NMRG LM. Contreras
Internet-Draft Telefonica
Intended status: Informational P. Lucente
Expires: 27 April 2023 NTT
October 2022
Interconnection Intents
draft-contreras-nmrg-interconnection-intents-03
Abstract
This memo introduces the use case of the usage of intents for
expressing advance interconnection features, further than traditional
IP peering.
Status of This Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Evolution of Network interconnection . . . . . . . . . . . . 3
2.1. Potential interconnection intent types . . . . . . . . . 3
2.2. Interconnection intent lifecycle . . . . . . . . . . . . 4
2.3. Protocol aspects . . . . . . . . . . . . . . . . . . . . 5
3. Interconnection intent structure . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
The success of Internet-based services has been built on top of the
global reachability of content accessed by the end-users, which is
facilitated by the interconnection of individual networks owned by
distinct service providers constituting independent administrative
domains.
Such interconnection services have been initially based simply on
delivery of IP traffic between the interconnected parties leveraging
on BGP. This peer model enables full connectivity. However, the
traditional interconnection model shows some limitations when
additional information to that related to routing is needed.
New network capabilities based on programmability and virtualization
are producing service situations where a connectivity-only approach
is not sufficient. The increasing availability of computing
capabilities internal to the networks, or attached to them, enable
new scenarios where those capabilities can be consumed through the
advertisement or exposure of these execution environments (i.e., in
terms of compute, storage and associated networking resources). Such
information from an interconnected provider can be obtained from e.g.
[I-D.llc-teas-dc-aware-topo-model].
In addition or complementary to that, even services or network
functions could be advertised in order to make them available for
interconnection. For example, as service we could consider the
advertisement of CDN capabilities as in CDNi approach [RFC7336],
while as network function we could consider functions like firewall,
CGNAT, etc, present in the network
[I-D.ietf-teas-sf-aware-topo-model].
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All these scenarios present clear evolutions of the interconnection
model which can not be simply expressed through existing mechanisms,
or at least, cannot be expressed in a simple (and comprehensive) way
with such existing mechanisms. Here is where an advanced
interconnection intent can assist on declaring the goal of the
interconnection transcending pure IP traffic exchange and including
more advance capabilities as the ones mentioned before.
2. Evolution of Network interconnection
It becomes clear the trend to increasingly rely on multi-domain
scenarios for the provision of services. For instance, the access
today to an on-demand OTT video on Internet implies the interaction
of more than one single administrative domain. Thus, end-to-end
service delivery over multiple providers or domains is becoming the
norm.
Complex network services leveraging on virtualization solutions and
different infrastructure environments pertaining to distinct
administrative domains (i.e., operated and managed by distinct
providers) can be easily foreseen.
It is then necessary to explore mechanisms for interconnecting that
multiple domain environments in a common, portable way independently
of the owner of such infrastructure.
2.1. Potential interconnection intent types
The interconnection intent should provide enough abstractions to
express a variety of interconnection options.
The purpose of the interconnection intent can be multiple:
* To enable multi-domain network service programming, by soliciting
interconnection of service / network functions in different
domains
* To enable multi-domain deployment of virtualized network
functions, by advertising the availability of compute and storage
resources in different domains
* To facilitate multi-domain network function or service charging,
by advertising (cumulative) costs in the different domains
* To enable traffic interchange, ie. IP as in traditional peering
or optical
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* To put in place the right collection of policies to implement and
operate the interconnection
* To facilitate whatever combination of all of them
2.2. Interconnection intent lifecycle
[RFC9315] defines an intent lifecycle composed of two phases, namely
fulfillment and assurance. Figure 1 captures the intent procedure
for the fulfillment phase.
User Space : Translation / IBS : Network Ops
: Space : Space
: :
+----------+ : +----------+ +-----------+ : +-----------+
Fulfill |recognize/|---> |translate/|-->| learn/ |-->| configure/|
|generate | | | | plan/ | | provision |
|intent |<--- | refine | | render | : | |
+----------+ : +----------+ +-----------+ : +-----------+
: :
.........................................................................
Provider A : Provider B
---------- : ----------
:
- Select interconn. : - Mapping of intent types to : - Establishment of
intent type : protocols / APIs for : protocol sessions
- Specify targeted : coveying targeted resources : or API requests
resources (i.e., : - Parametrization of that : for configure or
routes, compute : protocols / APIs, e.g. : provisioning
quotes, service : leveraging on data models : targeted resources
functions, etc.) : :
: :
Figure 1: Fulfillment phase of the Interconnection Intent
Similarly, Figure 2 sketches the intent procedure for the assurance
phase.
