sconepro M. Boucadair
Internet-Draft Orange
Intended status: Standards Track D. Wing
Expires: 30 September 2024 Cloud Software Group
T. Reddy
Nokia
29 March 2024
Discovery of Network Rate-Limit Policies (NRLPs)
draft-brw-sconepro-rate-policy-discovery-00
Abstract
Traffic exchanged over an attachment circuit may be subject to rate-
limit policies. These policies may be intentional policies (e.g.,
enforced as part of the activation of the attachment circuit and
typically agreed upon service subscription) or be reactive policies
(e.g., enforced temporarily to manage an overload or during a DDoS
attack mitigation).
Networks already support mechanisms to advertize a set of network
properties to hosts using Neighbor Discovery options. Examples of
such properties are link MTU (RFC 4861) and PREFIX64 (RFC 8781).
This document complements these tools and specifies a Neighbor
Discovery option to be used in Router Advertisements (RAs) to
communicate these policies to hosts. For address family parity, a
new DHCP option is also defined.
Discussion Venues
This note is to be removed before publishing as an RFC.
Source for this draft and an issue tracker can be found at
https://github.com/boucadair/draft-xxx-ac-rate-policy-discovery.
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/.
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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 30 September 2024.
Copyright Notice
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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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provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Context . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2. Networks Are Already Sharing Network Properties with
Hosts . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3. What's In? . . . . . . . . . . . . . . . . . . . . . . . 6
1.4. What's Out? . . . . . . . . . . . . . . . . . . . . . . . 6
1.5. Design Motivation & Rationale . . . . . . . . . . . . . . 7
1.6. Sample Deployment Cases . . . . . . . . . . . . . . . . . 9
2. Conventions and Definitions . . . . . . . . . . . . . . . . . 10
3. NRLP Blob . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4. IPv6 RA NRLP Option . . . . . . . . . . . . . . . . . . . . . 13
4.1. Option Format . . . . . . . . . . . . . . . . . . . . . . 13
4.2. IPv6 Host Behavior . . . . . . . . . . . . . . . . . . . 14
5. DHCP NRLP Option . . . . . . . . . . . . . . . . . . . . . . 15
5.1. Option Format . . . . . . . . . . . . . . . . . . . . . . 15
5.2. DHCPv4 Client Behavior . . . . . . . . . . . . . . . . . 18
6. Operational Considerations . . . . . . . . . . . . . . . . . 18
7. Deployment Incentives . . . . . . . . . . . . . . . . . . . . 19
7.1. Networks . . . . . . . . . . . . . . . . . . . . . . . . 19
7.2. Applications . . . . . . . . . . . . . . . . . . . . . . 19
7.3. Host OS . . . . . . . . . . . . . . . . . . . . . . . . . 20
8. Security Considerations . . . . . . . . . . . . . . . . . . . 20
8.1. ND . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
8.2. DHCP . . . . . . . . . . . . . . . . . . . . . . . . . . 21
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21
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9.1. Neighbor Discovery Option . . . . . . . . . . . . . . . . 21
9.2. DHCP Option . . . . . . . . . . . . . . . . . . . . . . . 21
9.3. DHCP Options Permitted in the RADIUS DHCPv4-Options
Attribute . . . . . . . . . . . . . . . . . . . . . . . . 22
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 22
10.1. Normative References . . . . . . . . . . . . . . . . . . 22
10.2. Informative References . . . . . . . . . . . . . . . . . 23
Appendix A. Provisioning Domains . . . . . . . . . . . . . . . . 27
Appendix B. Example of Authentication, Authorization, and
Accounting (AAA) . . . . . . . . . . . . . . . . . . . . 27
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 28
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 28
1. Introduction
1.1. Context
Connectivity services are provided by networks to customers via
dedicated terminating points, such as customer edges (CEs) or User
Equipment (UE). To facilitate data transfer via the provider
network, it is assumed that appropriate setup is provisioned over the
links that connect customer terminating points and a provider network
(usually via a Provider Edge (PE)), allowing successfully data
exchange over these links. The required setup is referred to in this
document as Attachment Circuits (ACs), while the underlying link is
referred to as "bearers".
The bearer can be a physical or logical link that connects a customer
device to a provider network. A bearer can be a wireless or wired
link. The same or multiple bearer technologies can be used to
establish the bearer (e.g., WLAN, cellular) to graft customer
terminating points to a network.
Figure 1 shows an example of a network that connects CEs and hosts
(UE, for example).These CEs are servicing other (internal) hosts.
The identification of these hosts is hidden to the network. The
policies enforced at the network for an AC are per-subscriber, not
per-host. Typically, if a CE is provided with a /56 IPv6 prefix,
policies are enforced on that /56 not the individual /64s that will
be used by internal hosts. A customer terminating point may be
serviced with one (e.g., UE#1, CE#1, and CE#3) or multiple ACs (e.g.,
CE#2).
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Hosts
O O O
\|/
.------. .--------------------. .------.
| +------+ | +---AC----+ |
| UE#1 | | | +---AC----+ CE#2 |
'------' +---AC----+ | '------'
| Network |
.------. .---AC----+ |
| | | | | .------.
| CE#1 +------' | +---AC----+ CE#3 |
'------' | | '------'
/|\ '--------------------' /|\
O O O O O O
Hosts Hosts
Figure 1: Sample Attachment Circuits
Customer terminating points are provided with a set of information
(e.g., IP address/prefix) to successfully be able to send and receive
traffic over an attachment circuit. A comprehensive list of
provisioning parameters that are available on the PE-side of an
attachment circuit is documented in
[I-D.ietf-opsawg-ntw-attachment-circuit].
