Internet DRAFT - draft-sijeon-nfvrg-slice-stitching
draft-sijeon-nfvrg-slice-stitching
NFVRG S. Jeon
Internet-Draft Y. Kim
Intended status: Informational Soongsil University
Expires: January 4, 2019 July 3, 2018
Use Cases and Requirements for Dynamic Slice Stitching
draft-sijeon-nfvrg-slice-stitching-00.txt
Abstract
This document describes use cases and requirements for dynamic slice
stitching.
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Table of Contents
1. Overview and Use Cases . . . . . . . . . . . . . . . . . . . 2
2. Requirements for Dynamic Slice Stitching . . . . . . . . . . 5
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
4. Security Considerations . . . . . . . . . . . . . . . . . . . 6
5. Informative References . . . . . . . . . . . . . . . . . . . 6
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Overview and Use Cases
Network slicing means that a communication network is divided into
multiple, logical end-to-end networks (slices), all sharing the same
physical network infrastructure [_3GPP.23.501]. Multiple services
belonging to different service categories such as eMBB, massive IoT,
mission-critical IoT can be supported by different slices. Network
slicing does not remain multiple services support with virtualization
effect but the potential is with beyond regional domain boundary for
global vertical industry service.
A vertical industry service may remain in a single operator domain or
require multiple domains operated by the same network/service
providers. In the multiple domain scenario, network slices created
from each domain should be federated and associated. We call it
'slice stitching'. In the design phase, slice stitching can be
treated and handled by network slice description that defines overall
characteristics of the network slice with types of service function,
link connectivity between network functions, resource of each service
function and link, etc.
The need of slice stitching could be found in load balancing,
differentiated WAN services with more bandwidth and advanced
middlebox support, security-enhanced purpose on demand, which can be
provided by dynamic instantiation of a new slice and interconnection
among the existing ones. In addition, one very interesting use case
can be found in providing virtualized home domain service support
with low latency in a visited roaming domian. The dynamic slice
stitching can be illustrated and explained by high-level operations
in Figs. 1 and 2. (a), (b), (c) in Figs. 1 and 2 denote the order of
the operations in each figure.
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========== ==========
= = = =
-- = A = -------------------------------- = B = --
= = = =
========== ==========
(a) Slices A and B interconnected
========== ==========
= = = =
-- = A = -------------------------------- = B = --
= = ========== = =
========== = = ==========
= C =
= =
==========
(b) Slices A and B interconnected, and Slice C is created
but not interconnected with Slices A and B
========== ==========
= = = =
-- = A = --+--------------------------+-- = B = --
= = \ ========== / = =
========== \ = = / ==========
+-- = C = --+
= =
==========
(c) Slices A and C interconnected with Slice B
Figure 1: High-Level Operation Scenario of Dynamic Slice Stitching
for New Slice Stitching
Fig. 1 describes an operation operation for new slice stitching. In
Fig. 1 (a), Slices A and B are connected, where each slice is
instantiated at different domains operated by the same operator. In
Fig. 1 (b), Slice C is created and instantiated for differentiated
WAN service support with high availability and reliability by
following one of the needs explained above. One thing to notice here
is, Slice C is not connected with Slice A and Slice B. In Fig. 1
(c), Slice C is interconnected with Slices A and B, so a tenant with
premium connection demand/subscription can be served by Slices A, C,
B, while Slice A and Slice B serve on-going service sessions.
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========== ========== ==========
= = = = = =
-- = A = -------- = B = -------- = C = --
= = = = = =
========== ========== ==========
(a) Slices A and C interconnected with Slice B
==========
= =
+-- = B = --+
========== / = = \ ==========
= = / ========== \ = =
-- = A = --+ +-- = C = --
= = ========== = =
========== = = ==========
= B' =
= =
==========
(b) Slices A and C interconnected with Slice B, and
newly created Slice B' but not interconnected with other slices
==========
= =
+-- = B = --+
========== / = = \ ==========
= = / ========== \ = =
-- = A = --+ +-- = C = --
= = \ ========== / = =
========== \ = = / ==========
+-- = B' = --+
= =
==========
(c) Slices A and C interconnected with Slice B and Slice B'
Figure 2: High-Level Operation Scenario of Dynamic Slice Stitching
for Additional Slice Stitching
Another operation scenario for dynamic slice stitching can be found
in additional slice creation and interconnection illustrated in Fig.
2. In Fig. 2 (a), Slices A, B, C are interconnected, where each
slice is instantiated at different domains operated by the same
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operator. In Fig. 2 (b), Slice B' is created for security-enhanced
support by following one of the needs explained above. One thing to
notice here is, Slices A and C are not interconnected each other. In
Fig. 2 (c), Slice B' is federated with Slices A and C, so a tenant
with premium connection demand/subscription can be served by Slices
A, B', C.
This document describes requirements for dynamic slice stitching
explained in Figs. 1 and 2. From the requirements, we check current
available approaches and measures.
2. Requirements for Dynamic Slice Stitching
Dynamic slice stitching basically requires interconnection between
Slice A and B(B'), Slice B(B') and C. The interconnection should be
made at network resource level to meet required connectivity demand
in the end-to-end connection perspective. The interconnection also
includes function level, so chaining of service functions between
Slice A and B(B'), Slice B(B') and C should dynamically be made.
1) Resource stitching between slices
Suppose that Slice A and Slice B in Fig. 1 were configured with 100
Mbps bandwidth and 100 ms latency in end-to-end connection. When
Slice C is interconnected with Slice A and Slice B, to meet the same
or better performance for service sessions going through Slice A,
Slice C, Slice B in order, dynamic adjustment such as scaling up/down
of existing resouce assigned in Slice A to Slice B could be required.
The resource adjustment and reconfiguration may also happen in Fig.
2.
2) Service function stitching between slices
Suppose that each slice is composed of one or more service functions
and the service functions in each slice need to be stitched for end-
to-end service. Service functions should dynamically chained. When
it comes Service Function Chaining (SFC) with the Network Service
Header (NSH) approach or routing controller, dynamic calculation of
chaining should be orchestrated by the multi-domain slice
orchestrator and configuration should be made at proper entity such
as NSH classifier or dataplane node. However, such approach may
bring about chaining scalability issue with chaining burden.
Isolating SF chaining list per slice with such as hierarchical SFC
(hSFC) could be effective and efficient for smooth operation support
in the function stitching [I-D.ietf-sfc-hierarchical].
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3. IANA Considerations
This document does not require any IANA actions.
4. Security Considerations
This document does not have security considerations.
5. Informative References
[_3GPP.23.501]
3GPP, "System Architecture for the 5G System", 3GPP
TS 23.501 15.0.0, December 2018,
<http://www.3gpp.org/ftp/Specs/html-info/23501.htm>.
[I-D.ietf-sfc-hierarchical]
Dolson, D., Homma, S., Lopez, D., and M. Boucadair,
"Hierarchical Service Function Chaining (hSFC)", draft-
ietf-sfc-hierarchical-11 (work in progress), June 2018.
Authors' Addresses
Seil Jeon
Soongsil University
369 Sangdo-ro, Dongjak-gu
Seoul
Korea
Email: sijeon@dcn.ssu.ac.kr
Younghan Kim
Soongsil University
369 Sangdo-ro, Dongjak-gu
Seoul
Korea
Email: younghak@ssu.ac.kr
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