Internet DRAFT - draft-dcn-dmm-cats-mup
draft-dcn-dmm-cats-mup
Distributed Mobility Management N. Tran
Internet-Draft Y. Kim
Intended status: Informational Soongsil University
Expires: 5 September 2024 4 March 2024
Computing Aware Traffic Steering Consideration for Mobile User Plane
Architecture
draft-dcn-dmm-cats-mup-00
Abstract
The document [I-D.draft-mhkk-dmm-srv6mup-architecture] describes the
Mobile User Plane (MUP) architecture for Distributed Mobility
Management. The proposed architecture converts the user mobility
session information from the control plane entity to an optimal IPv6
dataplane routing information. However, when anycast address is used
for service in data network (DN), this solution can be enhanced to
dynamically set up the dataplane to the optimal service instance.
This document discusses a solution to integrate computing-aware
traffic steering capabilities to the mentioned MUP architecture. The
target applied use-case is the anycast IP services scenario, where
different instances that share the same anycast address of the
service can serve the user request. For each session request, based
on the up-to-date collected computing and network information, the
MUP controller can convert the session information to the dataplane
routing information to the optimal service instance.
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
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Internet-Drafts are draft documents valid for a maximum of six months
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 5 September 2024.
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Copyright Notice
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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
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology used in this draft . . . . . . . . . . . . . . . 3
3. Proposed Architecture . . . . . . . . . . . . . . . . . . . . 4
4. Possible Procedure and MUP Route Types changes . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6
7.1. Informative References . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7
1. Introduction
The document [I-D.draft-mhkk-dmm-srv6mup-architecture] describes the
Mobile User Plane architecture for Distributed Mobility Management.
The MUP controller (MUP-C) is the core component of this
architecture. It converts the user mobility session information from
the upper mobility management system (e.g. 5G control plane) to IPv6
dataplane routing information. Therefore, mobile user plane specific
nodes for the anchor or intermediate points are no longer required.
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This document discusses a potential enhancement to this architecture
capabilities in terms of supporting for anycast IP services. To
support high reliability and low latency services, multiple computing
instances of the same service can be often geographically distributed
to multiple nodes. A single anycast address can be used to represent
different instances of the same service. Once the User Equipment
(UE) device sends a service request, the control plane entity of the
mobile network establishes an user session. Based on the
architecture procedure in the document
[I-D.draft-mhkk-dmm-srv6mup-architecture], the session information is
then sent to the MUP-C. The MUP-C converts the session information
to the dataplane routing information between the two MUP Provider
Edges (MUP-PE) that connect to the UE connecting RAN and the chosen
service instance's location.
To support anycast IP service, the control plane should choose the
suitable service instance's location for the requested service.
However, without application server's computing and underlay network
information, the service instance's location might be simply selected
based on the closest geographical location to the user. However, it
might not be the optimal service instance's location as pointed out
in the problem statement document of IETF Computing-Aware Traffic
Steering (CATS) working group
[I-D.draft-ietf-cats-usecases-requirements].
Therefore, a solution to integrate CATS capabilities into the
mentioned MUP architecture is presented in this document. It can
provide the anycast address support for the mentioned MUP
architecture's distributed mobility management abilities.
Regarding the Distributed Mobility Management requirements described
in [RFC7333], this document addresses the "Multicast considerations"
requirement for the mentioned MUP architecture. As described in
[RFC4786], anycast is the practice of making a particular service
address available in multiple locations. Anycast support could be in
the scope of multicast support for distributed mobility management.
Besides, anycast address is one of the possible implementation
methods of CATS Service ID (CS-ID) as described in
[I-D.draft-ldbc-cats-framework]. Hence, the mentioned MUP
architecture can support anycast service by integrating CATS
capabilities.
2. Terminology used in this draft
CATS-MUP-C: Computing-aware traffic steering MUP-C which integrates
CATS path selection and MUP-C features.
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Besides, this document uses the following terminologies which has
been defined in [I-D.draft-ldbc-cats-framework]
CATS: Computing-Aware Traffic Steering takes into account the dynamic
nature of computing resource metrics and network state metrics to
steer service traffic to a service instance.
Service: An offering that is made available by a provider by
orchestrating a set of resources (networking, compute, storage,
etc.). The same service can be provided in many locations; each of
them constitutes a service instance.
Service instance: An instance of running resources according to a
given service logic.
Service contact instance: A client-facing service function instance
that is responsible for receiving requests in the context of a given
service. A single service can be represented and accessed via
several contact instances that run in different regions of a network.
CATS Path Selector (C-PS): A functional entity that computes and
selects paths towards service locations and instances and which
accommodates the requirements of service requests. Such a path
computation engine takes into account the service and network status
information.
CATS Service Metric Agent (C-SMA): A functional entity that is
responsible for collecting service capabilities and status, and for
reporting them to a C-PS.
CATS Network Metric Agent (C-NMA): functional entity that is
responsible for collecting network capabilities and status, and for
reporting them to a C-PS.
