6man Working Group S. Krishnan Internet-Draft A. Kavanagh Intended status: Standards Track Ericsson Expires: November 24, 2010 S. Ooghe Alcatel-Lucent B. Varga Magyar Telekom May 23, 2010 Line identification in IPv6 Router Solicitation messages draft-krishnan-6man-rs-mark-05 Abstract In Ethernet and PON based aggregation networks, several subscriber premises may be logically connected to the same interface of an edge router. This document proposes a method for the edge router to identify the subscriber premises using the contents of the received Router Solicitation messages. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on November 24, 2010. Copyright Notice Copyright (c) 2010 IETF Trust and the persons identified as the document authors. All rights reserved. Krishnan, et al. Expires November 24, 2010 [Page 1] Internet-Draft Line Identification in RS May 2010 This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://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 and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Conventions used in this document . . . . . . . . . . . . 3 2. Issues with identifying the subscriber in an N:1 Vlan model . 4 3. Basic operation . . . . . . . . . . . . . . . . . . . . . . . 5 4. Access Node Behavior . . . . . . . . . . . . . . . . . . . . . 6 4.1. On receiving a Router Solicitation from the subscriber . . 6 4.2. On receiving a Router Advertisement from the Edge Router . . . . . . . . . . . . . . . . . . . . . . . . . . 6 5. Edge Router Behavior . . . . . . . . . . . . . . . . . . . . . 7 5.1. On receiving a Router Solicitation from the subscriber . . 7 5.2. On sending a Router Advertisement towards the subscriber . . . . . . . . . . . . . . . . . . . . . . . . 7 6. Line Identification Option . . . . . . . . . . . . . . . . . . 8 7. Interactions with SEND . . . . . . . . . . . . . . . . . . . . 10 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 11 9. Security Considerations . . . . . . . . . . . . . . . . . . . 12 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13 11. Normative References . . . . . . . . . . . . . . . . . . . . . 14 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15 Krishnan, et al. Expires November 24, 2010 [Page 2] Internet-Draft Line Identification in RS May 2010 1. Introduction DSL is a widely deployed access technology for Broadband Access for Next Generation Networks. While traditionally DSL access networks were PPP based some networks are migrating from the traditional PPP access model into a pure IP-based Ethernet aggregated access environment. Architectural and topological models of an Ethernet aggregation network in context of DSL aggregation are described in [TR101]. One of the Ethernet or PON aggregation models specified in this document bridges sessions from multiple subscribers behind a DSL Access Node (AN), also referred to as a DSLAM or OLT, into a single VLAN in the aggregation network. This is called the N:1 VLAN allocation model. +---+ +----+ +----------+ |CPE|---| RG |----| | +---+ +----+ | | | AN |\ +---+ +----+ | | \ |CPE|---| RG |----| | \ +---+ +----+ +----------+ \ +----------+ \ | | +-------------+ | | | Aggregation | | Edge | | Node |-------| Router | +-------------+ | | / | | +----------+ / +----------+ | | / +---+ +----+ | | / |CPE|---| RG |----| AN |/ +---+ +----+ | | | | +----------+ Figure 1: Broadband Forum Network Architecture 1.1. Conventions used in this document The key words "MUST", "MUST NOT", "REQUIRED", "SHALL","SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. Krishnan, et al. Expires November 24, 2010 [Page 3] Internet-Draft Line Identification in RS May 2010 2. Issues with identifying the subscriber in an N:1 Vlan model In a fixed Broadband Network, IPv6 hosts are connected to an Access Node (AN). These hosts today will typically send a Router Solicitation Message to the Edge Router, to which the Edge Router responds with a Router Advertisement message. The Router Advertisement typically contains a prefix that the host will use to automatically configure an IPv6 Address. Upon sending the Route Solicitation message the node connecting the host on the access circuit, typically an Access Node (AN), would forward the RS to the Edge Router upstream over a switched network. However, in such Ethernet based aggregation networks, several subscriber premises may be connected to the same interface of an edge router (e.g. on the same VLAN). Therefore, the edge router requires some information to identify the host on the circuit line the host is connected on. To accomplish this, the AN needs to add line identification information (LIO) to the Router Solicitation message and forward this to the Edge Router. This document proposes a method for transporting access loop related information from AN towards the edge router to identify the subscriber premises using the contents of the received Router Solicitation messages. Krishnan, et al. Expires November 24, 2010 [Page 4] Internet-Draft Line Identification in RS May 2010 3. Basic operation This document recommends tunneling Neighbor discovery packets inside another IPv6 packet that uses a destination option to convey line identification information. The Neighbor discovery packets initiated by the host are left unmodified inside the encapsulating IPv6 packet. In particular, the Hop Limit field of the ND message is not decremented when the packet is being tunneled. This is because ND messages whose Hop Limit is not 255 will be discarded by the receiver of such messages. Krishnan, et al. Expires November 24, 2010 [Page 5] Internet-Draft Line Identification in RS May 2010 4. Access Node Behavior 4.1. On receiving a Router Solicitation from the subscriber When a host sends out a Router Solicitation, it is received by the access node. The AN then tunnels the received Router Solicitation in a newly created IPv6 datagram with the LIO destination option. The AN forms a new IPv6 datagram whose payload is the received Router Solicitation message as described in [RFC2473] except that the Hop Limit field of the Router Solicitation message MUST NOT be decremented. If the AN has an IPv6 address, it SHOULD use this address in the Source Address field of the outer IPv6 datagram. Otherwise it MUST use the unspecified address as the Source Address of the outer IPv6 datagram. The destination address of the outer IPv6 datagram MUST be copied from the destination address of the tunneled RS. The AN MUST insert a destination options header between the outer IPv6 header and the payload. It MUST also insert a LIO destination option and set (i) the line identification data of the option to contain the subscriber agent circuit identifier and (ii) the agent remote identifier containing the link-layer address of the sender. LIO related data values MUST correspond to the logical access loop port of the Access Node from which the RS was initiated. 