RADIUS attributes for National Security and Emergency Preparedness Service
draft-ietf-radext-epcs-00
| Document | Type | Active Internet-Draft (radext WG) | |
|---|---|---|---|
| Authors | Sri Gundavelli , Subir Das , Mark Grayson , Martin Dolly , An Nguyen | ||
| Last updated | 2026-09-24 | ||
| Replaces | draft-gundavelli-radepcs | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
| Intended RFC status | (None) | ||
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| Additional resources | Mailing list discussion | ||
| Stream | WG state | WG Document | |
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| IESG | IESG state | I-D Exists | |
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draft-ietf-radext-epcs-00
RADEXT Working Group S. Gundavelli
Internet-Draft Ameriband
Intended status: Standards Track S. Das
Expires: 27 March 2027 Independent
M. Grayson
Cisco Systems
M. Dolly
AT&T
A. Nguyen
US DHS/CISA
23 September 2026
RADIUS attributes for National Security and Emergency Preparedness
Service
draft-ietf-radext-epcs-00
Abstract
This document describes RADIUS attributes for supporting
authorization of Emergency Preparedness Communication Service (EPCS),
enabling authorized users to benefit from preferential access to Wi-
Fi network resources during congestion.
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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This Internet-Draft will expire on 27 March 2027.
Copyright Notice
Copyright (c) 2026 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
1.2. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Overview of EPCS Provisioning . . . . . . . . . . . . . . . . 4
3. EPCS Authorization RADIUS Exchange . . . . . . . . . . . . . 5
4. RADIUS EPCS Attributes . . . . . . . . . . . . . . . . . . . 8
4.1. EPCS-Capable-Indication . . . . . . . . . . . . . . . . . 8
4.2. EPCS-Regulatory-Info . . . . . . . . . . . . . . . . . . 9
4.3. EPCS-Subscription-Info . . . . . . . . . . . . . . . . . 10
5. Security Considerations . . . . . . . . . . . . . . . . . . . 11
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
7.1. Normative References . . . . . . . . . . . . . . . . . . 11
7.2. Informative References . . . . . . . . . . . . . . . . . 12
Changelog . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction
Priority Services (PS) communications in support of National
Security/Emergency Preparedness (NS/EP) services are operational in
various countries around the world. While these have traditionally
only been supported over cellular networks [TS.22153], the recent
addition of Emergency Preparedness Communications Service (EPCS)
functionality into Wi-Fi 7 [IEEE80211BE] means that Wi-Fi now
supports preferred or prioritized channel access (PCA) to authorized
users that can be used for Multimedia Priority Services (MPS)
communications over public/private Wi-Fi networks in emergency
service (ES) scenarios.
Whereas Wi-Fi 7 defines the interactions between the Wi-Fi Access
Point (AP) and the Wi-Fi Station (STA) device for prioritized channel
access, it does not provide an end-to-end architecture for enabling
EPCS authorization capability on a per device basis.
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CISRCVIII WG4 recommendations for FCC highlight the opportunities for
regulatory bodies, like the FCC, to assess and promote Wi-Fi's role
in emergency services [CSRC8-WG4].
Earlier deliverables from CISRCV WG8 have provided recommendations
for the role of the network within the priority services platform and
to enforce priority levels on traffic associated with priority users
[CSRC5-WG8]. There are number of factors critical to this
enforcement function:
* The priority user must be authenticated and authorized to receive
priority treatment.
* The network must be able to uniquely identify priority user
traffic and associate the authorized level of priority to that
traffic.
* The network must then have the means to apply prioritization to
the identified traffic.
* For cases where networks interconnect, traffic prioritization
indicators must be securely passed to interconnected networks for
downstream prioritization.
This document specifies an extension to the Remote Authentication
Dial-In User Service (RADIUS) protocol [RFC2865] that enables a Wi-Fi
Network Access Server (NAS) to indicate to a RADIUS server that it is
EPCS capable, as well as enabling a RADIUS server to indicate to a
NAS that an authenticated user is authorized to receive the EPCS
service.
1.1. Requirements Language
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. Terminology
Authorizing Entity:
Refers to the Authority (e.g., Government entity) responsible for
vetting and assigning priority privileges and user priority levels to
an individual or organization.
Priority Services:
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A feature designed to enable NS (National Security) or EP (Emergency
Preparedness) subscribers to make priority calls or data sessions on
a Service Providers network, particularly at times of congestion.
Service user:
Means an individual or organization to whom or which a priority
access assignment has been made.
Wireless service provider:
Refers to a provider of a wireless communications service or Internet
Protocol-based service, including commercial or private mobile
service. The term includes agents of the licensed provider and
resellers of wireless service.
