<?xmlversion='1.0' encoding='utf-8'?>version="1.0" encoding="UTF-8"?> <!DOCTYPE rfc SYSTEM"rfc2629.dtd" [ <!ENTITY RFC2119 SYSTEM "https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.2119.xml"> <!ENTITY RFC8174 SYSTEM "https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8174.xml"> <!ENTITY RFC2516 SYSTEM "https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.2516.xml"> ]>"rfc2629-xhtml.ent"> <rfcsubmissionType="IETF"xmlns:xi="http://www.w3.org/2001/XInclude" docName="draft-allan-5g-fmc-encapsulation-08" number="8822" submissionType="IETF" category="info"ipr="trust200902"> <!-- Generated by id2xml 1.5.0 on 2021-02-26T02:20:32Z --> <?rfc strict="yes"?> <?rfc compact="yes"?> <?rfc subcompact="no"?> <?rfc symrefs="yes"?> <?rfc sortrefs="no"?> <?rfc text-list-symbols="-o*+"?> <?rfc toc="yes"?>consensus="true" ipr="trust200902" obsoletes="" updates="" xml:lang="en" symRefs="true" sortRefs="true" tocInclude="true" version="3"> <front> <title abbrev="5GWireless Wireline ConvergenceWWC UserPl">5GPlane Encapsulation">5G Wireless Wireline Convergence User Plane Encapsulation (5WE)</title> <seriesInfo name="RFC" value="8822"/> <author initials="D." surname="Allan" fullname="Dave Allan" role="editor"> <organization>Ericsson</organization><address><postal><street>2455<address> <postal> <street>2455 Augustine Drive</street> <city>San Jose</city> <region>CA</region> <code>95054</code><country>USA</country><country>United States of America</country> </postal> <email>david.i.allan@ericsson.com</email> </address> </author> <author initials="D." surname="Eastlake 3rd" fullname="Donald E. Eastlake 3rd"> <organization>Futurewei Technologies</organization><address><postal><street>2386<address> <postal> <street>2386 Panoramic Circle</street> <city>Apopka</city> <region>FL</region> <code>32703</code><country>USA</country><country>United States of America</country> </postal> <phone>+1-508-333-2270</phone> <email>d3e3e3@gmail.com</email> </address> </author> <author initials="D." surname="Woolley" fullname="David Woolley"> <organization>Telstra Corporation</organization><address><postal><street>242<address> <postal> <street>242 Exhibition St</street> <city>Melbourne</city><region></region><region/> <code>3000</code> <country>Australia</country> </postal> <email>david.woolley@team.telstra.com</email> </address> </author> <dateyear="2021" month="March"/> <abstract><t>month="April" year="2021"/> <keyword>PPPoE</keyword> <keyword>W-AGF</keyword> <keyword>QFI</keyword> <keyword>RQI</keyword> <keyword>WWC</keyword> <abstract> <t> As part of providing wireline access to the 5G Core (5GC), deployed wireline networks carry user data between 5G residential gateways and the 5G Access Gateway Function (AGF). The encapsulation method specified in this document supports the multiplexing of traffic for multiple PDU sessions within aVLAN delineatedVLAN-delineated access circuit, permits legacy equipment in the data path to inspect certain packet fields, carries 5G QoS information associated with the packet data, and provides efficient encoding. It achieves this by specific points of similarity with theRFC 2516 PPPoEPoint-to-Point Protocol over Ethernet (PPPoE) data packetencapsulation.</t>encapsulation (RFC 2516).</t> </abstract> </front> <middle> <sectiontitle="Introduction" anchor="sect-1"><t>anchor="sect-1" numbered="true" toc="default"> <name>Introduction</name> <t> Converged 5G ("fifth generation") wireline networks carry user data between 5G residential gateways(5G-RG)(5G-RGs) and the 5G Access Gateway Function (identified as a Wireline-AGF (W-AGF) by 3GPP in[TS23316])<xref target="TS23316" format="default"/>) across deployed access networks based on Broadband Forum <xreftarget="TR101"/>target="TR101" format="default"/> and <xreftarget="TR178"/>.target="TR178" format="default"/>. This form of wireline access is considered to be trusted non-3GPP access by the 5G system.