RAW WG CJ. Bernardos
Internet-Draft UC3M
Intended status: Standards Track A. Mourad
Expires: July 22, 2021 InterDigital
January 18, 2021
Extensions to enable wireless reliability and availability in multi-
access edge deployments
draft-bernardos-raw-mec-01
Abstract
There are several scenarios involving multi-hop heterogeneous
wireless networks requiring reliable and available features combined
with multi-access edge computing, such as Industry 4.0. This
document describes solutions integrating IETF RAW and ETSI MEC,
fostering discussion about extensions at both IETF and ETSI MEC to
better support these scenarios.
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 July 22, 2021.
Copyright Notice
Copyright (c) 2021 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 extracted from this document must
Bernardos & Mourad Expires July 22, 2021 [Page 1]
Internet-Draft RAW and MEC integration January 2021
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. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 5
4. RAW and MEC integration . . . . . . . . . . . . . . . . . . . 7
4.1. MEC app request for RAW . . . . . . . . . . . . . . . . . 8
4.2. RAW OAM triggering MEC app migration . . . . . . . . . . 11
4.3. MEC OAM for RAW updates . . . . . . . . . . . . . . . . . 13
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
6. Security Considerations . . . . . . . . . . . . . . . . . . . 15
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 15
8. Informative References . . . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction
Wireless operates on a shared medium, and transmissions cannot be
fully deterministic due to uncontrolled interferences, including
self-induced multipath fading. RAW (Reliable and Available Wireless)
is an effort to provide Deterministic Networking on across a path
that include a wireless interface. RAW provides for high reliability
and availability for IP connectivity over a wireless medium. The
wireless medium presents significant challenges to achieve
deterministic properties such as low packet error rate, bounded
consecutive losses, and bounded latency. RAW extends the DetNet
Working Group concepts to provide for high reliability and
availability for an IP network utilizing scheduled wireless segments
and other media, e.g., frequency/time-sharing physical media
resources with stochastic traffic: IEEE Std. 802.15.4 timeslotted
channel hopping (TSCH), 3GPP 5G ultra-reliable low latency
communications (URLLC), IEEE 802.11ax/be, and L-band Digital
Aeronautical Communications System (LDACS), etc. Similar to DetNet,
RAW technologies aim at staying abstract to the radio layers
underneath, addressing the Layer 3 aspects in support of applications
requiring high reliability and availability.
As introduced in [I-D.pthubert-raw-architecture], RAW separates the
path computation time scale at which a complex path is recomputed
from the path selection time scale at which the forwarding decision
is taken for one or a few packets. RAW operates at the path
selection time scale. The RAW problem is to decide, amongst the
redundant solutions that are proposed by the Patch Computation
Element (PCE), which one will be used for each packet to provide a
Bernardos & Mourad Expires July 22, 2021 [Page 2]
Internet-Draft RAW and MEC integration January 2021
Reliable and Available service while minimizing the waste of
constrained resources. To that effect, RAW defines the Path
Selection Engine (PSE) that is the counter-part of the PCE to perform
rapid local adjustments of the forwarding tables within the diversity
that the PCE has selected for the Track. The PSE enables to exploit
the richer forwarding capabilities with Packet (hybrid) ARQ,
Replication, Elimination and Ordering (PAREO), and scheduled
transmissions at a faster time scale.
Multi-access Edge Computing (MEC) -- formerly known as Mobile Edge
Computing -- capabilities deployed in the edge of the mobile network
can facilitate the efficient and dynamic provision of services to
mobile users. The ETSI ISG MEC working group, operative from end of
2014, intends to specify an open environment for integrating MEC
capabilities with service providers' networks, including also
applications from 3rd parties. These distributed computing
capabilities will make available IT infrastructure as in a cloud
environment for the deployment of functions in mobile access
networks.
