Realizing Network Slices in IP/MPLS Networks
draft-bestbar-teas-ns-packet-05
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Replaced".
|
|
|---|---|---|---|
| Authors | Tarek Saad , Vishnu Pavan Beeram , Bin Wen , Daniele Ceccarelli , Joel M. Halpern , Shaofu Peng , Ran Chen , Xufeng Liu , Luis M. Contreras , Reza Rokui | ||
| Last updated | 2021-11-16 (Latest revision 2021-10-25) | ||
| Replaced by | draft-ietf-teas-ns-ip-mpls | ||
| RFC stream | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
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| Send notices to | (None) |
draft-bestbar-teas-ns-packet-05
TEAS Working Group T. Saad
Internet-Draft V. Beeram
Intended status: Standards Track Juniper Networks
Expires: 20 May 2022 B. Wen
Comcast
D. Ceccarelli
J. Halpern
Ericsson
S. Peng
R. Chen
ZTE Corporation
X. Liu
Volta Networks
L. Contreras
Telefonica
R. Rokui
Nokia
16 November 2021
Realizing Network Slices in IP/MPLS Networks
draft-bestbar-teas-ns-packet-05
Abstract
Network slicing provides the ability to partition a physical network
into multiple logical networks of varying sizes, structures, and
functions so that each slice can be dedicated to specific services or
customers. Network slices need to operate in parallel while
providing slice elasticity in terms of network resource allocation.
The Differentiated Service (Diffserv) model allows for carrying
multiple services on top of a single physical network by relying on
compliant nodes to apply specific forwarding treatment (scheduling
and drop policy) on to packets that carry the respective Diffserv
code point. This document adopts the Diffserv principles and
proposes a scalable approach to realize network slicing in IP/MPLS
networks. The solution does not mandate Diffserv to be enabled in
the network to provide a specific forwarding treatment, but can co-
exist with and complement it when enabled.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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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/
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Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 5
1.2. Acronyms and Abbreviations . . . . . . . . . . . . . . . 6
2. Network Resource Slicing Membership . . . . . . . . . . . . . 7
3. IETF Network Slice Realization . . . . . . . . . . . . . . . 7
3.1. Network Topology Filters . . . . . . . . . . . . . . . . 9
3.2. IETF Network Slice Service Request . . . . . . . . . . . 9
3.3. Slice-Flow Aggregation Mapping . . . . . . . . . . . . . 9
3.4. Path Placement over Slice-Flow Aggregate Topology . . . . 10
3.5. NRP Policy Installation . . . . . . . . . . . . . . . . . 10
3.6. Path Instantiation . . . . . . . . . . . . . . . . . . . 10
3.7. Service Mapping . . . . . . . . . . . . . . . . . . . . . 10
3.8. Network Slice-Flow Aggregate Relationships . . . . . . . 11
4. Network Resource Partition Modes . . . . . . . . . . . . . . 11
4.1. Data plane Network Resource Partition Mode . . . . . . . 12
4.2. Control Plane Network Resource Partition Mode . . . . . . 12
4.3. Data and Control Plane Network Resource Partition Mode . 14
5. Network Resource Partition Instantiation . . . . . . . . . . 15
5.1. NRP Policy Definition . . . . . . . . . . . . . . . . . . 15
5.1.1. Network Resource Partition Data Plane Selector . . . 16
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5.1.2. Network Resource Partition Resource Reservation . . . 19
5.1.3. Network Resource Partition Per Hop Behavior . . . . . 20
5.1.4. Network Resource Partition Topology . . . . . . . . . 21
5.2. Network Resource Partition Boundary . . . . . . . . . . . 21
5.2.1. Network Resource Partition Edge Nodes . . . . . . . . 21
5.2.2. Network Resource Partition Interior Nodes . . . . . . 22
5.2.3. Network Resource Partition Incapable Nodes . . . . . 22
5.2.4. Combining Network Resource Partition Modes . . . . . 23
5.3. Mapping Traffic on Slice-Flow Aggregates . . . . . . . . 24
6. Path Selection and Instantiation . . . . . . . . . . . . . . 24
6.1. Applicability of Path Selection to Slice-Flow
Aggregates . . . . . . . . . . . . . . . . . . . . . . . 24
6.2. Applicability of Path Control Technologies to Slice-Flow
Aggregates . . . . . . . . . . . . . . . . . . . . . . . 25
6.2.1. RSVP-TE Based Slice-Flow Aggregate Paths . . . . . . 25
6.2.2. SR Based Slice-Flow Aggregate Paths . . . . . . . . . 25
7. Network Resource Partition Protocol Extensions . . . . . . . 26
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 26
9. Security Considerations . . . . . . . . . . . . . . . . . . . 27
10. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . 27
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 27
12. References . . . . . . . . . . . . . . . . . . . . . . . . . 28
12.1. Normative References . . . . . . . . . . . . . . . . . . 28
12.2. Informative References . . . . . . . . . . . . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31
1. Introduction
Network slicing allows a Service Provider to create independent and
logical networks on top of a common or shared physical network
infrastructure. Such network slices can be offered to customers or
used internally by the Service Provider to facilitate or enhance
their service offerings. A Service Provider can also use network
slicing to structure and organize the elements of its infrastructure.
This document provides a path control technology agnostic solution
that a Service Provider can deploy to realize network slicing in IP/
MPLS networks.
[I-D.ietf-teas-ietf-network-slices] specifies the definition of a
network slice for use within the IETF and discusses the general
framework for requesting and operating IETF Network Slices, their
characteristics, and the necessary system components and interfaces.
It also discusses the function of an IETF Network Slice Controller
and the requirements on its northbound and southbound interfaces.
This document introduces the notion of a Slice-Flow Aggregate which
comprises of one of more IETF network slice traffic streams. It also
describes the Network Resource Partition (NRP) and the NRP Policy
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that can be used to instantiate control and data plane behaviors on
select topological elements associated with the NRP that supports a
Slice-Flow Aggregate - refer Section 5.1 for further details.
The IETF Network Slice Controller is responsible for the aggregation
of multiple IETF network traffic streams into a Slice-Flow Aggregate,
and for maintaining the mapping required between them. The
mechanisms used by the controller to determine the mapping of one or
more IETF network slice to a Slice-Flow Aggregate are outside the
scope of this document. The focus of this document is on the
mechanisms required at the device level to address the requirements
of network slicing in packet networks.
In a Differentiated Service (Diffserv) domain [RFC2475], packets
requiring the same forwarding treatment (scheduling and drop policy)
are classified and marked with a Class Selector (CS) at domain
ingress nodes. At transit nodes, the CS field inside the packet is
inspected to determine the specific forwarding treatment to be
applied before the packet is forwarded further. Similar principles
are adopted by this document to realize network slicing. The
solution proposed in this document does not mandate Diffserv to be
enabled in the network to provide a specific forwarding treatment.
When logical networks associated with an NRP are realized on top of a
shared physical network infrastructure, it is important to steer
traffic on the specific network resources partition that is allocated
for the Slice-Flow Aggregate. In packet networks, the packets of a
specific Slice-Flow Aggregate MAY be identified by one or more
specific fields carried within the packet. An NRP ingress boundary
node populates the respective field(s) in packets that are mapped to
a Slice-Flow Aggregate in order to allow interior NRP nodes to
identify and apply the specific Per Hop Behavior (PHB) associated
with the Slice-Flow Aggregate. The PHB defines the scheduling
treatment and, in some cases, the packet drop probability.