4.2. On receiving a Router Advertisement from the Edge Router The Edge Router SHOULD send Router Advertisement messages per endpoint without Tunnel Encapsulation. Therefore AN MUST forward RA message towards the appropriate endpoint based on the destination link-layer address of the RA. Krishnan, et al. Expires November 24, 2010 [Page 6] Internet-Draft Line Identification in RS May 2010 5. Edge Router Behavior 5.1. On receiving a Router Solicitation from the subscriber When the edge router receives a tunneled Router Solicitation forwarded by the access node, it needs to check if there is an LIO destination option present in the outer datagram. If an LIO option is present, the edge router can use the contents of the line identification field to lookup the addressing information and policy that need to be applied to the subscriber. The edge router MUST then process the inner RS message as specified in [RFC4861] 5.2. On sending a Router Advertisement towards the subscriber When the edge router sends out a Router Advertisement in response to a tunneled RS that included an LIO option, it SHOULD unicast the RA back to the sender of the RS. If the source address of the RS was the unspecified address, then the IPv6 destination address of the RA MUST be set to the all-nodes multicast address, but the link-layer destination address MUST be set to the unicast link-layer address of the sender of the RS. Edge Router MUST send periodic RA messages as defined above in order to update e.g. default-router table in IPv6 hosts. Krishnan, et al. Expires November 24, 2010 [Page 7] Internet-Draft Line Identification in RS May 2010 6. Line Identification Option The Line Identification Option (LIO) is a destination option that can be included in IPv6 datagrams that tunnel Router Solicitation and Router Advertisement messages. Multiple Line Identification options MUST NOT be present in the same IPv6 datagram. The LIO has an alignment requirement of (none). 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Option Type | Option Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Line Identification... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: Line Identification Option Layout Krishnan, et al. Expires November 24, 2010 [Page 8] Internet-Draft Line Identification in RS May 2010 Option Type 8-bit identifier of the type of option. The option identifier for the line identification option will be allocated by the IANA. Option Length 8-bit unsigned integer. The length of the option (excluding the Option Type and Option Length fields). The value 0 is considered invalid. Line Identification In a Router Solicitation: Variable length data inserted by the Access Node describing the subscriber agent circuit identifier and agent remote identifier corresponding to the logical access loop port of the Access Node from which the RS was initiated. In a Router Advertisement: Variable length data inserted by the Edge Router describing the subscriber agent circuit identifier and agent remote identifier corresponding to the logical access loop port of the Access Node on which the RA needs to be sent out. Note: Considering the scenario, where multiple customers' IPv6 hosts are located behind a bridged modem, there may be multiple tunneled RS messages containing the same agent circuit identifier but different agent remote identifier. Krishnan, et al. Expires November 24, 2010 [Page 9] Internet-Draft Line Identification in RS May 2010 7. Interactions with SEND Since the SEND [RFC3971] protected RS/RA packets are not modified in anyway by the mechanism described in this document, there are no issues with SEND verification. Krishnan, et al. Expires November 24, 2010 [Page 10] Internet-Draft Line Identification in RS May 2010 8. Acknowledgements The authors would like to thank Margaret Wasserman, Mark Townsley, David Miles, John Kaippallimalil, Eric Levy-Abegnoli, Thomas Narten, Erik Nordmark and Jonne Soininen for reviewing this document and suggesting changes. Krishnan, et al. Expires November 24, 2010 [Page 11] Internet-Draft Line Identification in RS May 2010 9. Security Considerations The line identification information inserted by the access node or the edge router is not protected. This means that this option may be modifed, inserted, or deleted without being detected. In order to ensure validity of the contents of the line identification field, the network between the access node and the edge router needs to be trusted. Krishnan, et al. Expires November 24, 2010 [Page 12] Internet-Draft Line Identification in RS May 2010 10. IANA Considerations This document defines a new IPv6 destination option for carrying line identification. IANA is requested to assign a new destination option type in the Destination Options registry maintained at http://www.iana.org/assignments/ipv6-parameters Line Identification Option [RFCXXXX] The act bits for this option need to be 10 and the chg bit needs to be 0. Krishnan, et al. Expires November 24, 2010 [Page 13] Internet-Draft Line Identification in RS May 2010 11. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2473] Conta, A. and S. Deering, "Generic Packet Tunneling in IPv6 Specification", RFC 2473, December 1998. [RFC3971] Arkko, J., Kempf, J., Zill, B., and P. Nikander, "SEcure Neighbor Discovery (SEND)", RFC 3971, March 2005. [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, September 2007. [TR101] Broadband Forum, "Migration to Ethernet-based DSL aggregation", . Krishnan, et al. Expires November 24, 2010 [Page 14] Internet-Draft Line Identification in RS May 2010 Authors' Addresses Suresh Krishnan Ericsson 8400 Blvd Decarie Town of Mount Royal, Quebec Canada Email: suresh.krishnan@ericsson.com Alan Kavanagh Ericsson 8400 Blvd Decarie Town of Mount Royal, Quebec Canada Email: alan.kavanagh@ericsson.com Sven Ooghe Alcatel-Lucent Copernicuslaan 50 2018 Antwerp, Belgium Phone: Email: sven.ooghe@alcatel-lucent.com Balazs Varga Magyar Telekom Magyar Tudosok krt. 9 1117 Budapest, Hungary Email: varga.balazs@telekom.hu Krishnan, et al. Expires November 24, 2010 [Page 15]