</t> <t> The transport encapsulation used needs to meet a variety ofrequirementsrequirements, including the following:</t><t><list style="symbols"><t>The<ul spacing="normal"> <li>The ability to multiplex multiple logical connections (Protocol Data Unit (PDU)Sessionssessions as defined by 3GPP) within aVLAN identified point to pointVLAN-identified point-to-point logical circuit between a 5G-RG and aW-AGF.</t> <t>ToW-AGF.</li> <li>To allow unmodified legacy equipment in the data path to identify the encapsulation and inspect specific fields in the payload. Some access nodes in the data path between the 5G-RG and the W-AGF(Such(such as digital subscriber loop access multiplexers (DSLAMs) and optical line terminations (OLTs)) currently inspect packets identified by specific Ethertypes to identify protocols such as thepoint to point protocolPoint-to-Point Protocol overethernetEthernet (PPPoE), IP, ARP, and IGMP. This may be for the purpose of enhanced QoS, the policing ofidentifiersidentifiers, and other applications. Some deployments are dependent upon this inspection. Such devices are able to do this for PPPoE orIP over ethernetIP-over-Ethernet (IPoE) packet encodings but would be unable to do so if a completely new encapsulation, or an existing encapsulation using a new Ethertype, wereused.</t> <t>Toused.</li> <li>To carryper packetper-packet 5G QoSinformation.</t> <t>Fixedinformation.</li> <li>An encapsulation that minimizes processing since fixed access residential gateways are sensitive to the complexity of packetprocessing, therefore an encapsulation that minimizes processingprocessing. While not a strict requirement, this is an importantconsideration.</t> </list> </t>consideration.</li> </ul> <t> A data encapsulation that uses a common Ethertype and has certain fields appearing at the same offset as the PPPoE<xref target="RFC2516"/>data encapsulation <xref target="RFC2516" format="default"/> can address these requirements. This data encapsulation is referred to as the 5G WWC user planeEncapsulationencapsulation or 5WE. Currently deployed access nodes do not police the VER,TYPE andTYPE, or CODE fields of an RFC 2516header,PPPoE header and only perform limited policing of stateful functions with respect to the procedures documented in RFC 2516. Therefore, these fields have a different definition for 5WE and are used to:</t><t><list style="symbols"><t>Identify<ul spacing="normal"> <li>Identify that the mode of operation for packets encapsulated in such a fashion uses 5G WWC session establishment based on non-access stratum (NAS, a logical control interface between user equipment (UE) and5GCa 5th Generation Core Network (5GC) as specified by 3GPP)based 5G WWC session establishmentandlife cyclelife-cycle maintenance procedures as documented in[TS23502][TS23316]<xref target="TS23502" format="default"/> and <xref target="TS23316" format="default"/> instead of legacy PPP/PPPoE session establishment procedures(i.e.<xref target="RFC2516"/> (i.e., PADI discipline, LCP,NCPNCP, etc.). In thisscenarioscenario, "discovery" is performed by means outside the scope of thisdocument.</t> <t>Permitdocument.</li> <li>Permit the session ID field to be used to identify the 5G PDU session the encapsulated packet is partof.</t> <t>Communicateof.</li> <li>Communicate per-packet 5G QoS Flow Identifier (QFI) and Reflective QoS Indication (RQI) information from the 5GC to the5G-RG.</t> </list> </t>5G-RG.