If Diffserv is enabled within the network, the Slice-Flow Aggregate
traffic can further carry a Diffserv CS to enable differentiation of
forwarding treatments for packets within the same Slice-Flow
Aggregate.
For example, when using MPLS as a dataplane, it is possible to
identify packets belonging to the same Slice-Flow Aggregate by
carrying an identifier in an MPLS Label Stack Entry (LSE).
Additional Diffserv classification may be indicated in the Traffic
Class (TC) bits of the global MPLS label to allow further
differentiation of forwarding treatments for traffic traversing the
same NRP.
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This document covers different modes of NRPs and discusses how each
mode can ensure proper placement of Slice-Flow Aggregate paths and
respective treatment of Slice-Flow Aggregate traffic.
1.1. Terminology
The reader is expected to be familiar with the terminology specified
in [I-D.ietf-teas-ietf-network-slices].
The following terminology is used in the document:
IETF Network Slice:
a well-defined composite of a set of endpoints, the connectivity
requirements between subsets of these endpoints, and associated
requirements; the term 'network slice' in this document refers to
'IETF network slice' as defined in
[I-D.ietf-teas-ietf-network-slices].
IETF Network Slice Controller (NSC):
controller that is used to realize an IETF network slice
[I-D.ietf-teas-ietf-network-slices].
Network Resource Partition:
the collection of resources that are used to support a Slice-Flow
Aggregate.
Slice-Flow Aggregate:
a collection of packets that match an NRP Policy selection
criteria and are given the same forwarding treatment; a Slice-Flow
Aggregate comprises of one or more IETF network slice traffic
streams; the mapping of one or more IETF network slices to a
Slice-Flow Aggregate is maintained by the IETF Network Slice
Controller.
Network Resource Partition Policy:
a policy construct that enables instantiation of mechanisms in
support of IETF network slice specific control and data plane
behaviors on select topological elements; the enforcement of an
NRP Policy results in the creation of an NRP.
NRP Capable Node:
a node that supports one of the NRP modes described in this
document.
NRP Incapable Node:
a node that does not support any of the NRP modes described in
this document.
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Slice-Flow Aggregate Path:
a path that is setup over the NRP that is associated with a
specific Slice-Flow Aggregate.
Slice-Flow Aggregate Packet:
a packet that traverses over the NRP that is associated with a
specific Slice-Flow Aggregate.
NRP Topology:
a set of topological elements associated with a Network Resource
Partition.
Slice-Flow Aggregate Aware TE:
a mechanism for TE path selection that takes into account the
available network resources associated with a specific Slice-Flow
Aggregate.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
1.2. Acronyms and Abbreviations
BA: Behavior Aggregate
CS: Class Selector
NRP-PHB: NRP Per Hop Behavior as described in Section 5.1.3
SAS: Slice-Flow Aggregate Selector
SASL: Slice-Flow Aggregate Selector Label as described in
Section 5.1.1
SLA: Service Level Agreement
SLO: Service Level Objective
Diffserv: Differentiated Services
MPLS: Multiprotocol Label Switching
LSP: Label Switched Path
RSVP: Resource Reservation Protocol
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TE: Traffic Engineering
SR: Segment Routing
VRF: VPN Routing and Forwarding
AC: Attachment Circuit
CE: Customer Edge
PE: Provider Edge
PCEP: Path Computation Element (PCE) Communication Protocol (PCEP)
2. Network Resource Slicing Membership
An NRP that supports a Slice-Flow Aggregate can be instantiated over
parts of an IP/MPLS network (e.g., all or specific network resources
in the access, aggregation, or core network), and can stretch across
multiple domains administered by a provider. The NRP topology may be
comprised of dedicated and/or shared network resources (e.g., in
terms of processing power, storage, and bandwidth).
The physical network resources may be fully dedicated to a specific
Slice-Flow Aggregate. For example, traffic belonging to a Slice-Flow
Aggregate can traverse dedicated network resources without being
subjected to contention from traffic of other Slice-Flow Aggregates.
Dedicated physical network resource slicing allows for simple
partitioning of the physical network resources amongst Slice-Flow
Aggregates without the need to distinguish packets traversing the
dedicated network resources since only one Slice-Flow Aggregate
traffic stream can traverse the dedicated resource at any time.
To optimize network utilization, sharing of the physical network
resources may be desirable. In such case, the same physical network
resource capacity is divided among multiple NRPs that support
multiple Slice-Flow Aggregates. The shared physical network
resources can be partitioned in the data plane (for example by
applying hardware policers and shapers) and/or partitioned in the
control plane by providing a logical representation of the physical
link that has a subset of the network resources available to it.
3. IETF Network Slice Realization
Figure 1 describes the steps required to realize an IETF network
slice service in a provider network using the solution proposed in
this document. Each of the steps is further elaborated on in a
subsequent section.
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-- -- --
---------- |CE| |CE| |CE|
| Network | -- -- --
| Slice | AC : AC : AC :
| Orchstr | ---------------------- -------
---------- ( |PE|....|PE|....|PE| ) ( IETF )
| IETF ( --: -- :-- ) ( Network )
| Network ( :............: ) ( Slice )
| Slice Svc ( IETF Network Slice ) ( ) Customer
| Req ---------------------- ------- View
..|....................................\........./..................
--v---------- ----> Slice-Flow \ / Controller
|Controllers| | Aggregation Mapping v v View
| ------- | | -----------------------------------------
| |IETF | |-- ( |PE|.......|PE|........|PE|.......|PE| )
| |Network| | ( --: -- :-- -- )
| |Slice | | ( :...................: )
| |Cntrlr | | ( Slice-Flow Aggregate )
| |(NSC) | | -----------------------------------------
| ------- |---------.
| ------- | | Path Placement
| | | | v
| | | | -----------------------------------------
| | | | ( |PE|....-..|PE| |PE|.......|PE| )
| |Network| | ( -- |P| --......-...-- - :-- )
| |Cntrlr | | ( -:.........|P|.......|P|..: )
| |(NC) | | ( Path Set - - )
| | | | -----------------------------------------
| | | |-------.
| | | | | Apply Topology Filters
| | | | v
| ------- | ----------------------------- --------
| | (|PE|..-..|PE|... ..|PE|..|PE|) ( Policy )
----------- ( :-- |P| -- :-: -- :-- ) ( Filter )
| | | ( :.- -:.......|P| :- ) ( Topology )
| | | ( |P|...........:-:.......|P| ) ( )
| | \ ( - Policy Filter Topology ) --------
| | \ ----------------------------- A
| | \ A /
..............\.......................\............../..............
| | Path v Service Mapping \ / Physical N/w
\ \Inst ------------------------------------------------
\ \ ( |PE|.....-.....|PE|....... |PE|.......|PE| )
\ \ ( -- |P| -- :-...:-- -..:-- )
NRP \ --->( : -:..............|P|.........|P| )
Policy\ ( -.......................:-:..- - )
Inst ----->( |P|..........................|P|......: )
( - - )
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------------------------------------------------
Figure 1: IETF network slice realization steps.