The required set of parameters is a function of the service offering.
For example, a very limited set of parameters is required for mass-
market service offering while a more elaborated set is required for
Enterprise services (e.g., Layer 2 VPN [RFC9291] or Layer 3 VPN
[RFC9182]). This document *leverages access control, authorization,
and authentication mechanisms that are already in place for the
delivery of services over these attachment circuits*. An example of
an attachment circuit provided over a 3GPP network is depicted in
Figure 2. It is out of the scope of this document to describe all
involved components. Readers may refer to [TS-23.501] for more
details.
Appendix B provides another example of how existing tools can be
leveraged for AAA purposes.
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.-----. .-----. .-----. .-----. .-----. .-----.
|NSSF | | NEF | | NRF | | PCF | | UDM | | AF |
'--+--' '--+--' '--+--' '--+--' '--+--' '--+--'
Nnssf| Nnef| Nnrf| Npcf| Nudm| |Naf
---+--------+--+-----+--+-------+---+----+--------+---
Nausf| Namf| Nsmf|
.--+--. .--+--. .--+------.
│AUSR │ │ AMF │ │ SMF │
'-----' '--+--' '----+----'
╱ | | ╲
Control Plane N1 ╱ |N2 |N4 ╲N4
â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•â•
User Plane ╱ | │ ╲
.---. .-------. N3 .--+--. N9 .--+--. N6 .--.
|UE +--+ (R)AN +-----+ UPF +----+ UPF +-----( DN )
'---' '-------' '-----' '-----' '--'
|-------AC----------|
Figure 2: 5GS Architecture
The "AC" mention in Figure 2 is not present in [TS-23.501]. It is
added to the figure for the readers' convenience to position an
attachment circuit.
1.2. Networks Are Already Sharing Network Properties with Hosts
To optimally deliver connectivity services, networks also advertize a
set of network properties [RFC9473] to connected hosts such as:
Link Maximum Transmission Unit (MTU): For example, the 3GPP
[TS-23.501] specifies that "the link MTU size for IPv4 is sent to
the UE by including it in the PCO (see TS 24.501). The link MTU
size for IPv6 is sent to the UE by including it in the IPv6 Router
Advertisement message (see RFC 4861)".
Section 2.10 of [RFC7066] indicates that a cellular host should
honor the MTU option in the Router Advertisement (Section 4.6.4 of
[RFC4861]) given that the 3GPP system architecture uses extensive
tunneling in its packet core network below the 3GPP link, and this
may lead to packet fragmentation issues.
MTU is cited as an example of path properties in Section 4 of
[RFC9473].
Prefixes of Network Address and Protocol Translation from IPv6
clients to IPv4 servers (NAT64) [RFC8781]: This option is useful to
enable local DNSSEC validation, support networks with no DNS64,
support IPv4 address literals on an IPv6-only host, etc.
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NAT is cited as an example of path properties (see "Service
Function" bullet in Section 4 of [RFC9473]).
Encrypted DNS option [RFC9463]: This option is used to discover
encrypted DNS resolvers of a network.
1.3. What's In?
[I-D.rwbr-tsvwg-signaling-use-cases] discusses some use cases where
it is beneficial to share policies with the hosts. *Given that all
IPv6 hosts and networks are required to support Neighbor Discovery
[RFC4861]*, this document specifies a Neighbor Discovery option to be
used in Router Advertisements (RAs) to communicate these policies to
hosts. For address family parity, a DHCP option [RFC2132] is also
defined for IPv4.
These options are called: Network Rate-Limit Policy (NRLP).
This document uses the host/network metadata specified in Section 5.1
of [I-D.rwbr-sconepro-flow-metadata].
In order to ensure consistent design for both IPv4 and IPv6
attachment circuits, Section 3 groups the set of NRLP parameters that
are returned independent of the address family. This blob can be
leveraged in networks where DHCP is not used and ease the mapping
with specific protocols used in these networks. For example, *_a
Protocol Configuration Option (PCO) [TS-24.008] NRLP Information
Element can be defined in 3GPP_*.
Whether host-to-network, network-to-host, or both policies are
returned in an NRLP is deployment specific. All these combinations
are supported in this document.
Also, the design supports returning one more NRLP instances for a
given traffic direction.
Appendix A describes a candidate discovery approach using
Provisioning Domains (PvDs) [RFC8801]. That approach requires
more discussion as PvD is not currently deployed in mobile
networks.
1.4. What's Out?
This document does not make any assumption about the type of the
network (fixed, cellular, etc.) that terminates an attachment
circuit.
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Likewise, the document does not make any assumption about the
services or applications that are delivered over an attachment
circuit. Whether one or multiple services are bound to the same
attachment circuit is deployment specific.
Applications will have access to all these NRLPs and will, thus,
adjust their behavior as a function of scope and traffic category
indicated in a policy (all traffic, streaming, etc.). An application
that couples multiple flow types will adjust each flow type to be
consistent with the specific policy for the relevant traffic
category. Likewise, a host with multiple ACs may use the discovered
NRLPs AC to decide how to distribute its flows over these ACs (prefer
an AC to place an application session, migrate connection, etc.).
That's said, this document does not make any recommendation about how
a receiving host uses the discovered policy. Readers should refer,
e.g., to [I-D.rwbr-tsvwg-signaling-use-cases] for some examples.