</li> </ul> <t> This5G specific5G-specific redesign of fields not inspected by deployed equipment results in an encapsulation uniquely applicable to the requirements for the communication of PDU session traffic between the subscriber premises and the 5G system over wireline networks. The6 byte6-byte RFC 2516 data packet header followed by a2 byte2-byte PPP protocol ID is also the most frugal of the encapsulations that are currently supported by legacy access equipment that could be adapted to meet these requirements.</t> <t> This encapsulation is expected to be used in environments where RFC 2516 is deployed. Therefore, implementationsMUST<bcp14>MUST</bcp14> examine the version number:</t><t><list style="symbols"><t>if<ul spacing="normal"> <li>If the version number is1,1 and PPPoE <xreftarget="RFC2516"/>target="RFC2516" format="default"/> is supported, process the framefurther, elsefurther; else, silently discardit.</t> <t>ifit.</li> <li>If the version number is 2 and 5WE is supported, process the framefurther, elsefurther; else, silently discardit.</t> </list> </t>it.</li> </ul> <t> In bothcasescases, frames for the supported version number should have session IDs corresponding to established sessions for the respective protocol models. A 5WE frame with an unrecognized session IDMUST<bcp14>MUST</bcp14> be silently discarded.</t> <t> This encapsulation may have MTU issues when used for Ethernet multiplexing in networks where the underlying Ethernet payload is limited to 1500 bytes.</t> <t> This encapsulation is not suitable for other network environments, e.g., general use over the public Internet.</t> <sectiontitle="Requirements Language" anchor="sect-1.1"><t>anchor="sect-1.1" numbered="true" toc="default"> <name>Requirements Language</name> <t> The key words"MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY","<bcp14>MUST</bcp14>", "<bcp14>MUST NOT</bcp14>", "<bcp14>REQUIRED</bcp14>", "<bcp14>SHALL</bcp14>", "<bcp14>SHALL NOT</bcp14>", "<bcp14>SHOULD</bcp14>", "<bcp14>SHOULD NOT</bcp14>", "<bcp14>RECOMMENDED</bcp14>", "<bcp14>NOT RECOMMENDED</bcp14>", "<bcp14>MAY</bcp14>", and"OPTIONAL""<bcp14>OPTIONAL</bcp14>" in this document are to be interpreted as described inBCP 14BCP 14 <xref target="RFC2119"/> <xref target="RFC8174"/> when, and only when, they appear in all capitals, as shownhere.</t>here. </t> </section> <sectiontitle="Acronyms" anchor="sect-1.2"><t>anchor="sect-1.2" numbered="true" toc="default"> <name>Acronyms</name> <t> This document uses the following acronyms:</t><figure><artwork><![CDATA[ 3GPP 3rd<dl indent="10"> <dt>3GPP</dt> <dd>3rd Generation PartnershipProject 5WEProject</dd> <dt>5WE</dt> <dd> 5GWWC Encapsulation 5GCWireless Wireline Convergence User Plane Encapsulation</dd> <dt>5GC</dt> <dd> 5th Generation Core(network) DSLAM Digital(network)</dd> <dt>DSLAM</dt> <dd>Digital Subscriber Loop AccessMultiplexer W-AGF WirelineMultiplexer</dd> <dt>W-AGF</dt> <dd>Wireline Access GatewayFunction IPoE IPFunction</dd> <dt>IPoE</dt> <dd>IP overEthernet NAS Non-Access Stratum OLT OpticalEthernet</dd> <dt>NAS</dt> <dd>Non-Access Stratum</dd> <dt>OLT</dt> <dd>Optical LineTermination PDU ProtocolTermination</dd> <dt>PDU</dt> <dd>Protocol DataUnit PPPoE PPPUnit</dd> <dt>PPPoE</dt> <dd>PPP overEthernet QFI QoSEthernet</dd> <dt>QFI</dt> <dd>QoS FlowIdentifier QoS Quality of Service RGIdentifier</dd> <dt>QoS</dt> <dd>Quality of Service</dd> <dt>RG</dt> <dd> ResidentialGateway RQIGateway</dd> <dt>RQI</dt> <dd> Reflective QoSIndicator WWC WirelessIndicator</dd> <dt>WWC</dt> <dd>Wireless WirelineConvergence ]]></artwork> </figure>Convergence</dd> </dl> </section> </section> <sectiontitle="Dataanchor="sect-2" numbered="true" toc="default"> <name>Data EncapsulationFormat" anchor="sect-2"><t>Format</name> <t> The