3.1. Network Topology Filters
The Physical Network may be filtered into a number of Policy Filter
Topologies. Filter actions may include selection of specific nodes
and links according to their capabilities and are based on network-
wide policies. The resulting topologies can be used to host IETF
Network Slices and provide a useful way for the network operator to
know that all of the resources they are using to plan a network slice
meet specific SLOs. This step can be done offline during planning
activity, or could be performed dynamically as new demands arise.
Section 5.1.4 describes how topology filters can be associated with
the NRP instantiated by the NRP Policy.
3.2. IETF Network Slice Service Request
The customer requests an IETF Network Slice Service specifying the
CE-AC-PE points of attachment, the connectivity matrix, and the SLOs
as described in [I-D.ietf-teas-ietf-network-slices]. These
capabilities are always provided based on a Service Level Agreement
(SLA) between the network slice costumer and the provider.
This defines the traffic flows that need to be supported when the
slice is realized. Depending on the mechanism and encoding of the
Attachment Circuit (AC), the IETF Network Slice Service may also
include information that will allow the operator's controllers to
configure the PEs to determine what customer traffic is intended for
this IETF Network Slice.
IETF Network Slice Service Requests are likely to arrive at various
times in the life of the network, and may also be modified.
3.3. Slice-Flow Aggregation Mapping
A network may be called upon to support very many IETF Network
Slices, and this could present scaling challenges in the operation of
the network. In order to overcome this, the IETF Network Slices may
be aggregated into groups according to similar characteristics.
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A Slice-Flow Aggregate is a construct that comprises the traffic
flows of one or more IETF Network Slices. The mapping of IETF
Network Slices into an Slice-Flow Aggregate is a matter of local
operator policy is a function executed by the Controller. The Slice-
Flow Aggregate may be preconfigured, created on demand, or modified
dynamically.
3.4. Path Placement over Slice-Flow Aggregate Topology
Depending on the underlying network technology, a Controller may plan
the paths that the traffic flows will take through the network in
order to best deliver the SLOs for the different services in the
Slice-Flow Aggregate. The Controller performs the path placement
function on the Policy Filter Topology selected to support the Slice-
Flow Aggregate.
Note that this step may indicate the need to increase the capacity of
the underlying Policy Filter Topology or to create a new Policy
Filter Topology.
3.5. NRP Policy Installation
A Controller function programs the physical network with policies for
handling the traffic flows belonging to the Slice-Flow Aggregate.
These policies instruct network routers how to handle traffic for a
specific Slice-Flow Aggregate: the routers correlate markers present
in the packets that belong to the Slice-Flow Aggregate. The way in
which the NRP Policy is installed in the routers and the way that the
traffic is marked is implementation specific. The NRP Policy
instantiation in the network is further described in Section 5.
3.6. Path Instantiation
Depending on the underlying network technology, a Controller function
may install the forwarding state specific to the Slice-Flow Aggregate
so that traffic is routed along paths derived in the Path Placement
step described in Section 3.4. The way in which the paths are
instantiated is implementation specific.
3.7. Service Mapping
Once the network has been set up, the edge points (PEs) can be
configured to support the service. This involves telling them what
customer traffic should be mapped to which Slice-Flow Aggregate
possibly using information supplied when the IETF network slice
service was requested. It also instructs the edge points how to mark
the packets so that the network routers will know which policies and
routing instructions to apply.
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3.8. Network Slice-Flow Aggregate Relationships
The following describes the generalization relationships between the
IETF network slice and different parts of the solution as described
in Figure 1.
o A customer may request 1 or more IETF Network Slices.
o Any given Attachment Circuit (AC) may support the traffic for 1 or
more IETF Network Slice, but if there is more than one IETF Network
Slice using a single AC, the IETF Network Slice Service request must
include enough information to allow the edge nodes to demultiplex the
traffic for the different IETF Network Slices.
o By definition, multiple IETF Network Slices may be mapped to a
single Slice-Flow Aggregate. However, it is possible for an Slice-
Flow Aggregate to contain just a single IETF Network Slice.
Furthermore, a Slice-Flow Aggregate can be planned and preconfigured,
and may be "empty" having no IETF Network Slices mapped to it.
o The physical network may be filtered to multiple Policy Filter
Topologies. Each such Policy Filter Topology provides a short-cut to
planning the placement and support of Slice-Flow Aggregate by
presenting only the subset of links and nodes that meet specific
criteria. Note, however, that a network operator does not need to
derive any Policy Filter Topologies, choosing to operate directly on
the full physical network.
o It is anticipated that there may be very many IETF Network Slices
supported by a network operator over a single physical network. The
scaling mechanisms are deployment choices, but it may be that there
are no more than 1000 Slice-Flow Aggregates supported by a network,
with each Slice-Flow Aggregate supporting any number of IETF Network
Slices.
4. Network Resource Partition Modes
An NRP Policy can be used to dictate if the network resource
partitioning of the shared network resources among multiple Slice-
Flow Aggregates can be achieved:
a) in data plane only,
b) in control plane only, or
c) in both control and data planes.
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4.1. Data plane Network Resource Partition Mode
The physical network resources can be partitioned on network devices
by applying a Per Hop forwarding Behavior (PHB) onto packets that
traverse the network devices. In the Diffserv model, a Class
Selector (CS) is carried in the packet and is used by transit nodes
to apply the PHB that determines the scheduling treatment and drop
probability for packets.
When data plane NRP mode is applied, packets need to be forwarded on
the specific NRP that supports the Slice-Flow Aggregate to ensure the
proper forwarding treatment dictated in the NRP Policy is applied
(refer to Section 5.1 below). In this case, a Slice-Flow Aggregate
Selector (SAS) MUST be carried in each packet to identify the Slice-
Flow Aggregate that it belongs to.
The ingress node of an NRP domain, in addition to marking packets
with a Diffserv CS, MAY also add an SAS to each Slice-Flow Aggregate
packet. The transit nodes within an NRP domain MAY use the SAS to
associate packets with a Slice-Flow Aggregate and to determine the
Network Resource Partition Per Hop Behavior (NRP-PHB) that is applied
to the packet (refer to Section 5.1.3 for further details). The CS
MAY be used to apply a Diffserv PHB on to the packet to allow
differentiation of traffic treatment within the same Slice-Flow
Aggregate.
When data plane only NRP mode is used, routers may rely on a network
state independent view of the topology to determine the best paths to
reach destinations. In this case, the best path selection dictates
the forwarding path of packets to the destination. The SAS field
carried in each packet determines the specific NRP-PHB treatment
along the selected path.
For example, the Segment-Routing Flexible Algorithm
[I-D.ietf-lsr-flex-algo] may be deployed in a network to steer
packets on the IGP computed lowest cumulative delay path. An NRP
Policy may be used to allow links along the least latency path to
share its data plane resources amongst multiple Slice-Flow
Aggregates. In this case, the packets that are steered on a specific
NRP carry the SAS that enables routers (along with the Diffserv CS)
to determine the NRP-PHB to enforce on the Slice-Flow Aggregate
traffic streams.