Networks that advertize NLRPs are likely to maintain the policing in
place within the network because of the trust model (hosts are not
considered as trusted devices). Per-subscriber rate-limit policies
are generally recommended to protect nodes against Denial of Service
(DoS) attacks (e.g., Section 9.3 of [RFC8803] or Section 8 of
[I-D.ietf-masque-quic-proxy]). Discussion about conditions under
which such a trust model can be relaxed is out of scope of this
document.
This document does not assume nor preclude that other mechanims,
e.g., Low Latency, Low Loss, and Scalable Throughput (L4S) [RFC9330],
are enabled in a bottleneck link.
1.5. Design Motivation & Rationale
The main motivations for the use of ND for such a discovery are
listed in Section 3 of [RFC8781]:
* Fate sharing
* Atomic configuration
* Updatability: change the policy at any time
* Deployability
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The solution specified in the document is designed to *ease
integration with network managment tools* that are used to manage and
expose policies. It does so by leveraging the policy structure
defined in [I-D.ietf-opsawg-ntw-attachment-circuit]. That same
structure is also used in the context of service activation such as
Network Slicing [RFC9543]; see the example depicted in Appendix B.5
of [I-D.ietf-teas-ietf-network-slice-nbi-yang].
The solution defined in this document:
* *Does not require any data plane change*.
* *Applicable to any transport protocol*.
* *Does not impact the connection setup delay*.
* *Does not require to reveal the identity of the target server or
the application itself* to consume the signal.
* *Supports cascaded environments* where multiple levels to enforce
rate-limiting polices is required (e.g., WAN and LAN shown in
Figure 3). NRLP signals can be coupled or decoupled as a function
of the local policy.
* *Supports signaling policies bound to one or both traffic
directions*.
* Is able to *signal wether a policy applies to a specific host or
all hosts of a given subscriber*.
.------. .--------------------.
| Host +---+ .---. | |
| #1 | | | | | |
'------' +-----+ C | | |
nrlp#2 | P +--------+ Network |
.------. .-----+ E | nrlp#1 | |
| Host | | | | | |
| #2 +---' '---' | |
'------' nrlp#3 | |
'--------------------'
Figure 3: Example of Cascaded NRLPs
Compared to a proxy or an encapsulation-based proposal (e.g.,
[I-D.ihlar-masque-sconepro-mediabitrate]), the solution defined in
this document:
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* *Does not impact the MTU tweaking*: No packet overhead is
required.
* *Does not suffer from side effects of multi-layer encryption
schemes* on the packet processing and overall performance of
involved network nodes. Such issues are encountered, e.g., with
the tunneled mode or long header packets in the forwarded QUIC
proxy mode [I-D.ietf-masque-quic-proxy].
* *Does not suffer from nested congestion control* for tunneled
proxy mode.
* *Does not impact the forwarding peformance of network nodes*. For
example, the proxy forwarded mode [I-D.ietf-masque-quic-proxy]
requires rewriting connection identifiers; that is, the
performance degradation will be at least equivalent to NAT.
* *Does not suffer from the complications of IP address sharing
[RFC6269]*. Such issues are likely to be experienced for proxy-
based solutions that multiplex internal connections using one or
more external IP addresses.
* *Does not require manipulating extra steering policies on the
host* to decide which flows can be forwarded over or outside the
proxy connection.
* *Requires a minor change to the network*: For IPv6, upgrade PE
nodes to support a new ND option. Note that all IPv6 hosts and
networks are required to support Neighbor Discovery [RFC4861].
For IPv4, configure DHCP servers to include a new DHCP option.
1.6. Sample Deployment Cases
Some deployment use cases for NRLP are provided below:
* A network may advertize an NRLP when it is overloaded, including
when it is under attack. The rate-limit policy is basically a
reactive policy that is meant to adjust the behavior of connected
hosts to better control the load during these exceptional events
(issue with RAN resources, for example). The mechanism can also
be used to enrich the tools that are already available to better
handle attack traffic close to the source [RFC9066].
* Discovery of intentional policy applied on attachment circuits
(peering links, CE-PE links, etc.) when such information is not
made available during the service activation or when network
upgrades are performed.
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* A user may configure policies on the CPE such as securing some
resources to a specific internal host used for gaming or video
streaming. The CPE can use the NRLP option to share these rate-
limit policies to connected hosts to adjust their forwarding
behavior.
Operational considerations are discussed in Section 6, while
deployment incentives are described in Section 7.
2. Conventions and Definitions
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.
This document uses the terms defined in Section 2 of
[I-D.ietf-opsawg-ntw-attachment-circuit] and [RFC9473].
Also, this document makes use fo the following terms:
Reactive policy: Treatment given to a flow when an exceptional event
occurs, such as diminished throughput to the host caused by radio
interference or weak radio signal, congestion on the network
caused by other users or other applications on the same host.
Intentional policy: Configured bandwidth, pps, or similar throughput
constraints applied to a flow, application, host, or subscriber.
Rate-limit: Used as a generic term to refer to a policy to restrict
the maximum bitrate of a flow.
It can be used with or without any traffic classification.
3. NRLP Blob
This section defines the set of attributes that are included in an
NRLP blob:
D: 1-bit flag which indicates the direction on which to apply the
enclosed policy.
When set to "1", this flag indicates that this policy is for
network-to-host direction.
When set to "0", this flag indicates that this policy is for host-
to-network direction.
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E: When set to "1", this flag indicates the presence of Excess
Information Rate (EIR).