One relevant exemplary scenario showing the need for an integration
of RAW and MEC is introduced next. One of the main (and distinct)
use cases of 5G is Ultra Reliable and Low Latency Communications
(URLLC). Among the many so-called "verticals" that require URLLC
features, the Industry 4.0 (also referred to as Wireless for
Industrial Applications) is probably the one with more short-term
potential. As identified in [I-D.bernardos-raw-use-cases], this
scenario also calls for RAW solutions, as cables are not that
suitable for the robots and mobile vehicles typically used in
factories. This is also a very natural scenario for MEC deployments,
as bounded, and very low latencies are needed between the robots and
physical actuators and the control logic managing them. Figure 1
depicts an exemplary scenario of a factory where terminals (robots
and mobile automated guided vehicles) are wirelessly connected.
Control applications running in the edge (implemented as MEC
applications) require bounded low latencies and a guaranteed
availability, despite the mobility of the terminals and the changing
wireless conditions. An heterogeneous wireless mesh network is used
to provide connectivity inside the factory.
Bernardos & Mourad Expires July 22, 2021 [Page 3]
Internet-Draft RAW and MEC integration January 2021
-----------
| PCE |
-----+-----
|
--+--
( )
( )
( )
--+--
|
-----------
| RAW PSE |
-----+-----
|
____________________+__________________________________
| *( ( o ) ) |
| RAW * * ^ |
| network ****** * / \ |
| ******* * / \ ----- |
| * ** ------- |app| |
| * * | RAW | ------- |
| ( ( o ) )* * |node |-| MEC | |
| ----- ^ *( ( o ) ) ------- ------- |
| |app| / \ ^ * |
| ----- / \ / \ ** |
| |app| ------- / \ *( ( o ) ) |
| ------- | RAW | ------- ^ (o |
| | MEC |------|node | | RAW | / \ -\---- |
| ------- ------- |node | / \ |term| |
| o) o) ------- ------- -0--0- |
| ----/- ----/- | RAW | |
| |term| |term| |node | |
| -0--0- -0--0- ------- |
|_______________________________________________________|
Figure 1: Exemplary scenario depicting MEC and RAW in an industrial
environments
This scenario includes a wireless domain, involving multiple MEC
platforms to ensure low latency to applications, by being able to
host MEC applications in several locations, and dynamically migrate
the apps as the terminals move around and the serving MEC platform
might no longer be capable of meeting the latency requirements.
Bernardos & Mourad Expires July 22, 2021 [Page 4]
Internet-Draft RAW and MEC integration January 2021
2. Terminology
The following terms used in this document are defined by the ETSI MEC
ISG, and the IETF:
MEC host. The mobile edge host is an entity that contains a
mobile edge platform and a virtualization infrastructure which
provides compute, storage, and network resources, for the purpose
of running mobile edge applications.
MEC platform. The mobile edge platform is the collection of
essential functionalities required to run mobile edge applications
on a particular virtualization infrastructure and enable them to
provide and consume mobile edge services.
MEPM. MEC Platform Manager.
MEC applications. Mobile edge applications are instantiated on
the virtualization infrastructure of the mobile edge host based on
configuration requests validated by the mobile edge management.
PAREO. Packet (hybrid) ARQ, Replication, Elimination and
Ordering. PAREO is a superset Of DetNet's PREOF that includes
radio-specific techniques such as short range broadcast, MUMIMO,
constructive interference and overhearing, which can be leveraged
separately or combined to increase the reliability.
PSE. The Path Selection Engine (PSE) is the counter-part of the
PCE to perform rapid local adjustments of the forwarding tables
within the diversity that the PCE has selected for the Track. The
PSE enables to exploit the richer forwarding capabilities with
PAREO and scheduled transmissions at a faster time scale over the
smaller domain that is the Track, in either a loose or a strict
fashion.
3. Problem Statement
With current standards, the MEC platform(s) would have to interact
with a Path Computation Element (PCE) for data plane requests and
updates. This tremendously limits the capabilities to guarantee
real-time forwarding decisions, as it will make it challenging and
not possible to manage forwarding decisions in real or near-real
time.