4.2. Control Plane Network Resource Partition Mode
Multiple NRPs can be realized over the same set of physical
resources. It is possible in this case to allow the state
reservations to occur on each NRP.
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The network reservation state for a specific partition can then be
represented in a topology that may can contain all or a subset of the
physical network elements (nodes and links). The logical network
resources that appear in the topology can reflect a part, whole, or
in-excess of the physical network resource capacity (e.g., when
oversubscription is desired).
For example, the physical link bandwidth can be divided into
fractions, each dedicated to an NRP that supports a Slice-Flow
Aggregate. The topology associated with the NRP supporting a Slice-
Flow Aggregate can be used by routing protocols, or by the ingress/
PCE when computing Slice-Flow Aggregate aware TE paths.
To perform network state dependent path computation in this mode
(Slice-Flow Aggregate aware TE), the resource reservation on each
link needs to be Slice-Flow Aggregate aware. Details of required IGP
extensions to support SA-TE are described in
[I-D.bestbar-lsr-slice-aware-te].
The same physical link may be member of multiple slice policies that
instantiate different NRPs. The NRP reservable or utilized bandwidth
on such a link is updated (and may be advertised) whenever new paths
are placed in the network. The NRP reservation state, in this case,
MAY be maintained on each device or off the device on a resource
reservation manager that holds reservation states for those links in
the network.
Multiple NRPs that support Slice-Flow Aggregates can form a group and
share the available network resources allocated to each. In this
case, a node can update the reservable bandwidth for each NRP to take
into consideration the available bandwidth from other NRPs in the
same group.
For illustration purposes, the diagram below represents bandwidth
isolation or sharing amongst a group of NRPs. In Figure 1a, the
NRPs: NRP1, NRP2, NRP3 and NRP4 are not sharing any bandwidths
between each other. In Figure 1b, the NRPs: NRP1 and NRP2 can share
the available bandwidth portion allocated to each amongst them.
Similarly, NRP3 and NRP4 can share amongst themselves any available
bandwidth allocated to them, but they cannot share available
bandwidth allocated to NRP1 or NRP2. In both cases, the Max
Reservable Bandwidth may exceed the actual physical link resource
capacity to allow for over subscription.
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I-----------------------------I I-----------------------------I
<--NRP1-> I I-----------------I I
I---------I I I <-NRP1-> I I
I I I I I-------I I I
I---------I I I I I I I
I I I I-------I I I
<-----NRP2------> I I I I
I-----------------I I I <-NRP2-> I I
I I I I I---------I I I
I-----------------I I I I I I I
I I I I---------I I I
<---NRP3----> I I I I
I-------------I I I NRP1 + NRP2 I I
I I I I-----------------I I
I-------------I I I I
I I I I
<---NRP4----> I I-----------------I I
I-------------I I I <-NRP3-> I I
I I I I I-------I I I
I-------------I I I I I I I
I I I I-------I I I
I NRP1+NRP2+NRP3+NRP4 I I I I
I I I <-NRP4-> I I
I-----------------------------I I I---------I I I
<--Max Reservable Bandwidth--> I I I I I
I I---------I I I
I I I
I NRP3 + NRP4 I I
I-----------------I I
I NRP1+NRP2+NRP3+NRP4 I
I I
I-----------------------------I
<--Max Reservable Bandwidth-->
(a) No bandwidth sharing (b) Sharing bandwidth between
between NRPs. NRPs of the same group.
Figure 2: Bandwidth isolation/sharing among NRPs.
4.3. Data and Control Plane Network Resource Partition Mode
In order to support strict guarantees for Slice-Flow Aggregates, the
network resources can be partitioned in both the control plane and
data plane.
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The control plane partitioning allows the creation of customized
topologies per NRP that each supports a Slice-Flow Aggregate. The
ingress routers or a Path Computation Engine (PCE) can use the
customized topologies to determine optimal path placement for
specific demand flows (Slice-Flow Aggregate aware TE).
The data plane partitioning provides isolation for Slice-Flow
Aggregate traffic, and protection when resource contention occurs due
to bursts of traffic from other Slice-Flow Aggregate traffic that
traverses the same shared network resource.
5. Network Resource Partition Instantiation
A network slice can span multiple technologies and multiple
administrative domains. Depending on the network slice customer
requirements, a network slice can be differentiated from other
network slices in terms of data, control or management planes.
The customer of a network slice expresses their intent by specifying
requirements rather than mechanisms to realize the slice as described
in Section 3.2.
The network slice controller consumes the network slice service
intent and realizes it with an appropriate Network Resource Partition
Policy (NRP Policy). Multiple IETF network slices MAY be mapped to
the same Slice-Flow Aggregate as described in Section 3.3.
The network wide consistent NRP Policy definition is distributed to
the devices in the network as shown in Figure 1. The specification
of the network slice intent on the northbound interface of the
controller and the mechanism used to map the network slice to a
Slice-Flow Aggregate are outside the scope of this document.
5.1. NRP Policy Definition
The NRP Policy is network-wide construct that is consumed by network
devices, and may include rules that control the following:
* Data plane specific policies: This includes the SAS, any firewall
rules or flow-spec filters, and QoS profiles associated with the
NRP Policy and any classes within it.
* Control plane specific policies: This includes guaranteed
bandwidth, any network resource sharing amongst slice policies,
and reservation preference to prioritize any reservations of a
specific NRP over others.
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* Topology membership policies: This defines the topology filter
policies that dictate node/link/function membership to a specific
NRP.
There is a desire for flexibility in realizing network slices to
support the services across networks consisting of products from
multiple vendors. These networks may also be grouped into disparate
domains and deploy various path control technologies and tunnel
techniques to carry traffic across the network. It is expected that
a standardized data model for NRP Policy will facilitate the
instantiation and management of the NRP on the topological elements
selected by the NRP Policy topology filter. A YANG data model for
the Network Resource Partition Policy instantiation on the controller
and network devices is described in
[I-D.bestbar-teas-yang-slice-policy].
It is also possible to distribute the NRP Policy to network devices
using several mechanisms, including protocols such as NETCONF or
RESTCONF, or exchanging it using a suitable routing protocol that
network devices participate in (such as IGP(s) or BGP). The
extensions to enable specific protocols to carry an NRP Policy
definition will be described in separate documents.
5.1.1. Network Resource Partition Data Plane Selector
A router MUST be able to identify a packet belonging to a Slice-Flow
Aggregate before it can apply the associated forwarding treatment or
NRP-PHB. One or more fields within the packet MAY be used as an SAS
to do this.
Forwarding Address Based Selector:
It is possible to assign a different forwarding address (or MPLS
forwarding label in case of MPLS network) for each Slice-Flow
Aggregate on a specific node in the network. [RFC3031] states in
Section 2.1 that: 'Some routers analyze a packet's network layer
header not merely to choose the packet's next hop, but also to
determine a packet's "precedence" or "class of service"'.
Assigning a unique forwarding address (or MPLS forwarding label)
to each Slice-Flow Aggregate allows Slice-Flow Aggregate packets
destined to a node to be distinguished by the destination address
(or MPLS forwarding label) that is carried in the packet.