3. Proposed Architecture
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+----------------+
| Mobility |
| Management |
| System |
+----------------+
|
UE Location, Session Info, Service Anycast Address
|
+--------v-------+
| CATS-MUP-C |
+----------| +------+ |---------+
| | | C-PS | | | Service1
| +----------------+ | +----------+ Contact
UE- | | | C-SMA |/Instance
\+---+ +------+ +-----+ +------+ |----------|\
UE--|RAN|---| PE | |C-NMA| | PE |---| Service | Service2
+---+ +------+ +-----+ +------+ | Site 1 | Contact
UE-/ | | +----------+ Instance
| |
| MUP | Service1
UE- | Network | Contact
\+---+ +------+ +------+ +----------+ Instance
UE--|RAN|---| PE | | PE |---| Service |/
+---+ +------+ +------+ | Site 2 |\Service2
UE-/ | | |----------| Contact
+-------------------------------------+ | C-SMA | Instance
+----------+
Figure 1: CATS MUP Architecture using Segment Routing
Figure 1 describes the CATS-MUP architecture.
Regarding the information sent from the mobility management system,
besides session information, UE location and the requested service
anycast address of the session are also required.
The controller MUP-C in previous mentioned document is enhanced with
CATS capabilities and renamed to CATS-MUP-C. Besides converting
session information into underaly routing information function, the
CATS-MUP-C can also decide the optimal service instance's location
for the requested service in the session information. Application
servers computing and underlay network information are collected by
C-SMA and C-NMA respectively. The sub-component C-PS inside the
CATS-MUP-C is responsible for select optimal service instance's
location to serve the requested anycast service and the routing path
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to it. The decision is based on the collected CATS metrics from
C-NMA and C-SMA, and UE location. Based on this decision, the CATS-
MUP-C convert the session information into the SRv6 routing path via
the transform routes defined in
[I-D.draft-mhkk-dmm-srv6mup-architecture].
This architecture separates the CATS-based service instance's
location selection from the upper control plane and integrates to the
MUP-C. Hence, for the same requested anycast IP-based service,
different UEs can be dynamically routes to service instances at
different location if necessary based on the CATS information and UE
location.
This document only discusses the possible architecture and design to
the previous defined MUP architecture in
[I-D.draft-mhkk-dmm-srv6mup-architecture] when integrating CATS
capabilities. The CATS measurement data collection, data delivery
mechansim, and CATS optimal path selection algorithm are in the scope
of CATS, not in this document.
4. Possible Procedure and MUP Route Types changes
TBD
5. Security Considerations
TBD
6. IANA Considerations
This document makes no requests for IANA action.
7. References
7.1. Informative References
[I-D.draft-ietf-cats-usecases-requirements]
Yao, K., Trossen, D., Boucadair, M., Contreras, LM., Shi,
H., Li, Y., Zhang, S., and Q. An, "Mobile User Plane
Architecture using Segment Routing for Distributed
Mobility Management", 2 January 2024,
<https://datatracker.ietf.org/doc/draft-ietf-cats-
usecases-requirements/>.
[I-D.draft-ldbc-cats-framework]
Li, C., Du, Z., Boucadair, M., Contreras, L. M., Drake,
J., Huang, D., and G. S. Mishra, "A Framework for
Computing-Aware Traffic Steering (CATS)", Work in
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Progress, Internet-Draft, draft-ldbc-cats-framework-03, 22
June 2023, <https://datatracker.ietf.org/doc/html/draft-
ldbc-cats-framework-03>.
[I-D.draft-mhkk-dmm-srv6mup-architecture]
Matsushima, S., Horiba, K., Khan, A., Kawakami, Y.,
Murakami, T., Patel, K., Kohno, M., Kamata, T., Camarillo,
P., Horn, J., Voyer, D., Zadok, S., Meilik, I., Agrawal,
A., and K. Perumal, "Mobile User Plane Architecture using
Segment Routing for Distributed Mobility Management", Work
in Progress, Internet-Draft, mhkk-dmm-srv6mup-
architecture, 23 October 2023,
<https://datatracker.ietf.org/doc/draft-mhkk-dmm-srv6mup-
architecture/>.
[RFC4786] Abley, J. and K. Lindqvist, "Operation of Anycast
Services", December 2006,
<https://datatracker.ietf.org/doc/rfc4786/>.
[RFC7333] Chan, H., Liu, D., Seite, P., Yokota, H., and J. Korhonen,
"Requirements for Distributed Mobility Management", August
2014, <https://datatracker.ietf.org/doc/rfc7333/>.
[TS23501] "System architecture for the 5G System (5GS)", December
2023,
<https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3144>.
Authors' Addresses
Minh-Ngoc Tran
Soongsil University
369, Sangdo-ro, Dongjak-gu
Seoul
06978
Republic of Korea
Email: mipearlska1307@dcn.ssu.ac.kr
Younghan Kim
Soongsil University
369, Sangdo-ro, Dongjak-gu
Seoul
06978
Republic of Korea
Phone: +82 10 2691 0904
Email: younghak@ssu.ac.kr
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