Ethernet payload[IEEE802]<xref target="IEEE802" format="default"/> for PPPoE <xreftarget="RFC2516"/>target="RFC2516" format="default"/> is indicated by an Ethertype of 0x8864. The information following that Ethertype uses a value of 2 in the VER field for the repurposing of the PPPoE data encapsulation as the 5G WWC user plane encapsulation (5WE). The 5G WWCUser Planeuser plane encapsulation is structured as follows:</t><figure><artwork><![CDATA[<artwork name="" type="" align="left" alt=""><![CDATA[ 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | VER | TYPE | QFI |R|0| SESSION_ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | LENGTH | PROTOCOL ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | DATA PAYLOAD ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- ]]></artwork></figure><t>The description of each field is as follows:<list> <t>VER is the</t> <dl indent="9"> <dt>VER: </dt> <dd>The version. ItMUST<bcp14>MUST</bcp14> be set to0x02.</t> <t>TYPE is the0x02. </dd> <dt>TYPE: </dt> <dd>The message type. ItMUST<bcp14>MUST</bcp14> be set to0x01.</t> <t>QFI encodes0x01. </dd> <dt>QFI: </dt> <dd>Encodes the 3GPP 5G QoS Flow Identifier[TS38415]<xref target="TS38415" format="default"/> to be used for mapping 5G QoS to IP DSCP/802.1 P-bits[IEEE802].</t> <t>R (short<xref target="IEEE802" format="default"/>. </dd> <dt>R: </dt> <dd>(Short for Reflective QoS Indication[TS38415]) encodes<xref target="TS38415" format="default"/>) Encodes theone bitone-bit RQI. It is set by thenetwork sidenetwork-side 5WE termination for downstream traffic and ignored by the network for upstreamtraffic.</t> <t>0 indicatestraffic. </dd> <dt>0: </dt> <dd>Indicates the bit(s)MUSTthat <bcp14>MUST</bcp14> be sent as zero and ignored onreceipt.</t> <t>SESSION_ID is areceipt. </dd> <dt>SESSION_ID: </dt> <dd>A 16-bit unsigned integer in network byte order. It is used to distinguish different PDU sessions that are in theVLAN delineatedVLAN-delineated multiplex. A value of 0xffff is reserved for future use andMUST NOT<bcp14>MUST NOT</bcp14> beused.</t> <t>LENGTH is theused. </dd> <dt>LENGTH: </dt> <dd>The length in bytes of the datapayloadpayload, including the initial Protocol ID. It is 16 bits in network byteorder.</t> <t>PROTOCOL ID is the 16 bitorder. </dd> <dt>PROTOCOL ID: </dt> <dd><t>The 16-bit identifier of the data payload type encoded using values from the IANAPPP"PPP DLLprotocol numbers registry. (<eref target="https://www.iana.org/assignments/ppp-numbers/ppp-numbers.xhtml#ppp-numbers-2"/>) <list>Protocol Numbers" registry <eref target="https://www.iana.org/assignments/ppp-numbers" brackets="angle"/>.</t> <t>The following values are valid in this field for 5G WWCuse: <list> <t>0x0021: IPv4</t> <t>0x0031: Ethernet (referred to in PPP as "bridging")</t> <t>0x0057: IPv6</t> </list> </t> <t> Packetsuse:</t> <ul> <li>0x0021: IPv4 </li> <li>0x0031: Bridging PDU (Ethernet) </li> <li>0x0057: IPv6 </li> </ul> <t>Packets received that do not contain one of the above protocol IDs are silentlydiscarded.</t> </list> </t> </list>discarded. </t><t><list style="hanging" hangIndent="3"><t> DATA PAYLOAD is encoded</dd> <dt>DATA PAYLOAD: </dt> <dd>Encoded as per the protocolID.</t> </list> </t> </section> <section title="Acknowledgements" anchor="sect-3"><t> This memo is a result of comprehensive discussions by the Broadband Forum's Wireline Wireless Convergence Work Area. The authors would also like to thank Joel Halpern and Dirk Von Hugo for their detailed review of this draft.</t>ID. </dd> </dl> </section> <sectiontitle="Security Considerations" anchor="sect-4"><t>anchor="sect-4" numbered="true" toc="default"> <name>Security Considerations</name> <t> 5G NAS procedures used for sessionlife cyclelife-cycle maintenance employ ciphering and integrity protection[TS23502].