This approach requires maintaining per Slice-Flow Aggregate state
for each destination in the network in both the control and data
plane and on each router in the network. For example, consider a
network slicing provider with a network composed of 'N' nodes,
each with 'K' adjacencies to its neighbors. Assuming a node can
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be reached over 'M' different Slice-Flow Aggregates, the node
assigns and advertises reachability to 'N' unique forwarding
addresses, or MPLS forwarding labels. Similarly, each node
assigns a unique forwarding address (or MPLS forwarding label) for
each of its 'K' adjacencies to enable strict steering over the
adjacency for each slice. The total number of control and data
plane states that need to be stored and programmed in a router's
forwarding is (N+K)*M states. Hence, as 'N', 'K', and 'M'
parameters increase, this approach suffers from scalability
challenges in both the control and data planes.
Global Identifier Based Selector:
An NRP Policy MAY include a Global Identifier SAS (GISS) field as
defined in [I-D.kompella-mpls-mspl4fa] that is carried in each
packet in order to associate it to the NRP supporting a Slice-Flow
Aggregate, independent of the forwarding address or MPLS
forwarding label that is bound to the destination. Routers within
the NRP domain can use the forwarding address (or MPLS forwarding
label) to determine the forwarding next-hop(s), and use the GISS
field in the packet to infer the specific forwarding treatment
that needs to be applied on the packet.
The GISS can be carried in one of multiple fields within the
packet, depending on the dataplane used. For example, in MPLS
networks, the GISS can be encoded within an MPLS label that is
carried in the packet's MPLS label stack. All packets that belong
to the same Slice-Flow Aggregate MAY carry the same GISS in the
MPLS label stack. It is also possible to have multiple GISS's map
to the same Slice-Flow Aggregate.
The GISS can be encoded in an MPLS label and may appear in several
positions in the MPLS label stack. For example, the VPN service
label may act as a GISS to allow VPN packets to be mapped to the
Slice-Flow Aggregate. In this case, a single VPN service label
acting as a GISS MAY be allocated by all Egress PEs of a VPN.
Alternatively, multiple VPN service labels MAY act as GISS's that
map a single VPN to the same Slice-Flow Aggregate to allow for
multiple Egress PEs to allocate different VPN service labels for a
VPN. In other cases, a range of VPN service labels acting as
multiple GISS's MAY map multiple VPN traffic to a single Slice-
Flow Aggregate. An example of such deployment is shown in
Figure 3.
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SR Adj-SID: GISS (VPN service label) on PE2: 1001
9012: P1-P2
9023: P2-PE2
/-----\ /-----\ /-----\ /-----\
| PE1 | ----- | P1 | ------ | P2 |------ | PE2 |
\-----/ \-----/ \-----/ \-----/
In
packet:
+------+ +------+ +------+ +------+
| IP | | 9012 | | 9023 | | 1001 |
+------+ +------+ +------+ +------+
| Pay- | | 9023 | | 1001 | | IP |
| Load | +------+ +------+ +------+
+----- + | 1001 | | IP | | Pay- |
+------+ +------+ | Load |
| IP | | Pay- | +------+
+------+ | Load |
| Pay- | +------+
| Load |
+------+
Figure 3: GISS or VPN label at bottom of label stack.
In some cases, the position of the GISS may not be at a fixed
position in the MPLS label header. In this case, the GISS label
can show up in any position in the MPLS label stack. To enable a
transit router to identify the position of the GISS label, a
special purpose label (ideally a base special purpose label
(bSPL)) can be used to indicate the presence of a GISS in the MPLS
label stack. [I-D.kompella-mpls-mspl4fa] proposes a new bSPL
called Forwarding Actions Identifier (FAI) that is assigned to
alert of the presence of multiple actions and action data
(including the presence of the GISS). The NRP ingress boundary
node, in this case, imposes two labels: the FAI label and a
forwarding actions label that includes the GISS to identify the
Slice-Flow Aggregate packets as shown in Figure 4.
[I-D.decraene-mpls-slid-encoded-entropy-label-id] also proposes to
repurpose the ELI/EL [RFC6790] to carry the Slice Identifier in
order to minimize the size of the MPLS stack and ease incremental
deployment.
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SR Adj-SID: GISS: 1001
9012: P1-P2
9023: P2-PE2
/-----\ /-----\ /-----\ /-----\
| PE1 | ----- | P1 | ------ | P2 |------ | PE2 |
\-----/ \-----/ \-----/ \-----/
In
packet:
+------+ +------+ +------+ +------+
| IP | | 9012 | | 9023 | | FAI |
+------+ +------+ +------+ +------+
| Pay- | | 9023 | | FAI | | 1001 |
| Load | +------+ +------+ +------+
+------+ | FAI | | 1001 | | IP |
+------+ +------+ +------+
| 1001 | | IP | | Pay- |
+------+ +------+ | Load |
| IP | | Pay- | +------+
+------+ | Load |
| Pay- | +------+
| Load |
+------+
Figure 4: FAI and GISS label in the label stack.
When the slice is realized over an IP dataplane, the GISS can be
encoded in the IP header. For example, the GISS can be encoded in
portion of the IPv6 Flow Label field as described in
[I-D.filsfils-spring-srv6-stateless-slice-id].
5.1.2. Network Resource Partition Resource Reservation
Bandwidth and network resource allocation strategies for slice
policies are essential to achieve optimal placement of paths within
the network while still meeting the target SLOs.
Resource reservation allows for the managing of available bandwidth
and for prioritization of existing allocations to enable preference-
based preemption when contention on a specific network resource
arises. Sharing of a network resource's available bandwidth amongst
a group of NRPs may also be desirable. For example, a Slice-Flow
Aggregate may not be using all of the NRP reservable bandwidth; this
allows other NRPs in the same group to use the available bandwidth
resources for other Slice-Flow Aggregates.
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Congestion on shared network resources may result from sub-optimal
placement of paths in different slice policies. When this occurs,
preemption of some Slice-Flow Aggregate paths may be desirable to
alleviate congestion. A preference based allocation scheme enables
prioritization of Slice-Flow Aggregate paths that can be preempted.
Since network characteristics and its state can change over time, the
NRP topology and its network state need to be propagated in the
network to enable ingress TE routers or Path Computation Engine
(PCEs) to perform accurate path placement based on the current state
of the NRP network resources.
5.1.3. Network Resource Partition Per Hop Behavior
In Diffserv terminology, the forwarding behavior that is assigned to
a specific class is called a Per Hop Behavior (PHB). The PHB defines
the forwarding precedence that a marked packet with a specific CS
receives in relation to other traffic on the Diffserv-aware network.
The NRP Per Hop Behavior (NRP-PHB) is the externally observable
forwarding behavior applied to a specific packet belonging to a
Slice-Flow Aggregate. The goal of an NRP-PHB is to provide a
specified amount of network resources for traffic belonging to a
specific Slice-Flow Aggregate. A single NRP may also support
multiple forwarding treatments or services that can be carried over
the same logical network.
The Slice-Flow Aggregate traffic may be identified at NRP ingress
boundary nodes by carrying a SAS to allow routers to apply a specific
forwarding treatment that guarantee the SLA(s).
