6man Working Group S. Krishnan Internet-Draft A. Kavanagh Intended status: Standards Track Ericsson Expires: September 9, 2009 S. Ooghe Alcatel-Lucent B. Varga Magyar Telekom March 8, 2009 Line identification in IPv6 Router Solicitation messages draft-krishnan-6man-rs-mark-02 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 September 9, 2009. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Krishnan, et al. Expires September 9, 2009 [Page 1] Internet-Draft Line Identification in RS March 2009 Abstract In ethernet based aggregation networks, several subscriber premises may be 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. 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. Access Node Behavior . . . . . . . . . . . . . . . . . . . . . 5 3.1. On receiving a router solicitation from the subscriber . . 5 3.2. On receiving a router advertisement from the edge router . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Edge Router Behavior . . . . . . . . . . . . . . . . . . . . . 6 4.1. On receiving a router solicitation from the subscriber . . 6 4.2. On sending a router advertisement towards the subscriber . . . . . . . . . . . . . . . . . . . . . . . . 6 5. Line Identification Neighbor Discovery Option . . . . . . . . 7 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 8. Normative References . . . . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 11 Krishnan, et al. Expires September 9, 2009 [Page 2] Internet-Draft Line Identification in RS March 2009 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 aggregation models specified in this document bridges sessions from multiple subscribers behind a DSL Access Node (AN), also referred to as a DSLAM, 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 September 9, 2009 [Page 3] Internet-Draft Line Identification in RS March 2009 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 Route 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). However, 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 to the Route Solicitation message and forward this to the 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. Krishnan, et al. Expires September 9, 2009 [Page 4] Internet-Draft Line Identification in RS March 2009 3. Access Node Behavior 3.1. On receiving a router solicitation from the subscriber When a host sends out a router solicitation, it is received by the access node. First, the access node needs to verify if there are no LIO options present in the router solicitation. If there are any LIO options present, the AN MUST drop the router solicitation. If there are no LIO options present, the AN SHOULD insert a new LIO option into the router solicitation message. The AN MUST set the line identification data of the LIO option to contain the subscriber agent circuit identifier corresponding to the logical access loop port of the Access Node from which the RS was initiated. 3.2. On receiving a router advertisement from the edge router When the edge router sends out a router advertisement in response to the RS, it is received by the access node. If there is an LIO option present, the AN MUST use the line identification data of the LIO option to identify the subscriber agent circuit identifier corresponding to the logical access loop port of the Access Node on which the RA should be sent. If the LIO option was present in the received RA, the AN MUST remove the option before forwarding the RA to the subscriber premise. Krishnan, et al. Expires September 9, 2009 [Page 5] Internet-Draft Line Identification in RS March 2009 4. Edge Router Behavior 4.1. On receiving a router solicitation from the subscriber When the edge router receives a router solicitation forwarded by the access node, it needs to check if there is an LIO option present in the router solicitation. If an LIO option is present, the edge router MAY use the contents of the line identification field to lookup the addressing information and policy that need to be applied to the subscriber. 4.2. On sending a router advertisement towards the subscriber When the edge router sends out a router advertisement in response to an RS that contained an LIO option, it MUST unicast the RA back to the sender of the RS.Whenever the edge router needs to send out a multicast router advertisement message (e.g. because the unicast MAC address has aged out in the Neighbor Cache), it SHOULD insert an LIO option in the RA. If the LIO option is included, the line identification data field of the LIO option MUST be set to the same value as was received in the LIO option of the RS. Krishnan, et al. Expires September 9, 2009 [Page 6] Internet-Draft Line Identification in RS March 2009 5. Line Identification Neighbor Discovery Option The Line Identification Option (LIO) can be included in Router Solicitation and Router Advertisement messages. Multiple Line Identification options MUST NOT be present in a Neighbor Discovery message. The LIO has an alignment requirement of 4n. 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 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Line Identification... +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 2: Line Identification Option Layout Type 8-bit identifier of the type of option. The option identifier for the line identification option will be allocated by the IANA. Length 8-bit unsigned integer. The length of the option (including the type and length fields) in units of 8 octets. 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 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 corresponding to the logical access loop port of the Access Node on which the RA needs to be sent out. Krishnan, et al. Expires September 9, 2009 [Page 7] Internet-Draft Line Identification in RS March 2009 6. 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 September 9, 2009 [Page 8] Internet-Draft Line Identification in RS March 2009 7. IANA Considerations This document defines a new IPv6 neighbor discovery option for carrying line identification. IANA is requested to assign a new neighbor discovery option type in the registry maintained at http://www.iana.org/assignments/icmpv6-parameters Line Identification Option [RFCXXXX] Krishnan, et al. Expires September 9, 2009 [Page 9] Internet-Draft Line Identification in RS March 2009 8. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [TR101] Broadband Forum, "Migration to Ethernet-based DSL aggregation", . Krishnan, et al. Expires September 9, 2009 [Page 10] Internet-Draft Line Identification in RS March 2009 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 Email: varga.balazs@telekom.hu Krishnan, et al. Expires September 9, 2009 [Page 11]