Network Working Group S. Daniel Park Internet-Draft SAMSUNG Electronics Expires: December 7, 2005 June 8, 2005 IPv6 Fast Neighbor Discovery Option draft-daniel-dna-fastraopt-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of 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 December 10, 2005. Copyright Notice Copyright (C) The Internet Society (2005). Abstract To minimize router delay in response to Router Solicitation message, several scheme are being discussed in IETF. This document suggests a new Neighbor Discovery option which is included in Router Solicitation and/or Router Advertisement messages to achieve fast network attachment. 1. Introduction All router must delay a response to a Router Solicitation message by a random delay between 0 and 500 miliseconds which is defined in Park Expires December 7, 2005 [Page 1] Internet-Draft IPv6 Fast Neighbor Discovery Option June 2005 [RFC2461]. It is because if there is more than one router on the link, simultaneously transmitted responses will collide if the routers try to answer the Router Solicitation immediately, and, additionally, to avoid congestion when a link comes up and all hosts on the link solicit. It's not problem in wired networks, however, seems not appropriate in mobile environment since above ramdan delay cause a critical problem to achieve fast and seamless handover. In general, one proposel is being used to fast Router Solicitation / Router Advertisement messages exchange called Fast Router Advertisement [I-D.mkhalil-ipv6-fastra]. It newly defines a router variable to allow for faster response times in the process of Router Solicitations. Thus, network administrator must configure this variable on its router manually. In addition, routers enabling Fast RA will send Router Advertisement in response to all host request on the link although fixed hosts do not need fast response in the process of Router Solicitation. Along with this scheme, DNA Working Group defines new options and flags into Router Advertisement messages to eliminate the delays introduced by [RFC2461] in discovering the configuration. This document suggests a new Neighbor Discovery option which is included in Router Solicitation and/or Router Advertisement messages to allow the routers to answer the Router Solicitation immediately. It does not require any network administrator configuration at all. Network entities which can not recognize this option will silently discard this option. 2. Requirements notation 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]. 3. Fast Neighbor Discovery Option The new option is defined in this section. Park Expires December 7, 2005 [Page 2] Internet-Draft IPv6 Fast Neighbor Discovery Option June 2005 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 | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ o Option Type: To be defined by IANA o Option 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 invalid. Nodes MUST silently discard an Neighbor Discovery packet that contains an option with length zero. o Reserved: Reserved fields for further extensions. This option does not have any alignment requirements. 4. Procedure of Fast Neighbor Discovery The processing of Fast ND option is handled like any other ND option and no new procedure is needed. It is so hard to encode a new option into current ND stack which is already widely implemented in IPv6 equipment, so author recommends this option to be accomplished by DNA WG when defining its new ND options. The Router Solicitation sent by hosts which do not need fast ND message exchange in its link will not contain the new Fast ND option defined by this document. Routers which can not recognize the option will silently discard this option. Mobile entities (routers connected to wireless interface and mobile hosts) are able to be configured selectively by network administrator. Thus, mobile nodes will only receive fast Router Advertisement in response to Router Solicitation with Fast ND option. Once a node has IP-level connectivity with neighboring nodes, the node sends a Router Solicitation to obtain an advertisement quickly, rather than waits for an unsolicited advertisement from router. A host sends one or more Router Solicitations to the all-routers multicast group. To reduce packet flooding caused by Fast ND on its link, the host enabling Fast ND will send Router Solicitations as few as it can when generating its golbal scope addresses (I.e., defining a new host parameter). Also, the router enabling Fast ND will only answer Router Advertisements in response to link-local source address assigned to the sending host. Park Expires December 7, 2005 [Page 3] Internet-Draft IPv6 Fast Neighbor Discovery Option June 2005 +--------+ | Router | +----+---+ Fast RA (w/o delay)|/ | |RA (after random delay (0-500ms) v | v /-----------/ +----------------+ ^ | ^ |RS w/Fast ND | |RS / | | | +----+ +------+-----+ | MN | | Fixed Node | +----+ +------------+ 5. Security Considerations The security of Fast ND option is the same as ND protocol security concern. This option does not add any new vulnerability. Security issues regarding the ND protocol have been discussed at IETF SEND (Securing Neighbor Discovery) Working Group. 6 References [I-D.mkhalil-ipv6-fastra] Kempf, J., Khalil, M. and B. Pentland, "IPv6 Fast Router Advertisement", draft-mkhalil-ipv6-fastra-05 (work in progress), July 2004. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2461] Narten, T., Nordmark, E. and W. Simpson, "Neighbor Discovery for IP Version 6 (IPv6)", RFC 2461, December 1998. Park Expires December 7, 2005 [Page 4] Internet-Draft IPv6 Fast Neighbor Discovery Option June 2005 Author's Address Soohong Daniel Park SAMSUNG Electronics 416 Maetan-3dong, Yeongtong-gu Suwon-si, Gyeonggi-do 442-742 KOREA Phone: +82 31 200 4508 EMail: soohong.park@samsung.com Park Expires December 7, 2005 [Page 5] Internet-Draft IPv6 Fast Neighbor Discovery Option June 2005 Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. 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