With Differentiated Services (Diffserv) it is possible to carry
multiple services over a single converged network. Packets requiring
the same forwarding treatment are marked with a Class Selector (CS)
at domain ingress nodes. Up to eight classes or Behavior Aggregates
(BAs) may be supported for a given Forwarding Equivalence Class (FEC)
[RFC2475]. To support multiple forwarding treatments over the same
Slice-Flow Aggregate, a Slice-Flow Aggregate packet MAY also carry a
Diffserv CS to identify the specific Diffserv forwarding treatment to
be applied on the traffic belonging to the same NRP.
At transit nodes, the CS field carried inside the packets are used to
determine the specific PHB that determines the forwarding and
scheduling treatment before packets are forwarded, and in some cases,
drop probability for each packet.
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5.1.4. Network Resource Partition Topology
A key element of the NRP Policy is a customized topology that may
include the full or subset of the physical network topology. The NRP
topology could also span multiple administrative domains and/or
multiple dataplane technologies.
An NRP topology can overlap or share a subset of links with another
NRP topology. A number of topology filtering policies can be defined
as part of the NRP Policy to limit the specific topology elements
that belong to the NRP. For example, a topology filtering policy can
leverage Resource Affinities as defined in [RFC2702] to include or
exclude certain links that the NRP is instantiated on in supports of
the Slice-Flow Aggregate.
The NRP Policy may also include a reference to a predefined topology
(e.g., derived from a Flexible Algorithm Definition (FAD) as defined
in [I-D.ietf-lsr-flex-algo], or Multi-Topology ID as defined
[RFC4915]. A YANG data model that covers generic topology filters is
described in [I-D.bestbar-teas-yang-topology-filter]. Also, the Path
Computation Element (PCE) Communication Protocol (PCEP) extensions to
carry topology filters are defined in [I-D.xpbs-pce-topology-filter].
5.2. Network Resource Partition Boundary
A network slice originates at the edge nodes of a network slice
provider. Traffic that is steered over the corresponding NRP
supporting a Slice-Flow Aggregate may traverse NRP capable as well as
NRP incapable interior nodes.
The network slice may encompass one or more domains administered by a
provider. For example, an organization's intranet or an ISP. The
network provider is responsible for ensuring that adequate network
resources are provisioned and/or reserved to support the SLAs offered
by the network end-to-end.
5.2.1. Network Resource Partition Edge Nodes
NRP edge nodes sit at the boundary of a network slice provider
network and receive traffic that requires steering over network
resources specific to a NRP that supports a Slice-Flow Aggregate.
These edge nodes are responsible for identifying Slice-Flow Aggregate
specific traffic flows by possibly inspecting multiple fields from
inbound packets (e.g., implementations may inspect IP traffic's
network 5-tuple in the IP and transport protocol headers) to decide
on which NRP it can be steered.
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Network slice ingress nodes may condition the inbound traffic at
network boundaries in accordance with the requirements or rules of
each service's SLAs. The requirements and rules for network slice
services are set using mechanisms which are outside the scope of this
document.
When data plane NRP mode is employed, the NRP ingress nodes are
responsible for adding a suitable SAS onto packets that belong to
specific Slice-Flow Aggregate. In addition, edge nodes MAY mark the
corresponding Diffserv CS to differentiate between different types of
traffic carried over the same Slice-Flow Aggregate.
5.2.2. Network Resource Partition Interior Nodes
An NRP interior node receives slice traffic and MAY be able to
identify the packets belonging to a specific Slice-Flow Aggregate by
inspecting the SAS field carried inside each packet, or by inspecting
other fields within the packet that may identify the traffic streams
that belong to a specific Slice-Flow Aggregate. For example, when
data plane NRP mode is applied, interior nodes can use the SAS
carried within the packet to apply the corresponding NRP-PHB
forwarding behavior. Nodes within the network slice provider network
may also inspect the Diffserv CS within each packet to apply a per
Diffserv class PHB within the NRP Policy, and allow differentiation
of forwarding treatments for packets forwarded over the same NRP that
supports the Slice-Flow Aggregate.
5.2.3. Network Resource Partition Incapable Nodes
Packets that belong to a Slice-Flow Aggregate may need to traverse
nodes that are NRP incapable. In this case, several options are
possible to allow the slice traffic to continue to be forwarded over
such devices and be able to resume the NRP forwarding treatment once
the traffic reaches devices that are NRP capable.
When data plane NRP mode is employed, packets carry a SAS to allow
slice interior nodes to identify them. To enable end-to-end network
slicing, the SAS MUST be maintained in the packets as they traverse
devices within the network - including NRP incapable devices.
For example, when the SAS is an MPLS label at the bottom of the MPLS
label stack, packets can traverse over devices that are NRP incapable
without any further considerations. On the other hand when the SASL
is at the top of the MPLS label stack, packets can be bypassed (or
tunneled) over the NRP incapable devices towards the next device that
supports NRP as shown in Figure 5.
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SR Node-SID: SASL: 1001 @@@: NRP Policy enforced
1601: P1 ...: NRP Policy not enforced
1602: P2
1603: P3
1604: P4
1605: P5
@@@@@@@@@@@@@@ ........................
.
/-----\ /-----\ /-----\ .
| P1 | ----- | P2 | ----- | P3 | .
\-----/ \-----/ \-----/ .
| @@@@@@@@@@
|
/-----\ /-----\
| P4 | ------ | P5 |
\-----/ \-----/
+------+ +------+ +------+
| 1001 | | 1604 | | 1001 |
+------+ +------+ +------+
| 1605 | | 1001 | | IP |
+------+ +------+ +------+
| IP | | 1605 | | Pay- |
+------+ +------+ | Load |
| Pay- | | IP | +------+
| Load | +------+
+----- + | Pay- |
| Load |
+------+
Figure 5: Extending network slice over NRP incapable device(s).
5.2.4. Combining Network Resource Partition Modes
It is possible to employ a combination of the NRP modes that were
discussed in Section 4 to realize a network slice. For example, data
and control plane NRP modes can be employed in parts of a network,
while control plane NRP mode can be employed in the other parts of
the network. The path selection, in such case, can take into account
the NRP available network resources. The SAS carried within packets
allow transit nodes to enforce the corresponding NRP-PHB on the parts
of the network that apply the data plane NRP mode. The SAS can be
maintained while traffic traverses nodes that do not enforce data
plane NRP mode, and so slice PHB enforcement can resume once traffic
traverses capable nodes.
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5.3. Mapping Traffic on Slice-Flow Aggregates
The usual techniques to steer traffic onto paths can be applicable
when steering traffic over paths established for a specific Slice-
Flow Aggregate.
For example, one or more (layer-2 or layer-3) VPN services can be
directly mapped to paths established for a Slice-Flow Aggregate. In
this case, the per Virtual Routing and Forwarding (VRF) instance
traffic that arrives on the Provider Edge (PE) router over external
interfaces can be directly mapped to a specific Slice-Flow Aggregate
path. External interfaces can be further partitioned (e.g., using
VLANs) to allow mapping one or more VLANs to specific Slice-Flow
Aggregate paths.
Another option is steer traffic to specific destinations directly
over multiple slice policies. This allows traffic arriving on any
external interface and targeted to such destinations to be directly
steered over the slice paths.