When set to "0", this flag indicates that EIR is not present.
P: When set to "1", this flag indicates the presence of Peak
Information Rate (PIR).
When set to "0", this flag indicates that PIR is not present.
U: Unassigned bit.
Scope: 4-bit field which specifies whether the policy is per host,
per subscriber, etc.
The following values are supported:
* "0": Subscriber
* "1": Host
* 2-15: Unassigned values.
TC: 8-bit field which specifies a traffic category to which this
policy applies.
The following values are supported:
* "0": All traffic. This is the default value.
* "1": Streaming
* "2": Realtime
* "3": Bulk trafic
* 4-255: Unassigned values
Committed Information Rate (CIR) (Mbps): Specifies the maximum
number of bits that a network can receive or send during one
second over an attachment circuit for a traffic category.
If set to 0, this indicates to the host that an alternate path (if
any) should be preferred over this one.
See Section 5.1 of [I-D.rwbr-sconepro-flow-metadata].
This parameter is mandatory.
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Committed Burst Size (CBS) (bytes): Specifies the maximum burst size
that can be transmitted at CIR.
MUST be greated than zero.
This parameter is mandatory.
Excess Information Rate (EIR) (Mbps): MUST be present only if the E
flag is set to '1'.
Specifies the maximum number of bits that a network can receive or
send during one second over an attachment circuit for a traffic
category that is out of profile.
See Section 5.1 of [I-D.rwbr-sconepro-flow-metadata].
This parameter is optional.
Excess Burst Size (EBS) (bytes): MUST be present only if EIR is also
present.
Indicates that maximum excess burst size that is allowed while not
complying with the CIR.
MUST be greater than zero, if present.
This parameter is optional.
Peak Information Rate (PIR) (Mbps): MUST be present only if P flag
is set to '1'.
Traffic that exceeds the CIR and the CBS is metered to the PIR.
See Section 5.1 of [I-D.rwbr-sconepro-flow-metadata].
This parameter is optional.
Peak Burst Size (PBS) (bytes): MUST be present only if PIR is also
present.
Specifies the maximum burst size that can be transmitted at PIR.
MUST be greater than zero, if present.
The reader should refer to [RFC2697], [RFC2698], and [RFC4115] for
examples of how various combinations of CIR/CBS/EIR/EBS/PIR/PBS are
used for policing. Typically:
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* A Single-Rate, Three-Color Marker [RFC2697] uses CIR, CBS, and
EBS.
* A Dual-Rate, Three-Color Marker [RFC2698] uses CIR, CBS, PIR, and
PBS.
4. IPv6 RA NRLP Option
4.1. Option Format
The format of the IPv6 RA NRLP option, with only mandatory fields
included, is illustrated in Figure 4.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |D|E|P|U| Scope | TC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed Information Rate (CIR) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed Burst Size (CBS) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: NRLP Option Format with Mandatory Fields
The format of the IPv6 RA NRLP option, with optional fields included,
is illustrated in Figure 4.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |D|E|P|U| Scope | TC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed Information Rate (CIR) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed Burst Size (CBS) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Excess Information Rate (EIR) (Optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Excess Burst Size (EBS) (Optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peak Information Rate (PIR) (Optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Peak Burst Size (PBS) (Optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: NRLP Option Format with Optional Fields
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The fields of the option shown in Figure 5 are as follows:
Type: 8-bit identifier of the NRLP option as assigned by IANA
(TBD1).
Length: 8-bit unsigned integer. The length of the option (including
the Type and Length fields) is in units of 8 octets.
D: See Section 3.
E: See Section 3.
P: See Section 3.
U: Unassigned bit.
Scope: See Section 3.
TC: See Section 3.
Committed Information Rate (CIR) (Mbps): See Section 3.
Committed Burst Size (CBS) (bytes): See Section 3.
Excess Information Rate (EIR) (Mbps): See Section 3. This is an
optional field.
Excess Burst Size (EBS) (bytes): See Section 3. This is an optional
field.
Peak Information Rate (PIR) (Mbps): See Section 3. This is an
optional field.
Peak Burst Size (PBS) (bytes): See Section 3. This is an optional
field.
4.2. IPv6 Host Behavior
The procedure for rate-limit configuration is the same as it is with
any other Neighbor Discovery option [RFC4861].
The host MUST be prepared to receive multiple NRLP options in RAs;
each with distinct scope and/or application group.
If the host receives multiple NRLP options with overlapping scope/TC,
the host MUST silently discard all these options.
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If the receiving host has LAN capabilities (e.g., mobile CE or mobile
handset with tethering), the following behavior applies:
* If an RA NRLP is advertised from the network, and absent local
rate-limit policies, the device should send RAs to the downstream
attached LAN devices with the same NRLP values received from the
network.
* If local rate-limit policies are provided to the device, the
device may change the scope or values received from the network to
accommodate these policies. The device may decide to not relay
received RAs to internal nodes if local policies were already
advertized using RAs and those policies are consistent with the
network policies.
Applications running over a host can learn the bitrates associated
with a network attachment by invoking a dedicated API. The exact
details of the API is OS-specific and, thus, out of scope of this
document.
5. DHCP NRLP Option
Note that the base DHCP can only signal a rate policy change when
the client first joins the network or renews its lease, whereas
IPv6 ND can update the rate policy at the network's discretion.
[RFC6704] specifies an approach for forcing reconfiguration of
individual hosts without suffering from the limitations of the
FORCERENEW design in [RFC3203].