<xref target="TS23502" format="default"/>. They can be consideredto bea more secure session establishment discipline than existing RFC 2516 procedures, at least againston pathon-path attackers. The design of the 5WE encapsulation will not circumvent existing anti-spoofing and other security procedures in deployed equipment. The existing access equipment will be able to identify fields that they normally process andpolicedpolice as per existing RFC 2516 traffic.</t> <t> Therefore, the security of a fixed access network using 5WE will be equivalent or superior to current practice.</t> <t>5WE encapsulated5WE-encapsulated traffic is used on what the 5GC considers to be trusted non-3GPPinterfaces, thereforeinterfaces; therefore, it is not ciphered. 5WE is not suitable for use over an untrusted non-3GPP interface.</t> <t> The security requirements of the 5G system are documented in[TS33501]</t><xref target="TS33501" format="default"/>.</t> </section> <sectiontitle="IANA Considerations" anchor="sect-5"><t>anchor="sect-5" numbered="true" toc="default"> <name>IANA Considerations</name> <t> IANAis requested to create ahas created the following registry on thePoint-to-Point"Point-to-Point (PPP) Protocol FieldAssignments IANA Web page as follows:</t> <figure><artwork><![CDATA[ RegistryAssignments" page:</t> <dl> <dt>Registry Name:PPP</dt> <dd>PPP Over Ethernet VersionsRegistration</dd> <dt>Registration Procedure:Specification</dt> <dd>Specification RequiredReferences: [RFC2516] [this document] VER Description Reference ----- ----------------------------- ----------- 0 reserved</dd> <dt>References: </dt> <dd><xref target="RFC2516"/> [this document]1 PPPoE [RFC2516] 2 5G</dd> </dl> <table anchor="iana_table"> <name>PPP Over Ethernet Versions</name> <thead> <tr> <th>VER</th> <th>Description</th> <th>Reference</th> </tr> </thead> <tbody> <tr> <td>0</td> <td>Reserved</td> <td>[this document]</td> </tr> <tr> <td>1</td> <td>PPPoE</td> <td><xref target="RFC2516"/></td> </tr> <tr> <td>2</td> <td>5G WWC User PlaneEncapsulation [this document] 3-15 unassigned [this document] ]]></artwork> </figure>Encapsulation</td> <td>[this document]</td> </tr> <tr> <td>3-15</td> <td>unassigned</td> <td></td> </tr> </tbody> </table> <t> IANAis requested to add [this document]has added this document as an additional reference for Ethertype 0x8864 in theEthertypes table"Ether Types" registry on the IANA "IEEE 802 Numbers"web page.(<eref target="https://www.iana.org/assignments/ieee-802-numbers/ieee-802-numbers.xhtml#ieee-802-numbers-1"/>)</t>page <eref target="https://www.iana.org/assignments/ieee-802-numbers" brackets="angle"/>.</t> </section> </middle> <back><references title="Normative References"> &RFC2119; &RFC8174; &RFC2516; <!-- draft-allan-5g-fmc-encapsulation-08-manual.txt(315): Warning: Failed parsing a reference. Are all elements separated by commas (not periods, not just spaces)?: [TS38415] 3rd Generation Partnership Project, Technical Specification Group Radio Access Network, NG-RAN,<references> <name>References</name> <references> <name>Normative References</name> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.2119.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.8174.xml"/> <xi:include href="https://xml2rfc.ietf.org/public/rfc/bibxml/reference.RFC.2516.xml"/> <reference anchor="TS38415"> <front> <title>NG-RAN; PDUSession User Plane Protocol (Release 15), 3GPP TS38.415 --> <!