Network Working Group T. Sanda Internet Draft T. Ue Expires: August 2004 Panasonic February 2004 Pre CRN discovery from proxy on candidate new path draft-sanda-nsis-mobility-qos-proxy-01.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026 [1]. 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. Abstract NSIS WG has been discussing the ways to minimize/avoid QoS interruption during handover. One solution is to install new path before MN's move (fast state installation). This document proposes a procedure of pre CRN discovery for fast state installation by using proxies on candidate new paths. An example of fast state installation is shown. 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 RFC-2119 [2]. Sanda et al. Expires - August 2004 [Page 1] Internet-Draft February 2004 Table of Contents 1. Introduction................................................2 1.1 Terminology.............................................2 1.2 Assumption..............................................3 2. Proxy for Fast State Installation...........................3 3. Proxy discovery.............................................3 4. Pre CRN Discovery...........................................4 5. New path installation.......................................7 5.1 Fast state installation for downlink data flow..........7 5.2 Fast state installation for uplink data flow............8 6. Signaling messages for fast CRN discovery...................9 7. Security Considerations....................................10 References....................................................10 Author's Addresses............................................11 1. Introduction When a MN performs L3 level handover with a QoS state, it is required to establish new QoS paths before handover to avoid/minimize QoS interruption in new subnetwork. Discussions on this topic are taking place in the NSIS WG and some drafts are proposing "Fast State Installation", by which new QoS paths are established in advance [3][5][6][8]. The goal of this draft is to initiate discussion on concrete solutions for Fast State Installation. An example is provided of a procedure that includes crossover node (CRN) discovery. This procedure utilizes a proxy entity on the candidate new path, to perform CRN discovery and QoS state installation along the new path prior to the MN's move to the new subnetwork. Terminology definitions and assumptions in this document are described in the following section. 1.1 Terminology Uplink data flow: data flow from MN to CN Downlink data flow: data flow from CN to MN UCRN and DCRN: The same as defined in [6] mQNE: The NSIS aware node supporting QoS and mobility functionalities Sanda et al. Expires - August 2004 [Page 2] Internet-Draft February 2004 1.2 Assumption o Signaling messages are path-coupled [8]. Signaling messages from MN to CN are routed only through NEs that are in the Uplink data path, and signaling messages from CN to MN are routed only through NEs that are in the Downlink data path o Network supports Mobile IPv6 [13] o Only optimized route case is discussed in this document although several routes are possible such as triangle route, tunnel between OAR and NAR established by FMIP, and so on. o MN and CN are mQNE 2. Proxy for Fast State Installation MN cannot directly initiate resource reservation signaling on candidate new paths before it actually moves. Therefore NSIS proxy utilization will be necessary for fast state installation, as described in [3]. The proxy can be used for preparing new path installation, e.g. discovering CRN in advance of the MN's move(pre CRN discovery). Additionally the proxy may install the new path on behalf of the MN. The following section describes a procedure for pre CRN discovery followed by fast state installation. 