2. Overview of EPCS Provisioning
This section first provides background on how MPS service is
currently provisioned and authorized. The section then describes how
this can be adapted for EPCS to support Wi-Fi use cases.
The service user engages with an authorizing entity to request the
provision of Multimedia Priority Service for a device that has a
subscription with a service provider. If the request is successful,
the service provider, such as a cellular operator, will receive an
indication from the authorizing entity, by an out of band mechanism,
that a subscriber has been authorized for priority services. The
service provider will store such an indication as part of the
subscription profile of the subscriber (e.g., in the cellular network
defined Home Subscriber Server (HSS)).
Figure 1 illustrates the scenario where the service provider is a
cellular operator that is also operating as a Wi-Fi Identity
Provider, e.g., using SIM card credentials to authenticate users onto
third-party Wi-Fi networks. In such cases, the cellular operator can
mirror the priority service subscription profile information in their
Wi-Fi Authentication, Authorization and Accounting (AAA) system.
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.---------. .------------. .--------------. .-----------.
| Wi-Fi | |EPCS Enabled| | Cellular | | Priority |
|Priority | |Wi-Fi Access| |Operator/Wi-Fi| | Service |
| Service | | Network | | Identity | |Authorizing|
| User | | | | Provider | | Entity |
.----+----. .-----+------. .-------+------. .-----+-----.
| | | |
|1. Standard service user authorization for priority |
| Service (unchanged) | |
|<--------------------------------------------------->|
| | | |
| | |2. Receive Priority
| | | Authorization |
| | 3. Mirror HSS | (unchanged) |
| | Authorization |<--------------->|
| | in Wi-Fi AAA | |
| | .--------| |
| | | | |
| | .------->| |
| | | |
| | | |
Figure 1: Provisioning Priority Services over Wi-Fi Networks
3. EPCS Authorization RADIUS Exchange
The top level RADIUS Authorization flow for an EPCS Service User is
illustrated in Figure 2.
1. In step 1, the EPCS enabled Wi-Fi Access Network provider
configures the defined EPCS Roaming Consortium on its Wi-Fi
access network.
2. In step 2, the Wi-Fi Priority Service User enables an EPCS
Passpoint profile on their device. This enables normal
Passpoint automatic network selection.
3. In step 3, the Wi-Fi Priority Service User's device matches the
EPCS Roaming Consortium in the Wi-Fi beacon, probe response or
Access Network Query Protocol (ANQP) response with the Roaming
Consortium Organizational Indicator (RCOI) included in its
Passpoint profile.
4. In steps 4 and 5, the Wi-Fi device triggers an association with
the Wi-Fi Access Point/Wireless LAN Controller (AP/WLC). The
device includes the EPCS Passpoint RCOI in the Roaming
Consortium Selection element [PASSPOINT] and receives an
association response.
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5. In steps 6 and 7, the AP/WLC performs the Extensible
Authentication Protocol (EAP) exchange over the LAN using EAPOL
frames exchanged with the device, requesting the device's EAP
identity and receives the corresponding identity associated with
the EPCS Passpoint profile in the EAP response.
6. In step 8, the AP/WLC extracts the EAP identity and includes
this in a RADIUS Access-Request that is sent to the Identity
Provider. In this example, the identity realm corresponds to a
Cellular operator as defined in [TS.23003], e.g.,
wlan.mnc100.mcc313.3gppnetwork.org. The AP/WLC adds the Civic-
Location attribute [RFC5580] to the RADIUS Access-Request,
indicating the country code and optional subdivision (using
CAType 1) that identify the regulatory regime in which it is
operating, the HS2.0-Roaming-Consortium attribute [PASSPOINT]
indicating the EPCS Passpoint RCOI signaled by the device in
step 4, and the EPCS-Capable-Indication attribute, as specified
in Section 4.1. If the Wi-Fi AP/WLC is expecting to receive
payment for handling the priority service traffic, the AP/WLC
can include additional attributes related to charging, for
example the offered WBA-Linear-Volume-Rate [WBAVSAS].
7. In step 9. the EAP dialogue completes between the supplicant in
the Wi-Fi device and the Cellular Operator's EAP server.
8. In step 10, the authenticated device is matched against the
priority subscription profile. The provider MAY use the country
code signalled in step 6 and compare that with the regulatory
regimes in which priority service is authorized.
9. In step 11, assuming the user is authorized, the cellular
operator replies with a RADIUS Access-Accept including the EAP-
SUCCESS message and the EPCS-Subscription-Info attribute defined
in Section 4.3.
10. In step 12, the AP/WLC recovers the keying material from the
Access-Accept packet and forwards the EAP-SUCCESS message to the
device.
11. In step 13 and 14, the AP/WLC enables EPCS priority access by
sending the EPCS Priority Access Enable Request frame to the
device. The device (i.e., STA) responds with an EPCS Priority
Access Enable Response frame in step 14. (Note: These steps
assume the AP/WLC is configured or triggered to automatically
enable EPCS for the device.)