-- draft-allan-5g-fmc-encapsulation-08-manual.txt(319): Warning: Failed parsing a reference. Are all elements separated by commas (not periods, not just spaces)?: [TS23502] 3rd Generation Partnership Project, Technical Specification Group Services and System Aspects, Proceduressession user plane protocol</title> <author> <organization>3GPP</organization> </author> <date month="March" year="2018" /> </front> <seriesInfo name="TS" value="38.415" /> <refcontent>Release 15</refcontent> </reference> <reference anchor="TS23502"> <front> <title>Procedures for the 5G System(Release 16), 3GPP TS23.502 --> <!-- draft-allan-5g-fmc-encapsulation-08-manual.txt(323): Warning: Failed parsing a reference. Are all elements separated by commas (not periods, not just spaces)?: [TS23316] 3rd Generation Partnership Project, Technical Specification Group Services and System Aspects, Wireless(5GS)</title> <author> <organization>3GPP</organization> </author> <date month="December" year="2016" /> </front> <seriesInfo name="TS" value="23.502" /> <refcontent>Release 15</refcontent> </reference> <reference anchor="TS23316"> <front> <title>Wireless and wireline convergence access support for the 5G System(5GS) (Release 16), 3GPP TS23.316, November 2018 -->(5GS)</title> <author> <organization>3GPP</organization> </author> <date month="December" year="2018" /> </front> <seriesInfo name="TS" value="23.316" /> <refcontent>Release 16</refcontent> </reference> </references><references title="Informative References"><references> <name>Informative References</name> <referenceanchor="TR101"><front>anchor="TR101"> <front> <title>Migration to Ethernet Based Broadband Aggregation</title> <author> <organization>Broadband Forum</organization> </author> <date month="July" year="2011"/> </front><seriesInfo name="Broadband" value="Forum Technical Report: TR-101<refcontent>TR-101, issue2"/>2</refcontent> </reference> <referenceanchor="TR178"><front>anchor="TR178"> <front> <title>Multi-service Broadband Network Architecture and Nodal Requirements</title> <author> <organization>Broadband Forum</organization> </author> <date month="September" year="2014"/> </front><seriesInfo name="Broadband" value="Forum Technical Report: TR-178"/><refcontent>TR-178, issue 1</refcontent> </reference><!-- draft-allan-5g-fmc-encapsulation-08-manual.txt(339): Warning: Failed parsing a reference. Are all elements separated by commas (not periods, not just spaces)?: [IEEE802] 802, IEEE, "IEEE<reference anchor="IEEE802"> <front> <title>IEEE Standard for Local and Metropolitan Networks: Overview andArchitecture", IEEE Std 802-2014. --> <!-- draft-allan-5g-fmc-encapsulation-08-manual.txt(342): Warning: Failed parsing a reference. Are all elements separated by commas (not periods, not just spaces)?: [TS33501] 3rd Generation Partnership Project, Technical Specification Group Services and System Aspects, Security ArchitectureArchitecture</title> <author> <organization>IEEE</organization> </author> <date month="June" year="2014" /> </front> <seriesInfo name="Std" value="802-2014"/> <seriesInfo name="DOI" value="10.1109/IEEESTD.2014.6847097"/> </reference> <reference anchor="TS33501"> <front> <title>Security architecture andProceduresprocedures for 5GSystem (Release 16), 3GPP TS33.501, December 2019 -->System</title> <author> <organization>3GPP</organization> </author> <date month="December" year="2019" /> </front> <seriesInfo name="TS" value="33.501"/> <refcontent>Release 16</refcontent> </reference> </references> </references> <section anchor="sect-3" numbered="false" toc="default"> <name>Acknowledgements</name> <t> This memo is a result of comprehensive discussions by the Broadband Forum's Wireline Wireless Convergence Work Area. The authors would also like to thank <contact fullname="Joel Halpern"/> and <contact fullname="Dirk Von Hugo"/> for their detailed review of this document.</t> </section> </back> </rfc>