5.1. Option Format
The format of the DHCP NRLP option is illustrated in Figure 6.
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| OPTION_V4_NRLP| Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
~ NRLP Instance Data #1 ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ---
. ... . |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ optional
~ NRLP Instance Data #n ~ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ---
Figure 6: NRLP DHCP Option Format
The fields of the option shown in Figure 6 are as follows:
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Code: OPTION_V4_NRLP (TBD2).
Length: Indicates the length of the enclosed data in octets.
NRLP Instance Data: Includes a network rate-limit policy. The
format of this field with only mandatory parameters is shown in
Figure 7.
When several NRLPs are to be included, the "NRLP Instance Data"
field is repeated.
0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NRLP Instance Data Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|D|E|P|U| Scope | TC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed Information Rate |
| (CIR) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed Burst Size (CBS) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: NRLP Instance Data Format with Mandatory Fields
The format of this field, with optional parameters included, is shown
in Figure 7.
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0 1
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NRLP Instance Data Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|D|E|P|U| Scope | TC |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed Information Rate |
| (CIR) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed Burst Size (CBS) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ---
| Excess Information Rate | |
| (EIR) | O
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ P
| Excess Burst Size (CBS) | T
| | I
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ O
| Peak Information Rate | N
| (PIR) | A
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ L
| Peak Burst Size (PBS) | |
| | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ---
Figure 8: NRLP Instance Data Format with Optional Fields Included
The fields shown in Figure 8 are as follows:
NRLP Instance Data Length: Length of all following data in octets.
This field is set to '8' when only the nominal bitrate is provided
for an NLRP instance.
D: See Section 3.
E: See Section 3.
P: See Section 3.
U: Unassigned bit.
Scope: See Section 3.
TC: See Section 3.
Committed Information Rate (CIR) (Mbps): See Section 3.
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Committed Burst Size (CBS) (bytes): See Section 3.
Excess Information Rate (EIR) (Mbps): See Section 3. This is an
optional field.
Excess Burst Size (EBS) (bytes): See Section 3. This is an optional
field.
Peak Information Rate (PIR) (Mbps): See Section 3. This is an
optional field.
Peak Burst Size (PBS) (bytes): See Section 3. This is an optional
field.
OPTION_V4_NRLP is a concatenation-requiring option. As such, the
mechanism specified in [RFC3396] MUST be used if OPTION_V4_NRLP
exceeds the maximum DHCP option size of 255 octets.
OPTION_V4_NRLP is permitted to be included in the RADIUS
DHCPv4-Options Attribute [RFC9445].
5.2. DHCPv4 Client Behavior
To discover a network rate-limit policy, the DHCP client includes
OPTION_V4_NRLP in a Parameter Request List option [RFC2132].
The DHCP client MUST be prepared to receive multiple "NRLP Instance
Data" field entries in the OPTION_V4_NRLP option; each instance is to
be treated as a separate network rate-limit policy.
6. Operational Considerations
NRLP senders should be configured with instructions about the type of
network rate-limit policies to be shared with requesting hosts.
These types can be provided using mechanisms such as
[I-D.ietf-opsawg-ntw-attachment-circuit].
In contexts where the bitrate policies are known during the
establishment of the underlying bearer (e.g., GBR PDU Sessions),
sending NRLP signals over the attachment circuit may be redundant and
should thus be disabled.
In contexts where the (average) bitrate policies provided during the
establishment of a bearer cannot be refreshed to echo network-
specific conditions (e.g., overload) using bearer-specific
mechanisms, sending NRLP signals over the attachment circuit would
allow control the load at the source.
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When both bearer-specific policies and NRLP signals are communicated
to a host, the NRLP signals takes precedence.
Rate-limit policies enforced at the network are assumed to be
consistent with the local jurisdictions. For example, [BEREC] says
the following:
ISPs are prohibited from blocking or slowing down of Internet
traffic, except where necessary. The exceptions are limited to:
traffic management to comply with a legal order, to ensure network
integrity and security, and to manage congestion, provided that
equivalent categories of traffic are treated equally.
7. Deployment Incentives
7.1. Networks
There are a set of tradeoffs for networks to deploy NRLP discovery:
* Cost vs. benefit
* Impact on operations vs incentive to deploy
* Enhanced experience vs. impacts on nominal mode
The procedure defined in the document provides a mechanism to assist
networks managing the load at the source and, thus, contribute to
better handle network overloads and optimize the use of resources
under non nominal conditions. The mechanism allows also to enhance
the quality of experience at the LAN by providing a simple tool to
communicate local policies to hosts. A minimal change is required to
that aim.
Networks that throttle bandwidth for reasons that are not compliant
with local jurisdictions, not communicated to customers, etc. are
unlikely to share NRLP signals. If these signals are shared, it is
unlikely that they will mirror the actual network configuration
(e.g., application-specific policies).
7.2. Applications
Some applications support some forms of bandwidth measurements (e.g.,
[app-measurement]) which feed how the content is accessed to using
ABR. Complementing or replacing these measurements with explicit
signals depends upon:
* The extra cost that is required to support both mechanisms at the
application layer.
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* The complexity balance between performing the measurements vs.
consuming the signal.
* Whether the measurements ("assessed property" per [RFC9473])
reflect actual network conditions or severely diverge.
* The availability of the network signals at the first place: it is
unlikely that all networks will support sending the signals.
Deployment incentives at the network may vary.
* The host support may be variable.
Applications that don't support (embedded) bandwidth measurement
schemes will be enriched with the NRLP signals as this will be
exposed by an OS API.