RAW solutions and approaches being explored today consider the role
of the PSE, which computes at a short time scale which of the
available paths (called tracks) -- computed by a PCE -- should be
used per flow/packet and also which PAREO functions can be used, in
Bernardos & Mourad Expires July 22, 2021 [Page 5]
Internet-Draft RAW and MEC integration January 2021
order to provide the flow with the required availability and
reliability features. The PSE interacts with the PCE and with the
RAW nodes so they can setup the required per-flow state, to recognize
the flow and determine the forwarding policy to be applied. These
RAW forwarding decisions can be distributed among the necessary nodes
using in-band signaling (e.g., extending Segment Routing, BIER-TE or
DETNET tagging) or can be taken autonomously by each forwarding node
locally (based on its knowledge of the status of the network, gained
via OAM RAW-specific mechanisms).
Figure 1 shows an exemplary scenario, depicting an industrial
environment where different nodes are wirelessly connected to provide
connectivity to several stationary and mobile terminals (i.e.,
robots). Industry environments are a good example of applications
where reliability and availability are critical. Ensuring this in
wireless heterogeneous and multi-hop networks requires using multiple
paths, using PAREO functions and even using dual or multiple
connectivity. Terminal mobility makes it even more challenging to
guarantee certain reliability and availability levels, due to the
dynamic and fast changes that this needs at the data plane level.
The short-time scale forwarding decisions that are required to ensure
reliability and availability with terminal mobility cannot be managed
if MEC platforms can only interact with the data plane through the
PCE.
The PCE is responsible for routing computation and maintenance in a
network and it is typically a centralized entity that can even reside
outside the network. It is meant to compute and establish redundant
paths, but not to be sensitive/reactive to transient changes, and
therefore is not capable of ensuring a certain level of reliability
and availability in a wireless heterogeneous mesh network, especially
if some of the nodes (e.g., the end terminals) might be mobile. With
currently standardized solutions, a MEC platform could only interact
with the RAW network through the PCE, most possibly through the Mp2
reference point defined by ETSI MEC. This reference point is defined
between the MEC platform and the data plane of the virtualization
infrastructure to instruct the data plane on how to route traffic
among applications, networks, services, etc. This reference point is
not further specified by ETSI MEC, but it would be the one that could
be used by current solutions to allow for MEC to request the data
plane on the RAW network a certain behavior (in terms of availability
and reliability) for MEC app traffic flows. With existing solutions,
the PCE would be the entry point for configuring and managing the RAW
network, probably through the Mp2 reference point. Note that the PCE
might reside outside the RAW network, the path between the RAW
network and the PCE might be expensive and slow (e.g., it might need
to traverse the whole RAW network) and reaching to the PCE can also
Bernardos & Mourad Expires July 22, 2021 [Page 6]
Internet-Draft RAW and MEC integration January 2021
be slow in regards to the speed of events that affect the forwarding
operation at the radio layer.
Additionally, the MEC architecture as currently defined by ETSI does
not have any component designed to deal with the specifics of an
heterogeneous wireless multi-hop networks (such a RAW one), and
therefore, it is very limited in terms of what a MEC app (through the
MEC platform) can request to the data plane of an heterogeneous
wireless multi-hop network. Besides, this lack of RAW-aware
component at the ETSI MEC architecture prevents any enhancement at
either the MEC side (e.g., MEC app migrations triggered by RAW status
updates) or the RAW side (e.g., PAREO function updates triggered by
MEC app/terminal mobility).
Because of all these aforementioned reasons, it is needed to define a
new RAW-enabled component at the ETSI MEC architecture, aimed at
enabling a more direct interaction between the MEC platform and the
RAW network, allowing the MEC platform to notify events and/or
request actions to the RAW network quick enough. This involves some
challenges, as the RAW PSE has to understand the needs from the
running MEC applications, so it can properly configure the RAW nodes
so the data plane provides the required reliability and availability.
4. RAW and MEC integration
This document defines a new entity inside the MEC platform: the RAW
ctrl. This entity is responsible for computing what to instruct the
RAW PSE, based on the requirements of the MEC apps, as well as to
take decisions at the MEC side (e.g., migration of apps) based on
information about the RAW network status.