12. In step 15, the device receives EPCS Priority Access.
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.---------. .------------. .--------------.
| Wi-Fi | |EPCS Enabled| | Wireless |
|Priority | |Wi-Fi Access| |Operator/Wi-Fi|
| Service | | Network | | Identity |
| Device | | | | Provider |
.----+----. .-----+------. .-------+------.
| | |
| |1. Configure EPCS Roaming Consortium
| |----------. |
| | | |
|2. User enables|<---------. |
| EPCS Passpoint |
| profile | |
|------. | |
| | | |
|<-----. | |
|3. Beacon received with |
| Roaming Consortium |
| EPCS Priority Access Support |
|<--------------| |
|4. Association | |
| Request | |
| (Roaming Consortium Selection Element)
|-------------->| |
|5. Association | |
| Response | |
|<--------------| |
|6. EAP-Identity/ |
| Request | |
|<--------------| |
|7. EAP-Identity/ |
| Response | |
|-------------->|8. RADIUS Access-Request
| | EAP Response Identity
| | Civic-Location (Country Code/Subdivision)
| | EPCS-Capable-Indication
| | HS2.0-Roaming-Consortium
| | (opt) WBA-Linear-Volume-Rate
| |------------------>|
| 9. EAP Dialogue |
|<--------------------------------->|10. Match user with
| | | priority
| | | subscription
| | | authorization
| | |------.
| | | |
| | |<-----.
| |11. RADIUS Access-Accept
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| | EAP-Success |
| | EPCS-Regulatory-Info
| | EPCS-Subscription-Info
| |<------------------|
|12. EAP-SUCCESS| |
|<--------------| |
|13. EPCS Priority Access Enable Request
|<--------------| |
|14. EPCS Priority Access Enable Response
|-------------->| |
| | |
.---+---------------+----. |
|15. EPCS Priority Access| |
.---+---------------+----. |
| | |
Figure 2: Authorizing Priority Services over Wi-fi
4. RADIUS EPCS Attributes
The current RADIUS protocol does not have the support for the flow
described in the previous section and therefore, the following
attributes are defined in this document.
4.1. EPCS-Capable-Indication
Description
The EPCS-Capable-Indication (TBA1) Attribute allows a RADIUS NAS to
indicate to a RADIUS server that it is EPCS capable.
One EPCS-Capable-Indication Attribute MAY be included in an Access-
Request packet.
A summary of the EPCS-Capable-Indication Attribute format is shown in
Figure 3. The fields are transmitted from left to right.
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 | Value
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value (cont'd) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: Encoding EPCS-Capable-Indication Attribute
Type
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TBA1
Length
6 octet
Data Type
Integer
Value
The field encodes a 32-bit unsigned integer that represents
whether the NAS and the device support the EPCS capability and
what capabilities the NAS has to handle the traffic to the
authorized EPCS users. This document defines two such values used
with the EPCS-Capable-Indication attribute:
0 EPCS Priority Access is supported by the NAS,
irrespective of EPCS support by the authorized EPCS user
device [FCC]. When the authorized EPCS user's device does
not support EPCS, the NAS may prioritize downlink traffic.
When the authorized EPCS user's device supports EPCS, the
NAS prioritizes both uplink and downlink traffic.
1 EPCS Priority Access is only supported by the NAS for
EPCS supporting devices. The NAS will prioritize uplink and
downlink traffic for EPCS priority access to authorized EPCS
users. Flows from non-EPCS supporting devices will not be
prioritized.
Note: How the NAS prioritizes the traffic is vendor specific
implementation and is outside the scope of this document.
4.2. EPCS-Regulatory-Info
Description
The EPCS-Regulatory-Info (TBA2) Attribute allows a RADIUS Server that
is authorizing a user to receive priority channel access to indicate
the regulatory regime under which the RADIUS Server operates.
One EPCS-Regulatory-Info Attribute MAY be included in an Access-
Accept packet.
A summary of the EPCS-Regulatory-Info Attribute format is shown in
Figure 4. The fields are transmitted from left to right.
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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 | Country or Subdivision Code
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: Encoding EPCS-Regulatory-Info Attribute
Type
TBA2
Length
Variable
Data Type
String
Value
The field is a variable length string that encodes either an ISO
3166-1 two-letter country code in capital ASCII letters, e.g., US
or FR, or an ISO 3166-2 sub-division code, e.g., US-NY or FR-NC
[ISO3166].
4.3. EPCS-Subscription-Info
Description
The EPCS-Subscription-Info (TBA3) Attribute allows a RADIUS Server to
indicate to a NAS that a user is authorized to receive priority
service.