7.3. Host OS
TBC.
8. Security Considerations
8.1. ND
As discussed in [RFC8781], because RAs are required in all IPv6
configuration scenarios, RAs must already be secured, e.g., by
deploying an RA-Guard [RFC6105]. Providing all configuration in RAs
reduces the attack surface to be targeted by malicious attackers
trying to provide hosts with invalid configuration, as compared to
distributing the configuration through multiple different mechanisms
that need to be secured independently.
RAs are already used in mobile networks to advertize the link MTU.
The same security considerartions for MTU discovery apply for the
NRLP discover.
An attacker who has access to the RAs exchanged over an attachment
circuit may:
* Decrease the bitrate: This may lower the perceived QoS if the host
aggressively lowers its transmission rate.
* Increase the bitrate value: The attachment circuit will be
overloaded, but still the rate-limit at the network will discard
excess traffic.
* Drop RAs: This is similar to the current operations, where no NRLP
RA is shared.
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* Inject fake RAs: The implications are similar to the impacts of
tweaking the values of a legitimate RA.
8.2. DHCP
An attacker who has access to the DHCP exchanged over an attachment
circuit may do a lot of harm (e.g., prevent access to the network).
The following mechanisms may be considered to mitigate spoofed or
modified DHCP responses:
DHCPv6-Shield [RFC7610]: The network access node (e.g., a border
router, a CPE, an Access Point (AP)) discards DHCP response
messages received from any local endpoint.
Source Address Validation Improvement (SAVI) solution for DHCP
[RFC7513]: The network access node filters packets with forged
source IP addresses.
The above mechanisms would ensure that the endpoint receives the
correct NRLP information, but these mechanisms cannot provide any
information about the DHCP server or the entity hosting the DHCP
server.
9. IANA Considerations
9.1. Neighbor Discovery Option
This document requests IANA to assign the following new IPv6 Neighbor
Discovery Option type in the "IPv6 Neighbor Discovery Option Formats"
subregistry under the "Internet Control Message Protocol version 6
(ICMPv6) Parameters" registry maintained at [IANA-ND].
+======+=============+===============+
| Type | Description | Reference |
+======+=============+===============+
| TBD1 | NRLP Option | This-Document |
+------+-------------+---------------+
Table 1: Neighbor Discovery NRLP
Option
9.2. DHCP Option
This document requests IANA to assign the following new DHCP Option
Code in the "BOOTP Vendor Extensions and DHCP Options" registry
maintained at [IANA-BOOTP].
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+======+================+=============+=============+===============+
| Tag | Name | Data Length | Meaning | Reference |
+======+================+=============+=============+===============+
| TBD2 | OPTION_V4_NRLP | N | NRLP | This-Document |
| | | | Option | |
+------+----------------+-------------+-------------+---------------+
Table 2: DHCP NRLP Option
9.3. DHCP Options Permitted in the RADIUS DHCPv4-Options Attribute
This document requests IANA to add the following DHCP Option Code to
the "DHCP Options Permitted in the RADIUS DHCPv4-Options Attribute"
registry maintained at [IANA-BOOTP].
+======+================+===============+===========+
| Tag | Name | | Reference |
+======+================+===============+===========+
| TBD2 | OPTION_V4_NRLP | This-Document | |
+------+----------------+---------------+-----------+
Table 3: New DHCP Option Permitted in the RADIUS
DHCPv4-Options Attribute Registry
10. References
10.1. Normative References
[I-D.rwbr-sconepro-flow-metadata]
Rajagopalan, S., Wing, D., Boucadair, M., and T. Reddy.K,
"Flow Metadata for Collaborative Host/Network Signaling",
Work in Progress, Internet-Draft, draft-rwbr-sconepro-
flow-metadata-00, 4 March 2024,
<https://datatracker.ietf.org/doc/html/draft-rwbr-
sconepro-flow-metadata-00>.
[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/rfc/rfc2119>.
[RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 2132, DOI 10.17487/RFC2132, March 1997,
<https://www.rfc-editor.org/rfc/rfc2132>.
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[RFC3396] Lemon, T. and S. Cheshire, "Encoding Long Options in the
Dynamic Host Configuration Protocol (DHCPv4)", RFC 3396,
DOI 10.17487/RFC3396, November 2002,
<https://www.rfc-editor.org/rfc/rfc3396>.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
DOI 10.17487/RFC4861, September 2007,
<https://www.rfc-editor.org/rfc/rfc4861>.
[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/rfc/rfc8174>.
[RFC9445] Boucadair, M., Reddy.K, T., and A. DeKok, "RADIUS
Extensions for DHCP-Configured Services", RFC 9445,
DOI 10.17487/RFC9445, August 2023,
<https://www.rfc-editor.org/rfc/rfc9445>.
10.2. Informative References
[app-measurement]
Gurel, Z. and A. C. Begen, "Bandwidth measurement for
QUIC", 2024, <https://datatracker.ietf.org/doc/slides-119-
moq-bandwidth-measurement-for-quic/>.
[BEREC] BEREC, "All you need to know about Net Neutrality rules in
the EU", <https://www.berec.europa.eu/en/all-you-need-to-
know-about-net-neutrality-rules-in-the-eu-0>.
[I-D.ietf-masque-quic-proxy]
Pauly, T., Rosenberg, E., and D. Schinazi, "QUIC-Aware
Proxying Using HTTP", Work in Progress, Internet-Draft,
draft-ietf-masque-quic-proxy-01, 12 February 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-masque-
quic-proxy-01>.