As a result of the introduction of the RAW ctrl and the actions it is
responsible of, new interactions and interface semantics are added.
These interactions and semantics can be terminated at either the PCE
or the RAW PSE, depending on the requirements of the MEC apps. For
near real-time coordination and control between MEC and RAW
mechanisms, the interactions are between the RAW ctrl and the RAW
PSE. We mostly refer to this deployment model from now on, as it is
the one that allow for near real-time updates on the forwarding
plane, but note that an alternative deployment model in which the RAW
ctrl interacts with the PCE is also possible, though only supporting
non real-time interactions.
The MEC-RAW new interface semantics/extensions depicted in Figure 2
allows the MEC platform to issue requests to the RAW network, through
the RAW PSE, so it can behave as required by MEC apps.
Bernardos & Mourad Expires July 22, 2021 [Page 7]
Internet-Draft RAW and MEC integration January 2021
------------ --- Data plane
| MEC host | ------- ... Control plane
---------- ------------ .......+ PCE +..
| Mobile | . . ---+--- .( ( o ) ) ( ( o ) )
| edge | ------+--------------.------ | . ^ ^
| orch. | | MEC host . | | . / \ / \
----+----- | ------------.---- | | . / \ / \
. .............+ ------ ---+-- | --+-- ..+------ -------
----+----- . | ----- | | ME | |RAW +.....+RAW| | RAW +...+ RAW |
| Mobile | . | |app+..+ |serv| |ctrl| | | |PSE+....+node | |node +
| edge +.. | ----- | ------ ------ | | ----- ---+--+---+------
|platform| | |app+..+ MEC platform | | |
|manager | | --+-- ----------------- | |
---------- ----|----------------------- |
| |
+------------------------------------+
Figure 2: Block diagram
The new semantics of the interface between the MEC platform and the
RAW PSE do not only serve to convey the requests, but also to
synchronize the status and topology of the RAW (relevant portion of
the) network, enabling to perform real-time or near-real time
forwarding decisions. In the sequel, we show different exemplary
signaling diagrams for the most relevant procedures.
4.1. MEC app request for RAW
Here we specify the interface extensions and signaling procedures
needed to enable a MEC app describe and request its needs in terms of
availability and reliability. As it will be further developed in
other subsections, the wireless network conditions could also have an
impact back on the MEC platform (e.g., by triggering the migration of
the MEC app).
Figure 3 shows an exemplary signaling flow diagram, in which a
certain MEC app request a given behavior for the treatment of the
packets the app generates. We consider an industrial wireless
application scenario, as the one used in previous sections, as an
example for the sake of describing the interface and specified
interactions.
The MEC platform is enhanced with a RAW ctrl entity, as introduced in
the previous section. The RAW ctrl is a RAW-aware component within
the MEC architecture that enables the required interactions with the
RAW network, through the RAW PSE. This allows MEC apps to: (i) adapt
to RAW conditions (e.g., if the requested reliability and
availability is not possible), and (ii) dynamically modify the
Bernardos & Mourad Expires July 22, 2021 [Page 8]
Internet-Draft RAW and MEC integration January 2021
requested flow forwarding to the RAW network, based on the MEC app
and mobility conditions.
+-----------+ +-----+ +----+ +----+ +----+ +----+
| RAW | | RAW | |RAW | |RAW | |RAW | |RAW |
| app ctrl | | PSE | |node| |node| |node| |term|
+-----------+ +-----+ +----+ +----+ +----+ +----+
| | | | | | |
1.MEC app req. | | | | |
|....>| | | | | |
| | | | | | |
| 2a.MEC-to-RAW req. | | | |
|(flow ID,flow spec,reqs.) | | | |
| |..........>| | | | |
| | | | | | |
| 2b.MEC-to-RAW resp. | | | |
| (flow ID,status=OK) | | | |
| |<..........| | | | |
| | | 3.RAW control | | |
| | | (flow ID,flow spec,PAREO) | |
| | |..........>| | | |
| | |.....................>| | |
| | |................................>| |
| | | | | | |
| 4a.MEC app | |4b.MEC app traffic w/ in-band |
| traffic | | RAW control (flow ID, PAREO) |
|<--------------------------->|<------------------->| |
| | | | (example: packet replication/ |
| | | | overhearing, elimination) |
| | | |<-------->|<-------->|<------->|
| | | | | | |
Figure 3: MEC app request for RAW
We next explain each of the steps illustrated in the figure:
1. A MEC app which is going to be consumed by a given terminal (or
set of terminals, though in this example we show just one
consumer), specifies to the MEC platform the characteristics of
the traffic is going to generate and its associated requirements.
