-01, 2019-06-21:
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- Editorial corrections
* draft-jiang-service-oriented-ip-02, 2019-10-29:
- Added overview diagram
- Added discussion of dispatcher function
- Clarifications and editorial corrections
* draft-jiang-service-oriented-ip-03, 2020-05-15:
- Editorial corrections
- Converted to xml2rfc v3
Authors' Addresses
Brian Carpenter
The University of Auckland
School of Computer Science
University of Auckland
PB 92019
Auckland 1142
New Zealand
Email: brian.e.carpenter@gmail.com
Sheng Jiang
Huawei Technologies Co., Ltd
Q14, Huawei Campus, No.156 Beiqing Road
Hai-Dian District, Beijing, 100095
P.R. China
Email: jiangsheng@huawei.com
Guangpeng Li
Huawei Technologies
Q14, Huawei Campus
No.156 Beiqing Road
Hai-Dian District, Beijing
100095
P.R. China
Email: liguangpeng@huawei.com
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