Network Working Group Chern Nam Yap Internet Draft Seamoby Forum Nov 2001 Realm Based Mobility Status of This Memo This document is an Internet-Draft and is NOT offered in accordance with Section 10 of RFC2026, and the author does not provide the IETF with any rights other than to publish as an Internet-Draft 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 obsolete by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/lid-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html Abstract Realm Based Mobility described ways and method to achieve local realm mobility in contrast to flat private circuit switch model. Chern Nam Yap Expires May 2002 Page i Internet Draft Realm Based Nov 2001 Mobility Contents Status of This Memo i Abstract i 1. Introduction 1 2. Terminology 1 3. Overview of Realm Based Mobility 2 4. Latest Address Convergence Mechanism 3 5. Security Consideration 3 6. Intellectual Property Right 3 Authors' Addresses 3 Chern Nam Yap Expires May 2002 Page ii Internet Draft Realm Based Nov 2001 Mobility 1. Introduction Network Address Translation allows a private network so as to host a large number of hosts. Normally this only exists in an enterprise or an Institution. Due to the fact ease of today technology, even home user will soon also experience such type of benefits. When a large network exist, it is inevitable that further sub-networking will exist. These documents describe how to allow mobility to exist in such environment. 2. Terminology 2.1 General Term IP Internet Protocol. RBM Realm Based Mobility IIP Itinerant Internet Protocol. Node A device that implements IP. Router A node that forwards IP packets not explicitly address to itself. Host Any node that is not a router. Packet An IP header plus payload. 2.2 Realm Based Mobility Terms Mobile node A node whose movement between subnets has minimum effect on its applications. Correspondent node A peer node that the mobile node is communicating with. It can be mobile or stationary. MPR (Mobile Proxy Register) An anchoring points for the mobile node at the HOME link that aids the mobile node to diverse its address. It also forwards packets to the mobile node when there is necessity to do so. Binding The association of the Home/Visit address with the co- located address for any mobile node, along with the remaining lifetime of that association. 2.3 Specification Language The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENEDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119. Chern Nam Yap Expires May 2002 Page 1 Internet Draft Realm Based Nov 2001 Mobility 3. Overview of Realm Based Mobility In Realm Based Mobility, due to the ability to control every single node in the organisation, this makes life much easier to put mobile awareness. Due to the way IP is being designed, RBM puts the mobile awareness in the realm top- level gateway (Mobile Proxy Register) and the node that is moving. Due to the fact that every node belongs to the organisation, all mobile nodes in this case have already a pre-determined hard coded security association with top- level gateway. In addition to that, the MPR must link to the DHCP service that provides all mobile nodes their dynamic address, as it moves from subnet to subnet. Based on mobile node latest address convergence mechanism, any mobile aware node would be able to communicate with one another without directly in an optimal way. In some case, some node that does not have latest address convergence mechanism would still able to communicate with a mobile node using the MPR latest address convergence mechanism. This also applies to any node that is not within the realm. DNS within this network will always return 1 fixed IP address that is in the same subnet as the MPR. MPR proxy this addresses with its MAC address. A mobile aware node will send a binding request to the MPR for the latest mobile address. The top-level gateway will reply binding updates. Latest address convergence address is nothing but change the packet destination IP address. Whenever a mobile node moves from a subnet to another subnet, the MPR will send binding updates to the mobile aware correspondent node. If there were a need to support non-mobile aware node in the network, then each mobile node would need 2 IP address. One static, one dynamically assigned. <<<< Note: Half of the realm address will goes to this static address. There is ways to overcome this problem that is to use Class E IP address. >>>> DNS within this network then always have to return the mobile node fixed IP address. The non-mobile aware node would just send the packet to the MPR. The MPR then use proxy mechanism to route the packet accordingly. The mobile node based on the router advertisement to determine it's latest position when it moves from a subnet to another. It is suggested to speed up the rate for the router advertisement for any radio networks that does not support link layer hint (for example wireless LAN). When there the radio network supports link layer hint (for example PPP or other circuit sensitive) the mobile will based on that information and request a new DHCP address accordingly. Cross realm mobility extension will not be mentioned in this document, but RBM mobile MUST support cross realm mobility with the help of IIP as RBM is a part of IIP architecture. RBM Signalling, Conceptual Data Structures and Binding Management will also be the same as IIP. On the other hand it can operate as a standalone system. Chern Nam Yap Expires May 2002 Page 2 Internet Draft Realm Based Nov 2001 Mobility The requirements for RBM mobile aware nodes are the same as IIP. As for MPR, the requirement is quite similar to BHR. The difference is: instead of tunnelling, latest address convergence mechanism is done when non-mobile node is required to deal with. 4. Latest Address Convergence Mechanism Due to the fact that every mobile node obtains its latest address though MPR. MPR always knows mobile node latest address. The address convergence lies in two fold. The correspondent node like in IIP always uses the latest mobile node address to construct packets. MPR on the other hand recreate the packet with the latest mobile node local address. Note that the source address of the packet is kept, but the checksum is recalculated. To do quick implementation, NAT/NATP methods currently used. 5. Security Consideration This model is used when all the Network Interfaces used registered with MPR DHCP service. Further more with address translator kept the source address and the checksum modified by the MPR to ensure no middleman attack. 6. Intellectual Property Right The Internet Draft is currently under serious consideration for patent. Comments about this document SHOULD be discussed on the seamoby@egroups.com mailing list or Authors' Addresses Questions about this document can also be directed to the authors: Chern Nam Yap Seamoby Forum Web: http://www.seamoby.org E-mail: cny@ieee.org Chern Nam Yap Expires May 2002 Page 3