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: +--------+ :
: |validate| : +----------+
: +----^---+ <----| monitor/ |
Assure +-------+ : +---------+ +-----+---+ : | observe/ |
|report | <---- |abstract |<---| analyze | <----| |
+-------+ : +---------+ |aggregate| : +----------+
: +---------+ :
.....................................................................
Provider A : Provider B
---------- : ----------
:
- Analysis of the : - Checking of monitored data : - Collection of
reported metrics : for internal closed loops : telemetry info
against the intent : to ensure commited SLOs : related to allocated
request : (inner closed loop) : resources (i.e.,
- Trigger of actions : - Aggregation of data : routes, compute
if needed, e.g., : producing an abstracted view: quotes, service
new intent (outer : fitted to the intent request: functions, etc.)
closed loop) : :
Figure 2: Assurance phase of the Interconnection Intent
Both Fulfillment and Assurance phases are integral part of the
interconnection intent.
2.3. Protocol aspects
Ultimately the ideas and notions elaborated in this document will
need to find room in a framework made of one or multiple protocols
(ie. BGP, LISP, ALTO, etc.) and/or API definitions. While the exact
definition of such framework is left as future work, in this document
we intend to perform some seminal work in this sense (ie. identify
existing protocols that could fit, determine gaps of such protocols,
etc.).
3. Interconnection intent structure
In order to address the different interconnection intent types
described in section 2.1, the structure of the intent should be
sufficiently flexible to allow the expression of different targets.
Thus, the intent structure could include:
* Information of the type of data traffic being subject of the
interconnection intent (e.g., IP prefixes involved) among
providers.
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* Service functions expected to be supported by the peer provider.
These could be expressed in terms of type of service function and
number of instances required. Furthermore, it can be necessary to
consider how the service functions are expected to be connected in
terms of topology (i.e., service function graph).
* Resources expected to be offered by the peer provider. These
could be expressed in terms of raw values of number of CPUs,
memory and storage size, or bandwidth capacity, or alternatively,
in terms of quotas grouping resources in a predefined manner.
* Constraints that could apply to whatever of the elements included
in the interconnection intent, including traffic steering ones.
Aspects such as committed rates, burst size, cumulative traffic,
service function affinity, redundancy, traffic engineering (e.g.,
latency), etc., could be part of such constraints.
* Further information that could be necessary for delivering an end-
to-end service by means of the intent.
4. Security Considerations
To be done.
5. IANA Considerations
This draft does not include any IANA considerations
6. References
[I-D.ietf-teas-sf-aware-topo-model]
Bryskin, I., Liu, X., Lee, Y., Guichard, J., Contreras, L.
M., Ceccarelli, D., Tantsura, J., and D. Shytyi, "SF Aware
TE Topology YANG Model", Work in Progress, Internet-Draft,
draft-ietf-teas-sf-aware-topo-model-09, 27 February 2022,
<https://www.ietf.org/archive/id/draft-ietf-teas-sf-aware-
topo-model-09.txt>.
[I-D.llc-teas-dc-aware-topo-model]
Lee, Y., Liu, X., and M. Luis Contreras, "DC aware TE
topology model", Work in Progress, Internet-Draft, draft-
llc-teas-dc-aware-topo-model-02, 11 July 2022,
<https://www.ietf.org/archive/id/draft-llc-teas-dc-aware-
topo-model-02.txt>.
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[RFC7336] Peterson, L., Davie, B., and R. van Brandenburg, Ed.,
"Framework for Content Distribution Network
Interconnection (CDNI)", RFC 7336, DOI 10.17487/RFC7336,
August 2014, <https://www.rfc-editor.org/info/rfc7336>.
[RFC9315] Clemm, A., Ciavaglia, L., Granville, L. Z., and J.
Tantsura, "Intent-Based Networking - Concepts and
Definitions", RFC 9315, DOI 10.17487/RFC9315, October
2022, <https://www.rfc-editor.org/info/rfc9315>.
Acknowledgments
This work has been partly funded by the European Commission through
the H2020 project 5GROWTH (Grant Agreement no. 856709).
Authors' Addresses
Luis M. Contreras
Telefonica
Ronda de la Comunicacion, s/n
Sur-3 building, 1st floor
28050 Madrid
Spain
Email: luismiguel.contrerasmurillo@telefonica.com
URI: http://lmcontreras.com/
Paolo Lucente
NTT
Siriusdreef 70-72
2132 Hoofddorp, WT
Netherlands
Email: paolo@ntt.net
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