2. The MEC platform -- namely the RAW ctrl component, which is RAW-
aware and knows the characteristics of the deployment -- analyzes
the characteristics of the MEC app traffic and the provided
requirements, and generates a new request -- over a new interface
between the MEC platform and the RAW PSE -- that includes, among
others, the following parameters:
Bernardos & Mourad Expires July 22, 2021 [Page 9]
Internet-Draft RAW and MEC integration January 2021
* An ID for the given flow, which can be used for future near
real-time update/configuration operations on the same flow.
* The flow specification, describing the characteristics of the
packets, allowing an efficient identification of flow(s) based
on well-known fields in IPv4, IPv6, and transport layer
headers like TCP and UDP. An example of how to do this is
defined in the Traffic Selectors for Flow Bindings [RFC6088].
* The requirements of the flow in terms of reliability and
availability.
3. The RAW PSE processes the request, and based on its knowledge of
the network (topology, node capabilities and ongoing flows)
computes the best way of transmitting the packets over the RAW
network (using the available paths/tracks, previously computed by
a PCE). Note that at this point it might be possible that the
RAW PSE realizes that it is not possible to provide the requested
reliability and availability characteristics, and would report
that back to the MEC platform (which might issue a new request
with less requirements). The RAW PSE sends control packets to
each of the RAW nodes involved, instructing how to deal with the
packets belonging to the MEC app flow. This includes:
* assigning an ID to the flow;
* instructing the entry point in the RAW network to tag packets
with that ID;
* specific PAREO functions to be used by each of the RAW nodes.
This might be signaled to each of the RAW nodes, or just to
some of them (e.g., only the entry point) who can then use in-
band signaling to specify it.
4. The MEC app generates traffic (step 4a in the figure) which
arrives at the RAW entry point in the network, which following
the instructions of the RAW PSE, encapsulates and tags the
packet, and might also include in-band signaling (e.g., using
Segment Routing). Some PAREO functions are applied to the MEC
app traffic packets (step 4b in the figure) to achieve the
required levels of reliability and availability. In the figure,
as an example, packets are replicated (this could be done by
means of wireless overhearing) at one point of the network, and
then later duplicated packets eliminated.
Bernardos & Mourad Expires July 22, 2021 [Page 10]
Internet-Draft RAW and MEC integration January 2021
4.2. RAW OAM triggering MEC app migration
Here we specify the mechanisms for MEC to benefit from RAW OAM
information, for example, to trigger the migration of a MEC
application to a different MEC platform, to ensure that the
requirements of the MEC app continue to be met.