[I-D.ietf-opsawg-ntw-attachment-circuit]
Boucadair, M., Roberts, R., de Dios, O. G., Barguil, S.,
and B. Wu, "A Network YANG Data Model for Attachment
Circuits", Work in Progress, Internet-Draft, draft-ietf-
opsawg-ntw-attachment-circuit-05, 9 February 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-opsawg-
ntw-attachment-circuit-05>.
[I-D.ietf-teas-ietf-network-slice-nbi-yang]
Wu, B., Dhody, D., Rokui, R., Saad, T., and J. Mullooly,
"A YANG Data Model for the RFC 9543 Network Slice
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Service", Work in Progress, Internet-Draft, draft-ietf-
teas-ietf-network-slice-nbi-yang-10, 16 March 2024,
<https://datatracker.ietf.org/doc/html/draft-ietf-teas-
ietf-network-slice-nbi-yang-10>.
[I-D.ihlar-masque-sconepro-mediabitrate]
Ihlar, M. and M. Kühlewind, "MASQUE extension for
signaling media bitrate", Work in Progress, Internet-
Draft, draft-ihlar-masque-sconepro-mediabitrate-00, 9
February 2024, <https://datatracker.ietf.org/doc/html/
draft-ihlar-masque-sconepro-mediabitrate-00>.
[I-D.rwbr-tsvwg-signaling-use-cases]
Rajagopalan, S., Wing, D., Boucadair, M., and T. Reddy.K,
"Host to Network Signaling Use Cases for Collaborative
Traffic Differentiation", Work in Progress, Internet-
Draft, draft-rwbr-tsvwg-signaling-use-cases-02, 17 March
2024, <https://datatracker.ietf.org/doc/html/draft-rwbr-
tsvwg-signaling-use-cases-02>.
[IANA-BOOTP]
IANA, "BOOTP Vendor Extensions and DHCP Options",
<https://www.iana.org/assignments/bootp-dhcp-parameters/>.
[IANA-ND] IANA, "IPv6 Neighbor Discovery Option Formats",
<https://www.iana.org/assignments/icmpv6-parameters/>.
[RFC2697] Heinanen, J. and R. Guerin, "A Single Rate Three Color
Marker", RFC 2697, DOI 10.17487/RFC2697, September 1999,
<https://www.rfc-editor.org/rfc/rfc2697>.
[RFC2698] Heinanen, J. and R. Guerin, "A Two Rate Three Color
Marker", RFC 2698, DOI 10.17487/RFC2698, September 1999,
<https://www.rfc-editor.org/rfc/rfc2698>.
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)",
RFC 2865, DOI 10.17487/RFC2865, June 2000,
<https://www.rfc-editor.org/rfc/rfc2865>.
[RFC3203] T'Joens, Y., Hublet, C., and P. De Schrijver, "DHCP
reconfigure extension", RFC 3203, DOI 10.17487/RFC3203,
December 2001, <https://www.rfc-editor.org/rfc/rfc3203>.
[RFC4115] Aboul-Magd, O. and S. Rabie, "A Differentiated Service
Two-Rate, Three-Color Marker with Efficient Handling of
in-Profile Traffic", RFC 4115, DOI 10.17487/RFC4115, July
2005, <https://www.rfc-editor.org/rfc/rfc4115>.
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[RFC6105] Levy-Abegnoli, E., Van de Velde, G., Popoviciu, C., and J.
Mohacsi, "IPv6 Router Advertisement Guard", RFC 6105,
DOI 10.17487/RFC6105, February 2011,
<https://www.rfc-editor.org/rfc/rfc6105>.
[RFC6269] Ford, M., Ed., Boucadair, M., Durand, A., Levis, P., and
P. Roberts, "Issues with IP Address Sharing", RFC 6269,
DOI 10.17487/RFC6269, June 2011,
<https://www.rfc-editor.org/rfc/rfc6269>.
[RFC6704] Miles, D., Dec, W., Bristow, J., and R. Maglione,
"Forcerenew Nonce Authentication", RFC 6704,
DOI 10.17487/RFC6704, August 2012,
<https://www.rfc-editor.org/rfc/rfc6704>.
[RFC7066] Korhonen, J., Ed., Arkko, J., Ed., Savolainen, T., and S.
Krishnan, "IPv6 for Third Generation Partnership Project
(3GPP) Cellular Hosts", RFC 7066, DOI 10.17487/RFC7066,
November 2013, <https://www.rfc-editor.org/rfc/rfc7066>.
[RFC7513] Bi, J., Wu, J., Yao, G., and F. Baker, "Source Address
Validation Improvement (SAVI) Solution for DHCP",
RFC 7513, DOI 10.17487/RFC7513, May 2015,
<https://www.rfc-editor.org/rfc/rfc7513>.
[RFC7610] Gont, F., Liu, W., and G. Van de Velde, "DHCPv6-Shield:
Protecting against Rogue DHCPv6 Servers", BCP 199,
RFC 7610, DOI 10.17487/RFC7610, August 2015,
<https://www.rfc-editor.org/rfc/rfc7610>.
[RFC8781] Colitti, L. and J. Linkova, "Discovering PREF64 in Router
Advertisements", RFC 8781, DOI 10.17487/RFC8781, April
2020, <https://www.rfc-editor.org/rfc/rfc8781>.
[RFC8801] Pfister, P., Vyncke, É., Pauly, T., Schinazi, D., and W.
