Liaison statement
LS on initiation of two new work items Q.CSSIWF and Q.SSP4SIP

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State Posted
Submitted Date 2026-04-01
From Group ITU-T-SG-11
From Contact tsbsg11@itu.int
To Group stir
To Contacts Ben Campbell <ben@nostrum.com>
Russ Housley <housley@vigilsec.com>
Cc Russ Housley <housley@vigilsec.com>
Scott Mansfield <Scott.Mansfield@Ericsson.com>
Charles Eckel <eckelcu@cisco.com>
Ben Campbell <ben@nostrum.com>
Andy Newton <andy@hxr.us>
Secure Telephone Identity Revisited Discussion List <stir@ietf.org>
Response Contact tejpal.singh70@gov.in
licheng@caict.ac.cn
assaf.klinger@gmail.com
cwendt@somos.com
Technical Contact tejpal.singh70@gov.in
Action Holder Contacts scott.mansfield@ericsson.com
Purpose For information
Attachments SG11-LS118-Att2
SG11-LS118-Att1
Body 
ITU-T Study Group 11 would like to inform ITU-T Study Group 2, SG17, IETF STIR
WG and ATIS on the initiation of two new work items: Q.CSSIWF and Q.SSP4SIP.

ITU-T SG11 initiated these two new work items in its meeting which was held in
Geneva from 3 to 11 March 2026:

1.      Q.SSP4SIP “Secure signalling procedures for the session initiation
protocol in telecommunications networks”;

2.      Q.CSSIWF “Certificate based secure signalling interworking function
between voice over internet protocol networks and legacy public switched
telephone networks/ integrated service digital networks”

Both work items handle gaps in the interworking of VoIP signalling security
(commonly referred to as “STIR/SHAKEN”) with the signaling security framework
defined by ITU-T Recommendations Q.3057, Q.3062, Q.3063 and ongoing work item
Q.TSCA in SG11.

Attached are the baseline texts for these two new work items.
SG11 looks forward to collaborating with ITU-T SG2, SG17, IETF STIR WG and ATIS
on these matters.