Bernardos & Mourad Expires July 22, 2021 [Page 11]
Internet-Draft RAW and MEC integration January 2021
+----+ +--------+ +---+ +----+ +----+ +----+ +----+
| | | RAW | |RAW| |RAW | |RAW | |RAW | |RAW |
|MEPM| |app ctrl| |PSE| |node| |node| |node| |term|
+----+ +--------+ +---+ +----+ +----+ +----+ +----+
| | | | | | | |
| | MEC app | MEC app traffic w/ in-band |
| | traffic | RAW control (flow ID, PAREO) |
| |<--------------------->|<------------->| |
| | | | (example: packet replication/ |
| | | | overhearing, elimination) |
| | | | |<----->|<----->|<------>|
| | | | | | | |
| | | | 1.RAW OAM signalling | |
| +--------+ | | |<.......| | | |
| | RAW | | 2.MEC-to-RAW |<...............| | |
| |app ctrl| | (flow ID, |<.......................| |
| +--------+ | status=KO)|<................................|
| | | | |<........| | | | |
|3.MEC app migration| | | | | |
|<.................>| | | | | |
|<.......>| | | | | | | |
| | | | | | | | | |
| | | 4a.MEC-to-RAW req.| | | | |
| | (flow ID,flow spec,reqs.) | | | |
| | |..................>| | | | |
| | 4b.MEC-to-RAW resp. | | | | |
| | (flow ID,status=OK) | 5.RAW control | | |
| | |<..................| (flow ID,flow spec,PAREO) |
| | | | | |.......>| | | |
| | | | | |...............>| | |
| | | | | |.......................>| |
| | | | | |................................>|
| | | | | | | | | |
| 6a.MEC app| | | 6b.MEC app traffic w/ in-band |
| | traffic| | | RAW control (flow ID, PAREO) |
| |<------------------------------->|<------------->| |
| | | | | | (example: packet replication/ |
| | | | | | overhearing, elimination) |
| | | | | | |<----->|<----->|<------>|
| | | | | | | | | |
Figure 4: RAW OAM triggering MEC app migration
Figure 4 shows an exemplary signaling flow diagram, in which changes
in the RAW network, detected thanks to RAW OAM, trigger the migration
of a MEC app. We assume there is already a MEC app deployed and
traffic is already flowing (i.e., all the procedures explained in the
Bernardos & Mourad Expires July 22, 2021 [Page 12]
Internet-Draft RAW and MEC integration January 2021
previous section took already place). We next explain each of the
steps illustrated in the figure:
1. RAW OAM signaling is periodically and reactively exchanged
between the RAW nodes and the RAW PSE
[I-D.theoleyre-raw-oam-support].
2. If the conditions of the network get worse (e.g., because of
changes in the radio propagation of a critical link), making it
impossible to guarantee the required levels of reliability and
availability, this generates a message from the RAW PSE to the
MEC platform, indicating that a given MEC app flow can no longer
be served.
3. The currently serving MEC platform triggers a MEC app migration
to a different MEC platform. This involves the MEC platform
manager. Note that the MEC platform might provide suggestions
regarding where to migrate the MEC app, based on its knowledge of
the RAW network status, acquired by the RAW ctrl through
interactions with the PSE.
4. The same steps 2-3-4 specified in the procedure described in
Section 4.1 take place. In this step, the MEC platform generates
a new request to the RAW PSE.
5. The RAW PSE processes the request, and based on its knowledge of
the network computes the best way of transmit the packets over
the RAW network. The RAW PSE sends control packets to each of
the RAW nodes involved.
6. The MEC app generates traffic, arriving at the RAW entry point in
the network, which following the instructions of the RAW PSE,
encapsulates and tags the packet.
4.3. MEC OAM for RAW updates
There are scenarios and situations where -- due to the mobility of
the terminals or the nodes hosting the MEC platform hosting a given
MEC app -- it might be needed to take actions on the RAW network:
e.g., to update the paths, apply different PAREO functions, migrate
the MEC app (thus involving a change in the RAW forwarding). This
triggers the need for mechanisms enabling the RAW PSE to get and use
MEC OAM information to update traffic forwarding at the RAW network
as needed to adapt to varying conditions, e.g., due to node mobility.