3. Proxy discovery Either old (current) or candidate new adjacent mQNEs of MN (see Figure1) can act as a proxy. An example of the former case is described in an appendix of [5]. Here we aim to consider the latter case, i.e. new adjacent mQNE acts as a proxy and prepares new path creation. If candidate NAR(s) has mQNE functionalities, the NAR(s) acts as a proxy. Sanda et al. Expires - August 2004 [Page 3] Internet-Draft February 2004 new adjacent mQNE +..+ +---+ +----+ .MN.---|NAR|---|mQNE|---...-------- +..+ +---+ +----+ | ^ | | | +--+ +---+ +-+ +----+ +----+ +--+ |MN|===|OAR|==|R|==|mQNE|==...==|mQNE|==...==|CN| +--+ +---+ +-+ +----+ +----+ +--+ old (current) adjacent mQNE === current path --- expected new path R: Router or NE (not QNE) Figure1: New and old adjacent mQNE If MN and network support suitable mobility protocol, such as CARD [12], MN can obtain proxies information through the CARD server. When the network does not support CARD, the MN may have to rely on pre-stored information. This information could be in the form of tables contains mapping information between APs and their connecting ARs, and neighboring mQNEs (proxies) of the ARs. The MN would then be able to associate the information on candidate APs to mQNEs that will likely be on the new path and would be able to act as proxies. Given though that determining whether an mQNE router will be on a data path to an arbitrary CN is difficult, it is proposed that only access routers with mQNE capabilities are used as proxies as described in [6]. This has the added advantage that these routers will be able to perform DAD on prospective new CoAs which would enable them to also perform the state installation on behalf of the MN. 4. Pre CRN Discovery The idea of pre CRN (both UCRN and DCRN) discovery is as follows. a. After determining proxies, MN sends PROXY_INIT message to the proxies. The PROXY_INIT message is a NSLP signaling message and contains current flow identifier and session identifier (for both uplink and downlink, or either) information. Sanda et al. Expires - August 2004 [Page 4] Internet-Draft February 2004 b. On receipt of PROXY_INIT message, each proxy sends a DCRN_DISCOVERY message to CN. A DCRN_DISCOVERY is NSLP signaling message and containing the flow identifier and session identifier received from the MN. An IP address of CN is contained in flow identifier. c. Each QNE belonging to the signaling path from proxy to CN intercepts DCRN_DISCOVERY, and checks if any interface has resource reservation for the pair of flow identifier and session identifier for uplink. If one of interface has the reservation, the QNE appends IP address of the interface to DCRN_DISCOVERY. When DCRN_DISCOVERY message arrives to CN, DCRN_DISCOVERY message contains the information of all overlapping interfaces belonging to current uplink QoS path (from MN to CN) and expected new uplink path (from proxy to CN) in order. current path =======================> IF1 IF2 +--+ +----+ +----+ +----+ +----+ +--+ |MN|>>>>|mQNE|>>>|mQNE|>>>|mQNE|>>>|mQNE|>>>>|CN| +--+ +----+ +----+ >+----+>>>+----+>>>>+--+ ^ ^ -----> ^ | +-----+ +----+ ^ | |Proxy|>>>>>|mQNE|>>>> | +-----+ +----+ | | ------------------- DCRN_DISCOVERY IF=Interface to be appended to the message Figure2: Interfaces' information collected by DCRN_DISCOVERY d. On receipt of DCRN_DISCOVERY message, CN sends a UCRN_DISCOVERY to the proxy. A UCRN_DISCOVERY message is NSLP signaling message and containing the flow identifier and session identifier received from MN via DCRN_DISCOVERY message. A UCRN_DISCOVERY message also contains the information of IP addresses appended to DCRN_DISCOVERY message. e. Each QNE belonging to the signaling path from CN to proxy intercepts UCRN_DISCOVERY, and checks if any interface has resource reservation for the pair of flow identifier and session identifier for downlink. If one of interface has the reservation, the QNE appends IP address of the interface to UCRN_DISCOVERY. Sanda et al. Expires - August 2004 [Page 5] Internet-Draft February 2004 When UCRN_DISCOVERY message arrives to proxy, UCRN_DISCOVERY message contains the information