A third option that can also be used is to utilize a data plane
firewall filter or classifier to enable matching of several fields in
the incoming packets to decide whether the packet belongs to a
specific Slice-Flow Aggregate. This option allows for applying a
rich set of rules to identify specific packets to be mapped to a
Slice-Flow Aggregate. However, it requires data plane network
resources to be able to perform the additional checks in hardware.
6. Path Selection and Instantiation
6.1. Applicability of Path Selection to Slice-Flow Aggregates
The path selection in the network can be network state dependent, or
network state independent as described in Section 5.1 of
[I-D.ietf-teas-rfc3272bis]. The latter is the choice commonly used
by IGPs when selecting a best path to a destination prefix, while the
former is used by ingress TE routers, or Path Computation Engines
(PCEs) when optimizing the placement of a flow based on the current
network resource utilization.
When path selection is network state dependent, the path computation
can leverage Traffic Engineering mechanisms (e.g., as defined in
[RFC2702]) to compute feasible paths taking into account the incoming
traffic demand rate and current state of network. This allows
avoiding overly utilized links, and reduces the chance of congestion
on traversed links.
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To enable TE path placement, the link state is advertised with
current reservations, thereby reflecting the available bandwidth on
each link. Such link reservations may be maintained centrally on a
network wide network resource manager, or distributed on devices (as
usually done with RSVP). TE extensions exist today to allow IGPs
(e.g., [RFC3630] and [RFC5305]), and BGP-LS [RFC7752] to advertise
such link state reservations.
When the network resource reservations are maintained for NRPs, the
link state can carry per NRP state (e.g., reservable bandwidth).
This allows path computation to take into account the specific
network resources available for an NRP. In this case, we refer to
the process of path placement and path provisioning as Slice-Flow
Aggregate aware TE.
6.2. Applicability of Path Control Technologies to Slice-Flow
Aggregates
The NRP modes described in this document are agnostic to the
technology used to setup paths that carry Slice-Flow Aggregate
traffic. One or more paths connecting the endpoints of the mapped
IETF network slices may be selected to steer the corresponding
traffic streams over the resources allocated for the NRP that
supports a Slice-Flow Aggregate.
The feasible paths can be computed using the NRP topology and network
state subject the optimization metrics and constraints.
6.2.1. RSVP-TE Based Slice-Flow Aggregate Paths
RSVP-TE [RFC3209] can be used to signal LSPs over the computed
feasible paths in order to carry the Slice-Flow Aggregate traffic.
The specific extensions to the RSVP-TE protocol required to enable
signaling of Slice-Flow Aggregate aware RSVP LSPs are outside the
scope of this document.
6.2.2. SR Based Slice-Flow Aggregate Paths
Segment Routing (SR) [RFC8402] can be used to setup and steer traffic
over the computed Slice-Flow Aggregate feasible paths.
The SR architecture defines a number of building blocks that can be
leveraged to support the realization of NRPs that support Slice-Flow
Aggregates in an SR network.
Such building blocks include:
* SR Policy with or without Flexible Algorithm.
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* Steering of services (e.g. VPN) traffic over SR paths
* SR Operation, Administration and Management (OAM) and Performance
Management (PM)
SR allows a headend node to steer packets onto specific SR paths
using a Segment Routing Policy (SR Policy). The SR policy supports
various optimization objectives and constraints and can be used to
steer Slice-Flow Aggregate traffic in the SR network.
The SR policy can be instantiated with or without the IGP Flexible
Algorithm (Flex-Algorithm) feature. It may be possible to dedicate a
single SR Flex-Algorithm to compute and instantiate SR paths for one
Slice-Flow Aggregate traffic. In this case, the SR Flex-Algorithm
computed paths and Flex-Algorithm SR SIDs are not shared by other
Slice-Flow Aggregates traffic. However, to allow for better scale,
it may be desirable for multiple Slice-Flow Aggregates traffic to
share the same SR Flex-Algorithm computed paths and SIDs. Further
details on how the NRP modes presented in this document can be
realized in an SR network are discussed in
[I-D.bestbar-spring-scalable-ns], and [I-D.bestbar-lsr-spring-sa].
7. Network Resource Partition Protocol Extensions
Routing protocols may need to be extended to carry additional per NRP
link state. For example, [RFC5305], [RFC3630], and [RFC7752] are
ISIS, OSPF, and BGP protocol extensions to exchange network link
state information to allow ingress TE routers and PCE(s) to do proper
path placement in the network. The extensions required to support
network slicing may be defined in other documents, and are outside
the scope of this document.
The instantiation of an NRP Policy may need to be automated.
Multiple options are possible to facilitate automation of
distribution of an NRP Policy to capable devices.
For example, a YANG data model for the NRP Policy may be supported on
network devices and controllers. A suitable transport (e.g., NETCONF
[RFC6241], RESTCONF [RFC8040], or gRPC) may be used to enable
configuration and retrieval of state information for slice policies
on network devices. The NRP Policy YANG data model is outside the
scope of this document, and is defined in
[I-D.bestbar-teas-yang-slice-policy].
8. IANA Considerations
This document has no IANA actions.
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9. Security Considerations
The main goal of network slicing is to allow for varying treatment of
traffic from multiple different network slices that are utilizing a
common network infrastructure and to allow for different levels of
services to be provided for traffic traversing a given network
resource.
A variety of techniques may be used to achieve this, but the end
result will be that some packets may be mapped to specific resources
and may receive different (e.g., better) service treatment than
others. The mapping of network traffic to a specific NRP is
indicated primarily by the SAS, and hence an adversary may be able to
utilize resources allocated to a specific NRP by injecting packets
carrying the same SAS field in their packets.
Such theft-of-service may become a denial-of-service attack when the
modified or injected traffic depletes the resources available to
forward legitimate traffic belonging to a specific NRP.
The defense against this type of theft and denial-of-service attacks
consists of a combination of traffic conditioning at NRP domain
boundaries with security and integrity of the network infrastructure
within an NRP domain.
10. Acknowledgement
The authors would like to thank Krzysztof Szarkowicz, Swamy SRK,
Navaneetha Krishnan, Prabhu Raj Villadathu Karunakaran, and Jie Dong
for their review of this document and for providing valuable feedback
on it. The authors would also like to thank Adrian Farrel for
detailed discussions that resulted in Section 3.
11. Contributors
The following individuals contributed to this document:
Colby Barth
Juniper Networks
Email: cbarth@juniper.net
Srihari R. Sangli
Juniper Networks
Email: ssangli@juniper.net
Chandra Ramachandran
Juniper Networks
Email: csekar@juniper.net
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12. References
12.1. Normative References
[I-D.bestbar-lsr-slice-aware-te]
Britto, W., Shetty, R., Barth, C., Wen, B., Peng, S., and
R. Chen, "IGP Extensions for Support of Slice Aggregate
Aware Traffic Engineering", Work in Progress, Internet-
Draft, draft-bestbar-lsr-slice-aware-te-00, 22 February
2021, <https://www.ietf.org/archive/id/draft-bestbar-lsr-
slice-aware-te-00.txt>.