Shao, "Discovering Provisioning Domain Names and Data",
RFC 8801, DOI 10.17487/RFC8801, July 2020,
<https://www.rfc-editor.org/rfc/rfc8801>.
[RFC8803] Bonaventure, O., Ed., Boucadair, M., Ed., Gundavelli, S.,
Seo, S., and B. Hesmans, "0-RTT TCP Convert Protocol",
RFC 8803, DOI 10.17487/RFC8803, July 2020,
<https://www.rfc-editor.org/rfc/rfc8803>.
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[RFC9066] Reddy.K, T., Boucadair, M., Ed., and J. Shallow,
"Distributed Denial-of-Service Open Threat Signaling
(DOTS) Signal Channel Call Home", RFC 9066,
DOI 10.17487/RFC9066, December 2021,
<https://www.rfc-editor.org/rfc/rfc9066>.
[RFC9182] Barguil, S., Gonzalez de Dios, O., Ed., Boucadair, M.,
Ed., Munoz, L., and A. Aguado, "A YANG Network Data Model
for Layer 3 VPNs", RFC 9182, DOI 10.17487/RFC9182,
February 2022, <https://www.rfc-editor.org/rfc/rfc9182>.
[RFC9291] Boucadair, M., Ed., Gonzalez de Dios, O., Ed., Barguil,
S., and L. Munoz, "A YANG Network Data Model for Layer 2
VPNs", RFC 9291, DOI 10.17487/RFC9291, September 2022,
<https://www.rfc-editor.org/rfc/rfc9291>.
[RFC9330] Briscoe, B., Ed., De Schepper, K., Bagnulo, M., and G.
White, "Low Latency, Low Loss, and Scalable Throughput
(L4S) Internet Service: Architecture", RFC 9330,
DOI 10.17487/RFC9330, January 2023,
<https://www.rfc-editor.org/rfc/rfc9330>.
[RFC9463] Boucadair, M., Ed., Reddy.K, T., Ed., Wing, D., Cook, N.,
and T. Jensen, "DHCP and Router Advertisement Options for
the Discovery of Network-designated Resolvers (DNR)",
RFC 9463, DOI 10.17487/RFC9463, November 2023,
<https://www.rfc-editor.org/rfc/rfc9463>.
[RFC9473] Enghardt, R. and C. Krähenbühl, "A Vocabulary of Path
Properties", RFC 9473, DOI 10.17487/RFC9473, September
2023, <https://www.rfc-editor.org/rfc/rfc9473>.
[RFC9543] Farrel, A., Ed., Drake, J., Ed., Rokui, R., Homma, S.,
Makhijani, K., Contreras, L., and J. Tantsura, "A
Framework for Network Slices in Networks Built from IETF
Technologies", RFC 9543, DOI 10.17487/RFC9543, March 2024,
<https://www.rfc-editor.org/rfc/rfc9543>.
[TS-23.501]
3GPP, "TS 23.501: System architecture for the 5G System
(5GS)", 2024,
<https://portal.3gpp.org/desktopmodules/Specifications/
SpecificationDetails.aspx?specificationId=3144>.
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[TS-24.008]
3GPP, "Technical Specification Group Core Network and
Terminals; Mobile radio interface Layer 3 specification;
Core network protocols; Stage 3 (Release 18)", 2024,
<https://www.3gpp.org/DynaReport/24008.htm>.
Appendix A. Provisioning Domains
PvD may also be considered as a mechanism to discover NRLP.
Typically, the network will configured to set the H-flag so clients
can request PvD Additional Information (Section 4.1 of [RFC8801]).
Figure 9 provides an example of the returned "application/pvd+json"
to indicate a network-to-host NRLP for all subscriber traffic. The
NRLP list may include multiple instances if distinct policies are to
be returned for distinct traffic categories.
{
"nrlp":[
{
"direction":1,
"scope":1,
"tc":0,
"cir":50,
"cbs":10000,
"ebs":20000
}
]
}
Figure 9: NRLP Example with PvD
Appendix B. Example of Authentication, Authorization, and Accounting
(AAA)
Figure 10 provides an example of the exchanges that might occur
between a DHCP server and an Authentication, Authorization, and
Accounting (AAA) server to retrive the per-subscriber NRLPs.
This example assumes that the Network Access Server (NAS) embeds both
Remote Authentication Dial-In User Service (RADIUS) [RFC2865] client
and DHCP server capabilities.
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.-------------. .-------------. .-------.
| Host | | NAS | | AAA |
| DHCP Client | | DHCP Server | |Server |
| | |RADIUS Client| | |
'------+------' '------+------' '---+---'
| | |
o------DHCPDISCOVER------>| |
| o----Access-Request ---->|
| | |
| |<----Access-Accept------o
| | DHCPv4-Options |
|<-----DHCPOFFER----------o (OPTION_V4_NRLP) |
| (OPTION_V4_NRLP) | |
| | |
o-----DHCPREQUEST-------->| |
| (OPTION_V4_NRLP) | |
| | |
|<-------DHCPACK----------o |
| (OPTION_V4_NRLP) | |
| | |
DHCP RADIUS
Figure 10: An Example of RADIUS NRLP Exchanges
Acknowledgments
TODO acknowledge.
Authors' Addresses
Mohamed Boucadair
Orange
Email: mohamed.boucadair@orange.com
Dan Wing
Cloud Software Group Holdings, Inc.
United States of America
Email: danwing@gmail.com
Tirumaleswar Reddy
Nokia
India
Email: kondtir@gmail.com
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