of all overlapping interfaces belonging to current uplink QoS path (from MN to CN) and expected new downlink path (from proxy to CN) in order. current path <======================= IF4 IF3 +--+ +----+ +----+ +----+ +----+ +--+ |MN|<<<<|mQNE|<<<|mQNE|<<<|mQNE|<<<|mQNE|<<<<|CN| +--+ +----+ +----+ <+----+<<<+----+<<<<+--+ v v ------ v | +-----+ +----+ v | |Proxy|<<<<<|mQNE|<<<< | +-----+ +----+ | | <------------------ UCRN_DISCOVERY IF=Interface to be appended to the message Figure3: Interfaces' information collected by UCRN_DISCOVERY f. The proxy receiving UCRN_DISCOVERY from CN checks appended information in UCRN_DISCOVERY and decides CRN(s). The first interface IP address appended to DCRN_DISCOVERY (and set into UCRN_DISCOVERY) is DCRN, and the last interface IP address appended to UCRN_DISCOVERY is UCRN. collected by collected by DCRN_DISCOVERY UCRN_DISCOVERY <===============> <===============> +------+--------+--------+------+--------+--------+ |up- |IP addr.|IP addr.|down- |IP addr.|IP addr.| |stream| of IF1 | of IF2 |stream| of IF1 | of IF2 | +------+--------+--------+------+--------+--------+ ^ ^ | | DCRN UCRN Figure4: collected information and DCRN/UCRN Sanda et al. Expires - August 2004 [Page 6] Internet-Draft February 2004 The proxy sends PROXY_INIT_ACK message to the MN. PROXY_INIT_ACK message is NSLP message and used for informing whether pre CRN discovery is successfully done or failed. 5. New path installation DCRN/UCRN discovered by proxy can be used for fast state installation. For this purpose, it is required that RESERVE message contains IP addresses of DCRN/UCRN. When the RESERVE message reaches the DCRN, it is also required for the DCRN to translate the RESERVE (create) message into RESERVE (update) message and vice versa for UCRN in order to avoid duplicate reservation of common QoS path (CN-UCRN/DCRN). This section describes an example of fast state installation. 5.1 Fast state installation for downlink data flow The following scenario assumes that the data flow is downlink only. a. When the MN listens to neighboring AP's beacons, MN refers a proxy table (see Chapter 3). This table has mapping information between APs and their connecting ARs, and whether the ARs have mQNE functionalities. MN selects target subnetwork of which AR has mQNE (proxy) functionalities. b. MN configures NCoA from the AR's information in the table, i.e. AR's IP address and prefix length. c. MN sends PROXY_INIT message with NCoA to the new AR (NAR). This PROXY_INIT message may contain IP address of MN's old (current) mQNE as well. d. The NAR executes DAD for NCoA. e. Simultaneously with d., the NAR performs pre CRN discovery as described in Chapter 4 and discovers UCRN. f. If the NCoA is valid, the NAR send RESERVE message with UCRN to CN. QSpec information may be obtained form mQNE in old (current) path such as MN or old adjacent mQNE of MN. Sanda et al. Expires - August 2004 [Page 7] Internet-Draft February 2004 MN NAR CN (Proxy) | | | +--------+ | | |HO | | | |Decision| | | +--------+ | | +-------------+ | | |NCoA | | | |Configuration| | | +-------------+ | | | | | |PROXY_INIT | | |------------------->| | | | | | +-------+ | | |DAD for| | | |NCoA | | | +-------+ | | | | | |DCRN_DISCOVERY | | |------------------->| | | | | | UCRN_DISCOVERY| | |<-------------------| | | | | +---------+ | | |Obtaining| | | |UCRN | | | +---------+ | | | | | |RESERVE | | |------------------->| | | | | | | Figure5: An example of Fast state installation for downlink 5.2 Fast state installation for uplink data flow If data flow is uplink only or duplicate, the following procedure can be used in addition to downlink case. o DCRN_DISCOVERY message contains NCoA (which is valid). o The CN receiving DCRN_DISCOVERY message performs RESERVE message to NAR (proxy) for uplink, as it can obtain DCRN and MN's NCoA. Sanda et al. Expires - August 2004 [Page 8] Internet-Draft February 2004 MN NAR CN (Proxy) | | | +--------+ | | |HO | | | |Decision| | | +--------+ | | +-------------+ | | |NCoA | | | |Configuration| | | +-------------+ | | | | | |PROXY_INIT | | |------------------->| | | | | | +-------+ | | |DAD for| | | |NCoA | | | +-------+ | | | | | |DCRN_DISCOVERY | | |------------------->| | | | | | +---------+ | | |Obtaining| | | |DCRN and | | | |NCoA | | | +---------+ | | | | | RESERVE| | |<-------------------| | | | | | UCRN_DISCOVERY| | |<-------------------| | | | | | | Figure6: An example of Fast state installation for uplink 6. Signaling messages for fast CRN discovery PROXY_INIT, DCRN_DISCOVERY, UCRN_DISCOVERY and PROXY_INIT_ACK may be extended existing QoS NSLP message, such as QUERY, RESPONSE and NOTIFY [7]. If DCRN_DISCOVERY and UCRN_DISCOVERY are QUERY and RESPONSE respectively, proxy can obtain downlink path information simultaneously with UCRN discovery. Sanda et al. Expires - August 2004 [Page 9] Internet-Draft February 2004 7. Security Considerations Security issues are addressed in section 12 of [6] but they are not covering candidate proxies (mQNEs) which are described in this document. Proper security handling must be provided in candidate proxy discovery. It is also required to consider the issues caused by sending PROXY_INIT which includes session and flow identifiers from MN to candidate proxies, such as session/reservation ownership. Future draft will include these issues. References 1. Bradner, S., "The Internet Standards Process -- Revision 3", BCP 9, RFC 2026, October 1996. 2. Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997 3 X. Fu, et al., "Mobility Issues in Next Steps in Signaling (NSIS)", Internet Draft (work in progress), draft-fu-nsis-mobility-01.txt, October 2003 4 H. Chaskar, et al., "Requirements of a Quality of Service (QoS) Solution for Mobile IP", RFC3583, September 2003 5 S. Lee, et al., "Mobility Functions in the QoS-NSLP", Internet Draft (work in progress), draft-lee-nsis-mobility-nslp- 01.txt, October 2003 6 Roland Bless, et al., "Mobility and Internet Signaling Protocols", Internet Draft (work in progress), draft-manyfolks- signaling-protocol-mobility-00.txt, January 2004 7 Sven Van den Bosch (Editor), "NSLP for Quality-of-Service signaling", Internet Draft (work in progress), draft-ietf-nsis- qos-nslp-01.txt, October 2003 8 Robert Hancock et al., "Next Step in Signaling: Framework", Internet Draft (work in progress), draft-ietf-nsis-fw-05.txt, October 2003 9 R. Hancock, et al., "Interactions of Routing and Mobility on NTLP and NSLP", Internet Draft (work in progress), draft- hancock-nsis-routing-mobility-00.txt, October, 2003 10 S. Jeong, et al., "Mobility Functions in the NTLP", Internet Draft (work in progress), draft-jeong-nsis-mobility-ntlp-01.txt, October 2003 Sanda et al. Expires - August 2004 [Page 10] Internet-Draft February 2004 11 H. Schulzrinne, et al., "GIMPS: General Internet Messaging Protocol for Signaling", Internet Draft (Work in progress), draft-ietf-nsis-ntlp-00, October 2003 12 M. Liebsch, et al., "Candidate Access Router Discovery", Internet Draft (work in progress), draft-ietf-seamoby-card- protocol-06.txt, December 2003 13 D.Johnson, C. Perkins and J. Arkko, "Mobility Support in IPv6", Internet Draft (work in progress), draft-ietf-mobileip- ipv6-24.txt, June 2003 Author's Addresses Takako Sanda Panasonic (Matsushita Electric Industrial Co., Ltd.) 5-3, Hikarino-oka, Yokosuka City, Kanagawa 239-0847, Japan Phone: (+81) 46 840 5764 Email: sanda.takako@jp.panasonic.com Toyoki Ue Panasonic (Matsushita Electric Industrial Co., Ltd.) 5-3, Hikarino-oka, Yokosuka City, Kanagawa 239-0847, Japan Phone: (+81) 46 840 5816 Email: ue.toyoki@jp.panasonic.com Full Copyright Statement Copyright (C) The Internet Society (2003). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE Sanda et al. Expires - August 2004 [Page 11] Internet-Draft February 2004 OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 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