[I-D.bestbar-lsr-spring-sa]
Saad, T., Beeram, V. P., Chen, R., Peng, S., Wen, B., and
D. Ceccarelli, "IGP Extensions for SR Slice Aggregate
SIDs", Work in Progress, Internet-Draft, draft-bestbar-
lsr-spring-sa-01, 16 September 2021,
<https://www.ietf.org/archive/id/draft-bestbar-lsr-spring-
sa-01.txt>.
[I-D.bestbar-spring-scalable-ns]
Saad, T., Beeram, V. P., Chen, R., Peng, S., Wen, B., and
D. Ceccarelli, "Scalable Network Slicing over SR
Networks", Work in Progress, Internet-Draft, draft-
bestbar-spring-scalable-ns-02, 16 September 2021,
<https://www.ietf.org/archive/id/draft-bestbar-spring-
scalable-ns-02.txt>.
[I-D.bestbar-teas-yang-slice-policy]
Saad, T., Beeram, V. P., Wen, B., Ceccarelli, D., Peng,
S., Chen, R., Contreras, L. M., and X. Liu, "YANG Data
Model for Slice Policy", Work in Progress, Internet-Draft,
draft-bestbar-teas-yang-slice-policy-02, 25 October 2021,
<https://www.ietf.org/archive/id/draft-bestbar-teas-yang-
slice-policy-02.txt>.
[I-D.decraene-mpls-slid-encoded-entropy-label-id]
Decraene, B., Filsfils, C., Henderickx, W., Saad, T.,
Beeram, V. P., and L. Jalil, "Using Entropy Label for
Network Slice Identification in MPLS networks.", Work in
Progress, Internet-Draft, draft-decraene-mpls-slid-
encoded-entropy-label-id-02, 6 August 2021,
<https://www.ietf.org/archive/id/draft-decraene-mpls-slid-
encoded-entropy-label-id-02.txt>.
[I-D.filsfils-spring-srv6-stateless-slice-id]
Filsfils, C., Clad, F., Camarillo, P., Raza, K., Voyer,
D., and R. Rokui, "Stateless and Scalable Network Slice
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Identification for SRv6", Work in Progress, Internet-
Draft, draft-filsfils-spring-srv6-stateless-slice-id-04,
30 July 2021, <https://www.ietf.org/archive/id/draft-
filsfils-spring-srv6-stateless-slice-id-04.txt>.
[I-D.ietf-lsr-flex-algo]
Psenak, P., Hegde, S., Filsfils, C., Talaulikar, K., and
A. Gulko, "IGP Flexible Algorithm", Work in Progress,
Internet-Draft, draft-ietf-lsr-flex-algo-18, 25 October
2021, <https://www.ietf.org/archive/id/draft-ietf-lsr-
flex-algo-18.txt>.
[I-D.kompella-mpls-mspl4fa]
Kompella, K., Beeram, V. P., Saad, T., and I. Meilik,
"Multi-purpose Special Purpose Label for Forwarding
Actions", Work in Progress, Internet-Draft, draft-
kompella-mpls-mspl4fa-01, 12 July 2021,
<https://www.ietf.org/archive/id/draft-kompella-mpls-
mspl4fa-01.txt>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
Label Switching Architecture", RFC 3031,
DOI 10.17487/RFC3031, January 2001,
<https://www.rfc-editor.org/info/rfc3031>.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
<https://www.rfc-editor.org/info/rfc3209>.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630,
DOI 10.17487/RFC3630, September 2003,
<https://www.rfc-editor.org/info/rfc3630>.
[RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P.
Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF",
RFC 4915, DOI 10.17487/RFC4915, June 2007,
<https://www.rfc-editor.org/info/rfc4915>.
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, DOI 10.17487/RFC5305, October
2008, <https://www.rfc-editor.org/info/rfc5305>.
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Internet-Draft IP/MPLS Network Slicing November 2021
[RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and
L. Yong, "The Use of Entropy Labels in MPLS Forwarding",
RFC 6790, DOI 10.17487/RFC6790, November 2012,
<https://www.rfc-editor.org/info/rfc6790>.
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016,
<https://www.rfc-editor.org/info/rfc7752>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[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>.
12.2. Informative References
[I-D.bestbar-teas-yang-topology-filter]
Beeram, V. P., Saad, T., Gandhi, R., and X. Liu, "YANG
Data Model for Topology Filter", Work in Progress,
Internet-Draft, draft-bestbar-teas-yang-topology-filter-
02, 25 October 2021, <https://www.ietf.org/archive/id/
draft-bestbar-teas-yang-topology-filter-02.txt>.
[I-D.ietf-teas-ietf-network-slices]
Farrel, A., Gray, E., Drake, J., Rokui, R., Homma, S.,
Makhijani, K., Contreras, L. M., and J. Tantsura,
"Framework for IETF Network Slices", Work in Progress,
Internet-Draft, draft-ietf-teas-ietf-network-slices-05, 25
October 2021, <https://www.ietf.org/archive/id/draft-ietf-
teas-ietf-network-slices-05.txt>.
[I-D.ietf-teas-rfc3272bis]
Farrel, A., "Overview and Principles of Internet Traffic
Engineering", Work in Progress, Internet-Draft, draft-
ietf-teas-rfc3272bis-13, 8 November 2021,
<https://www.ietf.org/archive/id/draft-ietf-teas-
rfc3272bis-13.txt>.
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[I-D.xpbs-pce-topology-filter]
Xiong, Q., Peng, S., Beeram, V. P., Saad, T., and M.
Koldychev, "PCEP Extensions for Topology Filter", Work in
Progress, Internet-Draft, draft-xpbs-pce-topology-filter-
01, 8 October 2021, <https://www.ietf.org/archive/id/
draft-xpbs-pce-topology-filter-01.txt>.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z.,
and W. Weiss, "An Architecture for Differentiated
Services", RFC 2475, DOI 10.17487/RFC2475, December 1998,
<https://www.rfc-editor.org/info/rfc2475>.
[RFC2702] Awduche, D., Malcolm, J., Agogbua, J., O'Dell, M., and J.
McManus, "Requirements for Traffic Engineering Over MPLS",
RFC 2702, DOI 10.17487/RFC2702, September 1999,
<https://www.rfc-editor.org/info/rfc2702>.
[RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed.,
and A. Bierman, Ed., "Network Configuration Protocol
(NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011,
<https://www.rfc-editor.org/info/rfc6241>.
[RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF
Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017,
<https://www.rfc-editor.org/info/rfc8040>.
Authors' Addresses
Tarek Saad
Juniper Networks
Email: tsaad@juniper.net
Vishnu Pavan Beeram
Juniper Networks
Email: vbeeram@juniper.net
Bin Wen
Comcast
Email: Bin_Wen@cable.comcast.com
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Daniele Ceccarelli
Ericsson
Email: daniele.ceccarelli@ericsson.com
Joel Halpern
Ericsson
Email: joel.halpern@ericsson.com
Shaofu Peng
ZTE Corporation
Email: peng.shaofu@zte.com.cn
Ran Chen
ZTE Corporation
Email: chen.ran@zte.com.cn
Xufeng Liu
Volta Networks
Email: xufeng.liu.ietf@gmail.com
Luis M. Contreras
Telefonica
Email: luismiguel.contrerasmurillo@telefonica.com
Reza Rokui
Nokia
Email: reza.rokui@nokia.com
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