One EPCS-Subscription-Info Attribute MAY be included in an Access-
Accept packet and its presence indicates the authenticated user is
authorized to receive priority service together with the priority
level associated with the user's subscription. .
A summary of the EPCS-Subscription-Info Attribute format is shown in
Figure 5. The fields are transmitted from left to right.
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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 | Priority-level |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Priority-level (cont'd) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Encoding EPCS-Subscription-Info Attribute
Type
TBA3
Length
6 octet
Data Type
Integer
Value
The field encodes a 32-bit unsigned integer that represents the
priority level associated with the user's subscription. Priority
levels are administered by the regulatory regime identified by the
EPCS-Regulatory-Info attribute, specified in Section 4.2.
5. Security Considerations
All systems which send RADIUS packets outside of secure networks MUST
use either IPsec, RADIUS/TLS, or RADIUS/DTLS
[I-D.ietf-radext-deprecating-radius].
6. IANA Considerations
This document creates three new RADIUS message types.
7. References
7.1. Normative References
[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>.
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[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>.
7.2. Informative References
[CSRC5-WG8]
WG8, C. S. R. A. I. C. V., "PRIORITY SERVICES", March
2017, <https://www.fcc.gov/sites/default/files/
CSRIC5-WG8-FinalReport031517.pdf>.
[CSRC8-WG4]
COMMUNICATIONS SECURITY, RELIABILITY, AND INTEROPERABILITY
COUNCIL VIII WG4, "REPORT ON 911 SERVICE OVER WI-FI",
March 2023, <https://www.fcc.gov/sites/default/files/
CSRIC8-Report-911overWi-Fi032123.pdf>.
[FCC] Federal Communications Commission, "Review of Rules and
Requirements For Priority Services", May 2022,
<https://docs.fcc.gov/public/attachments/FCC-
22-36A1_Rcd.pdf>.
[I-D.ietf-radext-deprecating-radius]
DeKok, A., "Deprecating Insecure Practices in RADIUS",
Work in Progress, Internet-Draft, draft-ietf-radext-
deprecating-radius-06, 25 May 2025,
<https://datatracker.ietf.org/doc/html/draft-ietf-radext-
deprecating-radius-06>.
[IEEE80211BE]
IEEE, "Enhancements for Extremely High Throughput (EHT)",
IEEE 802.11be-2024 Wireless LAN Medium Access Control
(MAC) and Physical Layer (PHY) Specifications Amendment ,
October 2024.
[ISO3166] ISO, "The International Standard for country codes and
codes for their subdivisions", n.d.,
<https://www.iso.org/iso-3166-country-codes.html>.
[PASSPOINT]
Wi-Fi Alliance, "Passpoint Specification, v3.3.7",
February 2024, <https://www.wi-fi.org/file/passpoint-
specification-package>.
[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>.
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[RFC5580] Tschofenig, H., Ed., Adrangi, F., Jones, M., Lior, A., and
B. Aboba, "Carrying Location Objects in RADIUS and
Diameter", RFC 5580, DOI 10.17487/RFC5580, August 2009,
<https://www.rfc-editor.org/rfc/rfc5580>.
[TS.22153] 3GPP, "Multimedia priority service", 3GPP TS 22.153
20.0.0 , January 2025.
[TS.23003] 3GPP, "Numbering, addressing and identification", 3GPP TS
23.003 19.0.0 , September 2024.
[WBAVSAS] Wireless Broadband Alliance, "Wireless Broadband Alliance
Defined Vendor Specific Attributes", May 2023,
<https://github.com/wireless-broadband-alliance/RADIUS-
VSA>.
Changelog
* 01 - switched all integers to unit32. Updated regulatory info
attribute to support both ISO 3166-1 two-letter country code as
well as ISO 3166-2 subdivision code as well as corresponding
support with RFC5580 CAType.
Acknowledgements
The authors would like to thank the members of the Wireless Broadband
Alliance Mission Critical and Emergency Services workgroup, as well
as the participants of the IETF RADEXT Working Group, with special
thanks to Alan DeKok for his valuable feedback and guidance.
Authors' Addresses
Sri Gundavelli
Ameriband
San Jose, 95135
United States of America
Email: sri.ietf@gmail.com
Subir Das
Independent
United States of America
Email: subirdas21@gmail.com
Mark Grayson
Cisco Systems
10 New Square Park
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Feltham
TW14 8HA
United Kingdom
Email: mgrayson@cisco.com
Martin C Dolly
AT&T
200 Laurel Avenue
Middletown, 07748
United States of America
Email: Md3135@att.com
An Nguyen
US DHS/CISA
245 Murray Lane SW, MS0123
Washington, DC, 20528-0123
United States of America
Email: an.p.nguyen@cisa.dhs.gov
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