Bernardos & Mourad Expires July 22, 2021 [Page 13]
Internet-Draft RAW and MEC integration January 2021
+---------+ +-----+ +----+ +----+ +----+ +----+ +----+
| RAW | | RAW | |RAW | |RAW | |RAW | |RAW | |RAW |
|app ctrl| | PSE | |node| |node| |node| |node| |term|
+---------+ +-----+ +----+ +----+ +----+ +----+ +----+
| | | | | | | |
| MEC app | | MEC app traffic w/ in-band |
| traffic | | RAW control (flow ID, PAREO) |
|<------------------------>|<--------------->| | |
| | | | (example: packet replication/ |
| | | | overhearing, elimination) |
| | | |<------>|<------>|<-------------->|
| | | | | | | |
| |1a.Mobility trigger | | | | |
| |(flow ID,trajectory)| | | | |
| |........>| | | | | |
| | | | | | | |
| |1b.Mobility trigger ACK | | | |
| |(flow ID)| | | | | |
| |<........| | | | | |
| | | 2.RAW control | | | |
| | | (flow ID,flow spec,PAREO) | | |
| | |.........>| | | | |
| | |..................>| | | |
| | |...........................>| | |
| | |....................................>| |
| | |............................................>|
| | | | | | | |
| 3a.MEC app | |3b.MEC app traffic w/ in-band |
| traffic | | RAW control (flow ID, PAREO) |
|<------------------------>|<--------------->|<------>| |
| | | | (example: packet replication/ |
| | | | overhearing, elimination) |
| | | |<-------->|<---->|<------>|<----->|
| | | | | | | |
Figure 5: MEC OAM for RAW updates
Figure 5 shows an exemplary signaling flow diagram, in which the
mobility of the a node (in this case the terminal, but it could have
been the MEC platform hosting the MEC app) triggers the need for
updating RAW forwarding mechanisms. As in the previous section, we
assume there is already a MEC app deployed and traffic is already
flowing (i.e., all the procedures explained in Section 4.1 took
already place). We next explain each of the steps illustrated in the
figure:
1. The MEC platform notifies that the terminal consuming the MEC app
is moving (note that it other events can be notified, such as the
Bernardos & Mourad Expires July 22, 2021 [Page 14]
Internet-Draft RAW and MEC integration January 2021
mobility of the MEC platform itself), including the expected
trajectory (if can be known or predicted in advance, as it will
be the case in most cases in several scenarios, such as
industrial use cases).
2. The RAW PSE uses this information to re-compute how to best
provided the reliability and availability needed by the MEC app
traffic flow, and updates the RAW nodes about the PAREO functions
that they have to apply.
3. After this, traffic from the MEC app benefits from updated
policies, computed according to the new conditions, and ensuring
that the requirements of the MEC app continue to be fulfilled.
5. IANA Considerations
TBD.
6. Security Considerations
TBD.
7. Acknowledgments
The work in this draft will be further developed and explored under
the framework of the H2020 5Growth (Grant 856709).
8. Informative References
[I-D.bernardos-raw-use-cases]
Papadopoulos, G., Thubert, P., Theoleyre, F., and C.
Bernardos, "RAW use cases", draft-bernardos-raw-use-
cases-04 (work in progress), July 2020.
[I-D.pthubert-raw-architecture]
Thubert, P., Papadopoulos, G., and R. Buddenberg,
"Reliable and Available Wireless Architecture/Framework",
draft-pthubert-raw-architecture-05 (work in progress),
November 2020.
[I-D.theoleyre-raw-oam-support]
Theoleyre, F., Papadopoulos, G., and G. Mirsky,
"Operations, Administration and Maintenance (OAM) features
for RAW", draft-theoleyre-raw-oam-support-04 (work in
progress), October 2020.
Bernardos & Mourad Expires July 22, 2021 [Page 15]
Internet-Draft RAW and MEC integration January 2021
[RFC6088] Tsirtsis, G., Giarreta, G., Soliman, H., and N. Montavont,
"Traffic Selectors for Flow Bindings", RFC 6088,
DOI 10.17487/RFC6088, January 2011,
<https://www.rfc-editor.org/info/rfc6088>.
Authors' Addresses
Carlos J. Bernardos
Universidad Carlos III de Madrid
Av. Universidad, 30
Leganes, Madrid 28911
Spain
Phone: +34 91624 6236
Email: cjbc@it.uc3m.es
URI: http://www.it.uc3m.es/cjbc/
Alain Mourad
InterDigital Europe
Email: Alain.Mourad@InterDigital.com
URI: http://www.InterDigital.com/
Bernardos & Mourad Expires July 22, 2021 [Page 16]