Re: [Enum] ENUM Query

Brian Rosen <> Tue, 03 March 2020 17:51 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id DDF4D3A242A for <>; Tue, 3 Mar 2020 09:51:32 -0800 (PST)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -1.887
X-Spam-Status: No, score=-1.887 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, HTML_MESSAGE=0.001, SPF_HELO_NONE=0.001, T_SPF_TEMPERROR=0.01, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (2048-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id NvxynDhYtY9e for <>; Tue, 3 Mar 2020 09:51:27 -0800 (PST)
Received: from ( [IPv6:2607:f8b0:4864:20::c36]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 6306B3A2421 for <>; Tue, 3 Mar 2020 09:51:27 -0800 (PST)
Received: by with SMTP id t141so4129515ywc.11 for <>; Tue, 03 Mar 2020 09:51:27 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20150623; h=from:message-id:mime-version:subject:date:in-reply-to:cc:to :references; bh=MuGVTtrVFhpXshr1S1yA8EK1mZv5vriDSBrqNkIElDA=; b=P+qI2Nah2zs/EfW4v1XXa+S0WXmXTTyyWI+eFTYxgl3m8sFJXewmPO5Z5v8e8KPHq+ hKMLjOgU4J4SD4DwTZ11ogMrIsMng7QNwPCOHFvmasXE8IoAYFWle/JN+Mg8XWadgX/A VO3vvzJiO0mA4ceXaGK35Ynn/S3OQRwjkh2zWu7wlTCt0E/53oiK356Sk+FWU6Rx4Zkn zKqnziZoaoi7b2Gs9jrjYs1MRa9RcNPUfvjUshIIZWSqJnpqxaAM74Mr87LsBkBLbSxT ciTapDQmSZkTBwNLjktrbCeLWWC3rP3NWUvRXyCoI2CQJ6v6yC2gTHwsA0jgG/B7TdMC ZRjw==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20161025; h=x-gm-message-state:from:message-id:mime-version:subject:date :in-reply-to:cc:to:references; bh=MuGVTtrVFhpXshr1S1yA8EK1mZv5vriDSBrqNkIElDA=; b=oWivjKbQ11BIXsAp4gDgMeVZOg5EtkdekeMIJQPldJUraJWXSJA1AXaAfqpjcNR8Cb evcUaPFtOYxDUf59bRrNNbDVLXX0hJT0/YSMfGgDAHAUZ95jE9RPwnEDPDegfVqb0rhp j9jkwVfNFO5ym71oCWprc2NrOBIkXNlBOKNm/jR961m2KIzr8fYZ19TEPjxR/BAy+ese jLIm0gOFTZTModoxo/qZNilEH3AUyLvXqgaNJQtFzA3GHwSVpZP1xdLhvvgpr7vlXhn2 StXt1ndWxPXd+XjlA9U7x5qLWF28CYr/bPYgXCqSWrdFUVz2Cd3FD54rIjCJhsoRapAt H7Bw==
X-Gm-Message-State: ANhLgQ2qCBod0jQVU5WURU+/QlaSznBF1OikcQczolx8Xbno3MfRVfAR 9ysl2C2qt6wFyYwdXZ9NyTlxMA==
X-Google-Smtp-Source: =?utf-8?q?ADFU+vsggdbIwRzD3DcOc9kClULhH9JsNHyem9HhIKLh?= =?utf-8?q?0oP+tAtvSo88WIElvtx4e4hPaDigGZObAQ=3D=3D?=
X-Received: by 2002:a81:4b43:: with SMTP id y64mr5568196ywa.248.1583257885084; Tue, 03 Mar 2020 09:51:25 -0800 (PST)
Received: from brians-mbp-2871.lan ([]) by with ESMTPSA id d4sm6843029ywb.67.2020. (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 03 Mar 2020 09:51:24 -0800 (PST)
From: Brian Rosen <>
Message-Id: <>
Content-Type: multipart/alternative; boundary="Apple-Mail=_D0B5DB80-F5FF-4572-BBF0-DB7C753F87FF"
Mime-Version: 1.0 (Mac OS X Mail 13.0 \(3608.\))
Date: Tue, 3 Mar 2020 12:51:23 -0500
In-Reply-To: =?utf-8?q?=3CDB7PR04MB54183341C4145762B969A0B1C3E40=40DB7PR04MB?= =?utf-8?q?5418=2Eeurprd04=2Eprod=2Eoutlook=2Ecom=3E?=
Cc: "" <>
To: Wayne Cutler <>
References: =?utf-8?q?=3CDB7PR04MB54183341C4145762B969A0B1C3E40=40DB7PR04MB5?= =?utf-8?q?418=2Eeurprd04=2Eprod=2Eoutlook=2Ecom=3E?=
X-Mailer: Apple Mail (2.3608.
Archived-At: <>
Subject: Re: [Enum] ENUM Query
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Enum Discussion List <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Tue, 03 Mar 2020 17:51:33 -0000

One question: are the services that are provided on these two networks distinct?  
Do one or both of them supply messaging service?  Calling Service?

If both, then how is a message/call to the TN routed?

I think we would want to have some service differentiation as the discriminator if its one network that supplies each service.


> On Mar 3, 2020, at 6:00 AM, Wayne Cutler <> wrote:
> Dear ENUM List,
> I have an ENUM Registry query that I’d like to run past you to solicit expert feedback/recommendations on the best way forward.
> The scenario that is applicable concerns the deployment of MMTEL (Multi-Media Telephony) & Advanced RCS Messaging by MNOs (Mobile Network Operators). For historic reasons, there are two different ways that MNOs have deployed MMTEL & RCS Messaging services :-
> i)                    Both MMTEL & RCS Messaging services are provided by a single IMS Core Network and the UE registers to this single IMS core to receive all of its services. All terminating service requests are required to be routed to the single IMS network. Therefore, the existing ENUM infrastructure is fine for this scenario as the telephone number of a given user resolves to a SIP URI that identifies the target IMS core network.
> ii)                   The MMTEL and RCS services are provided by 2 separate IMS Core Networks - one for MMTEL and one for RCS Messaging. In this scenario, the UE registers to both IMS core networks (so-called "dual registration") and gets its full suite of services via a combination of the 2 IMS cores.  The same IMPU (IMS Public User Id) is used for both IMS registrations and the same phone number is used to route terminating service requests for both MMTEL & RCS Messaging related requests. Therefore, in this case, an ENUM request for a given telephone number needs to be able to identify 2 different target IMS cores. The related service request can then be passed onto the correct IMS core based on the its context (i.e. does the request relate to a MMTEL or RCS Messaging service). This is the scenario that doesn't seem to be covered in the existing ENUM Registry. 
> So, the problem we have is how to resolve a single telephone number to 2 different SIP URIs. Looking at the existing ENUM registry, there seems to be 3 options :-
> ·       Enhance the current ProtocolBasedClass of SIP as defined in RFC 3764 to add a sub-type - e.g. "SIP/MMTEL" & "SIP/RCS" - with the absence of a sub-type meaning "all services".
> ·       Re-use (or perhaps re-interpret?) an existing result (e.g. ApplicationBasedClass of IM or unifmsg) to mean RCS Messaging - but this feels like a kludge,
> ·       Define a new ENUM registry entry to identify RCS Messaging.
> I would be grateful of any advice / recommendation that you have and am happy to answer any further questions for clarification.
> Best Regards,
> Wayne Cutler 
> .
> _______________________________________________
> enum mailing list
> <>
> <>